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Author |
Lezaack, M.B.; Hannard, F.; Zhao, L.; Orekhov, A.; Adrien, J.; Miettinen, A.; Idrissi, H.; Simar, A. |
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Title |
Towards ductilization of high strength 7XXX aluminium alloys via microstructural modifications obtained by friction stir processing and heat treatments |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Materialia |
Abbreviated Journal |
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Volume |
20 |
Issue |
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Pages |
101248 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
High strength 7XXX aluminium series reach exceptional strength, higher than all other industrial aluminium alloys. However, they suffer from a lack of ductility compared to softer series. This work presents a procedure to improve the ductility of 7475 Al alloy in high strength condition, reaching a true fracture strain of 70% at full 500 MPa T6 yield strength. Using friction stir processing (FSP) and post-FSP heat treatments, 100% of industrial rolled material T6 yield stress is maintained but a 180% increase in fracture strain is measured for the processed material. This ductility improvement is studied by in-situ synchrotron X-ray tomography and is explained by the reduction of intermetallic particles size and the homogenization of their spatial distribution. Furthermore, the microstructure after FSP shows equiaxed refined grains which favour crack deviation as opposed to large cracks parallel to the elongated coarse grains in rolled plate. These results are paving the way to better formability and crashworthiness of 7XXX alloys. |
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Wos |
000718127100006 |
Publication Date |
2021-10-19 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2589-1529 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
Not_Open_Access |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:184145 |
Serial |
6894 |
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Permanent link to this record |
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Author |
Ding, L.; Zhao, M.; Ehlers, F.J.H.; Jia, Z.; Zhang, Z.; Weng, Y.; Schryvers, D.; Liu, Q.; Idrissi, H. |
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Title |
“Branched” structural transformation of the L12-Al3Zr phase manipulated by Cu substitution/segregation in the Al-Cu-Zr alloy system |
Type |
A1 Journal article |
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Year |
2024 |
Publication |
Journal of materials science & technology |
Abbreviated Journal |
Journal of Materials Science & Technology |
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Volume |
185 |
Issue |
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Pages |
186-206 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
The effect of Cu on the evolution of the Al3Zr phase in an Al-Cu-Zr cast alloy during solution treatment at 500 °C has been thoroughly studied by combining atomic resolution high-angle annular dark-field scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy and first-principles cal- culations. The heat treatment initially produces a pure L12-Al3Zr microstructure, allowing for about 13 % Cu to be incorporated in the dispersoid. Cu incorporation increases the energy barrier for anti-phase boundary (APB) activation, thus stabilizing the L12 structure. Additional heating leads to a Cu-induced “branched”path for the L12 structural transformation, with the latter process accelerated once the first APB has been created. Cu atoms may either (i) be repelled by the APBs, promoting the transformation to a Cu-poor D023 phase, or (ii) they may segregate at one Al-Zr layer adjacent to the APB, promoting a transformation to a new thermodynamically favored phase, Al4CuZr, formed when these segregation layers are periodically arranged. Theoretical studies suggest that the branching of the L12 transformation path is linked to the speed at which an APB is created, with Cu attraction triggered by a comparatively slow process. This unexpected transformation behavior of the L12-Al3Zr phase opens a new path to understanding, and potentially regulating the Al3Zr dispersoid evolution for high temperature applications. |
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Wos |
001154261100001 |
Publication Date |
2023-12-24 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1005-0302 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
10.9 |
Times cited |
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Open Access |
Not_Open_Access |
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Notes |
This work was supported by the National Key Research and Development Program (No. 2020YFA0405900), the National Natural Science Foundation of China (Grant No. 52371111 and U2141215 ), the Natural Science Foundation of Jiangsu Province (No. BE2022159 ). We are grateful to the High Performance Computing Center of Nanjing Tech University for supporting the computational resources. H. Idrissi is mandated by the Belgian National Fund for Scientific Research (FSR- FNRS). |
Approved |
Most recent IF: 10.9; 2024 IF: 2.764 |
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Call Number |
EMAT @ emat @c:irua:202392 |
Serial |
8981 |
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Permanent link to this record |
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Author |
Poulain, R.; Lumbeeck, G.; Hunka, J.; Proost, J.; Savolainen, H.; Idrissi, H.; Schryvers, D.; Gauquelin, N.; Klein, A. |
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Title |
Electronic and chemical properties of nickel oxide thin films and the intrinsic defects compensation mechanism |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
ACS applied electronic materials |
Abbreviated Journal |
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Volume |
4 |
Issue |
6 |
Pages |
2718-2728 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Although largely studied, contradictory results on nickel oxide (NiO) properties can be found in the literature. We herein propose a comprehensive study that aims at leveling contradictions related to NiO materials with a focus on its conductivity, surface properties, and the intrinsic charge defects compensation mechanism with regards to the conditions preparation. The experiments were performed by in situ photo-electron spectroscopy, electron energy loss spectroscopy, and optical as well as electrical measurements on polycrystalline NiO thin films prepared under various preparation conditions by reactive sputtering. The results show that surface and bulk properties were strongly related to the deposition temperature with in particular the observation of Fermi level pinning, high work function, and unstable oxygen-rich grain boundaries for the thin films produced at room temperature but not at high temperature (>200 degrees C). Finally, this study provides substantial information about surface and bulk NiO properties enabling to unveil the origin of the high electrical conductivity of room temperature NiO thin films and also for supporting a general electronic charge compensation mechanism of intrinsic defects according to the deposition temperature. |
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Place of Publication |
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Wos |
000819431200001 |
Publication Date |
2022-06-07 |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2637-6113 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:189555 |
Serial |
7081 |
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Permanent link to this record |
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Author |
Arseenko, M.; Hannard, F.; Ding, L.; Zhao, L.; Maire, E.; Villanova, J.; Idrissi, H.; Simar, A. |
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Title |
A new healing strategy for metals : programmed damage and repair |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Acta materialia |
Abbreviated Journal |
Acta Mater |
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Volume |
238 |
Issue |
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Pages |
118241-10 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Self-healing strategies aim at avoiding part repair or even replacement, which is time consuming, expen-sive and generates waste. However, strategies for metallic systems are still under-developed and solid-state solutions for room temperature service are limited to nano-scale damage repair. Here we propose a new healing strategy of micron-sized damage requiring only short and low temperature heating. This new strategy is based on damage localization particles, which can be healed by fast diffusing atoms of the matrix activated during heat treatment. The healing concept was successfully validated with a com-mercial aluminum alloy and manufactured by Friction Stir Processing (FSP). Damage was demonstrated to initiate on particles that were added to the matrix during material processing. In situ 2D and 3D nano -imaging confirmed healing of the damaged material and showed that heating this material for 10 min at 400 degrees C is sufficient to heal incipient damage with complete filling of 70% of all damage (and up to 90% when their initial size is below 0.2 mu m). Furthermore, strength is retained and the work of fracture of the alloy is improved by about 40% after healing. The proposed Programmed Damage and Repair healing strategy could be extended to other metal based systems presenting precipitation. (C) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. |
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Place of Publication |
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Wos |
000843502700006 |
Publication Date |
2022-08-03 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1359-6454 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.4 |
Times cited |
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Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 9.4 |
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Call Number |
UA @ admin @ c:irua:190561 |
Serial |
7121 |
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Permanent link to this record |
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Author |
Kashiwar, A.; Arseenko, M.; Simar, A.; Idrissi, H. |
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Title |
On the role of microstructural defects on precipitation, damage, and healing behavior in a novel Al-0.5Mg2Si alloy |
Type |
A1 Journal article |
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Year |
2024 |
Publication |
Materials & design |
Abbreviated Journal |
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Volume |
239 |
Issue |
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Pages |
112765-112769 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
A recently developed healable Al-Mg2Si designed by the programmed damage and repair (PDR) strategy is studied considering the role microstructural defects play on precipitation, damage, and healing. The alloy incorporates sacrificial Mg2Si particles that precipitate after friction stir processing (FSP). They act as damage localization sites and are healable based on the solid-state diffusion of Al-matrix. A combination of different transmission electron microscopy (TEM) imaging techniques enabled the visualization and quantification of various crystallographic defects and the spatial distribution of Mg2Si precipitates. Intragrain nucleation is found to be the dominant mechanism for precipitation during FSP whereas grain boundaries and subgrain boundaries mainly lead to coarsening of the precipitates. The statistical and spatial analyses of the damaged particles have shown particle fracture as the dominant damage mechanism which is strongly dependent on the size and aspect ratio of the particles whereas the damage was not found to depend on the location of the precipitates within the matrix. The damaged particles are associated with dislocations accumulated around them. The interplay of these dislocations is directly visualized during healing based on in situ TEM heating which revealed recovery in the matrix as an operative mechanism during the diffusion healing of the PDR alloy. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
001194110200001 |
Publication Date |
2024-02-17 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0264-1275; 1873-4197 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
8.4 |
Times cited |
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Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 8.4; 2024 IF: 4.364 |
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Call Number |
UA @ admin @ c:irua:203298 |
Serial |
9068 |
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Permanent link to this record |
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Author |
Tang, X.; Reckinger, N.; Poncelet, O.; Louette, P.; Urena, F.; Idrissi, H.; Turner, S.; Cabosart, D.; Colomer, J.-F.; Raskin, J.-P.; Hackens, B.; Francis, L.A. |
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Title |
Damage evaluation in graphene underlying atomic layer deposition dielectrics |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Scientific reports |
Abbreviated Journal |
Sci Rep-Uk |
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Volume |
5 |
Issue |
5 |
Pages |
13523 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Based on micro-Raman spectroscopy (muRS) and X-ray photoelectron spectroscopy (XPS), we study the structural damage incurred in monolayer (1L) and few-layer (FL) graphene subjected to atomic-layer deposition of HfO2 and Al2O3 upon different oxygen plasma power levels. We evaluate the damage level and the influence of the HfO2 thickness on graphene. The results indicate that in the case of Al2O3/graphene, whether 1L or FL graphene is strongly damaged under our process conditions. For the case of HfO2/graphene, muRS analysis clearly shows that FL graphene is less disordered than 1L graphene. In addition, the damage levels in FL graphene decrease with the number of layers. Moreover, the FL graphene damage is inversely proportional to the thickness of HfO2 film. Particularly, the bottom layer of twisted bilayer (t-2L) has the salient features of 1L graphene. Therefore, FL graphene allows for controlling/limiting the degree of defect during the PE-ALD HfO2 of dielectrics and could be a good starting material for building field effect transistors, sensors, touch screens and solar cells. Besides, the formation of Hf-C bonds may favor growing high-quality and uniform-coverage dielectric. HfO2 could be a suitable high-K gate dielectric with a scaling capability down to sub-5-nm for graphene-based transistors. |
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Address |
ICTEAM Institute, Universite catholique de Louvain, Place du Levant 3, 1348 Louvain-la-Neuve, Belgium |
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Corporate Author |
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Publisher |
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Place of Publication |
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Editor |
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Language |
English |
Wos |
000360147400001 |
Publication Date |
2015-08-27 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2045-2322; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.259 |
Times cited |
18 |
Open Access |
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Notes |
The authors thank the staff of UCL’s Winfab and Welcome for technical support. Xiaohui Tang is a senior research of UCL. This work is financially supported by the Multi-Sensor-Platform for Smart Building Management project (No. 611887) and the Action de Recherche Concertée (ARC) “StressTronics”, Communauté française de Belgique. Part of this work is financially supported by the Belgian Fund for Scientific Research (FRS-FNRS) under FRFC contract “Chemographene” (No. 2.4577.11). J.-F. Colomer and B. Hackens are Research Associates of FRS-FNRS. This research used resources of the Electron Microscopy Service located at the University of Namur (“Plateforme Technologique Morphologie – Imagerie”). This research used resources of the ELISE Service of the University of Namur. This Service is member of the “Plateforme Technologique SIAM”. The research leading to this work has received partial funding from the European Union Seventh Framework Program under grant agreement No 604391 Graphene Flagship. |
Approved |
Most recent IF: 4.259; 2015 IF: 5.578 |
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Call Number |
c:irua:129193 |
Serial |
3958 |
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Permanent link to this record |
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Author |
Leusink, D.P.; Coneri, F.; Hoek, M.; Turner, S.; Idrissi, H.; Van Tendeloo, G.; Hilgenkamp, H. |
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Title |
Thin films of the spin ice compound Ho2Ti2O7 |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
APL materials |
Abbreviated Journal |
Apl Mater |
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Volume |
2 |
Issue |
3 |
Pages |
032101-32107 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
The pyrochlore compounds Ho2Ti2O7 and Dy2Ti2O7 show an exotic form of magnetism called the spin ice state, resulting from the interplay between geometrical frustration and ferromagnetic coupling. A fascinating feature of this state is the appearance of magnetic monopoles as emergent excitations above the degenerate ground state. Over the past years, strong effort has been devoted to the investigation of these monopoles and other properties of the spin ice state in bulk crystals. Here, we report the fabrication of Ho2Ti2O7 thin films using pulsed laser deposition on yttria-stabilized ZrO2 substrates. We investigated the structural properties of these films by X-ray diffraction, scanning transmission electron microscopy, and atomic force microscopy, and the magnetic properties by vibrating sample magnetometry at 2 K. The films not only show a high crystalline quality, but also exhibit the hallmarks of a spin ice: a pronounced magnetic anisotropy and an intermediate plateau in the magnetization along the [111] crystal direction. |
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Wos |
000334220300002 |
Publication Date |
2014-03-04 |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2166-532X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.335 |
Times cited |
18 |
Open Access |
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Notes |
The authors acknowledge support from the Dutch FOM and NWO foundations and from the European Union under the Framework 7 program under a contract from an Integrated Infrastructure Initiative (Reference 312483 ESTEEM2). G.V.T. acknowledges the ERC Grant N246791- COUNTATOMS. S.T. gratefully acknowledges financial support from the Fund for Scientific Research Flanders (FWO). H.I. acknowledges the IAP program of the Belgian State Federal Office for Scientific, Technical and Cultural Affairs under Contract No. P7/21. The microscope used in this study was partially financed by the Hercules Foundation of the Flemish Government. The authors acknowledge fruitful interactions with A. Brinkman, M. G. Blamire, M. Egilmez, F. J. G. Roesthuis, J. N. Beukers, C. G. Molenaar, M. Veldhorst, and X. Renshaw Wang; esteem2_ta |
Approved |
Most recent IF: 4.335; 2014 IF: NA |
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Call Number |
UA @ lucian @ c:irua:115555 |
Serial |
3641 |
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Permanent link to this record |
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Author |
Pardoen, T.; Colla, M.-S.; Idrissi, H.; Amin-Ahmadi, B.; Wang, B.; Schryvers, D.; Bhaskar, U.K.; Raskin, J.-P. |
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Title |
A versatile lab-on-chip test platform to characterize elementary deformation mechanisms and electromechanical couplings in nanoscopic objects |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Comptes rendus : physique |
Abbreviated Journal |
Cr Phys |
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Volume |
17 |
Issue |
17 |
Pages |
485-495 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
A nanomechanical on-chip test platform has recently been developed to deform under a variety of loading conditions freestanding thin films, ribbons and nanowires involving submicron dimensions. The lab-on-chip involves thousands of elementary test structures from which the elastic modulus, strength, strain hardening, fracture, creep properties can be extracted. The technique is amenable to in situ transmission electron microscopy (TEM) investigations to unravel the fundamental underlying deformation and fracture mechanisms that often lead to size-dependent effects in small-scale samples. The method allows addressing electrical and magnetic couplings as well in order to evaluate the impact of large mechanical stress levels on different solid-state physics phenomena. We had the chance to present this technique in details to Jacques Friedel in 2012 who, unsurprisingly, made a series of critical and very relevant suggestions. In the spirit of his legacy, the paper will address both mechanics of materials related phenomena and couplings with solids state physics issues. |
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Place of Publication |
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Language |
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Wos |
000373524300020 |
Publication Date |
2015-12-01 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1631-0705 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.048 |
Times cited |
7 |
Open Access |
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Notes |
This research has been performed with the financial support of the “Politique scientifique fédérale” under the framework of the interuniversity attraction poles program, IAP7/21, as well as with the support of the “Communauté française de Belgique” under the program “Actions de recherche concertées” ARC 05/10-330 and ARC Convention No. 11/16-037. The support of the “Fonds belge pour la recherche dans l'industrie et l'agriculture (FRIA)” for M.-S. Colla is also gratefully acknowledged as are the FWO research projects G012012N “Understanding nanocrystalline mechanical behavior from structural investigations” for B. Amin-Ahmadi. |
Approved |
Most recent IF: 2.048 |
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Call Number |
c:irua:129995 |
Serial |
4014 |
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Permanent link to this record |
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Author |
Amin-Ahmadi, B.; Connétable, D.; Fivel, M.; Tanguy, D.; Delmelle, R.; Turner, S.; Malet, L.; Godet, S.; Pardoen, T.; Proost, J.; Schryvers, D.; Idrissi, H. |
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Title |
Dislocation/hydrogen interaction mechanisms in hydrided nanocrystalline palladium films |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Acta materialia |
Abbreviated Journal |
Acta Mater |
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Volume |
111 |
Issue |
111 |
Pages |
253-261 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
The nanoscale plasticity mechanisms activated during hydriding cycles in sputtered nanocrystalline Pd films have been investigated ex-situ using advanced transmission electron microscopy techniques. The internal stress developing within the films during hydriding has been monitored in-situ. Results showed that in Pd films hydrided to β-phase, local plasticity was mainly controlled by dislocation activity in spite of the small grain size. Changes of the grain size distribution and the crystallographic texture have not been observed. In contrast, significant microstructural changes were not observed in Pd films hydrided to α-phase. Moreover, the effect of hydrogen loading on the nature and density of dislocations has been investigated using aberration-corrected TEM. Surprisingly, a high density of shear type stacking faults has been observed after dehydriding, indicating a significant effect of hydrogen on the nucleation energy barriers of Shockley partial dislocations. Ab-initio calculations of the effect of hydrogen on the intrinsic stable and unstable stacking fault energies of palladium confirm the experimental observations. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000375812100027 |
Publication Date |
2016-04-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1359-6454 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
5.301 |
Times cited |
14 |
Open Access |
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Notes |
This work was carried out in the framework of the IAP program of the Belgian State Federal Office for Scientific, Technical and Cultural Affairs, under Contract No. P7/21. The support of the FWO research project G012012N “Understanding nanocrystalline mechanical behaviour from structural investigations” for B. Amin-Ahmadi is also gratefully acknowledged. This work was granted access to the HPC resources of CALMIP (CICT Toulouse, France) under the allocations 2014-p0912 and 2014-p0749. |
Approved |
Most recent IF: 5.301 |
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Call Number |
c:irua:132678 |
Serial |
4054 |
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Permanent link to this record |
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Author |
Turner, S.; Idrissi, H.; Sartori, A.F.; Korneychuck, S.; Lu, Y.-G.; Verbeeck, J.; Schreck, M.; Van Tendeloo, G. |
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Title |
Direct imaging of boron segregation at dislocations in B:diamond heteroepitaxial films |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
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Volume |
8 |
Issue |
8 |
Pages |
2212-2218 |
|
|
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
|
|
Abstract |
A thin film of heavily B-doped diamond has been grown epitaxially by microwave plasma chemical vapor deposition on an undoped diamond layer, on top of a Ir/YSZ/Si(001) substrate stack, to study the boron segregation and boron environment at the dislocations present in the film. The density and nature of the dislocations were investigated by conventional and weak-beam dark-field transmission electron microscopy techniques, revealing the presence of two types of dislocations: edge and mixed-type 45 degrees dislocations. The presence and distribution of B in the sample was studied using annular dark-field scanning transmission electron microscopy and spatially resolved electron energy-loss spectroscopy. Using these techniques, a segregation of B at the dislocations in the film is evidenced, which is shown to be intermittent along the dislocation. A single edge-type dislocation was selected to study the distribution of the boron surrounding the dislocation core. By imaging this defect at atomic resolution, the boron is revealed to segregate towards the tensile strain field surrounding the edge-type dislocations. An investigation of the fine structure of the B-K edge at the dislocation core shows that the boron is partially substitutionally incorporated into the diamond lattice and partially present in a lower coordination (sp(2)-like hybridization). |
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|
Address |
EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium. stuart.turner@uantwerpen.be |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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|
|
Language |
English |
Wos |
000368860900053 |
Publication Date |
2015-12-21 |
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|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
2040-3364 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
7.367 |
Times cited |
15 |
Open Access |
|
|
|
Notes |
S. T. acknowledges the fund for scien tific research Flanders (FWO) for a post-doctoral scholarship and under contract number G.0044.13N |
Approved |
Most recent IF: 7.367 |
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|
Call Number |
c:irua:131597UA @ admin @ c:irua:131597 |
Serial |
4121 |
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Permanent link to this record |
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Author |
Heidari, H.; Rivero, G.; Idrissi, H.; Ramachandran, D.; Cakir, S.; Egoavil, R.; Kurttepeli, M.; Crabbé, A.C.; Hauffman, T.; Terryn, H.; Du Prez, F.; Schryvers, D. |
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Title |
Melamine–Formaldehyde Microcapsules: Micro- and Nanostructural Characterization with Electron Microscopy |
Type |
A1 Journal article |
|
Year |
2016 |
Publication |
Microscopy and microanalysis |
Abbreviated Journal |
Microsc Microanal |
|
|
Volume |
22 |
Issue |
22 |
Pages |
1222-1232 |
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|
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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|
Abstract |
A systematic study has been carried out to compare the surface morphology, shell thickness, mechanical properties, and binding behavior of melamine–formaldehyde microcapsules of 5–30 μm diameter size with various amounts of core content by using scanning and transmission electron microscopy including electron tomography, in situ nanomechanical tensile testing, and electron energy-loss spectroscopy. It is found that porosities are present on the outside surface of the capsule shell, but not on the inner surface of the shell. Nanomechanical tensile tests on the capsule shells reveal that Young’s modulus of the shell material is higher than that of bulk melamine–formaldehyde and that the shells exhibit a larger fracture strain compared with the bulk. Core-loss elemental analysis of microcapsules embedded in epoxy indicates that during the curing process, the microcapsule-matrix interface remains uniform and the epoxy matrix penetrates into the surface micro-porosities of the capsule shells. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000393853100011 |
Publication Date |
2016-12-21 |
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Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
1431-9276 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
1.891 |
Times cited |
2 |
Open Access |
|
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|
Notes |
This work was supported by SIM vzw, Technologiepark 935, BE-9052 Zwijnaarde, Belgium, within the InterPoCo project of the H-INT-S horizontal program. The authors are also thankful to Stijn Van den Broeck and Dr. Frederic Leroux for help in sample preparation and to S. Bals and J. Verbeeck for valuable discussions. H.I. acknowledges the IAP program of the Belgian State Federal Office for Scientific, Technical and Cultural Affairs, under Contract No. P7/21. |
Approved |
Most recent IF: 1.891 |
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Call Number |
EMAT @ emat @ c:irua:138980 |
Serial |
4333 |
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Permanent link to this record |
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Author |
Li, K.; Idrissi, H.; Sha, G.; Song, M.; Lu, J.; Shi, H.; Wang, W.; Ringer, S.P.; Du, Y.; Schryvers, D. |
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Title |
Quantitative measurement for the microstructural parameters of nano-precipitates in Al-Mg-Si-Cu alloys |
Type |
A1 Journal article |
|
Year |
2016 |
Publication |
Materials characterization |
Abbreviated Journal |
Mater Charact |
|
|
Volume |
118 |
Issue |
118 |
Pages |
352-362 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Size, number density and volume fraction of nano-precipitates are important microstructural parameters controlling the strengthening of materials. In this work a widely accessible, convenient, moderately time efficient method with acceptable accuracy and precision has been provided for measurement of volume fraction of nano-precipitates in crystalline materials. The method is based on the traditional but highly accurate technique of measuring foil thickness via convergent beam electron diffraction. A new equation is proposed and verified with the aid of 3-dimensional atom probe (3DAP) analysis, to compensate for the additional error resulted from the hardly distinguishable contrast of too short incomplete precipitates cut by the foil surface. The method can be performed on a regular foil specimen with a modem LaB6 or field-emission-gun transmission electron microscope. Precisions around +/- 16% have been obtained for precipitate volume fractions of needle-like beta ''/C and Q precipitates in an aged Al-Mg-Si-Cu alloy. The measured number density is dose to that directly obtained using 3DAP analysis by a misfit of 45%, and the estimated precision for number density measurement is about +/- 11%. The limitations of the method are also discussed. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000383292000042 |
Publication Date |
2016-06-07 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
1044-5803 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
2.714 |
Times cited |
9 |
Open Access |
|
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|
Notes |
This work is financially supported by National Natural Science Foundation of China (51501230 and 51531009) and Postdoctoral Science Foundation of Central South University (502042057). H.I. acknowledges the IAP program of the Belgian State Federal Office for Scientific, Technical and Cultural Affairs under Contract No. P7/21 and FWO project G.0576.09N. |
Approved |
Most recent IF: 2.714 |
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Call Number |
EMAT @ emat @ c:irua:137171 |
Serial |
4334 |
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Permanent link to this record |
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Author |
Idrissi, H.; Ghidelli, M.; Béché, A.; Turner, S.; Gravier, S.; Blandin, J.-J.; Raskin, J.-P.; Schryvers, D.; Pardoen, T. |
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Title |
Atomic-scale viscoplasticity mechanisms revealed in high ductility metallic glass films |
Type |
A1 Journal article |
|
Year |
2019 |
Publication |
Scientific reports |
Abbreviated Journal |
Sci Rep-Uk |
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|
Volume |
9 |
Issue |
1 |
Pages |
13426 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
The fundamental plasticity mechanisms in thin freestanding Zr65Ni35 metallic glass films are investigated in order to unravel the origin of an outstanding strength/ductility balance. The deformation process is homogenous until fracture with no evidence of catastrophic shear banding. The creep/relaxation behaviour of the films was characterized by on-chip tensile testing, revealing an activation volume in the range 100–200 Å3. Advanced high-resolution transmission electron microscopy imaging and spectroscopy exhibit a very fine glassy nanostructure with well-defined dense Ni-rich clusters embedded in Zr-rich clusters of lower atomic density and a ~2–3 nm characteristic length scale. Nanobeam electron diffraction analysis reveals that the accumulation of plastic deformation at roomtemperature
correlates with monotonously increasing disruption of the local atomic order. These results provide experimental evidences of the dynamics of shear transformation zones activation in metallic glasses. The impact of the nanoscale structural heterogeneities on the mechanical properties including the rate dependent behaviour is discussed, shedding new light on the governing plasticity mechanisms in metallic glasses with initially heterogeneous atomic arrangement. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000486139700008 |
Publication Date |
2019-09-17 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
|
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ISSN |
2045-2322 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.259 |
Times cited |
|
Open Access |
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|
Notes |
H. Idrissi is mandated by the Belgian National Fund for Scientific Research (FSR-FNRS). This work was supported by the FNRS under Grant PDR – T.0178.19. FWO project G093417N (‘Compressed sensing enabling low dose imaging in transmission electron microscopy’) and Hercules fund ‘Direct electron detector for soft matter TEM’ from Flemish Government are acknowledged. |
Approved |
Most recent IF: 4.259 |
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Call Number |
EMAT @ emat @c:irua:162786 |
Serial |
5375 |
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Permanent link to this record |
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Author |
Bagherpour, A.; Baral, P.; Colla, M.-S.; Orekhov, A.; Idrissi, H.; Haye, E.; Pardoen, T.; Lucas, S. |
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Title |
Tailoring Mechanical Properties of a-C:H:Cr Coatings |
Type |
A1 Journal Article |
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Year |
2023 |
Publication |
Coatings |
Abbreviated Journal |
Coatings |
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Volume |
13 |
Issue |
12 |
Pages |
2084 |
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Keywords |
A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ; |
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Abstract |
The development of coatings with tunable performances is critical to meet a wide range of technological applications each one with different requirements. Using the plasma-enhanced chemical vapor deposition (PECVD) process, scientists can create hydrogenated amorphous carbon coatings doped with metal (a-C:H:Me) with a broad range of mechanical properties, varying from those resembling polymers to ones resembling diamond. These diverse properties, without clear relations between the different families, make the material selection and optimization difficult but also very rich. An innovative approach is proposed here based on projected performance indices related to fracture energy, strength, and stiffness in order to classify and optimize a-C:H:Me coatings. Four different a-C:H:Cr coatings deposited by PECVD with Ar/C2H2 discharge under different bias voltage and pressures are investigated. A path is found to produce coatings with a selective critical energy release rate between 5–125 J/m2 without compromising yield strength (1.6–2.7 GPa) and elastic limit (≈0.05). Finally, fine-tuned coatings are categorized to meet desired applications under different testing conditions. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
001136013600001 |
Publication Date |
2023-12-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2079-6412 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
|
Times cited |
|
Open Access |
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Notes |
Walloon region under the PDR FNRS, C 62/5—PDR/OL 33677636 ; Belgian National Fund for Scientific Research, CDR—J.0113.20 ; National Fund for Scientific Reaserch; |
Approved |
Most recent IF: NA |
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Call Number |
EMAT @ emat @c:irua:202390 |
Serial |
8982 |
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Permanent link to this record |
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Author |
Wang, B.; Idrissi, H.; Galceran, M.; Colla, M.S.; Turner, S.; Hui, S.; Raskin, J.P.; Pardoen, T.; Godet, S.; Schryvers, D. |
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Title |
Advanced TEM investigation of the plasticity mechanisms in nanocrystalline freestanding palladium films with nanoscale twins |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
International journal of plasticity |
Abbreviated Journal |
Int J Plasticity |
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Volume |
37 |
Issue |
|
Pages |
140-156 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Nanocrystalline palladium thin films deposited by electron-beam evaporation and deformed by on-chip tensile testing reveal a surprisingly large strain hardening capacity when considering the small similar to 25 nm grain size. The as-grown films contain several coherent single and multifold twin boundaries. The coherency of the twin boundaries considerably decreases with deformation due to dislocation/twin boundary interactions. These reactions are described based on a detailed analysis of the number and the type of dislocations located at the twin boundaries using high-resolution TEM, including aberration corrected microscopy. Sessile Frank dislocations were observed at the twin/matrix interfaces, explaining the loss of the TB coherency due to the Burgers vector pointing out of the twinning plane. Grain boundary mediated processes were excluded as a mechanism dominating the plastic deformation based on the investigation of the grain size distribution as well as the crystallographic texture using Automated Crystallographic Orientation Indexation TEM. Other factors influencing the plastic deformation such as impurities and the presence of a native passivation oxide layer at the surface of the films were investigated using analytical TEM. The twin boundaries observed in the present work partly explain the high strain hardening capacity by providing both increasing resistance to dislocation motion with deformation and a source for dislocation multiplication. (C) 2012 Elsevier Ltd. All rights reserved. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Oxford |
Editor |
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Language |
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Wos |
000307416100009 |
Publication Date |
2012-05-16 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0749-6419; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
5.702 |
Times cited |
44 |
Open Access |
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Notes |
Iap; Fwo |
Approved |
Most recent IF: 5.702; 2012 IF: 4.356 |
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Call Number |
UA @ lucian @ c:irua:101082 |
Serial |
74 |
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Permanent link to this record |
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Author |
Schryvers, D.; Cao, S.; Tirry, W.; Idrissi, H.; Van Aert, S. |
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Title |
Advanced three-dimensional electron microscopy techniques in the quest for better structural and functional materials |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Science and technology of advanced materials |
Abbreviated Journal |
Sci Technol Adv Mat |
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Volume |
14 |
Issue |
1 |
Pages |
014206-14213 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
After a short review of electron tomography techniques for materials science, this overview will cover some recent results on different shape memory and nanostructured metallic systems obtained by various three-dimensional (3D) electron imaging techniques. In binary NiTi, the 3D morphology and distribution of Ni4Ti3 precipitates are investigated by using FIB/SEM slice-and-view yielding 3D data stacks. Different quantification techniques will be presented including the principal ellipsoid for a given precipitate, shape classification following a Zingg scheme, particle distribution function, distance transform and water penetration. The latter is a novel approach to quantifying the expected matrix transformation in between the precipitates. The different samples investigated include a single crystal annealed with and without compression yielding layered and autocatalytic precipitation, respectively, and a polycrystal revealing different densities and sizes of the precipitates resulting in a multistage transformation process. Electron tomography was used to understand the interaction between focused ion beam-induced Frank loops and long dislocation structures in nanobeams of Al exhibiting special mechanical behaviour measured by on-chip deposition. Atomic resolution electron tomography is demonstrated on Ag nanoparticles in an Al matrix. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Sendai |
Editor |
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Language |
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Wos |
000316463800008 |
Publication Date |
2013-03-13 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
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ISSN |
1468-6996;1878-5514; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.798 |
Times cited |
6 |
Open Access |
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Notes |
Fwo; Iap; Esteem |
Approved |
Most recent IF: 3.798; 2013 IF: 2.613 |
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Call Number |
UA @ lucian @ c:irua:107343 |
Serial |
77 |
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Permanent link to this record |
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Author |
Boulay, E.; Nakano, J.; Turner, S.; Idrissi, H.; Schryvers, D.; Godet, S. |
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Title |
Critical assessments and thermodynamic modeling of BaO-SiO2 and SiO2-TiO2 systems and their extensions into liquid immiscibility in the BaO-SiO2-TiO2 system |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
Calphad computer coupling of phase diagrams and thermochemistry |
Abbreviated Journal |
Calphad |
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Volume |
47 |
Issue |
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Pages |
68-82 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
This study discusses rational reproduction of liquid immiscibility in the BaO-SiO2-TiO2 system. While a ternary assessment requires sub-binary descriptions in the same thermodynamic model, the related sub-binary systems BaO-SiO2, BaO-TiO2 and SiO2-TiO2 liquid and solid phases have been evaluated using different thermodynamic models in the literature. In this study, BaO-SiO2 and SiO2-TiO2 were assessed using the Ionic Two Sublattice model (I2SL) based on experimental data from the literature. BaO-TiO2 was already assessed using this model. Binary descriptions developed were then used for the assessment of liquid immiscibility in the BaO-SiO2-TiO2 system. Ternary interaction parameters were found necessary for rational reproduction of the new ternary experimental data gathered in the present work. The model parameters for each system were evaluated using a CAPLHAD approach. A set of parameters is proposed. They show good agreement between the calculated and experimental equilibrium liquidus, liquid immiscibility and thermochemical properties in the BaO-SiO2-TiO2 system. (C) 2014 Elsevier Ltd. All rights reserved. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Oxford |
Editor |
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Language |
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Wos |
000346224700008 |
Publication Date |
2014-07-05 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
|
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ISSN |
0364-5916; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.6 |
Times cited |
9 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 1.6; 2014 IF: 1.370 |
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Call Number |
UA @ lucian @ c:irua:122776 |
Serial |
540 |
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Permanent link to this record |
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Author |
Schryvers, D.; Van Aert, S.; Delville, R.; Idrissi, H.; Turner, S.; Salje, E.K.H. |
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Title |
Dedicated TEM on domain boundaries from phase transformations and crystal growth |
Type |
A1 Journal article |
|
Year |
2013 |
Publication |
Phase transitions |
Abbreviated Journal |
Phase Transit |
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|
Volume |
86 |
Issue |
1 |
Pages |
15-22 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Investigating domain boundaries and their effects on the behaviour of materials automatically implies the need for detailed knowledge on the structural aspects of the atomic configurations at these interfaces. Not only in view of nearest neighbour interactions but also at a larger scale, often surpassing the unit cell, the boundaries can contain structural elements that do not exist in the bulk. In the present contribution, a number of special boundaries resulting from phase transformations or crystal growth and those recently investigated by advanced transmission electron microscopy techniques in different systems will be reviewed. These include macrotwins between microtwinned martensite plates in NiAl, austenite-single variant martensite habit planes in low hysteresis NiTiPd, nanotwins in non-textured nanostructured Pd and ferroelastic domain boundaries in CaTiO3. In all discussed cases these boundaries play an essential role in the properties of the respective materials. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York |
Editor |
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Language |
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Wos |
000312586700003 |
Publication Date |
2012-12-19 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
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ISSN |
0141-1594;1029-0338; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
1.06 |
Times cited |
|
Open Access |
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Notes |
Fwo; Iap |
Approved |
Most recent IF: 1.06; 2013 IF: 1.044 |
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Call Number |
UA @ lucian @ c:irua:101222 |
Serial |
612 |
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Permanent link to this record |
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Author |
Colla, M.-S.; Amin-Ahmadi, B.; Idrissi, H.; Malet, L.; Godet, S.; Raskin, J.-P.; Schryvers, D.; Pardoen, T. |
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Title |
Dislocation-mediated relaxation in nanograined columnar palladium films revealed by on-chip time-resolved HRTEM testing |
Type |
A1 Journal article |
|
Year |
2015 |
Publication |
Nature communications |
Abbreviated Journal |
Nat Commun |
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Volume |
6 |
Issue |
6 |
Pages |
5922 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
The high-rate sensitivity of nanostructured metallic materials demonstrated in the recent literature is related to the predominance of thermally activated deformation mechanisms favoured by a large density of internal interfaces. Here we report time-resolved high-resolution electron transmission microscopy creep tests on thin nanograined films using on-chip nanomechanical testing. Tests are performed on palladium, which exhibited unexpectedly large creep rates at room temperature. Despite the small 30-nm grain size, relaxation is found to be mediated by dislocation mechanisms. The dislocations interact with the growth nanotwins present in the grains, leading to a loss of coherency of twin boundaries. The density of stored dislocations first increases with applied deformation, and then decreases with time to drive additional deformation while no grain boundary mechanism is observed. This fast relaxation constitutes a key issue in the development of various micro- and nanotechnologies such as palladium membranes for hydrogen applications. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000348742300002 |
Publication Date |
2015-01-05 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
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ISSN |
2041-1723; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.124 |
Times cited |
34 |
Open Access |
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Notes |
Iap7/21; Fwo G012012n |
Approved |
Most recent IF: 12.124; 2015 IF: 11.470 |
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Call Number |
c:irua:122045 |
Serial |
731 |
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Permanent link to this record |
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Author |
Idrissi, H.; Cordier, P.; Jacob, D.; Walte, N. |
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Title |
Dislocations and plasticity of experimentally deformed coesite |
Type |
A1 Journal article |
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Year |
2008 |
Publication |
European journal of mineralogy |
Abbreviated Journal |
Eur J Mineral |
|
|
Volume |
20 |
Issue |
4 |
Pages |
665-671 |
|
|
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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|
Abstract |
Dislocation microstructures have been characterized by transmission electron microscopy in polycrystalline coesite deformed experimentally at 4 GPa, 1200 degrees C. Burgers vectors have been determined by large-angle convergent-beam electron diffraction. Sample orientation was assisted by precession electron diffraction to overcome difficulties arising from pseudo-hexagonal symmetry. The results are explained by using a pseudo-hexagonal setting. We found that most dislocations observed are of the 1/3 < 2 (1) over bar(1) over bar0 > type. No clear glide plane was identified, suggesting that climb is activated under these conditions. This conclusion is supported by the observation of numerous subgrain boundaries. We have also observed some [00011 dislocations. Finally, the C12/cl space group to which coesite belongs being centred, an additional slip system is observed: 1/6[(1) over bar2 (1) over bar3](01 (1) over bar1) (1/2[(1) over bar 10](110) in the monoclinic setting). |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Stuttgart |
Editor |
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Language |
|
Wos |
000262891900021 |
Publication Date |
2008-08-29 |
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|
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0935-1221; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
1.362 |
Times cited |
5 |
Open Access |
|
|
|
Notes |
|
Approved |
Most recent IF: 1.362; 2008 IF: 1.220 |
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|
Call Number |
UA @ lucian @ c:irua:94604 |
Serial |
733 |
|
Permanent link to this record |
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Author |
Amin-Ahmadi, B.; Idrissi, H.; Galceran, M.; Colla, M.S.; Raskin, J.P.; Pardoen, T.; Godet, S.; Schryvers, D. |
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Title |
Effect of deposition rate on the microstructure of electron beam evaporated nanocrystalline palladium thin films |
Type |
A1 Journal article |
|
Year |
2013 |
Publication |
Thin solid films : an international journal on the science and technology of thin and thick films |
Abbreviated Journal |
Thin Solid Films |
|
|
Volume |
539 |
Issue |
|
Pages |
145-150 |
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|
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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|
Abstract |
The influence of the deposition rate on the formation of growth twins in nanocrystalline Pd films deposited by electron beam evaporation is investigated using transmission electron microscopy. Statistical measurements prove that twin boundary (TB) density and volume fraction of grains containing twins increase with increasing deposition rate. A clear increase of the dislocation density was observed for the highest deposition rate of 5 Å/s, caused by the increase of the internal stress building up during deposition. Based on crystallographic orientation indexation using transmission electron microscopy, it can be concluded that a {111} crystallographic texture increases with increasing deposition rate even though the {101} crystallographic texture remains dominant. Most of the TBs are fully coherent without any residual dislocations. However, for the highest deposition rate (5 Å/s), the coherency of the TBs decreases significantly as a result of the interaction of lattice dislocations emitted during deposition with the growth TBs. The analysis of the grain boundary character of different Pd films shows that an increasing fraction of high angle grain boundaries with misorientation angles around 5565° leads to a higher potential for twin formation. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lausanne |
Editor |
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Language |
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Wos |
000321111100025 |
Publication Date |
2013-05-25 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0040-6090; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
1.879 |
Times cited |
13 |
Open Access |
|
|
|
Notes |
Fwo |
Approved |
Most recent IF: 1.879; 2013 IF: 1.867 |
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|
Call Number |
UA @ lucian @ c:irua:109268 |
Serial |
807 |
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Permanent link to this record |
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Author |
Delmelle, R.; Amin-Ahmadi, B.; Sinnaeve, M.; Idrissi, H.; Pardoen, T.; Schryvers, D.; Proost, J. |
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Title |
Effect of structural defects on the hydriding kinetics of nanocrystalline Pd thin films |
Type |
A1 Journal article |
|
Year |
2015 |
Publication |
International journal of hydrogen energy |
Abbreviated Journal |
Int J Hydrogen Energ |
|
|
Volume |
40 |
Issue |
40 |
Pages |
7335-7347 |
|
|
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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|
Abstract |
While the microstructure of a metal is well-known to affect its equilibrium hydrogen uptake and therefore the hydriding thermodynamics, microstructural effects on the hydriding kinetics are much less documented. Moreover, for thin film systems, such microstructural effects are difficult to separate from the internal stress effect, since most defects generate internal stresses. Such a decoupling has been achieved in this paper for nanocrystalline Pd thin film model systems through the use of a high-resolution, in-situ curvature measurement set-up during Pd deposition, annealing and hydriding. This set-up allowed producing Pd thin films with similar internal stress levels but significantly different microstructures. This was evidenced from detailed defect statistics obtained by transmission electron microscopy, which showed that the densities of grain boundaries, dislocations and twin boundaries have all been lowered by annealing. The same set-up was then used to study the hydriding equilibrium and kinetic behaviour of the resulting films at room temperature. A full quantitative analysis of their hydriding cycles showed that the rate constants of both the adsorption- and absorption-limited kinetic regimes were strongly affected by microstructure. Defect engineering was thereby shown to increase the rate constants for hydrogen adsorption and absorption in Pd by a factor 40 and 30, respectively. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Oxford |
Editor |
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Language |
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Wos |
000355884300012 |
Publication Date |
2015-05-02 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0360-3199; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
3.582 |
Times cited |
13 |
Open Access |
|
|
|
Notes |
Iap 7/21 |
Approved |
Most recent IF: 3.582; 2015 IF: 3.313 |
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Call Number |
c:irua:126429 |
Serial |
838 |
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Permanent link to this record |
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Author |
Amin-Ahmadi, B.; Idrissi, H.; Delmelle, R.; Pardoen, T.; Proost, J.; Schryvers, D. |
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Title |
High resolution transmission electron microscopy characterization of fcc -> 9R transformation in nanocrystalline palladium films due to hydriding |
Type |
A1 Journal article |
|
Year |
2013 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
|
|
Volume |
102 |
Issue |
7 |
Pages |
071911-71914 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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|
Abstract |
Sputtered nanocrystalline palladium thin films with nanoscale growth twins have been subjected to hydriding cycles. The evolution of the twin boundaries has been investigated using high resolution transmission electron microscopy. Surprisingly, the Sigma 3{112} incoherent twin boundaries dissociate after hydriding into two phase boundaries bounding a 9R phase. This phase which corresponds to single stacking faults located every three {111} planes in the fcc Pd structure was not expected because of the high stacking fault energy of Pd. This observation is connected to the influence of the Hydrogen on the stacking fault energy of palladium and the high compressive stresses building up during hydriding. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4793512] |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
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Language |
|
Wos |
000315596700023 |
Publication Date |
2013-02-26 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
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ISSN |
0003-6951; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
3.411 |
Times cited |
14 |
Open Access |
|
|
|
Notes |
Iap |
Approved |
Most recent IF: 3.411; 2013 IF: 3.515 |
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Call Number |
UA @ lucian @ c:irua:108303 |
Serial |
1462 |
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Permanent link to this record |
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Author |
Colla, M.-S.; Wang, B.; Idrissi, H.; Schryvers, D.; Raskin, J.-P.; Pardoen, T. |
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Title |
High strength-ductility of thin nanocrystalline palladium films with nanoscale twins : on-chip testing and grain aggregate model |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Acta materialia |
Abbreviated Journal |
Acta Mater |
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Volume |
60 |
Issue |
4 |
Pages |
1795-1806 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
The mechanical behaviour of thin nanocrystalline palladium films with an ∼30 nm in plane grain size has been characterized on chip under uniaxial tension. The films exhibit a large strain hardening capacity and a significant increase in the strength with decreasing thickness. Transmission electron microscopy has revealed the presence of a moderate density of growth nanotwins interacting with dislocations. A semi-analytical grain aggregate model is proposed to investigate the impact of different contributions to the flow behaviour, involving the effect of twins, of grain size and of the presence of a thin surface layer. This model provides guidelines to optimizing the strength/ductility ratio of the films. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Oxford |
Editor |
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Language |
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Wos |
000301989500035 |
Publication Date |
2012-02-02 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
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ISSN |
1359-6454; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
5.301 |
Times cited |
38 |
Open Access |
|
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|
Notes |
Iap |
Approved |
Most recent IF: 5.301; 2012 IF: 3.941 |
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Call Number |
UA @ lucian @ c:irua:94213 |
Serial |
1465 |
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Permanent link to this record |
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Author |
Boulay, E.; Ragoen, C.; Idrissi, H.; Schryvers, D.; Godet, S. |
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Title |
Influence of amorphous phase separation on the crystallization behavior of glass-ceramics in the BaO-TiO2-SiO2 system |
Type |
A1 Journal article |
|
Year |
2014 |
Publication |
Journal of non-crystalline solids |
Abbreviated Journal |
J Non-Cryst Solids |
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Volume |
384 |
Issue |
|
Pages |
61-72 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The possible role of a prior amorphous phase separation on the subsequent crystallization has been the topic of vigorous debates over the last decades and has not yet been clarified, especially regarding the role of the interfaces created by the phase separation. This study proposes to focus on the interplay between a prior amorphous phase separation and the crystallization of fresnoite in the BaO-TiO2-SiO2 system. The crystallization behavior of a non-stoichiometric composition inside the miscibility gap (called APS) is compared with the stoichiometric composition (called FRES) and a non-stoichiometric composition outside the miscibility gap (called NoAPS). The crystallization mechanisms are compared using differential thermal analysis (DTA) by calculating the Avrami parameters and the activation energies as a function of the particle size. The DTA study shows that the two non-stoichiometric compositions exhibit a pronounced surface crystallization behavior whereas FRES undergoes bulk nucleation. This is supported by a multi-scale microstructure characterization. Furthermore, this study demonstrates that the amorphous phase separation and the associated interfaces do not play any significant role in the nucleation step. Moreover, transmission electron microscope (TEM) and local orientation measurements show that the growth of the dendrites is not hindered by the SiO2-rich droplets. The final stage of crystallization of APS is tentatively explained by two composition effects that must be further investigated: the viscosity effect and the formation of a eutectic. (C) 2013 Elsevier B.V. All rights reserved. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000329422400010 |
Publication Date |
2013-07-24 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
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ISSN |
0022-3093; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
2.124 |
Times cited |
10 |
Open Access |
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Notes |
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Approved |
Most recent IF: 2.124; 2014 IF: 1.766 |
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Call Number |
UA @ lucian @ c:irua:114782 |
Serial |
1614 |
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Permanent link to this record |
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Author |
Idrissi, H.; Schryvers, D. |
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Title |
Investigation of the elementary mechanisms controlling dislocation/twin boundary interactions in fcc metals and alloys : from conventional to advanced TEM characterization |
Type |
H2 Book chapter |
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Year |
2012 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
1213-1224 |
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Keywords |
H2 Book chapter; Electron microscopy for materials research (EMAT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
Formatex Research Center |
Place of Publication |
S.l. |
Editor |
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Language |
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Wos |
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Publication Date |
0000-00-00 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
|
ISBN |
978-84-939843-6-6 |
Additional Links |
UA library record |
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Impact Factor |
|
Times cited |
|
Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:104694 |
Serial |
1737 |
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Permanent link to this record |
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Author |
van Oeffelen, L.; Van Roy, W.; Idrissi, H.; Charlier, D.; Lagae, L.; Borghs, G. |
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Title |
Ion current rectification, limiting and overlimiting conductances in nanopores |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
PLoS ONE |
Abbreviated Journal |
Plos One |
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Volume |
10 |
Issue |
10 |
Pages |
e0124171 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Previous reports on Poisson-Nernst-Planck (PNP) simulations of solid-state nanopores have focused on steady state behaviour under simplified boundary conditions. These are Neumann boundary conditions for the voltage at the pore walls, and in some cases also Donnan equilibrium boundary conditions for concentrations and voltages at both entrances of the nanopore. In this paper, we report time-dependent and steady state PNP simulations under less restrictive boundary conditions, including Neumann boundary conditions applied throughout the membrane relatively far away from the nanopore. We simulated ion currents through cylindrical and conical nanopores with several surface charge configurations, studying the spatial and temporal dependence of the currents contributed by each ion species. This revealed that, due to slow co-diffusion of oppositely charged ions, steady state is generally not reached in simulations or in practice. Furthermore, it is shown that ion concentration polarization is responsible for the observed limiting conductances and ion current rectification in nanopores with asymmetric surface charges or shapes. Hence, after more than a decade of collective research attempting to understand the nature of ion current rectification in solid-state nanopores, a relatively intuitive model is retrieved. Moreover, we measured and simulated current-voltage characteristics of rectifying silicon nitride nanopores presenting overlimiting conductances. The similarity between measurement and simulation shows that overlimiting conductances can result from the increased conductance of the electric double-layer at the membrane surface at the depletion side due to voltage-induced polarization charges. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000354916100012 |
Publication Date |
2015-05-15 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-6203; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
2.806 |
Times cited |
11 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 2.806; 2015 IF: 3.234 |
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Call Number |
c:irua:126366 |
Serial |
1744 |
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Permanent link to this record |
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Author |
Idrissi, H.; Ryelandt, L.; Veron, M.; Schryvers, D.; Jacques, P.J. |
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Title |
Is there a relationship between the stacking fault character and the activated mode of plasticity of FeMn-based austenitic steels? |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Scripta materialia |
Abbreviated Journal |
Scripta Mater |
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Volume |
60 |
Issue |
11 |
Pages |
941-944 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
By changing the testing temperature, an austenitic FeMnAlSi alloy presents either å-martensite transformation or mechanical twinning during straining. In order to understand the nucleation and growth mechanisms involved in both phenomena, defects and particularly stacking faults, were characterized by transmission electron microscopy. It is observed that the character of the stacking faults also changes (from extrinsic to intrinsic) together with the temperature and the activated mode of plasticity. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Oxford |
Editor |
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Language |
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Wos |
000265359900005 |
Publication Date |
2009-02-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1359-6462; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.747 |
Times cited |
84 |
Open Access |
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Notes |
Iap |
Approved |
Most recent IF: 3.747; 2009 IF: 2.949 |
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Call Number |
UA @ lucian @ c:irua:77276 |
Serial |
1751 |
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Permanent link to this record |
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Author |
Salje, E.K.H.; Zhang, H.; Idrissi, H.; Schryvers, D.; Carpenter, M.A.; Moya, X.; Planes, A. |
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Title |
Mechanical resonance of the austenite/martensite interface and the pinning of the martensitic microstructures by dislocations in Cu74.08Al23.13Be2.79 |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Physical review: B: condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
80 |
Issue |
13 |
Pages |
134114,1-1134114,8 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
A single crystal of Cu74.08Al23.13Be2.79 undergoes a martensitic phase transition at 246 and 232 K under heating and cooling, respectively. The phase fronts between the austenite and martensite regions of the sample are weakly mobile with a power-law resonance under external stress fields. Surprisingly, the martensite phase is elastically much harder than the austenite phase showing that interfaces between various crystallographic variants are strongly pinned and cannot be moved by external stress while the phase boundary between the austenite and martensite regions in the sample remains mobile. This unusual behavior was studied by dynamical mechanical analysis (DMA) and resonant ultrasound spectroscopy. The remnant strain, storage modulus, and internal friction were recorded simultaneously for different applied forces in DMA. With increasing forces, the remnant strain increases monotonously while the internal friction peak height shows a minimum at 300 mN. Transmission electron microscopy shows that the pinning is generated by dislocations which are inherited from the austenite phase. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000271351300033 |
Publication Date |
2009-10-22 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
3.836 |
Times cited |
38 |
Open Access |
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|
|
Notes |
Multimat |
Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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Call Number |
UA @ lucian @ c:irua:78542 |
Serial |
1975 |
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Permanent link to this record |
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Author |
Renard, K.; Idrissi, H.; Schryvers, D.; Jacques, P.J. |
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Title |
Multiscale characterization of the work hardening mechanisms in Fe-Mn based TWIP steels |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Steel research international |
Abbreviated Journal |
Steel Res Int |
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Volume |
83 |
Issue |
4 |
Pages |
385-390 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
When strained in tension, high-manganese austenitic twinning induced plasticity (TWIP) steels achieve very high strength and elongation before necking. The main hypotheses available in the literature about the origin of their excellent work hardening include deformation twinning and dynamic strain ageing. In order to provide some answers, various experiments at different scales were conducted on FeMnC steels and the Fe28 wt%Mn3.5 wt%Al2.8 wt%Si alloy. At a macroscopic scale, tensile tests were performed on all the studied grades. It was shown that, though the FeMnAlSi based alloy retains very high elongation, the FeMnC steels properties are even more extraordinary. Tensile tests at different strain rates with the help of digital image correlation were also performed on the Fe20 wt%Mn1.2 wt%C steel to study the PLC effect occurring in this type of steel. It is suggested that supplementary hardening could come from reorientation of MnC pairs in the cores of the dislocations. At a microscopic scale, the Fe20 wt%Mn1.2 wt%C TWIP steel and the FeMnAlSi grade were thoroughly investigated by means of in situ TEM analysis. In the FeMnC steel, the formed twins could also lead to a composite effect, since they contain plenty of sessile dislocations. In the FeMnAlSi alloy, mechanical twins are thicker and contain fewer defects, leading to a lower work hardening than the other grade. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
Verlag Stahleisen |
Place of Publication |
Düsseldorf |
Editor |
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Language |
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Wos |
000302471600016 |
Publication Date |
2012-02-22 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
|
|
|
ISSN |
1611-3683; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
1.235 |
Times cited |
12 |
Open Access |
|
|
|
Notes |
|
Approved |
Most recent IF: 1.235; 2012 IF: 0.493 |
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Call Number |
UA @ lucian @ c:irua:97391 |
Serial |
2239 |
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