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Author Delville, R.; Schryvers, D.; Zhang, Z.; James, R.D.
Title Transmission electron microscopy investigation of microstructures in low-hysteresis alloys with special lattice parameters Type A1 Journal article
Year 2009 Publication Scripta materialia Abbreviated Journal Scripta Mater
Volume 60 Issue 5 Pages 293-296
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract A sharp drop in hysteresis is observed for shape memory alloys satisfying the compatibility condition between austenite and martensite, i.e. ë2 = 1, where ë2 is the middle eigenvalue of the transformation strain matrix. The present work investigates the evolution of microstructure by transmission electron microscopy as the composition of the Ti50Ni50−xPdx system is systemically tuned to achieve the condition ë2 = 1. Changes in morphology, twinning density and twinning modes are reported along with twinless martensite and exact austenitemartensite interfaces.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000262553300007 Publication Date 2008-11-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-6462; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.747 Times cited (up) 56 Open Access
Notes Multimat Approved Most recent IF: 3.747; 2009 IF: 2.949
Call Number UA @ lucian @ c:irua:76017 Serial 3710
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Author Tirumalasetty, G.K.; van Huis, M.A.; Fang, C.M.; Xu, Q.; Tichelaar, F.D.; Hanlon, D.N.; Sietsma, J.; Zandbergen, H.W.
Title Characterization of NbC and (Nb, Ti)N nanoprecipitates in TRIP assisted multiphase steels Type A1 Journal article
Year 2011 Publication Acta materialia Abbreviated Journal Acta Mater
Volume 59 Issue 19 Pages 7406-7415
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Multiphase steels utilising composite strengthening may be further strengthened via grain refinement or precipitation by the addition of microalloying elements. In this study a Nb microalloyed steel comprising martensite, bainite and retained austenite has been studied. By means of transmission electron microscopy (TEM) we have investigated the size distribution and the structural properties of (Nb, Ti)N and NbC precipitates, their occurrence in the various steel phases, and their relationship with the Fe matrix. (Nb, Ti)N precipitates were found in ferrite, martensite, and bainite, while NbC precipitates were found only in ferrite. All NbC precipitates were found to be small (520 nm in size) and to have a face centred cubic (fcc) crystal structure with lattice parameter a = 4.36 ± 0.05 Å. In contrast, the (Nb, Ti)N precipitates were found to have a broader size range (5150 nm) and to have a fcc crystal structure with lattice parameter a = 8.09 ± 0.05 Å. While the NbC precipitates were found to be randomly oriented, the (Nb, Ti)N precipitates have a well-defined NishiyamaWasserman orientation relationship with the ferrite matrix. An analysis of the lattice mismatch suggests that the latter precipitates have a high potential for effective strengthening. Density functional theory calculations were performed for various stoichiometries of NbCx and NbxTiyNz phases and the comparison with experimental data indicates that both the carbides and nitrides are deficient in C and N content.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000296405200026 Publication Date 2011-09-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-6454; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.301 Times cited (up) 58 Open Access
Notes Approved Most recent IF: 5.301; 2011 IF: 3.755
Call Number UA @ lucian @ c:irua:93297 Serial 328
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Author Schryvers, D.; Firstov, G.S.; Seo, J.W.; van Humbeeck, J.; Koval, Y.N.
Title Unit cell determination in CuZr martensite by EM and X-ray diffraction Type A1 Journal article
Year 1997 Publication Scripta materialia Abbreviated Journal Scripta Mater
Volume 36 Issue Pages 1119-1125
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos A1997WV99600007 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-6462 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.747 Times cited (up) 76 Open Access
Notes Approved Most recent IF: 3.747; 1997 IF: 0.645
Call Number UA @ lucian @ c:irua:21344 Serial 3811
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Author Tirumalasetty, G.K.; van Huis, M.A.; Kwakernaak, C.; Sietsma, J.; Sloof, W.G.; Zandbergen, H.W.
Title Deformation-induced austenite grain rotation and transformation in TRIP-assisted steel Type A1 Journal article
Year 2012 Publication Acta materialia Abbreviated Journal Acta Mater
Volume 60 Issue 3 Pages 1311-1321
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Uniaxial straining experiments were performed on a rolled and annealed Si-alloyed TRIP (transformation-induced plasticity) steel sheet in order to assess the role of its microstructure on the mechanical stability of austenite grains with respect to martensitic transformation. The transformation behavior of individual metastable austenite grains was studied both at the surface and inside the bulk of the material using electron back-scattered diffraction (EBSD) and X-ray diffraction (XRD) by deforming the samples to different strain levels up to about 20%. A comparison of the XRD and EBSD results revealed that the retained austenite grains at the surface have a stronger tendency to transform than the austenite grains in the bulk of the material. The deformation-induced changes of individual austenite grains before and after straining were monitored with EBSD. Three different types of austenite grains can be distinguished that have different transformation behaviors: austenite grains at the grain boundaries between ferrite grains, twinned austenite grains, and embedded austenite grains that are completely surrounded by a single ferrite grain. It was found that twinned austenite grains and the austenite grains present at the grain boundaries between larger ferrite grains typically transform first, i.e. are less stable, in contrast to austenite grains that are completely embedded in a larger ferrite grain. In the latter case, straining leads to rotations of the harder austenite grain within the softer ferrite matrix before the austenite transforms into martensite. The analysis suggests that austenite grain rotation behavior is also a significant factor contributing to enhancement of the ductility. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000301157900054 Publication Date 2011-12-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-6454; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.301 Times cited (up) 80 Open Access
Notes Approved Most recent IF: 5.301; 2012 IF: 3.941
Call Number UA @ lucian @ c:irua:97210 Serial 630
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Author Idrissi, H.; Ryelandt, L.; Veron, M.; Schryvers, D.; Jacques, P.J.
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
Year 2009 Publication Scripta materialia Abbreviated Journal Scripta Mater
Volume 60 Issue 11 Pages 941-944
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000265359900005 Publication Date 2009-02-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-6462; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.747 Times cited (up) 84 Open Access
Notes Iap Approved Most recent IF: 3.747; 2009 IF: 2.949
Call Number UA @ lucian @ c:irua:77276 Serial 1751
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Author Tirry, W.; Schryvers, D.
Title Quantitative determination of strain fields around Ni4Ti3 precipitates in NiTi Type A1 Journal article
Year 2005 Publication Acta materialia Abbreviated Journal Acta Mater
Volume 53 Issue 4 Pages 1041-1049
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000226774500014 Publication Date 2004-12-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-6454; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.301 Times cited (up) 97 Open Access
Notes Approved Most recent IF: 5.301; 2005 IF: 3.430
Call Number UA @ lucian @ c:irua:55686 Serial 2750
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Author Delville, R.; Malard, B.; Pilch, J.; Schryvers, D.
Title Microstructure changes during non-conventional heat treatment of thin NiTi wires by pulsed electric current studied by transmission electron microscopy Type A1 Journal article
Year 2010 Publication Acta materialia Abbreviated Journal Acta Mater
Volume 58 Issue 13 Pages 4503-4515
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Transmission electron microscopy, electrical resistivity measurements and mechanical testing were employed to investigate the evolution of microstructure and functional superelastic properties of 0.1 mm diameter as-drawn NiTi wires subjected to a non-conventional heat treatment by controlled electric pulse currents. This method enables a better control of the recovery and recrystallization processes taking place during the heat treatment and accordingly a better control on the final microstructure. Using a stepwise approach of millisecond pulse annealing, it is shown how the microstructure evolves from a severely deformed state with no functional properties to an optimal nanograined microstructure (2050 nm) that is partially recovered through polygonization and partially recrystallized and that has the best functional properties. Such a microstructure is highly resistant against dislocation slip upon cycling, while microstructures annealed for longer times and showing mostly recrystallized grains were prone to dislocation slip, particularly as the grain size exceeds 200 nm.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000279787100020 Publication Date 2010-06-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-6454; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.301 Times cited (up) 110 Open Access
Notes Multimat; FWO IAA Approved Most recent IF: 5.301; 2010 IF: 3.791
Call Number UA @ lucian @ c:irua:83279 Serial 2062
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Author Idrissi, H.; Renard, K.; Schryvers, D.; Jacques, P.J.
Title On the relationship between the twin internal structure and the work-hardening rate of TWIP steels Type A1 Journal article
Year 2010 Publication Scripta materialia Abbreviated Journal Scripta Mater
Volume 63 Issue 10 Pages 961-964
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract FeMnC and FeMnSiAl TWIP steels deformed under the same conditions exhibit different work-hardening rates. The present study investigates the microstructure of plastically deformed FeMnC and FeMnSiAl samples, particularly the internal structure of the mechanically generated twins and their topology at the grain scale. Twins in the FeMnC steel are finer and full of sessile dislocations, rendering this material distinctly stronger with an improved work-hardening rate.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000282461800003 Publication Date 2010-07-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-6462; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.747 Times cited (up) 145 Open Access
Notes Iap Approved Most recent IF: 3.747; 2010 IF: 2.820
Call Number UA @ lucian @ c:irua:84472 Serial 2452
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Author Idrissi, H.; Renard, K.; Ryelandt, L.; Schryvers, D.; Jacques, P.J.
Title On the mechanism of twin formation in FeMnC TWIP steels Type A1 Journal article
Year 2010 Publication Acta materialia Abbreviated Journal Acta Mater
Volume 58 Issue 7 Pages 2464-2476
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Although it is well known that FeMnC TWIP steels exhibit high work-hardening rates, the elementary twinning mechanisms controlling the plastic deformation of these steels have still not been characterized. The aim of the present study is to analyse the extended defects related to the twinning occurrence using transmission electron microscopy. Based on these observations, the very early stage of twin nucleation can be attributed to the pole mechanism with deviation proposed by Cohen and Weertman or to the model of Miura, Takamura and Narita, while the twin growth is controlled by the pole mechanism proposed by Venables. High densities of sessile Frank dislocations are observed within the twins at the early stage of deformation, which can affect the growth and the stability of the twins, but also the strength of these twins and their interactions with the gliding dislocations present in the matrix. This experimental evidence is discussed and compared to recent results in order to relate the defects analysis to the macroscopic behaviour of this category of material.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000276523200018 Publication Date 2010-01-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-6454; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.301 Times cited (up) 244 Open Access
Notes Iap Approved Most recent IF: 5.301; 2010 IF: 3.791
Call Number UA @ lucian @ c:irua:82270 Serial 2441
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Author Berg, L.K.; Gjønnes, J.; Hansen, V.; Li, X.Z.; Knutson-Wedel, M.; Waterloo, G.; Schryvers, D.; Wallenberg, L.R.
Title GP-zones in Al-Zn-Mg alloys and their role in artificial aging Type A1 Journal article
Year 2001 Publication Acta materialia Abbreviated Journal Acta Mater
Volume 49 Issue Pages 3443-3451
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000171445700006 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-6454; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.301 Times cited (up) 261 Open Access
Notes Approved Most recent IF: 5.301; 2001 IF: 2.658
Call Number UA @ lucian @ c:irua:48363 Serial 1361
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