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“The role of phase compatibility in martensite”. Salman OU, Finel A, Delville R, Schryvers D, Journal of applied physics
T2 –, 22nd International Symposium on Integrated Functionalities (ISIF), JUN 13-16, 2010, San Juan, PR 111, 103517 (2012). http://doi.org/10.1063/1.4712629
Abstract: Shape memory alloys inherit their macroscopic properties from their mesoscale microstructure originated from the martensitic phase transformation. In a cubic to orthorhombic transition, a single variant of martensite can have a compatible (exact) interface with the austenite for some special lattice parameters in contrast to conventional austenite/twinned martensite interface with a transition layer. Experimentally, the phase compatibility results in a dramatic drop in thermal hysteresis and gives rise to very stable functional properties over cycling. Here, we investigate the microstructures observed in Ti50Ni50-xPdx alloys that undergo a cubic to orthorhombic martensitic transformation using a three-dimensional phase field approach. We will show that the simulation results are in very good agreement with transmission electron microscopy observations. However, the understanding of the drop in thermal hysteresis requires the coupling of phase transformation with plastic activity. We will discuss this point within the framework of thermoelasticity, which is a generic feature of the martensitic transformation. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4712629]
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 11
DOI: 10.1063/1.4712629
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“SAED and HREM results suggest a NiTi B19' based superstructure for CuZr martensite”. Schryvers D, Journal de physique: colloques, suppléments 5, 1047 (1995). http://doi.org/10.1051/jp4/1995581047
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 2
DOI: 10.1051/jp4/1995581047
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“Site occupation of Nb atoms in ternary Ni-Ti-Nb shape memory alloys”. Shi H, Frenzel J, Martinez GT, Van Rompaey S, Bakulin A, Kulkova A, Van Aert S, Schryvers D, Acta materialia 74, 85 (2014). http://doi.org/10.1016/j.actamat.2014.03.062
Abstract: Nb occupancy in the austenite B2-NiTi matrix and Ti2Ni phase in NiTiNb shape memory alloys was investigated by aberration-corrected scanning transmission electron microscopy and precession electron diffraction. In both cases, Nb atoms were found to prefer to occupy the Ti rather than Ni sites. A projector augmented wave method within density functional theory was used to calculate the atomic and electronic structures of the austenitic B2-NiTi matrix phase and the Ti2Ni precipitates both with and without addition of Nb. The obtained formation energies and analysis of structural and electronic characteristics explain the preference for Ti sites for Nb over Ni sites.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 5.301
Times cited: 21
DOI: 10.1016/j.actamat.2014.03.062
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“Some examples of electron microscopy studies of microstructures and phase transitions in solids”. Schryvers D, Van Tendeloo G, van Landuyt J, Amelinckx S, Meccanica 30, 433 (1995). http://doi.org/10.1007/BF01557075
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.949
Times cited: 1
DOI: 10.1007/BF01557075
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“Special microstructures and twin features in Ti50Ni50-x(Pd,Au)x at small hysteresis”. Delville R, Shi H, James RD, Schryvers D, Diffusion and defect data : solid state data : part B : solid state phenomena 172/174, 105 (2011). http://doi.org/10.4028/www.scientific.net/SSP.172-174.105
Abstract: The breaking of symmetry due to atomic displacements in the austenite-martensite phase transformation generally leads to their crystallographic incompatibility. Energy minimizing accommodation mechanisms such as martensite twinning have been recently shown to be a source of hysteresis and irreversible plastic deformation. Compatibility between the two phases can however be achieved by carefully tuning lattice parameters through composition change. A dramatic drop in hysteresis and novel microstructures such as a lowering of the amount of twin lamella are then observed. Related theoretical and simulation works also support the existence of such microstructures including peculiar self-accommodating configurations at near-compatibility. We present the transmission electron microscopy (TEM) study of these novel microstructures for the alloy systems Ti50Ni50-xPdx and Ti50Ni50-xAux where the composition was systemically tuned to approach perfect compatibility. High resolution imaging of the interface between austenite and martensite supplies evidences of compatibility at the atomic level.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 3
DOI: 10.4028/www.scientific.net/SSP.172-174.105
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“Stability of Ni in nitinol oxide surfaces”. Tian H, Schryvers D, Liu D, Jiang Q, van Humbeeck J, Acta biomaterialia 7, 892 (2011). http://doi.org/10.1016/j.actbio.2010.09.009
Abstract: The stability of Ni in titanium oxide surface layers on nitinol wires known to release certain amounts of Ni was investigated by first principles density functional theory and transmission electron microscopy. The oxides were identified as a combination of TiO and TiO2 depending on the thickness of the layer. The calculations indicate that free Ni atoms can exist in TiO at ambient temperature while Ni particles form in TiO2, which was confirmed by the transmission electron microscopy observations. The results are discussed with respect to surface stability and Ni release due to free Ni atoms and Ni particles.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 39
DOI: 10.1016/j.actbio.2010.09.009
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“Stress-assisted crystallisation in anodic titania”. Vanhumbeeck J-F, Tian H, Schryvers D, Proost J, Corrosion science 53, 1269 (2011). http://doi.org/10.1016/j.corsci.2010.12.020
Abstract: The relationship between the microstructural and internal stress evolution during Ti anodising is discussed. Samples anodised galvanostatically to 12 V and 40 V, corresponding to different stages of the internal stress evolution, were examined by in-plane and cross-section transmission electron microscopy. Electron diffraction patterns have been complemented with stoichiometry data obtained from energy loss near edge structure spectra. The sample anodised to 40 V was observed to consist of two regions, with a crystallised inner region adjacent to the metal/oxide interface. Crystallisation of this region is associated with the presence of large compressive internal stresses which build up during anodising up to 12 V.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.245
Times cited: 11
DOI: 10.1016/j.corsci.2010.12.020
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“Structural and chemical effects on EELS L3,2 ionization edges in Ni-based intermetallic compounds”. Potapov PL, Kulkova SE, Schryvers D, Verbeeck J, Physical review : B : condensed matter and materials physics 64, 184110 (2001). http://doi.org/10.1103/PhysRevB.64.184110
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 44
DOI: 10.1103/PhysRevB.64.184110
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“Structural characterisation of melt-spun Ti-Ni-Cu-ribbons”. Schryvers D, Potapov P, Ledda A, Shelyakov A, Journal de physique: 4 11, 363 (2001). http://doi.org/10.1051/jp4:2001861
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 1
DOI: 10.1051/jp4:2001861
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“Structural characterisation of nanostructured Ni3Al processed by inert gas condensation”. Yandouzi M, Pauwels B, Schryvers D, van Swygenhoven H, Van Tendeloo G, Defects and diffusion in metals 213/215, 19 (2003)
Keywords: A3 Journal article; Electron microscopy for materials research (EMAT)
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“Structural characterization of nanostructured Ni3Al processed by inert gas condensation”. Yandouzi M, Pauwels B, Schryvers D, Van Swygenhoven H, Van Tendeloo G, Diffusion and defect data : solid state data : part A : defect and diffusion forum 213, 19 (2003)
Abstract: High-resolution transmission electron microscopy was performed on compacted Ni(3)Al nanostructured material prepared by the inert gas condensation technique. From electron diffraction data an incomplete L1(2) ordering of the crystallites is observed in the free particles as well as in the room temperature compacted samples. However, a completely ordered L1(2) structure with much bigger and well-defined crystallites exhibiting several defects is observed in material compacted and annealed at 773 K. Sharp crystallite boundaries as well as amorphous material and voids are observed in between crystallites in all samples, the former being dominant in the annealed material, the latter in the as-prepared one.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
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“Structural instabilities associated with phase transitions: an electron microscopy study”. Van Tendeloo G, Schryvers D, Tanner LE, , 107 (1992)
Keywords: P3 Proceeding; Electron microscopy for materials research (EMAT)
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“Structural phase transformations in alloys: an electron microscopy study”. Van Tendeloo G, Schryvers D, Tanner LE, Broddin D, Ricolleau C, Loiseau A, Symposium on Pahse Transformations , 1 (1991)
Keywords: P3 Proceeding; Electron microscopy for materials research (EMAT)
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“Structure of multi-grain spherical particles in an amorphous Ti50Ni25Cu25 melt-spun ribbon”. Santamarta R, Schryvers D, Materials science and engineering: part A: structural materials: properties, microstructure and processing 378, 143 (2004). http://doi.org/10.1016/j.msea.2003.11.060
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.094
Times cited: 5
DOI: 10.1016/j.msea.2003.11.060
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“Structure refinement of L21 Cu-Zn-Al austenite, using dynamical electron diffraction data”. Satto S, Jansen J, Lexcellent C, Schryvers D, Solid state communications 116, 273 (2000). http://doi.org/10.1016/S0038-1098(00)00316-1
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.554
Times cited: 7
DOI: 10.1016/S0038-1098(00)00316-1
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“Structures in textured Cu-Al-Ni shape memory thin films grown by sputtering”. Espinoza Torres C, Condó, AM, Haberkorn N, Zelaya E, Schryvers D, Guimpel J, Lovey FC, Materials characterization 96, 256 (2014). http://doi.org/10.1016/j.matchar.2014.08.005
Abstract: The structure and texture formation in CuAlNi thin films of different thicknesses (1 μm to 5 μm) grown by DC magnetron sputtering without any intentional heating of the substrate are reported. The as-grown films present grains with an average size of 20 nm. The films with thickness of 1 μm have a single metastable phase with a hexagonal structure and are textured with planes (0002) parallel to the plane of the films. It was observed that thicker films present phase coexistence between metastable hexagonal and body centered cubic structures with a gradual increment of the body centered cubic phase fraction. The films with thickness of 5 μm are textured with planes (0002) and View the MathML source101¯0 in the hexagonal structure, whereas in the body centered cubic structure the films are textured with {110} planes parallel to the plane of the films. This fact can be associated with self-heating of the substrate during the growth of the films and with the relative stability of the metastable phases. Free standing films annealed in a second step (1123 K for 1 h) present austenitic phase with L21 structure and sub-micrometric grains textured with {220}L21 planes parallel to the plane of the films. The martensitic transformation temperature was determined from the analysis of resistance against temperature measurements.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.714
Times cited: 9
DOI: 10.1016/j.matchar.2014.08.005
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“Study of changes in composition and EELS ionization edges upon Ni4Ti3 precipitation in a NiTi alloy”. Yang Z, Schryvers D, Micron 37, 503 (2006). http://doi.org/10.1016/j.micron.2005.08.002
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.98
Times cited: 10
DOI: 10.1016/j.micron.2005.08.002
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“Study of changes in L32 EELS ionisation edges upon formation of Ni-based intermetallic compounds”. Potapov PL, Kulkova SE, Schryvers D, Journal of microscopy 210, 102 (2003). http://doi.org/10.1046/j.1365-2818.2003.01176.x
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.692
Times cited: 11
DOI: 10.1046/j.1365-2818.2003.01176.x
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“TEM and Raman characterisation of diamond micro- and nanostructures in carbon spherules from upper soils”. Yang ZQ, Verbeeck J, Schryvers D, Tarcea N, Popp J, Rösler W, Diamond and related materials 17, 937 (2008). http://doi.org/10.1016/j.diamond.2008.01.104
Abstract: Carbonaceous spherules of millimeter size diameter and found in the upper soils throughout Europe are investigated by TEM, including SAED, HRTEM and EELS, and Raman spectroscopy. The spherules consist primarily of carbon and have an open cell-like internal structure. Most of the carbon appears in an amorphous state, but different morphologies of nano- and microdiamond particles have also been discovered including flake shapes. The latter observation, together with the original findings of some of these spherules in crater-like structures in the landscape and including severely deformed rocks with some spherules being embedded in the fused crust of excavated rocks, points towards unique conditions of origin for these spherules and particles, possibly of exogenic origin. (C) 2008 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.561
Times cited: 26
DOI: 10.1016/j.diamond.2008.01.104
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“TEM investigation of the formation mechanism of deformation twins in Fe-Mn-Si-Al TWIP steels”. Idrissi H, Renard K, Schryvers D, Jacques PJ, Philosophical magazine 93, 4378 (2013). http://doi.org/10.1080/14786435.2013.832837
Abstract: The microstructure of a Fe-Mn-Si-Al twinning-induced plasticity (TWIP) steel exhibiting remarkable work hardening rate under uniaxial tensile deformation was investigated using transmission electron microscopy to uncover the mechanism(s) controlling the nucleation and growth of the mechanically induced twins. The results show that the stair-rod cross-slip deviation mechanism is necessary for the formation of the twins, while large extrinsic stacking faults homogenously distributed within the grains could act as preferential sources for the activation of the deviation process. The influence of such features on the thickness and strength of the twins and the resulting mechanical behaviour is discussed and compared to similar works recently performed on Fe-Mn-C TWIP steels.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 1.505
Times cited: 15
DOI: 10.1080/14786435.2013.832837
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“TEM investigation of the microstructure and defects of CuZr martensite: 1: morphology and twin systems”. Seo JW, Schryvers D, Acta materialia 46, 1165 (1998). http://doi.org/10.1016/S1359-6454(97)00333-9
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.301
Times cited: 46
DOI: 10.1016/S1359-6454(97)00333-9
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“TEM investigation of the microstructure and defects of CuZr martensite: 2: planar defects”. Seo JW, Schryvers D, Acta materialia 46, 1177 (1998). http://doi.org/10.1016/S1359-6454(97)00334-0
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.301
Times cited: 21
DOI: 10.1016/S1359-6454(97)00334-0
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“TEM study of B2 + L12 decomposition in a nanoscale Ni-rich Ni-Al film”. Schryvers D, Yandouzi M, Toth L, Thin solid films : an international journal on the science and technology of thin and thick films 326, 126 (1998). http://doi.org/10.1016/S0040-6090(98)00545-8
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.879
Times cited: 1
DOI: 10.1016/S0040-6090(98)00545-8
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“A TEM study of nanoparticles in lustre glazes”. Fredrickx P, Helary D, Schryvers D, Darque-Ceretti E, Applied physics A : materials science &, processing 79, 283 (2004). http://doi.org/10.1007/s00339-004-2515-3
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.455
Times cited: 16
DOI: 10.1007/s00339-004-2515-3
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“A TEM study of non-parallel twins inducing thickness growth in silver chloride {111} tabular crystals”. van Renterghem W, Schryvers D, van Landuyt J, Bollen D, van Roost C, de Keyzer R, The journal of imaging science and technology 45, 83 (2001)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.348
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“TEM study of the mechanism of Ni ion release from Nitinol wires with original oxides”. Tian H, Schryvers D, Shabalovskaya S, van Humbeeck J, , 05027 (2009). http://doi.org/10.1051/esomat/200905027
Abstract: The surface of commercial Nitinol wires with original oxides and a thickness in the 30-190 nm range was investigated by different state of art TEM techniques. The oxide surface layer was identified as a combination of TiO and TiO2 depending on the processing of the wire. Between the core of the wires and the oxidized surface, an interfacial Ni3Ti nanolayer was observed while Ni nanoparticles are found inside the original oxide. The particle sizes, their distribution in the surface and the Ti-O stoichiometry were deduced from the analysis of the obtained data. Molecular dynamics calculations performed for evaluation of the stability of Ni particles relative to the atomic state revealed that a pure Ni particle has a lower energy than free Ni atoms inside the TiO2 lattice. The obtained results are discussed with respect to surface stability and Ni release in the human body.
Keywords: P1 Proceeding; Electron microscopy for materials research (EMAT)
Times cited: 1
DOI: 10.1051/esomat/200905027
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“A temperature study of mixed AgBr-AgBrI tabular crystals”. Goessens C, Schryvers D, van Landuyt J, Geuens I, Gijbels R, Jacob W, de Keyzer R Hawaii, page 70 (1995).
Keywords: H1 Book chapter; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Times cited: 3
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“A temperature study of mixed AgBr-AgBrI tabular crystals”. Goessens C, Schryvers D, van Landuyt J, Geuens I, Gijbels R, Jacob W, de Keyzer R, , 36 (1992)
Keywords: P3 Proceeding; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Ni2Al versus Ni5Al3 ordering in Ni65Al35 austenite and martensite”. Schryvers D, Toth L, van Humbeeck J, Beyer J, Journal de physique: colloques, suppléments 5, 1029 (1995). http://doi.org/10.1051/jp4/1995581029
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 12
DOI: 10.1051/jp4/1995581029
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“Ni4Ti3 precipitates and their influence on the surrounding NiTi matrix”. Schryvers D, Tirry W, Yang Z, , 205 (2005)
Abstract: The properties of the shape memory behaviour of Ni-rich binary NiTi are strongly dependant on the thermal history of the material. In this respect the changing of transformation temperatures of the underlying martensitic transformation and the occurrence of multiple step transformations are the most important phenomena. Part of the explanation is found in the presence of Ni4Ti3 precipitates in the B2 matrix after particular heat treatments. The formation of these precipitates changes the Ni concentration of the matrix and induces a strain field, with both of these aspects expected to be of importance. In this work atomic resolution and analytical TEM (transmission electron microscopy) techniques are used to obtain quantitative information concerning these two main features. Furthermore, the known structure of Ni4Ti3 is refined by a least squares optimization of quantitative electron diffraction data. The high-resolution TEM results show that there are strains up to 2% in the matrix surrounding the precipitates and they gradually increase until a maximum is reached when moving away from the interface. Analytical results reveal a global decrease of Ni content in the matrix when sufficient precipitates are present and a gradient in their close vicinity. The refinement of the structure shows atomic displacements, thereby increasing our understanding of the shrinking of the precipitate lattice with respect to the matrix.
Keywords: P1 Proceeding; Electron microscopy for materials research (EMAT)
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