Microstructure changes during non-conventional heat treatment of thin Ni–Ti wires by pulsed electric current studied by transmission electron microscopy

Delville, Rémi; Malard, B.; Pilch, Ján; Šittner, Petr; Schryvers, D.

doi:10.1016/j.actamat.2010.04.046

Cited by 206 publications

(117 citation statements)

References 31 publications

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“…The same trend was also observed in Ti-Ni shape memory alloys where different nanostructures can be created in high-temperature B2-austenite phase as a result of postdeformation annealing (PDA) after severe deformation by high-pressure torsion [3][4][5][6][7], cold rolling (CR) [8][9][10][11][12][13], and cold drawing [14][15][16] techniques.…”

Section: Introductionmentioning

confidence: 65%

Gradation of Nanostructures in Cold-Rolled and Annealed Ti–Ni Shape Memory Alloys

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Braïlovski

Dubinskiy

et al. 2016

Shap. Mem. Superelasticity

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Nanostructures formed in Ti-50.26 at.%Ni shape memory alloy as a result of post-deformation annealing (PDA) at 400°C (1 h) after cold rolling (CR) in the e = 0.3-1.9 true strain range are classified and quantitatively studied. The statistical quantitative transmission electron microscopy analysis of bright and dark field images and selected area diffraction patterns reveal the following regularities. Two types of nanostructure form in B2-austenite as a result of PDA after CR: (a) a nanosubgrained structure, which consists of subgrains formed as a result of polygonization of the initially highly dislocated substructure; (b) a nanocrystalline structure, which represents a combination of the deformation-induced nanograins grown during PDA and new nano-grains formed during crystallization of the amorphous phase. After moderate CR (e = 0.3), mainly nanosubgrained structure forms as a result of PDA. After CR of moderate-to-high intensity (e = 0.5-1.0) followed by PDA, the structure is mixed (nanosubgrained?nanocrystalline). After high-intensity CR (e = 1.2-1.9) and PDA, the structure is mainly nanocrystalline. This nanostructure identification allows adequate analysis of the nature of the parent phase boundaries in the thermomechanically processed Ti-Ni alloys and of their effect on the transformation and mechanical behaviors.

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Section: Introductionmentioning

confidence: 65%

Gradation of Nanostructures in Cold-Rolled and Annealed Ti–Ni Shape Memory Alloys

Прокошкин

Braïlovski

Dubinskiy

et al. 2016

Shap. Mem. Superelasticity

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“…Delville et al [21] showed that, during superelastic cycling of NiTi, significant accumulated irrecoverable strain could occur due to the introduction of defects along cycling. Later, Sedmak et al [14] performed in-situ X-ray analysis using synchrotron radiation on the same material as in Delville's work.…”

Section: Resultsmentioning

confidence: 99%

Martensite stabilization during superelastic cycling of laser welded NiTi plates

et al. 2016

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“…Some material characteristics related to the phase transformation are quite sensitive to alloy composition, manufacturing and processing of nal or semi-nished (wires, plates, lms) products, e.g. [4,5].…”

Section: Proceedings Of the International Symposium On Physics Of Matmentioning

confidence: 99%

Characterization of Superelastic NiTi Alloys by Nanoindentation: Experiments and Simulations

et al. 2015

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NiTi-based shape memory alloys are metallic materials exhibiting remarkable response to mechanical and/or thermal loading, e.g. superelasticity, pseudoplasticity or one-way shape memory eect. They can be engineered into structures of micro-size dimensions, hence, they appear promising for application in micro-electromechanical systems. For their ecient utilization, appropriate characterization is important. Due to relative simplicity, indentation represents a very standard and popular technique for basic characterization of metallic materials providing information about stiness and hardness. Moreover, it can be used for identication of other events in the material. This study aims to verify applicability of the recently developed constitutive model for NiTi-based shape memory alloy in simulations of nanoindentation tests. The model is tted to a particular sample material using experimental data, and a series of simulations mimicking tests at various temperatures is performed. Since the model also captures two-stage martensitic transformation via the intermediate R-phase, its inuence on the simulations is investigated as well. It is conrmed that spherical indentation is a suitable method for simple and fast detection whether the material is in superelastic or pseudoplastic regime.

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Microstructure changes during non-conventional heat treatment of thin Ni–Ti wires by pulsed electric current studied by transmission electron microscopy

Cited by 206 publications

References 31 publications

Gradation of Nanostructures in Cold-Rolled and Annealed Ti–Ni Shape Memory Alloys

Gradation of Nanostructures in Cold-Rolled and Annealed Ti–Ni Shape Memory Alloys

Martensite stabilization during superelastic cycling of laser welded NiTi plates

Characterization of Superelastic NiTi Alloys by Nanoindentation: Experiments and Simulations

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