Young´s modulus of austenite and martensite phases in superelastic NiTi wires

0432480 - FZÚ 2015 RIV US eng J - Journal Article
Šittner, Petr - Heller, Luděk - Pilch, Jan - Curfs, C. - Alonso, T. - Favier, D.
Young´s modulus of austenite and martensite phases in superelastic NiTi wires.
Journal of Materials Engineering and Performance. Roč. 23, č. 7 (2014), s. 2303-2314. ISSN 1059-9495. E-ISSN 1544-1024.
[International Conference on Shape Memory and Superelastic Technologies (SMST 2013). Praha, 21.05.2013-24.05.2013]
R&D Projects: GA ČR GPP108/12/P111; GA ČR GAP107/12/0800; GA ČR GB14-36566G; GA ČR GA14-15264S
Institutional support: RVO:68378271
Keywords : mechanical * modeling and simulation * non-ferrous metals
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 0.998, year: 2014

Young s moduli of superelastic NiTi wires in austenite and stress-induced martensite states were evaluated by three different experimental methods (tensile tests, in situ synchrotron x-ray diffraction, and dynamic mechanical analysis) and estimated via theoretical calculation from elastic constants. The unusually low value of the Young s modulus of the martensite phase appearing in material property tables (<40 GPa) is generally ascribed in the literature to the fact that stress-driven martensitic transformation and/or twinning processes continue even beyond the transformation range and effectively decrease the value of the tangent modulus evaluated from macroscopic stress-strain curve. In this work, we claim that this low value is real in the sense that it corresponds to the appropriate combination of elastic constants of the B19´ martensite phase forming the polycrystalline wire.
Permanent Link: http://hdl.handle.net/11104/0236820