Evolution of elastic constants of the NiTi shape memory alloy during a stress-induced martensitic transformation

0542094 - ÚJF 2022 RIV GB eng J - Journal Article
Grabec, Tomáš - Sedlák, Petr - Zoubková, K. - Ševčík, Martin - Janovská, Michaela - Stoklasová, Pavla - Seiner, Hanuš
Evolution of elastic constants of the NiTi shape memory alloy during a stress-induced martensitic transformation.
Acta Materialia. Roč. 208, APR (2021), č. článku 116718. ISSN 1359-6454. E-ISSN 1873-2453
R&D Projects: GA ČR(CZ) GA20-12624S; GA MŠMT EF16_013/0001794
Institutional support: RVO:61389005 ; RVO:61388998
Keywords : NiTi * shape memory alloy (SMA) * in situ tension test * ultrasonic characterization * anisotropic elasticity
OECD category: Mechanical engineering; Acoustics (UT-L)
Impact factor: 9.209, year: 2021
Method of publishing: Limited access
https://doi.org/10.1016/j.actamat.2021.116718

We carried out an in situ ultrasonic characterization of a NiTi shape memory alloy polycrystal subjected to pseudoplastic straining. The measurement leads to a full elastic tensor of the transversely isotropic polycrystal during the stress-induced austenite -> R-phase -> B19' martensite transformation. The results reveal a strong anisotropy of the R-phase already in the low-strain state, which is then retained in character throughout the R-phase -> martensite transition and even in the stress-free oriented martensite after the unloading. By using a micromechanical model based on homogenization approaches, we show that this strong anisotropy is probably related to twin boundaries both in the R-phase and in martensite rather than to the anisotropy of the unit cell and the crystallographic texture.
Permanent Link: http://hdl.handle.net/11104/0319578