Deformation twinning in martensite affecting functional behavior of NiTi shape memory alloys

0524589 - ÚJF 2021 RIV DE eng J - Journal Article
Šittner, Petr - Molnárová, O. - Kadeřávek, Lukáš - Tyc, O. - Heller, Luděk
Deformation twinning in martensite affecting functional behavior of NiTi shape memory alloys.
Materialia. Roč. 9, č. 3 (2020), č. článku 100506. ISSN 2589-1529
R&D Projects: GA MŠMT EF16_013/0001794
Institutional support: RVO:61389005
Keywords : deformation twinning * functional fatigue * martensitic transformation * NiTi * shape setting * TWSME
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Method of publishing: Limited access
https://doi.org/10.1016/j.mtla.2019.100506

Functional stress-strain temperature responses of superelastic NiTi wire in purposely designed thermomechanical tests in tension were evaluated and lattice defects created by the tensile deformation were analyzed by transmission electron microscopy in this work with the aim to investigate potential involvement of deformation twinning in oriented martensite in thermomechanical loads and its consequences for NiTi superelastic and shape memory technologies. It was found that: i) the deformation twinning in oriented martensite taking place upon tensile loading beyond the yield point gives rise to large and stable two way shape memory effect, ii) its activity during the reverse transformation under high stress enables shape setting of superelastic NiTi wires and iii) its activity during tensile superelastic cycling brings about unrecoverable strains and causes functional fatigue.
Permanent Link: http://hdl.handle.net/11104/0308935