On the plastic deformation accompanying cyclic martensitic transformation in thermomechanically loaded NiTi

0501810 - FZÚ 2019 RIV US eng J - Journal Article
Heller, Luděk - Seiner, Hanuš - Šittner, Petr - Sedlák, Petr - Tyc, Ondřej - Kadeřávek, Lukáš
On the plastic deformation accompanying cyclic martensitic transformation in thermomechanically loaded NiTi.
International Journal of Plasticity. Roč. 111, Dec (2018), s. 53-71. ISSN 0749-6419. E-ISSN 1879-2154
R&D Projects: GA MŠMT(CZ) LM2015088; GA ČR GA16-20264S; GA ČR GA18-03834S; GA MŠMT LM2015087; GA ČR GB14-36566G; GA ČR GA16-20264S
Institutional support: RVO:68378271 ; RVO:61388998
Keywords : shape-memory alloys * structural fatigue * microstructure * constitutive-equations * crystal
OECD category: Condensed matter physics (including formerly solid state physics, supercond.); Condensed matter physics (including formerly solid state physics, supercond.) (UT-L)
Impact factor: 5.800, year: 2018

Cyclic thermomechanical loading tests were performed on a medical grade superelastic NiTi wire in wide temperature range −100 °C - +200 °C. It was observed, that plastic unrecoverable deformation occurs only when forward or reverse martensitic transformations proceed under external stress. Based on this, unrecovered strains generated separately by the forward and reverse martensitic transformations were evaluated using an originally proposed method and presented in a “3D unrecovered strain-stress-temperature diagram”. It was found, that the unrecovered strains increase exponentially with increasing stress and temperature, at which the forward and reverse transformations occurred and that comparable or even larger unrecovered strains were generated by the reverse transition than by the forward one.
Permanent Link: http://hdl.handle.net/11104/0293796