Constitutive model for NiTiFe shape memory alloys exhibiting pronounced R-phase transformation

0564407 - ÚT 2023 RIV US eng C - Conference Paper (international conference)
Frost, Miroslav - Sedlák, Petr - Jury, Antoine - Heller, Luděk
Constitutive model for NiTiFe shape memory alloys exhibiting pronounced R-phase transformation.
Conference Proceedings from International Conference on Shape Memory and Superelastic Technologies, SMST 2022. Materials Park, Ohio: ASM International, 2022, s. 67-68. ISBN 978-171385538-5.
[International Conference on Shape Memory and Superelastic Technologies 2022, SMST 2022. Carlsbad (US), 16.05.2022-20.05.2022]
R&D Projects: GA ČR(CZ) GA22-20181S; GA MŠMT(CZ) LTAUSA18199
Institutional support: RVO:61388998 ; RVO:68378271
Keywords : constitutive model * nickel-titanium-iron shape memory alloys * R-phase
OECD category: Materials engineering; Materials engineering (FZU-D)
https://dl.asminternational.org/shape-memory/proceedings/SMST%202022/84291/67/18984

Specific heat treatment or addition of a ternary element may induce a two-stage transformation sequence in NiTi shape memory alloys (SMA). A typical example of intermediating phases is so-called R-phase, a rhombohedral distortion of the cubic austenitic phase, which exhibits much lower transformation strain and thermal hysteresis than the subsequent transition to monoclinic martensite. In specific alloys, e.g., in NiTi slightly enriched by iron, the temperature and stress intervals in which R-phase is stable are quite broad. This paper presents an enhanced constitutive model for NiTi SMA featuring the R-phase transition. The model recognizes R-phase as a distinct phase, respects the coupled influence of stress and temperature on any phase transformation, and covers reorientation (reconfiguration) of both martensite and R-phase with applied stress.
Permanent Link: https://hdl.handle.net/11104/0336182