Ultra-high temperature shape memory in high-Hf content NiTiHf alloys

•Studied alloys exhibit B2-B19′ martensitic transformation.•NiTiHf alloys exhibit shape memory behavior up to ∼800 °C.•Recovered strain and work output decreases with increasing TT.•Creep processes manifest at high temperature. Microstructure and shape memory behavior of Ni50Ti25Hf25, Ni50Ti20Hf30,...

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Bibliographic Details
Published inJournal of materials science & technology Vol. 209; pp. 124 - 127
Main Authors Shuitcev, A.V., Li, Q.Z., Khomutov, M.G., Li, L, Tong, Y.X.
Format Journal Article
LanguageEnglish
Published Elsevier Ltd 20.02.2025
Subjects
B19′ martensite
High-temperature shape memory alloy
Martensitic transformation
NiTiHf
B19′ martensite
Martensitic transformation
High-temperature shape memory alloy
NiTiHf
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Summary:•Studied alloys exhibit B2-B19′ martensitic transformation.•NiTiHf alloys exhibit shape memory behavior up to ∼800 °C.•Recovered strain and work output decreases with increasing TT.•Creep processes manifest at high temperature. Microstructure and shape memory behavior of Ni50Ti25Hf25, Ni50Ti20Hf30, and Ni50Ti15Hf35 (at.%) were investigated. The self-accommodated monoclinic B19′ martensite was found in all studied alloys at room temperature. Transformation temperatures increase with increasing Hf content. Uniaxial constant-force thermal cycling test reveals that NiTiHf alloys can exhibit reversible shape memory behavior up to ∼800 °C. The work output decreases with increasing operating temperatures due to the dominance of creep mechanisms.
ISSN:1005-0302
DOI:10.1016/j.jmst.2024.05.022