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Tensile deformation of NiTi wires
Author(s) -
Gall Ken,
Tyber Jeff,
Brice Valerie,
Frick Carl P.,
Maier Hans J.,
Morgan Neil
Publication year - 2005
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.30464
Subject(s) - materials science , nickel titanium , shape memory alloy , deformation (meteorology) , dislocation , wire drawing , composite material , texture (cosmology) , ultimate tensile strength , alloy , metallurgy , image (mathematics) , artificial intelligence , computer science
We examine the structure and properties of cold drawn Ti‐50.1 at % Ni and Ti‐50.9 at % Ni shape memory alloy wires. Wires with both compositions possess a strong <111> fiber texture in the wire drawing direction, a grain size on the order of micrometers, and a high dislocation density. The more Ni rich wires contain fine second phase precipitates, while the wires with lower Ni content are relatively free of precipitates. The wire stress–strain response depends strongly on composition through operant deformation mechanisms, and cannot be explained based solely on measured differences in the transformation temperatures. We provide fundamental connections between the material structure, deformation mechanisms, and resulting stress–strain responses. The results help clarify some inconsistencies and common misconceptions in the literature. Ramifications on materials selection and design for emerging biomedical applications of NiTi shape memory alloys are discussed. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005