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Thermomechanical behavior of pseudoelastic NiTi shape memory alloys
Author(s) -
Luig Patrick,
Grabe Christian,
Bruhns Otto
Publication year - 2007
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.200700908
Subject(s) - shape memory alloy , pseudoelasticity , nickel titanium , materials science , martensite , hysteresis , crystallite , plateau (mathematics) , phase diagram , stress (linguistics) , thermodynamics , phase (matter) , metallurgy , condensed matter physics , mathematics , mathematical analysis , physics , microstructure , linguistics , philosophy , quantum mechanics
The thermomechanical behavior of polycrystalline Ni‐rich pseudoelastic NiTi shape memory alloys is analyzed. Special focus is on regions within the stress strain diagram which are regarded as linear elastic in common phenomenological material models, i.e. the region between zero stress and the beginning of the pseudoelastic plateau as well as the region within the hysteresis. In both cases, severe temperature changes can be observed. A possible explanation for this effect is twofold: On the one hand, it might be explained by the presence of an R‐phase transformation. On the other hand, unstructured martensite of the B19' phase may form. However, the assumption of a purely thermo‐elastic material behavior in those regions does not seem to hold true in general. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)