Investigation of the role of Ti oxide layer in the size-dependent superelasticity of NiTi pillars: Modeling and simulation
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Author(s)
Qiao, Lei
Radovitzky, Raul A
Date Issued
July 2013
Journal
Acta Materialia
Publisher
Elsevier
Citation
Qiao, Lei and Radovitzky, Raul. “Investigation of the Role of Ti Oxide Layer in the Size-Dependent Superelasticity of NiTi Pillars: Modeling and Simulation.” Acta Materialia 61, no. 16 (September 2013): 6213–6221. © 2013 Acta Materialia Inc
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Author's final manuscript
Abstract
Recent compression tests of NiTi pillars of a wide range of diameters have shown significant size dependency in the strain recovered upon unloading. In this paper, we propose a numerical model supporting the previously proposed explanation that the external Ti oxide layer may be responsible for the loss of superelasticity in the small pillars. The shape memory alloy at the center of the pillar is described using a nonlocal superelastic model, whereas the Ti oxide layer is modeled as elastoplastic. Voigt average analysis and finite element calculations are compared to experiments for the available range of pillar sizes. The simulation results also suggest a size-dependent strain hardening due to the constraint on the phase transformation effected by the confining Ti oxide layer.
MIT Department
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
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Creative Commons Attribution-NonCommercial-NoDerivs License
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DOI of Published Version
https://doi.org/10.1016/j.actamat.2013.07.004
