Nonlocal Superelastic Model of Size-Dependent Hardening and Dissipation in Single Crystal Cu-Al-Ni Shape Memory Alloys

TitleNonlocal Superelastic Model of Size-Dependent Hardening and Dissipation in Single Crystal Cu-Al-Ni Shape Memory Alloys
Publication TypeJournal Article
Year of Publication2011
AuthorsQiao, L, Rimoli, JJ, Chen, Y, Schuh, CA, Radovitzky, R
JournalPhysical Review Letters
Volume106
Issue8
Date Published2011/02/24/
Abstract

We propose a nonlocal continuum model to describe the size-dependent superelastic effect observed in recent experiments of single crystal Cu-Al-Ni shape memory alloys. The model introduces two length scales, one in the free energy and one in the dissipation, which account for the size-dependent hardening and dissipation in the loading and unloading response of micro-and nanopillars subject to compression tests. The information provided by the model suggests that the size dependence observed in the dissipation is likely to be associated with a nonuniform evolution of the distribution of the austenitic and martensitic phases during the loading cycle.