Thermomechanical model for NiTi-based shape memory alloys including R-phase and material anisotropy under multi-axial loadings
Abstract
This work presents a thermomechanical model for polycrystalline NiTi-based shape memory alloys developed within the framework of continuum thermodynamics of irreversible processes. The model is capable of realistic simulations of several physical phenomena, involving transformation between austenite.
R-phase and martensite and martensite reorientation, which may simultaneously occur under general thermomechanical loading. This is due to three key features of the model: a novel form of the dissipation function coupling martensite transformation and reorientation processes, inclusion of the material responses associated with the transformation between austenite and R-phase and implementation of the influence of material anisotropy.
Based on a mathematically consistent formulation, the model was implemented into finite elements providing a numerical tool particularly useful for analysis of NiTi-based highly-textured components, which are of great industrial importance. To explore and demonstrate further features of the proposed model several numerical simulations were performed and compared with experimental results. (C) 2012 Elsevier Ltd.
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