The effect of stress state and precipitation on stress-induced martensitic transformations in polycrystalline and single crystal shape memory alloys: Experiments and micro-mechanical modeling

The purpose of the present work is to answer several critical questions related to the mechanical behavior of shape memory alloys: (1) Why do polycrystalline NiTi and CuZnAl shape memory alloys sometimes demonstrate tension/compression asymmetry? (2) Why do peak aged NiTi single crystals demonstrate a decrease in the orientation dependence of critical transformation stress levels, ;To properly understand stress-induced transformations in aged NiTi single crystals, a micro-mechanical model is used to quantify the stress fields outside perfectly coherent Ti...