Constitutive description of shape memory alloys with phase transformation microstructure evolution

Based on the experimental results and the finite element analysis, and taking into account laminar microstructure, the thickness of martenite phase and the interaction between the two phases, the incremental form of the constitutive model is proposed for two-phase shape memory alloys using the modified strain method. The pseudoelastisity of NiTi shape memory alloy microtube subjected to pure tension or pure torsion are analyzed and compared with the experimental results. It can be seen that the pseudoelastic behavior, especially the phenomena of a stress drop during tension processes can be well described with the proposed model.