Experimentally validated constitutive model for NiTi-based shape memory alloys featuring intermediate R-phase transformation: A case study of Ni48Ti49Fe3

An important group of NiTi-based alloys employed in applications exhibits an intermediate R-phase transformation, which substantially modifies the material's thermomechanical response. Finite element analysis of products from such alloys requires a constitutive model covering the two-stage transformation sequence in its full thermodynamic nature. We propose an enhanced constitutive model for NiTi-based alloys, which incorporates R-phase as a distinctive phase with loading-dependent transformation strain. We validate the model on a newly acquired extensive experi-mental dataset on the thermomechanical response of Ni48Ti49Fe3 shape memory alloy and illustrate the capabilities of its implementation into finite element software on a computational structural analysis of a tightening ring. (C) 2021 The Authors. Published by Elsevier Ltd.

Automated summary

The study presents an enhanced constitutive model for NiTi-based alloys incorporating an intermediate R-phase transformation with loading-dependent transformation strain. Validated on experimental data, the model demonstrates capabilities for computational structural analysis in finite element software applications.