Physically-based constitutive modeling of NiTi intermetallic compound during hot deformation

Abstract

The hot compression behaviour of a binary nitinol alloy was studied at the temperature range of 700–1000°C under strain rate of 0.1 s− 1. First, the constitutive descriptions of flow stress versus the Zener-Hollomon parameter were used to determine the hot working constants of the investigated material. Subsequently, it was shown that the theoretical exponent of 5 and the self-diffusion activation energy as the hot deformation activation energy can be used in the classical hyperbolic sine equation to describe the peak flow stress, which is in accordance to the deformation mechanism controlled by glide and climb of dislocations. This resulted in a simple and more reliable constitutive equation from the physical and metallurgical standpoints.