A Simplified Model of the Strain-Induced Phase Transformation in Austenitic Stainless Steels for Low Temperature Applications

Austenitic stainless steels are commonly used in low temperature applications because of their mechanical properties specially preserving the ductility. The strain-induced martensitic transformation greatly affects the plastic behavior of the metastable austenitic stainless steels. This paper provides a simple constitutive model for considering the strain-induced martensitic transformation of the metastable austenitic stainless steels at low temperature. A modified kinetics model is represented to consider the effect of TRIP in martensite evolution explicitly. In addition, a modified power law hardening for the continuously reforming material is represented to describe the great hardening effect of the phase transformation. Developing an incremental integration algorithm, the constitutive model was implemented in the Abaqus/Standard via a user-defiened material subroutine (UMAT). The results showed that the rate of martensite evolution with plastic strain in the modified model is accelerated which significantly affects the plastic behavior. In addition, the hardening behavior could be well described with the modified power law. Numerical examples show the capability of the constituative model in simulating the strain-induced transformation at low temperatures.