A thermodynamic framework of modeling twinning-induced plasticity in advanced high strength steels

Abstract

Advanced materials are considered as the driving potential for all other technologies in Fourth Industrial Revolution (4IR) since their advancements are primarily dependent on the availability of functionally graded and efficient materials. More specifically, the production of geometrically intricate and desirable properties products or systems becomes reality through the development of advanced metallic materials. Twinning induced plasticity steels are considered the prominent members of the third-generation advanced high strength steels. The enhanced properties of these are due to chemical composition, volume fraction of phases, complex microstructure, and mechanical twinning. In the present work, twinning induced plasticity austenite-based steels is modeled for estimating the deformation behavior of advanced high strength steel by adopting crystal plasticity and thermodynamic frameworks. Initially, mechanical twinning is incorporated in slip-based plasticity model. The kinematic-based modeling of these phenomena is performed through elastic, plastic, and transformation deformation gradients. Secondly, a thermodynamic framework is developed for estimating the dissipated and Helmholtz free energies and driving potential of slip and twinning mechanisms. A numerical integration scheme is formed and implemented in ABAQUS as a user-defined subroutine. The 3D finite element models are established for predicting the elastic-plastic and twinning behaviors of single and polycrystal austenite. It is found that the simulation results are in good agreement with the published experimental observations. Furthermore, a prominent variation in stress magnitude, more specifically in polycrystal austenite, is observed once twinning mode is incorporated in slip mechanism. This refers to a substantial advantage, in view of strength and formability, of mechanical twinning.