Crystal Plasticity Based Transformation Induced Plasticity Formulation for Predictions of Forming Limit Diagrams

Abstract

Significant effort has been invested into the development and research of Advanced High Strength Steel. In particular, transformation induced plasticity (TRIP) steel has shown promise as a candidate for lightweighting of vehicles because of their enhanced formability. However, predictive modeling of TRIP steel in formability is difficult due the combination of dislocation and transformation mechanisms occurring during deformation for various strain paths. This work presents a crystal plasticity constitutive model to simulate the behaviour of deformation induced γ → α’ transformation. A physics based transformation model is implemented into the crystal plasticity framework to fully capture the behavior of TRIP assisted steels. Simulations are calibrated and compared to experimental measurements of Duplex Stainless Steel. The calibrated model is then used to predict the forming limit diagram using the Marciniak-Kuczynski approach. The results highlight the importance of a physics based used in simulation to fully utilize TRIP assisted steels.