Modeling of bainitic phase transformation

In this work, we present a macroscopic material model for simulation of austenite to bainite and of austenite to martensite transformations accompanied by transformation-induced plasticity (TRIP), which is an important phenomenon in metal forming processes. In order to account for the incubation time the model considers nucleation of the bainite phase. When this quantity attains a barrier term, growth of bainite volume fraction is started. The model formulation allows for individual evolutions of upper and lower bainite. Furthermore, the numerical implementation of the constitutive equations into a finite element program is described. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)