Prediction and experimental verification of phase transformation plasticity

Abstract

A finite element model was established to predict phase transformation plasticity (TP). Based on the simulated results, the factors that influence TP were revealed. A formula for predicting the TP coefficient K was proposed based on the identified influence factors, and the coefficients of the formula were determined by fitting with the experimental data from the published literature. The accuracy of the proposed formula was verified by measuring the TP coefficients of ferrite/pearlite, bainitic, and martensitic transformations of 42CrMo using Gleeble-3500. The predicted TP coefficient K values using the proposed formula were found to be closer to the experimental results compared to the formulas proposed by Leblond, Desalos, and Abrassart, particularly for the ferrite/pearlite transformation. Additionally, the normalized function f(φ) which depicts the evolution of TP with the transformed fraction φ during phase transformation, was discussed based on the finite element simulation. The predicted function f(φ) was verified with experimental results conducted by Liu. The simulation results demonstrated that the expression of f(φ) is influenced by the yield stress of the parent and product phases, which explains the existence of several expressions for f(φ) in the literature.