Prediction of Retained Austenite Fraction in Quenching-and-Partitioning (Q&P) Steels Using the Gibbs Energy Balance Approach

Prediction of retained austenite fraction is quite important in designing advanced high strength steels since retained austenite is the source of transformation-induced plasticity. The present study investigates the phase constitution of a medium-carbon Q&P steel by comparing various approaches to the transformation stasis of bainitic ferrite and applying them to the partitioning process. Among them, the modified GEB approach gave the best agreement with the experimental observation, including the effects of heat-treatment condition and chemical composition on phase constitution. This indicates phase transformation during partitioning can be effectively described by the physics of Gibbs energy balance approach.