Analysis of the relationship between retained austenite locations and the deformation behavior of quenching and partitioning treated steels

We studied the relationship between locations of retained austenite (RA) and the deformation behaviors of quenching and partitioning treated steels. By using a variety of quantitative characterization techniques and comparing ferrite and martensite dual-phase counterparts, we confirmed that the stability of RA within different matrix phases is largely dependent on the plastic incompatibility between ferrite and martensite phases. If there exists significant difference in strength between ferrite and martensite, the transformation of RA is discontinuous. The RA inside ferrite and martensite transforms under low and high strain, respectively. As a result, deformation behaviors of the matrix phases, especially the ferrite phase at low strain, can be substantially affected by the change of RA. Our analysis offers insight into the interactions among different phases, the stability of RA, and the strain hardening behavior of multi-phase steels.