The Effect of Intercritical Deformation on Microstructure Development in Thermomechanically-Processed Low-Silicon TRIP-Assisted Steels

摘要

The effects of intercritical deformation on development of microstructure in low-silicon contents multiphase TRIP-assisted steels were investigated by laboratory simulation of controlled-thermomechanical processing in an automated hot compression testing machine. A typical multiple cooling stages TMP program was applied and samples were deformed in intercritical region to different strains. Microstructures of samples were characterized by optical and scanning electron microscopy, XRD and Mossbauer. The result indicated that intercritical straining increases volume fraction of polygonal ferrite and granular-type retained austenite particles, but reduces fraction of bainite. The increase in retained austenite volume fraction is attributed to strain-assisted diffusion of carbon and to refinement of retained austenite particles.