A novel process to obtain ultrafine-grained low carbon steel with bimodal grain size distribution for potentially improving ductility

A novel process to obtain ultrafine-grained low carbon steel with bimodal grain size distribution was developed for potentially improving the ductility of ultrafine-grained steels. In this process, a low carbon steel with dual-phase starting microstructure composed of martensite and ferrite obtained by predeformation intercritical quenching was compressively deformed at room temperature and annealed at moderate temperatures. Results show that the ultrafine-grained ferrite with bimodal grain size distribution and dispersive nanoscale carbide particles was achieved.