Microstructure of ultra-fine-grained high carbon steel prepared by equal channel angular pressing

► A fully pearlitic Fe-0.8C steel was severely deformed by ECAP at 923 K via route Bc. ► After one pass, the cementite lamellae is bended, kinked, and fractured. ► After four passes, ultrafine microduplex structure (ferrite + cementite) was formed. ► Dynamic recrystallization of ferrite and spheroidization of cementite occur. ► AFM results show microstructure changes from planar lamellae to 3D equiaxed grains.