Superior strain-hardening by deformation-induced nano-HCP martensite in Fe–Mn–Si–C high-manganese steel

Abstract We propose that high strain-hardening in face-centered cubic (FCC) crystals containing interstitial atoms could be achieved through the formation of nanoscale hexagonal close-packed (HCP) martensite with severe lattice distortions. Our experimental results showed that carbon atoms could more effectively prevent the HCP martensite from thickening and result in the formation of nano-HCP martensite. This caused a higher strain-hardening rate in FeMnSiC steel with heavy carbon than in FeMnSiCrNi steel with trace carbon though the HCP martensite transformation kinetics was almost the same in these two steels.