Role of second phase cementite and martensite particles on strength and strain hardening in a plain C-Mn steel

This work investigated the role of second phase cementite and martensite particles on the strength and the strain-hardening rate in a plain C-Mn steel. The change in microstructure (including the change of the ferrite grain size and the change in the second phase particles from cementite to martensite) contributed to the change in the athermal component of the yield and the tensile strengths but caused little change in the thermal component. Second phase cementite and martensite particles improved the strain-hardening rate. The microstructure consisting of ferrite grains and martensite particles had a high potential for improving uniform elongation due to a high strain hardening rate which restrains the occurrence of necking.

► The change in microstructure contributed to the change in the athermal component of the strengths.
► Second phase cementite and martensite particles improved the strain-hardening rate.
► The microstructure consisting of ferrite grains and martensite particles had a high potential for ductility.