Effect of relative density on microstructure and mechanical properties of Fe-12Mn-0.2C alloy fabricated by powder metallurgy

The microstructure features and compressive strength of sintered Fe-12 wt.% Mn-0.2 wt.% C alloy steel have been investigated by considering the effect of relative density. Both the relative density and the strength increased linearly irrespective of the initial relative density during the room-temperature compressive test. The formation of the strain-induced martensite during deformation affected additional work hardening and brought about a higher actual compressive stress. The strain-induced martensite transformation from austenite was observed by means of optical micrograph and was distinguished by EDS line scan analysis with hardness measurement. The volume fraction of austenite during deformation was significantly decreased depending on the initial relative density of sintered sample. The rate of the strain-induced martensite transformation kinetics was accelerated and resulted in the relatively high work hardening when the initial relative density was higher.