Mechanical Properties of α + κ Two-phase Lamellar Structure in Fe-Mn-Al-C Alloy

E2₁-Fe₃AlC carbide (κ) in the Fe-Al-C ternary system is known to have ductility at room temperature. It forms a lamellar structure similar to the pearlite with a ferrite (α) phase through a eutectoid-like reaction from an austenite (γ) phase and improved mechanical properties are expected by replacing cementite to κ phase. The mechanical properties of α + κ two-phase lamellar structure were investigated through micro-Vickers hardness measurements and compression tests at room temperature in order to compare with those of pearlite steels. A typical mean inter-lamellar spacing of Fe-8at %Mn-13at %Al-7 at%C alloy aged at 773 K for 100 h was 60 nm and its yield stress and micro-Vickers hardness were 1880MPa and 580 HV, respectively. Yield stress and micro-Vickers hardness of these specimens were higher than those of pearlite steels regardless of the mean inter-lamellar spacing. Those results seem to be rationalized by taking the solid solution hardening of ferrite phase into account.