Microstructure and mechanical properties of an Fe-20Mn-11Al-1.8C-5Cr alloy prepared by powder metallurgy

In the present work, the combination of mechanical alloying (MA) and spark plasma sintering (SPS) has been utilized to improve the hardness and strength of the Fe-20Mn-11Al-1.8C-5Cr quinary alloy displaying good corrosion resistance. The mechanically alloyed powders consisted of a primary body-center cubic (BCC) phase and a small amount of face-center cubic (FCC) phase, however, the sintered alloy was composed of γ matrix, k-carbide ((Fe, Mn)3AlCx) and Cr7C3 carbide. In addition, nanoscale twins presented in some γ grains after SPS. Vickers hardness of the sintered Fe-20Mn-11Al-1.8C-5Cr quinary alloy with ultra-fine grains (UFGs) is 705 HV, which is markedly higher than that of the as-cast Fe-20Mn-11Al-1.8C-5Cr counterparts. The compressive yield strength of the sintered samples at room temperature (RT) and at 873 K are 2339 MPa and 980 MPa, respectively, which are both significantly higher than those of their as-cast counterparts, suggesting that the ultra-fine grained Fe-20Mn-11Al-1.8C-5Cr alloy can be potentially used in corrosion-wear conditions at elevated temperatures.