A New Austenitic FeMnAlCrC Alloy with High-Strength, High-Ductility, and Moderate Corrosion Resistance

Abstract

In this study, a new austenitic Fe-28%Mn-9%Al-6%Cr-1.8%C (in mass%) alloy is developed. Because the alloy contains a high density of fine (Fe,Mn)₃AlC carbides within the austenite matrix, the alloy in the as-quenched condition exhibits an excellent combination of strength and ductility comparable to that of the aged FeMnAlC alloys. In addition, owing to the formation of a layer of Cr and Al oxides in the passive film formed on the alloys, the corrosion potential E_corr (−538 mV) and the pitting potential E_pp (−25 mV) of the present alloy in 3.5% NaCl solution are considerably higher than the E_corr (−920∼−789 mV) and E_pp (−500∼−240 mV) values of the as-quenched and aged FeMnAlC alloys. Whereas the tensile strength of the present alloy is almost the same as that of conventional AISI 410 martensitic stainless steel, the present alloy possesses superior ductility than AISI 410 martensitic stainless steel. Furthermore, in 3.5% NaCl solution, the E_pp (−25 mV) of the present alloy is noticeably higher than that (−250∼−100 mV) of the conventional AISI 410 martensitic stainless steel. These results indicate that the present alloy in the as-quenched condition can possess high-strength and high-ductility as well as moderate corrosion resistance.