Effect of Nb content on the stacking fault energy, microstructure and mechanical properties of Fe-25Mn-9Al-8Ni-1C alloy

Abstract

In this study, Fe-25Mn-9Al-8Ni-1C-xNb alloys (x = 0, 0.1%, 0.2%, 0.3%, and 0.4%) were prepared by vacuum arc melting, and the effects of Nb content on the stacking fault energy, microstructure, hardness and room temperature tensile properties of the alloys were systematically studied. It is deduced from the literature on the estimation of stacking fault energy that the stacking fault energy of the Fe-25Mn-9Al-8Ni-1 C-xNb alloys increases the increase of Nb content. Within this range of stacking fault energies, twinning-induced plastic deformation is dominant. Microstructure analysis shows that main phases of the series alloys are austenite, ferrite, k-carbide, NiAl intermetallic compound and NbC phase. As the Nb content increases, the NbC quantity gradually increases. With increasing Nb content, the hardness and elongation of the material gradually increase, while the tensile strength first increases and then decreases. When the Nb content is 0.3%, the alloy has enhanced comprehensive properties, and the average tensile strength is about 853 MPa, and its average elongation is about 30%, which about 8 times higher than that of Fe-25Mn-9Al-8Ni-1C alloy.