Properties of Fe–Mn–Al alloys with different Mn contents using density functional theory

The chemical stability, electronic structures, mechanical properties and Debye temperature of Fe–Mn–Al alloys were investigated using first-principles calculations. The formation enthalpy and cohesive energy are negative for Fe–Mn–Al alloys, showing that they are thermodynamically stable. FeAl has the lowest formation enthalpy, indicating that FeAl is the most stable alloy in the Fe–Mn–Al system. The partial density of states, total density of states and electron density distribution maps were used to analyze the physical properties of the Fe–Mn–Al alloys. A combination of mainly covalent and metallic bonds exists in these Fe–Mn–Al alloys, resulting in good electronic conductivity, high melting points, and high hardness. These alloys display disparate anisotropy due to the calculated different shapes of the 3D curved surface of the Young’s modulus and anisotropic index. FeAl has the highest bulk modulus, shear modulus and Yong’s modulus of 187.1, 119.8 and 296.2 GPa, respectively. Further, the Debye temperatures and sound velocity of these Fe–Mn–Al compounds were explored.