Enhancement of the tensile strength by introducing alloy element Fe for Ti based alloy

The stability and the mechanical properties of beta type Ti1-xFex binary alloys were systematically studied by means of first-principles calculations based on the density functional theory. Our results have demonstrated that the Ti1-xFex alloys in our consideration are stabilized as beta phase and the formation energy decrease with the increase of alloy element Fe content. It is found that the mechanical parameters, such as Young's modulus E, shear modulus G and bulk modulus B almost linearly increase when the concentration of alloy element Fe increase for x ranging from 0.0625 to 0.5. Differently, the Poisson's ratio nu is decreased monotonously with the increase of Fe content. According to the stretching model, we have shown that the tensile strength of the Ti1-xFex alloys is significantly enhanced when we increase the concentration of the alloy element of Fe. The enhancement of the tensile strength is mainly contributed from the improvement of bond strength between Ti-Fe induced by the concentration of Fe according to analysis of the charge density and electron localization function. Our results indicate an effective way to improve the tensile strength as well as the toughness of Ti-based alloy for the application in aerospace industry and marine engineering.