Mechanical and electronic properties of Ti-7333 alloy under tension: First-principles calculations

The first-principles calculations are used to investigate the effects on mechanical and electronic properties of Ti-7333 alloy under the tension stress along [001], [100] and [110] directions. First, we study the structure and elastic properties of Ti-7333 alloy with 2, 16, 54 and 128 atoms, finding that the structural parameters of four models are comparative due to the approximate value of c/a and the elastic properties are also similar. Hence, we choose Ti-7333 alloy with 16 atoms to study the effects on mechanical and electronic properties under tension stress along [001], [100] and [110] directions. The changes of independent elastic constants, Debye temperature and anisotropic behavior under different tension stress along all the three directions can reflect that the tensile strength of Ti-7333 alloy may exist between -1 and -1.2 GPa and also find that it is easier to change the resistance to deformation of Ti-7333 alloy under the tension stress along [100] direction compared with [001] and [110] directions. What's more, the calculated mechanical parameters show that the Ti-7333 alloy is brittle and the tendency of variations is small with the increase in tension stress. The effects on electronic properties including metallic and covalent properties are not obvious due to the approximate height of TDOS, pseudogap and charge density.