Influence on the mechanical properties and electronic structures of Cu-alloyed Ti5Sn3 compounds from first-principles calculations

First -principles calculations within density functional theory are performed to evaluate the mechanical properties and electronic structures of Cu -alloyed Ti5Sn3 compounds. It was confirmed that the Cu atom prefers to occupy Ti6g site with the lowest site occupation energy. The mechanical properties show that the bulk modulus of Ti5Sn3 can be reduced after Cu alloying. In addition, both the Young's modulus and Poisson's ratio increase and then decrease as the increasing of Cu atoms. The density of states and electron density differences reveal that the replacement of Cu atoms generates new chemical bonds but weakens the p -d orbital hybridization between Ti and Sn atoms, leading to a first increase and then decrease in elastic modulus and hardness.