Insight into the influence of X (X = Cu, Mg and Zn) alloying on the mechanical and electronic properties of orthorhombic Ti 3 Sn compound by first-principles investigation

The mechanical properties and electronic structures of X (X = Cu, Mg and Zn) alloyed orthorhombic Ti3Sn compounds have been carried out by using first-principles calculations. It is revealed from formation energy that the all X-alloyed compounds are thermodynamically stable. According to the results of site occupancy energy, the X atom prefers to occupy the Ti 8g site of orthorhombic Ti3Sn compound. The calculated single crystal elastic constants showed that Ti47Sn16Cu8gTi and Ti47Sn16Zn8gTi possess the largest resistance to shear deformation in (100) crystal plane and the most compressible compound along c-axis, respectively. It is found that the mechanical properties of Cu-alloyed orthorhombic Ti3Sn compound are stronger than that of Mg- and Zn-alloyed. It can be revealed from electronic structures that the Ti-Sn, Ti-Cu and Cu-Sn covalent bonds in Ti47Sn16Cu8gTi are attributed to the hybridization of Cu-3d, Ti-3d and Sn-5p orbitals, while some ionic bonds and antibonding states are existed in Ti47Sn16Mg8gTi and Ti47Sn16Zn8gTi .