The Effect of Pressure on Phase Stability and Mechanical Properties of Ti-xSn Alloys

The reaction of Sn trace element with Ti will produce metal compounds and affect the mechanical properties of Ti-Sn alloy. Herein, Ti-xSn (x = 5, 10, 15, 20, 25 wt%) alloy is prepared by laser cladding technology. The phase composition is detected by X-ray diffraction. The effects of pressure on the mechanical properties and electronic structures of Ti3Sn, Ti2Sn compounds, alpha-Ti, and beta-Ti are calculated by first principles. The results show that there are four phases of Ti3Sn, Ti2Sn, alpha-Ti, and beta-Ti in the alloy. The calculation shows that Ti2Sn has the highest Young's modulus (154.97 GPa) and hardness (837.75 HV), followed by alpha-Ti and Ti3Sn, and beta-Ti has the lowest. The hardness calculation results show that Ti2Sn has the highest hardness (837.75 HV), alpha-Ti (561.22 HV), and Ti3Sn (290.81 HV), and beta-Ti has the lowest hardness (128.57 HV). The electron accumulation of each phase increases with the increase of pressure, and the covalent bond of Ti3Sn and Ti2Sn is strengthened. In particular, the presence of Ti2Sn significantly improves the hardness of the Ti-25Sn alloy. This research elucidates Ti-Sn compound phase stability and hardness, confirms the accuracy of the first principle, and provides valuable insights for the design of alloy compositions.