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

Abstract

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, α-Ti, and β-Ti are calculated by first principles. The results show that there are four phases of Ti₃Sn, Ti₂Sn, α-Ti, and β-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 α-Ti and Ti₃Sn, and β-Ti has the lowest. The hardness calculation results show that Ti₂Sn has the highest hardness (837.75 HV), α-Ti (561.22 HV), and Ti₃Sn (290.81 HV), and β-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.