1. Baoji Titanium Industry Co Ltd, Baoji 721014, China.
2. School of Materials Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China；
With the deepening of human exploration of the ocean, the erosion and corrosion of submarines by seawater are becoming increasingly significant, which puts forward more stringent requirements for the impact resistance of titanium alloy materials long-tern serving in harsh marine environments. In this paper, the effect of solution temperature on the impact toughness of TA31 alloy sheet is studied. The results show that when the solution temperature (870 ℃) is lower than the β transition temperature, the microstructure of the alloy is mainly composed of ellipticity primary α phase and β-transition structure. With the increase of solution temperature (970 ℃), the number of primary α phase decreases gradually, while the proportion of β-transformed structure increases correspondingly, and a small amount of lamellar α phase is observed in the β-transformed structure. When the solution temperature (1020 ℃) is further increased to higher than the β transition temperature, a large number of lamellar α phases is formed on the β matrix. These lamellar α phases are interlaced and arranged, forming a typical basket-weave microstructure. After solution treatment at 870 ℃ for 1 h, the impact specimen (V-notch) has the best impact performance, and the impact absorption energy reaches 108.81 J, among which the crack propagation energy is the main part. Specifically, the work of crack initiation is 18.97 J, and the work of crack propagation is 89.84 J. The solution temperature has a significant effect on the microstructure and impact properties of TA31 alloy. Specifically, with the increase of solution temperature, the impact toughness of TA31 alloy shows a significant downward trend.