关键词: TC6钛合金, 固溶处理, 冷却速率, 显微组织, 力学性能

Abstract: Effects of solution treatment temperature (880, 920, 960 ℃) and cooling method (slow cooling with asbestos coating, air cooling, oil cooling, water cooling) on the microstructure and mechanical properties of TC6 titanium alloy were studied. The results show that when the cooling method is air cooling (880-960 ℃×2 h, air cooling+550 ℃×4 h, air cooling), with the increase of solution treatment temperature, the content of primary α phase decreases, the content of secondary α phase increases with the increase of lamellar thickness, the content of β transformed phase increases significantly, and the strength of the TC6 titanium alloy shows a downward trend, while the impact absorbed energy increases. When the solution treatment temperature is 880 ℃(880 ℃×2 h, slow cooling with asbestos coating/air cooling/oil cooling/water cooling+550 ℃×4 h, air cooling), with the increase of cooling rate, both the size and content of primary α phase decrease, the content of secondary α phase reduces and the lamellar thickness decreases, while the content of acicular α phase increases, and the strength of the TC6 titanium alloy increases significantly, while the impact absorbed energy decreases. After solution treatment at 880 ℃ and water cooling, the alloy has the highest strength, which can reach 1280 MPa, and the impact absorbed energy is only 17.9 J. The decrease in strength is mainly due to the weakening of the strengthening effect of acicular α phase. The improvement of impact absorbed energy is related to the hindering effect of secondary α phase on crack propagation and the improvement of plastic deformation resistance of primary α phase. After heat treatment at 920 ℃ for 2 h followed by air cooling, and 550 ℃ for 4 h followed by air cooling, the TC6 titanium alloy has excellent comprehensive properties.

Key words: TC6 titanium alloy, solution treatment, cooling rate, microstructure, mechanical properties