Effects of microstructures on mechanical properties of Ti-63 titanium alloy

The microstructure and mechanical properties of Ti-63 pancakes were investigated under different heat-treatment modes. Pancake No. 1, with an as-forged bimodal structure, was β annealed at 930°C for 1 h. Its structure was changed to a Widmanstatten structure with continuous grain boundary α phase and long lamellar α phase. The pancake showed a good combination of strength, ductility and fracture toughness. Pancake No. 2, with an as-forged bimodal structure, was aged at 540°C for 8 h after annealing at 930°C for 1 h. Other than the fine secondary α precipitates, it showed a similar microstructure to that of pancake No. 1. The fine precipitates can enhance the pancake’s strength while reducing the ductility and fracture toughness. Pancake No. 3, with an as-forged basket-weave structure, was annealed at 750°C for 1 h. Its structure was nearly unchanged and it achieved a better ductility but a slightly lower fracture toughness than pancake No. 1.