两相区热处理对TC4-DT钛合金断裂韧性的影响

Effect of morphology and quantity of the primary α phase in TC4-DT titanium alloy on fracture toughness was discussed. Different α phase contents were obtained by heat treatment below phase transition point. The results show that contents of primary α phase drop with solution temperature increasing, and the size of grains changes little. The content of secondary α phase increases, and length-width radio increases with solution temperature increasing, which increases the fracture toughness. Compared with the alloy under air cooling, the alloy under furnace cooling exhibits larger primary α phase, thicker lamellar α, and much higher fracture toughness. Then the growth mechanism was analyzed through fracture.