两相区热处理对钛合金断裂韧性的影响

Effect of Heat Treatment in α+β zone on Fracture Toughness of Titanium Alloy

摘要:

主要讨论了TC4-DT钛合金中初生α相的形态和数量对合金断裂韧性的影响。试验通过相变点以下不同温度的热处理获得不同α相的微观组织,分析α相的形态和数量对合金断裂韧性的影响规律。结果表明：两相区不同温度热处理,随着固溶温度升高,初生α相含量降低,晶粒尺寸变化不大,次生α相含量增加,长宽比增加,断裂韧性增加。相变点以下炉冷处理,显微组织比同条件处理的空冷组织的初生α相晶粒尺寸增大,片层α相厚度增加,合金的断裂韧性明显提高,并通过裂纹扩展端口进行了机理分析。

Abstract:

Effect of Morphology and quantity for the primary α phase for TC4-DT titanium alloy on fracture toughness is discussed in this paper. Different α phase contents were obtained by heat treated below phase transition point. The result shows that contents of primary α phase drop with solution temperature increasing, and the size of grains change little. The content of secondary alpha phase increases, and length-width radio increases with solution temperature increasing, which leads to fracture toughness to increase. Sizes of primary α phase increase under furnace cooling than under air cooling, the thickness of lamellar α increase, fracture toughness of the alloy increases obviously, and the growth mechanism is analyzed through fracture.