准β锻造和β热处理对TC11组织和断裂韧性的影响

Effects of Quasi-beta Forging and β Heat Treatment on Microstructure and Fracture Toughness of TC11 Titanium Alloy

研究了准β锻造和β热处理对TC11钛合金显微组织和断裂韧性的影响。结果表明TC11钛合金经准β锻造及β热处理后断裂韧性相较于魏氏组织明显提升,延伸率提升约50%,断面收缩率提升约20%,KIC提升约20%。由于准β锻造改变了层片状α相的析出形态,形成了取向差异化明显的束集,抵抗裂纹扩展的组织协调性更佳,从而使得断裂韧性更优;而魏氏组织试样主要以晶界和大片次生α相增加裂纹扩展曲折性。

Effects of quasi-beta forging and β heat treatment for TC11 titanium alloy on microstructure and fracture toughness were investigated.The results showed that the fracture toughness of TC11 titanium alloy after quasi-beta forging and β heat treatment significantly improved compared to Widmanstatten microstructure.Elongation rate increased by about 50%,section shrinkage increased by about 20%,and the fracture toughness significantly increases by about 20%.The reason was that quasi-beta forging had changed the precipitation morphology of lamellar a-phase and contributed to the misorientation of colony,the coordination of the microstructure to resist the expansion of the cracks was better,which increased the fracture toughness.While the Widmanstatten microstructure mainly increased the crack-extension tortuosity with grain boundaries and large secondaryα-phases.