退火温度对TC4钛合金动态断裂韧性的影响

Effects of Annealing Temperature on Dynamic Fracture Toughness for TC4 Titanium Alloy

采用示波冲击法,对750℃、相变点以下(20～60)℃、相变点以上10℃等7种不同热处理状态TC4钛合金的动态断裂韧性进行了测试,结合金相组织观察及扫描电镜断口形貌观察,分析了初生α相含量及次生α相形貌对TC4钛合金动态断裂韧性的影响。结果表明,对于初生α+β转变组织的TC4合金,初生α相含量在47%～50%范围,次生α相片层呈短棒状,具备上述特征的合金在本研究涉及的加载速率范围内具有较好的动态断裂性能。

The dynamic fracture toughness of TC4 titanium alloy in 7 heat-treatment conditions,such as 750 ℃,（20-60） oC lower than or 10 ℃ higher than the phase transformation temperature,was tested by means of instrumented impact method.Combined with both metallography and fractographs,the influence of volume of primary α phase and ratio of length/width for secondary α phase was studied.Results show that the volume of primary α phase in 47%-50% with short rod-like secondary α phase leads to relatively good dynamic fracture toughness for TC4 titanium alloy with（primary α＋βTrans） microstructure under the dynamic loading condition.