热轧TC4钛合金力学性能各向异性及影响因素分析

Anisotropy of Mechanical Properties and Influencing Factors of Hot Rolling TC4 Titanium Alloy

摘要:

采用静、动态力学性能测试、XRD织构测试、金相及电子显微镜等分析方法，对热轧钛合金力学性能的各向异性及其影响因素进行了研究。结果表明，在准静态和动态加载条件下，930 ℃热轧TC4钛合金均具有显著的力学性能各向异性，表现为沿轧向加载材料具有最高的塑性，沿横向加载具有最高的静、动态屈服强度，沿法向加载时材料的塑性和强度介于轧向和横向之间。微观分析表明，经热轧变形后，TC4钛合金中形成了强度较弱的{0002}〈〉面织构；原始晶粒沿轧向被拉长而形成纤维组织；具有板状特征的片层集束，其面积最大面趋向于平行T面分布。TEM分析表明，热轧后TC4钛合金晶粒内形成了大量平行于横向的位错。以上4点原因共同引起了热轧TC4钛合金静、动态力学性能的各向异性

Abstract:

Anisotropy of mechanical properties and influencing factors of hot rolling TC4 alloy were studied through quasi-static tests, dynamic compression tests, XRD, metallographic study, and electron microscopy analysis. Results indicate that the quasi-static and dynamic compression properties of 930 oC hot rolling TC4 titanium alloy exhibit obvious anisotropy: the rolling direction shows the best ductility and lowest yielding strength, while the transverse direction shows the highest yielding strength and worse ductility. The ductility and strength of the normal direction are both between the rolling direction and the transverse direction. Microstructure analysis results show that there are four factors which are responsible for the anisotropy of the mechanical properties. Firstly, after the hot rolling process, a weak plane texture was formed; secondly, the original grains were deformed into fibrous structure; thirdly the plate-like α clusters' normal axis tended to be parallel to the transverse direction of the rolling sheet; finally, a large amount of dislocations which are distributed in the grain were being parallel to the transverse direction according to the TEM results. The anisotropy of the mechanical properties is attributed to the above four factors