Wang Xueli, Jia Penglai, Wang Taoqin, Li Fuguo, Wang Qiang
School of Materials Science and Engineering, North University of China, Taiyuan 030051, China.
State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China.
Materials (Basel). 2024 Dec 16;17(24):6145. doi: 10.3390/ma17246145.
In this paper, in order to investigate the harmonious relationship between the compression deformation behavior of metastable β titanium alloy and the microstructure evolution, the β solution-treated Ti-10V-2Fe-3Al (Ti-1023) alloy was compressed at room temperature and its deformation behavior was analyzed. Optical microscopy (OM) and field emission electron microscopy (FESEM) were used to study the microstructure evolution of alloys at different strain rates. The results show that the stress-induced martensite transformation (SIMT) is more easily activated by low strain rate compression deformation, which is conducive to improving its comprehensive mechanical properties. With the decrease in strain rate, the α″ martensite content increases significantly, the average grain size decreases substantially, and the Low Angle Grain Boundary (LAGB) volume fraction decreases correspondingly. In addition, after compression at different strain rates, the misorientation angle (MA) of the β matrix is mainly concentrated in the LAGBs. The change is small with the decrease in strain rate, but the α″ martensite orientation difference angle shows some peaks, which are ~60°, ~85°, and ~95°, respectively. Simultaneously, the strain rate has an important effect on the content and type of martensitic twins. Finally, the fracture morphology analysis shows that with the increase in strain rate, the fracture mode changes from ductile fracture to brittle fracture. The fracture surface presents a significantly elongated cavity along the direction of maximum shear stress.
在本文中，为了研究亚稳β钛合金的压缩变形行为与微观组织演变之间的协调关系，对经β固溶处理的Ti-10V-2Fe-3Al（Ti-1023）合金在室温下进行压缩，并分析其变形行为。利用光学显微镜（OM）和场发射电子显微镜（FESEM）研究了不同应变速率下合金的微观组织演变。结果表明，低应变速率压缩变形更容易激活应力诱发马氏体相变（SIMT），这有利于提高其综合力学性能。随着应变速率的降低，α″马氏体含量显著增加，平均晶粒尺寸大幅减小，低角度晶界（LAGB）体积分数相应降低。此外，在不同应变速率下压缩后，β基体的取向差（MA）主要集中在LAGB中。随着应变速率的降低，变化较小，但α″马氏体取向差角出现一些峰值，分别约为60°、85°和95°。同时，应变速率对马氏体孪晶的含量和类型有重要影响。最后，断口形貌分析表明，随着应变速率的增加，断裂模式从韧性断裂转变为脆性断裂。断口沿最大剪应力方向呈现出明显拉长的空洞。
