研磨光整处理Ti-6Al-4V钛合金表面组织及疲劳性能

Research on Surface Tissue and Fatigue Properties of Ti-6Al-4V Titanium Alloy under Grinding and Finishing

通过金相显微镜等测试仪器测试Ti-6Al-4V钛合金表面组织及疲劳寿命性能,对比研磨光整处理前后Ti-6Al-4V钛合金拉伸断口形貌以及微观组织。研究结果表明:双面加工时试样硬度随外径增大而显著上升。没有研磨光整处理的Ti-6Al-4V钛合金疲劳裂纹产生于表面区域,而经过研磨光整处理后的钛合金裂纹源转移到次表层中,裂纹源的周边组织中便不再存在类解理断裂形貌,形成的疲劳带宽度也更小。研磨处理前的钛合金具有较大的晶粒尺寸,经过研磨处理后钛合金表层的等轴晶粒被彻底击碎,转变为众多小晶粒。

The surface structure and fatigue life of Ti-6Al-4V titanium alloy are tested by the metallographic microscope and other test instruments, and the tensile fracture morphology and microstructure of Ti-6Al-4V titanium alloy before and after polishing are compared. The results show that the hardness increases with the outer diameter increasing. The fatigue crack of Ti-6Al-4V titanium alloy with out polishing treatment is produced in the surface area. When the titanium alloy crack source is transferred to the subsurface after the polishing process, there is no longer the cleavage fracture morphology in the surrounding tissues of the crack source, and the fatigue band width is also smaller. Before grinding, the titanium alloy has a large grain size. After grinding, its surface is completely crushed and transformed into many small grains.