TC11钛合金表面保护性摩擦氧化层的形成及作用

Formation and function of protective tribo-oxide layers on TC11 titanium alloy surface

采用MPX-2000型销盘式磨损试验机,在2.68 m/s和4 m/s滑动速率下对TC11钛合金进行干滑动磨损实验以及特殊设计的双滑动磨损实验。通过X射线衍射仪、扫描电镜和能谱仪对磨损表面及摩擦层的物相、成分和形貌进行详细分析。采用数字显微硬度仪测试摩擦层至钛合金基体的显微硬度分布。结果表明:不同滑动速率下TC11钛合金磨损表面均能形成一层摩擦层。摩擦层的物相、状态和性能随滑动条件改变而发生变化。摩擦层可以分为无氧化物摩擦层和摩擦氧化层。通过4 m/s和2.68 m/s双滑动磨损实验直接验证了TC11钛合金干滑动磨损过程中形成的摩擦氧化层具有良好的减磨效果。TC11钛合金在2.68 m/s速率下的磨损机理为剥层磨损;在4 m/s以及4 m/s和2.68 m/s双滑动时的磨损机理均为氧化磨损。

Dry sliding wear tests and specially designed double sliding wear tests of TC11 titanium alloys were carried out at sliding velocities of 2.68 m/s and 4 m/s by using a MPX-2000 type pin-on-disc wear tester.The phase,composition and morphology of worn surfaces and tribo-layers were analyzed in detail by X-ray diffractometer,scanning electron microscope and energy dispersive spectrometer.The microhardness distribution from tribo-layers to the matrix was measured by using a digital microhardness tester.The results show that tribo-layers are always found to be formed on the worn surface of TC11 titanium alloy at different sliding rates.The phase,state and property of the tribo-layer vary with the sliding conditions.Tribo-layers can be divided into tribo-oxide layer and no-oxide tribo-layer.Through 4 m/s&2.68 m/s double sliding wear test,the tribo-oxide layer formed in the dry sliding wear process of TC11 titanium alloy is proved to possess good wear-reducing effect.The wear mechanism of TC11 titanium alloy is delamination wear at 2.68 m/s,and oxidative wear at 4 m/s and 4 m/s&2.68 m/s.