WS_(2)增强CoCrTi复合材料的制备及高温摩擦学性能

Preparation and high-temperature tribological properties of WS_(2) reinforced CoCrTi composites

采用热压烧结技术制备了CoCrTi-(2.5, 4.0, 6.0)WS_(2)复合材料,并优化了WS_(2)的含量。通过球-盘式高温摩擦试验机研究了复合材料在室温至1000℃范围内的摩擦学性能。使用X射线衍射仪和扫描电镜等分析了复合材料的显微组织和物相组成。结果表明:适量WS_(2)的添加显著提高了材料的硬度与摩擦学性能。3种复合材料的摩擦因数和磨损率均表现出大致相同的变化趋势:在室温至400℃的试验条件下,摩擦因数随温度的升高而降低,磨损率变化趋势则相反。在400℃到1000℃,摩擦因数随温度的升高小幅增大;磨损率随温度的升高先减小后增大最后减小,在800℃时达到最大值。在给定的试验条件下,WS_(2)含量为4.0wt%的复合材料具有最佳的高温摩擦学性能。在低温下试样表现出不同程度的磨粒磨损,在高温下的磨损机理为氧化磨损。

CoCrTi-(2.5, 4.0, 6.0) WS_(2) composites were prepared by hot pressing sintering technology, and the content of WS_(2) was optimized. The tribological properties of the composites from room temperature to 1000 ℃ were studied by ball-disk high temperature friction tester. The microstructure and phase composition of the composites were analyzed by X-ray diffractometer and scanning electron microscope. The results show that the suitable addition of WS_(2) significantly improves the hardness and tribological properties of the composites. The friction coefficient and wear rate of the three composites have roughly the same trend as follows. The friction coefficient decreases with the increase of temperature from room temperature to 400 ℃, while the wear rate changes in the opposite trend. The friction coefficient increases slightly with the increase of temperature from 400 ℃ to 1000 ℃, while the wear rate first decreases, then increases, and finally decreases with the increase of temperature, and the wear rate reaches the maximum value at 800 ℃. Under the given test conditions, the composites with WS_(2) content of 4.0 wt% has the best high-temperature tribological properties. The specimens show different degree of abrasive wear at low temperatures, while the wear mechanism at high temperatures is oxidative wear.