载荷对激光选区烧结Cf/SiC复合材料摩擦磨损性能的影响

通过激光选区烧结技术和液相渗硅工艺制备了碳纤维增强碳化硅（Cf/SiC）复合材料。试样组织由C、SiC和Si三相组成，其密度和弯曲强度分别为2.89±0.01 g/cm3和237±9.8 MPa。采用UMT TriboLab多功能摩擦磨损试验机研究了Cf/SiC复合材料在不同载荷(10 N, 30 N, 50 N和70 N)条件下的摩擦学特性。研究结果表明：载荷较小(10 N)时，Cf/SiC复合材料的磨损由微凸起和SiC硬质点造成，磨损机制为磨粒磨损；载荷为30 N时，复合材料的摩擦磨损综合性能最好，其平均摩擦因数为0.564，磨损率低(5.24×10-7 cm3/（N·m）)，主要磨损机制为犁削形成的磨粒磨损和黏结磨损。载荷增大到70N时，材料磨损严重，磨粒脱落形成凹坑，产生裂纹，其磨损率(8.68×10-7 cm3/（N·m）)高，磨损机制主要为脆性剥落。

Effects of Load on Friction and Wear Properties of Cf/SiC Composites Prepared by SLS

Carbon fiber reinforced silicon carbide composites were prepared by SLS and liquid phase silicon infiltration. The composite microstructure consisted of three phases of C, SiC and Si. The density and flexural strength of the Cf/SiC composites were 2.89±0.01 g/cm3 and 237±9.8 MPa, respectively. The friction and wear properties of Cf/SiC composites under different loads (10N, 30N, 50N and 70N) were studied by UMT TriboLab multi-function friction and wear tester. The results show that the wear mechanism of the Cf/SiC composites caused by micro-protrusions and SiC hard sports is abrasive wear when the load is small (10 N). When the load is as 30N, the composites have the best comprehensive friction and wear properties, showing the average friction coefficient of 0.564, and low wear rate of 5.24×10-7 cm3/（N·m）. The main wear mechanism is abrasive wear and adhesive wear formed by plough. When the load is increased to 70 N, the wear is serious, and the particles fall off to form pits and cracks. It has a high wear rate (8.68×10-7 cm3/（N·m）). The wear mechanism is mainly brittle shedding.