表面粗糙度对UHMWPE微动摩擦磨损性能的影响

采用SRV-4微动摩擦磨损试验机,研究了在干摩擦和水润滑条件下,表面粗糙度对UHMWPE微动摩擦磨损性能的影响.结果表明:干摩擦时,随着UHMWPE表面粗糙度的增加,摩擦系数先降低后升高,比磨损率则单调递增.利用光学显微镜和扫描电子显微镜对磨损表面形貌进行分析观测,发现干摩擦时表面粗糙度较小的UHMWPE磨损表面有少量犁沟,并伴随轻微的塑性变形,随着表面粗糙度的增加,摩擦副接触表面间的黏合点增多,黏着磨损加剧,且在对偶钢球的表面形成转移膜.而在水润滑条件下,摩擦系数和比磨损率显著降低,随着表面粗糙度的增加,摩擦系数和比磨损率同干摩擦时的变化趋势一致,磨损以磨粒磨损为主.

Effects of Surface Roughness on Fretting Wear of UHMWPE under Different Conditions

In this paper, the fretting wear behaviors of ultra-high molecular weight polyethylene (UHMWPE) with different surface roughness were investigated using an Optimal SRV-IV oscillating friction and wear tester. It is found that the friction coefficient of UHMWPE decreased firstly and then increased while the specific wear rate monotonically increased as surface roughness increased under dry sliding. In order to identify the wear mechanisms of UHMWPE under different fretting conditions, the morphologies of the worn surfaces were analyzed by using optical microscope and scanning electron microscope. Under dry sliding conditions, obvious ploughing accompanied with local mild plastic deformation were observed on the worn region of a smooth surface UHMWPE. However, plastic deformation and adhesive wear became more severe with the increasing surface roughness, and the transfer films from UHMWPE were formed on the worn surface of the steel ball. Under water lubrication, friction coefficient and the specific wear rate decreased significantly and showed the similar tendency as that under dry sliding. Abrasive wear dominated the wear mechanism in the process of fretting under water lubrication.