Effect of two strengthening processes on the fretting wear mechanism of CoCrMo alloy

To alleviate fretting damage of the artificial joint CoCrMo alloy, the substrate was treated by ultrasonic surface rolling process (USRP) and solid solution treatment (SST) respectively. Meanwhile, the fretting wear behavior and failure mechanism of the treated-samples were quantitatively analyzed via experimental study. Compared with the substrate, the wear rates of USRP and SST samples are reduced by about 8.895 and 13.463 µm3/mJ in slip regime. In addition, the wear resistance of USRP samples is improved due to grain refinement, but the expanded grain boundary channels aggravate the oxidative wear degree (8.13% higher than substrate). The intergranular carbides are dispersed in grains and constructed into stacking faults through SST, hence, the fretting wear resistance of the alloy is greatly improved.