Effect of laser peening on friction and wear behavior of medical Ti6Al4V alloy

The aim of this study was to investigate the effects of laser peening (LP) on the friction and wear properties of medical Ti6Al4V alloy. Wear tests were conducted on the samples before and after LP with a ball-on-disk wear tester in Hank's solution. The surface roughness and micro-hardness of the differently treated samples were measured. The friction and wear properties of the samples were evaluated by comparing their coefficient of friction (COF) and wear mass loss. The morphologies of wear scar and the wear mechanism were characterized by optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results showed that the surface micro-hardness of the specimen subjected to LP was significantly increased by 25.7% and the corresponding depth of the hardened layer was more than 0.3 mm. The average COF and wear mass loss were significantly reduced to 50% and 29.2%, respectively, as a result of the increasing laser energy and impact times. After LP, the wear mechanism turned from the severe oxidative wear to a slight adhesive wear and abrasive wear. Experimental results proved that LP treatment could effectively improve the friction and wear properties of the medical Ti6Al4V alloy.