Effect of ultrasonic surface rolling process on microstructure and surface properties of Cu-8 wt.% Al alloy

The gradient nanostructured surface layer of Cu-8 wt.% Al alloy was obtained by surface ultrasonic rolling treatment (USRT). The microstructure and surface properties of the alloy surface before and after treatment were systematically investigated. The results revealed that USRT could refine grain effectively. The surface microhardness reached a maximum of 213.8 HV 0.2 with an increase of 102.5% and progressively decreased from the surface into the matrix. The friction coefficient and the wear scar width were notably reduced, while the wear resistance was significantly enhanced. The corrosion resistance was greatly improved and the sample with a rolling reduction of 0.15 mm was the best.