Wear behavior of 7075-aluminum after ultrasonic-assisted surface burnishing

Gradient nanostructure layer (GNL) is machined on 7075-aluminum by the ultrasonic-assisted surface burnishing (UASB) setup. Compared with the traditional burnishing, the advantages of UASB are discussed by the characterization of GNL. Furthermore, wear experiments with the samples machined by UASB and traditional burnishing are also performed, respectively. It introduces numerical simulation methods to investigate the varieties of grain sizes during UASB and reveal the relevant mechanism. The results exhibit that the obvious GNL forms on the sample surface after UASB, and the samples have ideal surface roughness and gradient hardness distribution. The dry wear experiments show that GNLs have good wear performances under low load, but poor wear performances under high load. Because GNL has high nanohardness, residual compressive stress and poor plasticity-toughness. These reasons result in such contradictory wear characteristics.