Wear behavior of Mg-3Al-1Zn alloy subjected to laser shock peening

Wear behavior of Mg-3Al-1Zn alloy subjected to laser shock peening (LSP) with three laser pulse energies of 6.5 J, 8.5 J and 10.5 J was investigated by dry sliding wear experiment at room temperature. The microstructure in the topmost surface, phase structure and the micro-hardness distribution for the laser processed samples were examined by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Vickers tester, respectively. Additionally, The three-dimensional (3D) profiles of micro-dents and wear track and surface roughness were observed by 3D profilometer. The results indicate that the grain size in the topmost surface of Mg-3Al-1Zn alloy decreases as laser energy increases. When laser energy is 10.5 J, a nanostructured surface layer could be fabricated on sample. Micro-hardness and surface roughness of the laser processed samples decrease with decreasing laser energy. Furthermore, compared with the untreated sample, the average wear rate of the laser shocked samples is decreased by 32.1%, 45.3% and 69.8% corresponding to laser energy of 6.5 J, 8.5 J and 10.5 J, respectively. The improvement of the wear resistance for laser treated samples is mainly ascribed to the grain refinement and strain-hardening generated by LSP.