Enhanced fretting wear resistance of 2A12 aluminium alloys through laser shock peening without coating

In order to further improve the service life of aluminium alloy components in harsh environments, in this study, laser shock peening without coating (LSPwC) was applied to 2A12 aluminium alloy. By controlling the laser energy, the maximum cross-section microhardness and maximum residual compressive stress of aluminium alloy can reach 79.8 HV and −163.6 MPa (at a depth of 100 μm), and the lowest wear volume is only 15 % of the untreated aluminium alloy. The high hardness and high residual compressive stress of the alloys are mainly attributed to dislocation accumulation and grain refinement induced by LSPwC. The enhanced fretting wear resistance of the aluminum alloy is attributed to the presence of oxide layers reinforced by amorphous nano-oxide particles, the bumps-holes staggered-type structure on the surface, and the plastic deformation and formation of strain-harding regions introduced by LSPwC.