Suitability of laser shock peening to impact-sliding wear in different system stiffnesses

Abstract

Abstract This paper focused on the suitability of laser shock peening (LSP) to impact-sliding wear in different system stiffnesses to improve the performance of aluminum alloy (AlSi7Mg0.6) used in high-speed catenary parts that encountered impact-sliding wear failure. The effects of different laser energies or multiple shocks were examined in low, medium and high system stiffnesses. Results showed that low laser energy LSP formed a uniform and consistent strengthening layer and exhibited excellent wear reduction for low and medium system stiffnesses. Higher laser energy or multiple shocks of LSP both improved the micro-hardness and depth of the strengthening layer, but more defects in the form of micro-cracks and voids appeared in the strengthening layer. These defects had negative effects on the wear resistance to delamination, resulting in inferior wear performance under low and medium system stiffnesses. However, LSP with some micro-cracks performed the best wear reduction for high system stiffness, with only 16% wear to the untreated sample. This was due to micro-cracks altering the damage mechanism from ploughing to delamination. The LSP with many void defects exhibited poor wear performance under the three system stiffnesses because voids weakened resistance to both delamination and ploughing. Therefore, LSP was suitable for improving the wear resistance of AlSi7Mg0.6 to impact-sliding wear under different system stiffness conditions, but the parameters must be carefully controlled.