Abstract:The effect of laser shock processing (LSP) on the hardness, surface morphology, residual stress, and thermal fatigue properties of a ZCuAl₁₀Fe₃Mn₂ alloy was investigated to improve the thermal fatigue performance and decrease the surface crack of high-temperature components. The microstructure and crack morphology were analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that laser shock could significantly improve the thermal fatigue performance of the alloy at a pulse energy of 4 J. Under the effect of thermal stress and alternating stress, microstructure around the specimen notch was oxidized and became porous, leading to the formation of multiple micro-cracks. The micro-cracks in the vertical direction became the main cracks, which mainly expanded with the conjoining of contiguous voids at the crack tip front. Micro-cracks in other directions grew along the grain boundaries and led to material shedding.

Key words: copper alloy; laser shock strengthening; surface morphology; thermal fatigue properties; crack initiation; crack propagation