Effect of laser shock peening on the high-temperature fatigue performance of 7075 aluminum alloy

Abstract 7075 aluminum alloy was subjected to intensive laser shock peening (LSP), and the effect of LSP on the microstructure and high-temperature fatigue properties of the alloy at various elevated temperatures was investigated. Microstructural characterization of the laser-shock-peened (LSPed) material was performed with scanning electron microscopy (SEM) and transmission electron microscopy. The LSPed sample exhibited an improved high-temperature fatigue performance. Its fatigue life increased by 110% at 150 °C. Grain refinement, work hardening, and precipitates were detected through SEM. After LSP, significant changes in surface morphology in three stages of high-temperature fatigue were examined. Results suggested that the highly dense dislocation structure and high compressive residual stress induced by LSP significantly improved the high-temperature fatigue performance of the 7075 aluminum alloy.