Effect of laser shock processing on the mechanical properties and fatigue lives of the turbojet engine blades manufactured by LY2 aluminum alloy

The aim of this paper was to address the effects of laser shock processing (LSP) on the residual stresses and micro-hardness of the turbojet engine blades manufactured by LY2 aluminum alloy, and fatigue performance of the notched specimens cut from LY2 blade plate. First, the effects of the number of shocks used in LSP on the residual stresses and micro-hardness at the edge of the turbojet engine blade were investigated. Second, the low cyclic fatigue performance on the specimens cut from the blade was evaluated. Experimental results showed that the compressive residual stresses and the high micro-hardness would be generated near the surface due to LSP. The thickness of the plastic deformation layer generated due to the shock wave in LSP was higher than 2.0 mm. By comparing with the untreated specimens, the fatigue lives of the specimens after LSP were obviously increased due to the compressive residual stresses near the surface.