Effects of laser shock processing on mechanical properties of AZ91 magnesium alloy

In order to study the influence of laser shock processing(LSP) and different laser shock model on the mechanical properties of magnesium alloy,an AZ91 magnesium alloy specimen was processed with two beams of nonsuperimposed Nd:glass laser pulses.The surface morphology,with an oval spot distribution,was observed and analyzed after shock,and then the model was compared with the traditional model of single-point-superposition.The nano-hardness of the shocked and non-shocked region was measured with a triboindenter nano-indentation instrument,and the measured value was 1.59GPa and 1.47GPa respectively.The residual stress in the shocked region was measured with a X2350A X-ray strain instrument,and the stress was simulated by means of the finite element software ABAQUS.Both experimental and simulation results were in good agreement,and showed that there was high residual stress distribution,about-120MPa in the shocked region.The results show that the non-superposition of dual-beam mode can improve the shock efficiency.The LSP can improve the nano-hardness and mechanical properties of magnesium alloy and enhance its resistance to foreign objects damages and antifatigue properties.