Laser peening has broad application prospects in the aviation manufacturing industry. Research on its strengthening mechanism is important for understanding the response of materials under laser peening and rationally planning the laser peening process. Electron backscatter diffraction and X-ray diffraction were used to characterize the microstructure evolution

and to analyze the microstructure strengthening mechanisms. The effect of laser peening on the mechanical properties of the aluminum alloy was studied through the tensile test of the 2024 – T351 aluminum alloy samples after laser peening. The results show that laser peening induces grain refinement in the rolling direction and generates low-angle grain boundaries by deformation strain gradient

and at the same time induces multiplication of statistical storage dislocations. Laser peening mainly improves the material strength through dislocation strengthening

and the grain refinement strengthening and the solution strengthening mechanisms do not contribute significantly.