Study On The Corrosion Resistance Of 7075 Aluminum Alloy Strengthened By Laser Shot Peenin

7075 aluminum alloy is widely used in aerospace structural parts due to its high strength,low density and good weldability.However,due to the poor corrosion resistance of 7075 aluminum alloy,when the structural parts of 7075 aluminum alloy are used in coastal areas for a long time,it is easy to suffer the corrosion of chloride ions in the environment.As a new surface modification technology,laser shot peening can improve the corrosion resistance of materials by improving their surface integrity.However,the research on laser shot peening enhanced corrosion resistance is still in its infancy.In this paper,the influence of laser shot peening on the surface integrity of 7075 aluminum alloy was analyzed by finite element and experimental methods.Combined with electrochemical experiments,the interaction effect of laser shot peening on the corrosion resistance of 7075 aluminum alloy was studied.The main research contents are as follows:(1)Based on the polycrystal dislocation evolution theory under large strain proposed by Estrin,the microstructure evolution mechanism of aluminum alloy strengthened by laser shot peening and the material science of plastic deformation theories,the microstructure evolution mechanism of laser shot peening strengthened 7075 aluminum alloy based on cold plastic deformation was explored.(2)Fortan and Python languages were used to conduct secondary development of the solver and post-processing module of Abaqus software,and the finite element prediction model of laser shot peening enhanced surface integrity was established.On this basis,a multi-process simulation study of laser shot peening for 7075 aluminum alloy was carried out,and the effects of laser energy and laser shot peening times on dislocation density,subcrystalline size,microhardness,residual stress and line roughness were analyzed.(3)The effects of laser energy and laser shot peening times on the surface morphology,linear roughness,surface roughness,microhardness and grain of 7075 aluminum alloy were analyzed through the experimental study of laser shot peening.The accuracy of the finite element prediction model of laser shot peening enhanced surface integrity was verified by comparing the simulation and test results of line roughness and microhardness from multiple angles.(4)The effects of laser energy and laser shot peening times on the corrosion resistance of7075 aluminum alloy were analyzed by electrochemical experiments.On this basis,combined with the surface integrity test of laser shot peening enhanced 7075 aluminum alloy and the finite element results,the interaction effect of laser shot peening enhanced surface integrity on the corrosion resistance of 7075 aluminum alloy was discussed.