Influence of Shot Peening Medium on Surface Integrity of 7050-T7451 Aluminum Alloy
The work aims to study the influence different shot peening medium on the surface morphology and surface roughness of 7050-T7451 aluminum alloy at the same shot peening intensity.The surface of 7050-T7451 aluminum alloy was subject to shot peening treatment by cast steel shot ASH230 and ceramic shot AZB425 under Almen intensities of 0.2 mmA and 0.3 mmA.The influence of shot peening medium on the surface morphology,surface roughness,and residual stress field was studied using scanning electron microscopy,roughness tester,and residual stress tester.When the shot peening intensity was 0.2 mmA and 0.3 mmA,the bullet diameter of the cast steel shot specimen was 198.3 μm and 230.8 μm,respectively,which was larger than that of the ceramic shot specimen.The surface roughness of the cast steel shot specimen was 4.84 μm and 6.24 μm,respectively,which was 29.5％and 23.6％higher than that of the ceramic shot specimen,respectively.At the same shot peening intensity,the surface microscopic strain of the ceramic shot specimen was higher than that of the cast steel shot specimen.In terms of residual stress,the surface residual compressive stress of the cast steel shot specimen at 0.2 mmA and 0.3 mmA was-175.5 MPa and-221.5 MPa,respectively,which was significantly lower than that of the ceramic shot specimen at-280.4 MPa and-335.6MPa.However,the depth of the residual compressive stress layer of the cast steel shot specimen was 255.8 μm and 278.9 μm,respectively,which was larger than that of the ceramic shot specimen.In conclusion,at the same shot peening inten-sity,compared with the cast steel shot specimen,the ceramic shot specimen has smaller diameter and lower roughness,but larger surface and maximum residual compressive stress.Shot peening with ceramic shots can result in better surface quality.
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