Effect Of High Energy Shot Peening On The Surface Treatment And Properties Of Magnesium Alloy

Magnesium alloy is a widely used metal material in the manufacturing industry.Its advantages are low density and high plasticity,but its corrosion resistance is not good,which limits its application to some extent.In this paper,the effect of high energy shot peening technology(HESP)on solid aluminum aluminizing technology and magnetron sputtering aluminum film on magnesium alloy surface is studied.The microstructure,properties,corrosion morphology and composition of each sample were analyzed by electrochemical corrosion test,salt spray corrosion test,scanning electron microscopy(SEM)and energy spectrum analysis(EDS).The magnesium alloy was revealed under different environments.Characteristics and mechanisms of corrosion.Research indicates:1.After high-energy shot peening,AZ91D Magnesium alloy surface is of the nano-crystalline,surface grain size changed from micron level to nano-level,0.2MPa pressure processing 40min is the best shot peening process,grain size refined to100nm.2.The thickness of aluminized layer of high energy shot peening is better than that without high-energy shot peening.High-energy shot peening+440?under the thermal insulation 12h is the best aluminizing process,its infiltration layer thickness is the biggest,up to 70?m,at the same time with the lowest self-corrosion current density 41.86?A/cm~2.3.The grain size of aluminum thin film produced by magnetron sputtering+AZ91D magnesium alloy shot-peened is smaller than that of without shot-peening,and the grain size is smaller with the increase of shot-peening time,and at the 0.2Mpa for 40min it can reach below 200nm.The surface of the sample was more even and the density of grains increased remarkably.The physical bonding force between the magnet ron sputtering film and the substrate was also significantly different,and it increased by 3 times from 5N before shot-peening to 16N after shot-peenig.4.The magnetron sputtering aluminum film on the surface of magnesium alloy has improved the corrosion resistance in 3.5%NaCl solution,and the corrosion-resistance of the aluminum film is 274?A/cm~2 before shot-peening,after the high energy shot peening under 0.2mpa-40min,and the self-corrosion current density is 59.88?A/cm~2 which is the best.5.The results of weight loss analysis show that the initial corrosion rate of magnesium alloy surface shot peening+magnetron sputtering aluminum film is larger,but with increasing time,the corrosion rate gradually increases and tends to be stable.The weight loss rate of the direct magnetron sputtering aluminum film on the surface of magnesium alloy was 0.145mg/(mm~2·h),and it decreased to 0.05mg/(mm~2·h)after0.2MPa-40min+magnetron sputtering aluminum film.The surface of the magnesium alloy is more dense by the high energy shot peening+magnetron sputtering aluminum film,and the bonding property between the film layer and the substrate is better,and the corrosion resistance is better.