Influence of Wetblast Treatment on Fatigue Strength of Magnesium Alloy AZ31

From the viewpoint of weight reduction in transportation equipment such as automobiles, the use of light metals is being promoted. Magnesium alloy is the lightest in practical metals, but it has the property that its strength is low. For improvement of fatigue strength, surface modification treatment such as shot peening is generally applied. Since the magnesium alloy has high reactivity with oxygen and may ignite, surface treatment in a dry environment like shot peening is difficult. In this study, we focused on wet blasting process with low probability of ignition and examined the influence of it on fatigue strength. The fatigue strength of wet blasting AZ31 showed higher results than untreated material. As this factor, improvement of hardness near the surface and application of compressive residual stress are conceivable. Also, the particles used in the wet blasting process are smaller than the particles used in the general shot peening process. Therefore, the fact that the surface roughness did not change significantly was also considered to be one factor. From the above results, we clarified that the wet blasting treatment can safely improve the fatigue strength of the magnesium alloy.