EFFECTS OF HIGH-TEMPERATURE SHOT PEENING ON SURFACE CHARACTERISTICS AND FATIGUE PROPERTIES OF FORGED AZ31 MAGNESIUM ALLOYS

摘要

In this present study, the effects of high-temperature shotpeening (HSP) on the surface characteristics and fatigueproperties of forged AZ31 magnesium alloys were investigated.The HSP process was performed with a low-carbon steel ballunder a shot pressure of 0.2 MPa and time of 6 s at a temperatureof 523 K. Gradable microstructures were formed in the nearsurfaceregion, about 150 μm from the surface edge. These werecomposed of an ultra-fine-grained region, a residual workingstrain region, and a twin region. The HSP-processed materialshowed increased fatigue strength compared with the non-HSPprocessedmaterial. From the measurement of the crackpropagationrate, it was found that the improvement in fatigueproperties led to a delay in the crack-propagation rate in the ultrafine-grained region and the residual working strain region.