Effects of Shot Peening on Fatigue Properties of Zr-based Amorphous Alloys Containing Ductile Crystalline Particles

In this study, the fatigue properties of a shot-peened Zr-based amorphous alloy containing ductile crystalline particles were investigated, and fatigue processes were analyzed and compared with those of a non–shot-peened (as-cast) alloy. The microstructural analysis results of the shot-peened alloy surface indicated that the flexion and microstructural deformation were observed as the hot-peening time or pressure increased. However, the compressive residual stress formed on the shot-peened surface was approximately half of the ultimate tensile strength and was not varied much with shot-peening time or pressure. The fatigue limit and fatigue ratio of the shot-peened alloy were 368 MPa and 0.24, respectively, which were considerably higher than those of the as-cast alloy. This was because the compressive residual stress formed by the shot peening induced the initiation of fatigue cracks at the specimen interior instead of the specimen surface and, thus, enhanced the overall fatigue limit and fatigue life. These findings suggested that the shot peening was useful for improving fatigue properties in amorphous alloys.