Effect of the impact energy of various peening techniques on the induced plastic deformation region

In order to clarify the relationship between the depth of dimples and the plastically deformed region beneath the surface induced by shot peening and compare the characteristics of various peening methods in terms of single impact energy, the plastic deformation regions induced by single impact at various peening techniques were visualized using Fry's etching method. The relationships between impact energy and both the dimple size and plastic deformation region in the high shot speed range (～50 m/s) were clarified, and the relationships were found to be different from those in the low speed range (～25 m/s). The plastic deformation zones induced by cavitation and laser peening were also studied in order to understand their features. The results showed that the ratio of the plastic deformation region to dimple depth induced by cavitation peening and laser peening was more than 3 times larger than that induced by conventional shot peening, though the plastic deformation volumes induced by cavitation and laser peening were smaller than that induced by conventional shot peening.