Research on the water cavitation peening process and mechanism of TC4 titanium alloy

Cavitation water shot peening is a new processing method of surface strengthening and modification that utilizes the cavitation bubbles in the cavitation water jet to destroy high-energy shock waves, causing the cavitation groups to collapse on the surface of the material. Strengthening research on TC4 titanium alloy cavitation water jet peening is limited. The process of cavitation water shot peening strengthening is small, and the mechanism of residual stress generation is not yet clear. Therefore, five typical shot peening strength tests of TC4 titanium alloy are taken as examples in this paper. Experiments and mechanistic studies are carried out through macro-micromorphology, metallographic structure and XRD analysis, microhardness, and residual stress methods. The research results are as follows: as the shot peening strength increases, the surface roughness Ra and the depth of the plastic deformation layer gradually increase, and the depth of the plastic deformation layer is saturated at 55–60 μm; the depth of the influence of the microhardness and residual stress reaches 130 μm; and the surface grains gradually refine and develop to the nanometre level.