Research on the multilevel energy decrement strategy for abrasive waterjet peening Ti6Al4V

Abrasive waterjet peening (AWJP) has the advantages of water jet peening and shot peening, which is a potential comprehensive peening process for metals. In this paper, the multilevel energy decrement strategies were proposed and their effects on the surface roughness, hardness and residual stress were studied under different pressures and traverse speeds. The results showed that the pressure group had advantages in modifying the surface morphology of the workpiece compared with the speed group, which can improve the hardness and compressive residual stress of the workpiece while ensuring that the workpiece surface is relatively smooth to achieve a comprehensive strengthening effect. In the pressure group, the surface roughness of the sample after triple AWJP treatment is 3.018 μm, which is reduced by 40% compared to that of the single AWJP treatment. The maximum hardness can be up to 410.12 HV_0.2, an increase of 27% compared to the original substrate. The depth of the hardened layer is about 110 μm, while the average hardness of the hardened layer is 397.24 HV_0.2 and the maximum compressive residual stress can reach up to − 860.8 MPa.