In order to investigate the influence of ultrasonic shot peening on the surface integrity of additive manufacturing γ–TiAl alloy

and verify the feasibility of the finite element simulation model

the samples of γ–TiAl alloy prepared by electron beam melting are studied

and a three-dimensional model of ultrasonic shot peening is established. The surface roughness and stress field distribution of ultrasonic shot peening samples under different shot peening parameters are simulated and analyzed. The ultrasonic shot peening tests with 0.15 A and 0.25 A shot peening intensities are carried out on the surface of samples by different shot peening parameters. The effects of shot peening process on the microstructure

residual stress distribution

surface roughness and microhardness of electron beam melted γ–TiAl alloy are revealed

and the validity of the simulation model is verified. The results show that the surface grain size of the samples are refined

the grain size gradient changes from surface to deep layer and the residual compressive stress layer about 150–250 μm depth is formed after ultrasonic shot peening. In addition

with the same projectile diameter

increasing shot peening intensity can significantly increase the distribution of sample surface roughness. Under the same shot peening intensity

the increase of projectile diameter can effectively reduce the sample surface roughness. The surface microhardness of ultrasonic shot peening samples are significantly higher than that of non-shot peening sample (305HV). The maximum microhardness occurs at the nearest measurement point from the surface

and the depth of the affected layer can reach 300–500 μm.