Surface Strengthening Effect of Nickel-Aluminum Bronze Treated by Shot Peening at Different Intensities

The cast nickel-aluminum bronze was shot peened at shot peening intensities of 0.15, 0.20, 0.25 mm. The surface residual stress, micro-hardness, micromorphology and surface roughness of the nickel-aluminum bronze before and after shot peening were analyzed and compared, and the domain size and micro-strain in the surface layer were calculated. The results show that with the increase of shot peening intensity,the compressive residual stress and the level of work-hardening of the nickel-aluminum bronze both increased grandually. The surface roughness increased obviously, accompanied by the increase of micro-cracks when the shot peening intensity was too large, thus leading to the surface stress relaxation and resulting in the decrease of strengthening effect.