不同喷丸强度下镍铝青铜的表面喷丸强化效果

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

采用0.15,0.20,0.25mm的喷丸强度对铸态镍铝青铜进行了表面喷丸强化处理,对比分析了喷丸前后镍铝青铜表层的残余应力、显微硬度、微观形貌及表面粗糙度,并计算了表层的亚晶尺寸和显微畸变。结果表明:随着喷丸强度的提高,镍铝青铜表面的残余压应力和加工硬化程度都逐渐增大;但喷丸强度过大时,表面粗糙度明显增大并伴随有显微裂纹产生,从而导致表层应力释放,使得残余压应力增大幅度下降,减弱了强化效果。

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.