(1. 常州大学 机械工程学院，常州 213164；
2. 江苏大学 机械工程学院，镇江 212013；
3. 常州大学 江苏省绿色过程装备实验室，常州 213164)
摘 要: 以铜锌合金为研究对象分别进行2.5 J和4.5 J能量下的激光喷丸强化实验，对喷丸前后试样的显微硬度、残余应力及疲劳特性进行研究。结果表明：试样经激光喷丸强化后深度方向的硬度和残余应力均明显提高，且喷丸能量越大两者提高幅度越明显。2.5 J、4.5 J激光能量处理下试样的疲劳寿命较未喷丸试样的分别提高1.27~1.49倍、1.42~1.66倍。疲劳断口形貌分析发现激光喷丸缓解试样表面缺陷等区域的应力集中，疲劳裂纹源位置内移；裂纹扩展区疲劳条带间距随着喷丸能量的增加逐渐减小，使得扩展区裂纹扩展速率显著降低；瞬断区等轴韧窝尺寸和深度随激光能量的增加而增加，从而提高铜锌合金的疲劳寿命。
关键字: 铜锌合金；激光喷丸；残余应力；疲劳寿命；疲劳断口
（1. School of Mechanical Engineering, Changzhou University, Changzhou 213164, China;
2. School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China;
3. Jiangsu Key Laboratory of Green Process Equipment, Changzhou University, Changzhou 213164, China）
Abstract:The brass was induced by laser shot peening (LSP) with the laser pulse energy of 2.5 J and 4.5 J, respectively. The micro-hardness, residual stress and fatigue properties of brass induced by LSP were investigated systematically. The results indicate that micro-hardness and residual stress significant increasing along depth are accompanied by improving laser pulse energy. Compared with the untreated, the fatigue lives of brass induced by 2.5 J LSP and 4.5 J LSP increase by 1.27-1.49 times and 1.42-1.66 times, respectively. Fatigue fracture morphologies indicate that the stress concentration on surface defects of brass is relieved after LSP. Meanwhile, the location of the fatigue crack initiation shifts inwards. Fatigue striation space in the crack propagation region decreases gradually, which causes crack growth rate reduces effectively, with increase of laser energy. The size and depth of the dimples in the fracture region distend with the increase of the energy, which improve the fatigue life of the brass.
Key words: brass; laser shot peening; residual stress; fatigue life; fatigue fracture
