(1. 常州大學 機械工程學院，常州 213164；
2. 江蘇大學 機械工程學院，鎮(zhèn)江 212013；
3. 常州大學 江蘇省綠色過程裝備實驗室，常州 213164)
摘 要: 以銅鋅合金為研究對象分別進行2.5 J和4.5 J能量下的激光噴丸強化實驗，對噴丸前后試樣的顯微硬度、殘余應力及疲勞特性進行研究。結果表明：試樣經激光噴丸強化后深度方向的硬度和殘余應力均明顯提高，且噴丸能量越大兩者提高幅度越明顯。2.5 J、4.5 J激光能量處理下試樣的疲勞壽命較未噴丸試樣的分別提高1.27~1.49倍、1.42~1.66倍。疲勞斷口形貌分析發(fā)現(xiàn)激光噴丸緩解試樣表面缺陷等區(qū)域的應力集中，疲勞裂紋源位置內移；裂紋擴展區(qū)疲勞條帶間距隨著噴丸能量的增加逐漸減小，使得擴展區(qū)裂紋擴展速率顯著降低；瞬斷區(qū)等軸韌窩尺寸和深度隨激光能量的增加而增加，從而提高銅鋅合金的疲勞壽命。
關鍵字: 銅鋅合金；激光噴丸；殘余應力；疲勞壽命；疲勞斷口
（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
