采用波长为1064 nm，脉冲宽度20 ns的YLSS-D25A/M型激光器，按预定轨迹对6061-T6铝合金紧凑拉伸(CT)疲劳试样进行大面积光斑搭接的双面激光喷丸强化(LSP)处理，研究了喷丸强化前后试样中残余应力的分布情况，讨论了激光喷丸处理对含预制裂纹CT样疲劳裂纹扩展速率的减缓程度，分析了激光喷丸后试样的疲劳断口特征。结果表明，激光喷丸强化诱导的残余压应力场能有效地降低疲劳裂纹扩展速率，疲劳寿命提高64.4%，观察试样激光喷丸后疲劳断口的宏微观形貌，发现在疲劳裂纹扩展区，张应力轴与裂纹平面垂直，正断面上出现明显的疲劳辉纹，疲劳辉纹间距随着裂纹的扩展而逐渐增大。

An investigation is proposed to evaluate fatigue crack performances of compact tension (CT) specimen of 6061-T6 aluminum alloy treated by large area overlapped both-sides lasr shot peening (LSP) along given orbit using YLSS-D25A/M laser, operating at 20 ns with 1064 nm radiation. Residual stress distributions before and after LSP are studied, effectiveness of LSP in retarding rate of pre-cracked CT specimen as well as their fatigue fracture characteristics after LSP are also discussed. Results show that LSP can effectively decrease crack growth rate, as a consequence, fatigue life is extended by 64.4%. Macro and micro fatigue fracture morphology of fatigue cracks of CT specimen after LSP indicates that tensile stress axis is perpendicular to crack plane in expansion area while apparent fatigue striation exists on section of front view. Fatigue striation space increases with gradual growth of crack.