目的 研究激光喷丸(LSP)、机械喷丸(SP)及其复合强化(LSP+SP)对2124-T851铝合金四点弯曲疲劳寿命的影响。方法 激光喷丸强化的脉冲激光能量为6 J，脉冲宽度为20 ns，光斑直径为2 mm，半圆搭接。喷丸强化采用直径为0.3 mm的陶瓷弹丸，喷丸压力为0.2 MPa，喷丸覆盖率大于100%。采用X射线衍射的方法测定强化层的残余应力。采用显微硬度仪测定显微硬度。在MTS伺服试验机上测定试样四点弯曲疲劳寿命。使用扫描电子显微镜观察疲劳试样断口。采用列表梯形法分析计算试样的疲劳裂纹扩展寿命和萌生寿命，分析机械喷丸和激光喷丸强化层性能对疲劳寿命的影响。结果 LSP+SP试样残余应力场和硬度场近表层的数值与SP试样相近，表面残余应力为–260 MPa，表面硬度为178HV。LSP+SP试样残余压应力场和应变硬化场深度与LSP试样相近，可达3 mm以上。与未强化(AR)试样相比，SP、LSP和LSP+SP试样的平均疲劳寿命分别提高了214%、217%和312%。结论 喷丸强化的显著应变硬化作用提高了SP试样和LSP+SP试样的裂纹萌生寿命，激光喷丸强化引入的深层残余压应力场提高了LSP和LSP+SP试样的裂纹扩展寿命，LSP+SP复合强化兼具SP和LSP工艺的疲劳寿命强化作用。

Effect of Laser shot peening (LSP)、shot peeing (SP) and compound strengthening (LSP+SP) process on fatigue life of 2124-T851 aluminum alloy were researched. The samples were laser shot peening with the pulse energy 6 J, pulse width 20 ns, spot diameter 2 mm and overlapping rate 50%, and were shot peeing with the ceramic shot f 0.3 mm, shot pressure 0.2 MPa and coverage more than 100%. Residual stress was test by X Ray diffraction. Meanwhile microhardness and four-point bending fatigue life were tested. The fatigue striation spacing was observed and measured by SEM, and the initiation and propagation life were obtained using schedule trapezium method. The results show that the value of near surface microhardness and residual stress on LSP+SP sample are similar with SP sample’s, the surface residual stress is about –260 MPa, the surface microhardness is about 178HV. On the other hand, the depth of residual compressive stress and strain-hardening field are as same as SP sample’s, which are about 3mm. Comparing with the unstrengthening samples, the average fatigue life of SP, LSP and LSP+SP sample increase by 214%, 217% and 312%. The increasing of initiation life results in the effect of strain-hardening induced by SP process. The deep residual compressive stress filed induced by LSP process increase the propagation life of LSP and LSP+SP samples. In conclusion, the LSP+SP compound strengthening process has the fatigue life-strengthen effect both the LSP and SP process.