采用激光冲击强化技术改善7075 铝合金疲劳性能,能够降低成本、提高效率.以 7075 铝合金为研究对象,通过对其在不同功率密度下的强化试验,测定其在激光冲击下的表面形貌及残余应力的分布情况,结合其疲劳试验,探究激光强化对材料性能的影响.结果表明:激光冲击强化使铝合金表面粗糙度增大,并产生残余压应力;当功率密度增加到10.19 GW/cm2时,残余压应力不再增大;激光冲击试样的疲劳寿命比未冲击试样提高了 1 倍,减小了断裂扩展范围;残余压应力的存在增加了铝合金的裂纹萌生难度,延长了其疲劳寿命.
Using laser shock strengthening technology to improve the fatigue performance of 7075 aluminum alloy can reduce costs and improve efficiency.Taking 7075 aluminum alloy as the study object,the surface morphology and residual stress distribution under laser shock are measured through strengthening ex-periments at different power densities.Combined with its fatigue experiments,the effect of laser strengthening on material properties is studied.The results show that laser shock strengthening increases the surface roughness of aluminum alloy and generates residual compressive stress;when the power density increases to 10.19 GW/cm2,the residual compressive stress no longer increases.The fatigue life of laser impact specimens is twice as long as that of unshocked specimens,and the fracture propagation range is also reduced.The presence of residual com-pressive stress increases the difficulty of crack initiation in aluminum alloys and prolongs their fatigue life.