7050航空铝合金激光冲击强化残余压应力研究

用激光冲击强化处理装置对重要航空铝合金结构材料7050T7451、7050T7452不同工艺条件下进行了冲击强化处理,并对试件激光冲击区存在的残余压应力进行了测量。结果显示经激光冲击处理后试件表面具有极高的残余压应力,可达-200MPa以上;经过两次迭加冲击处理能够极大提高强化效果,其残余压应力相比单次冲击处理提高1倍以上;单面两次迭加处理与双面依次迭加冲击处理相比,试件正面(先冲击一面)残余压应力水平相当,且双面依次迭加处理试件反面(后冲击一面)的残余压应力远小于正面。以上一系列重要结果均为首次通过试验发现,对激光冲击强化处理技术的实际工程应用具有指导性意义。最后还给出了相应的表层组织结构分析和疲劳寿命试验结果。

Research of residual compressive stress induced by laser shock processing on 7050 aerial aluminum alloy

Strengthening the important aerial aluminum alloy material, 7050T7451, 7050T7452 under different conditions by Laser Shock Processing ( LSP) technique with the device which is developed by ourselves and testing the residual compressive stress of LSP area. The comparing test results shows test piece will has very high residual compressive stress after LSP, the residual compressive stress can exceed -200MPa; After twice sequential repeated processing, the residual compressive stress will be increased over one - time than single processing; After twice sequential repeated processing on one side, the residual compressive stress of front side (the side was processed first) is equivalent to twice sequential repeated processing on both sides, and at the same time, after twice sequential repeated processing on both sides, the residual compressive stress of back side (the side was processed latter) is far less than front side. All above results are discovered through experiments first time, and have guide meaning to the practical engineering applications of LSP technique. At last, the corresponding analysis of surface structure and testing of fatigue life were given.