In order to improve the fatigue properties of airplane and aero-engine structures, the mechanical performances of typical aeronautical metal alloys with laser peening(LP) were investigated in this paper, LP experiment was undertaken with Q-switched Nd:Glass and Nd:YAG laser systems. As the commonest lasers for peening, the performance of Q-switched Nd:Glass and Nd:YAG lasers was compared with each other. The surface profile of LP with square spots was compared with that of circle spots, the results indicated that the array of square spots can get very smooth overlapped effects. Then, the effect of LP on the mechanical performances of TC4(Ti6Al4V) titanium alloy, 7050 aluminum alloy and GH2036 superalloy was researched, which were measured and observed by nondestructive X-ray diffraction method, SEM and TEM. High density dislocation and nanocrystallite were observed in LP zone of TC4. The average fatigue lives of laser peened 7050 samples with three different thickness were increased by 283%, 315% and 306% respectively, which benefit from crystal defect and high surface residual compressive stress in LP zone. LP could get thermal stable residual compressive stress and fine grain structures of GH2036, which is benefit to the fatigue properties of critical structures under cyclic stress and high temperature.
Laser Peening (Lp), Surface Profile, Microstructure, Fatigue Life, Titanium Alloy, Superalloy, Thermal Cycle
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