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In order to study the effects of laser shock peening on the fatigue life of LY2 aluminum alloy, water and aluminum foil were used for confining medium and ablation medium, respectively. LY2 specimens were processed with YAG laser. The laser peening parameters were: wavelength of 532 nm, pulse duration of 10 ns, and output energy of 5 J. The laser was focused on a spot of diameter 3 mm. The experimental results show that laser shock peening can increase aluminum fatigue life by 110%. Fracture analysis results show that laser shock peening strengthens the metal surface and suppresses the crack’s initiation and expansion, improving the aluminum fatigue performance．

The high-energy Nd: YAG laser YLSS-M60U was adopted for laser shock processing on K403/K3 cast superalloy test specimen from pressure-turbine blade materials of a certain type of engine. The processing parameters are: laser energy 3 J, spot diameter 2.6 mm, laser pulse 20 ns, laser wave length 1064 nm. An aluminium foil was used as the protection coating, along with water as the restraint layer, the overlap rate reached 50% after 3 times of shocking. The high-cycle fatigue (HCF) test was conducted under the room temperature at stress level of 420 MPa as well as the SEM observation and XRD (x-Ray diffraction) analysis after laser shock processing. The study shows that the leading reasons for improving the fatigue property of metal involve that the fatigue life of the test specimen was 2.4 times longer than the original after laser shock processing, the strong shock waves plastically deform the metal with high-strain rate and generate much larger and deeper residual compressive stress. (authors)