Effects of laser cladding on crack resistance improvement for aluminum alloy used in aircraft skin

In order to improve the damage tolerance ability of aircraft skin, the superiority of laser cladding aluminum alloy structures for crack resistance is investigated by establishing a three-dimensional (3D) finite element simulation model based on the double ellipsoid heat source and sequentially coupled thermal-mechanical analysis (SCTMA) method. The temperature field and residual stress field under different laser power, laser scanning velocity, laser cladding length, laser cladding patterns and laser cladding angles are investigated to evaluate the effectiveness of fatigue life improvement. Stress intensity factors are calculated by M-integral method and fatigue life is estimated by Paris equation, respectively. The results show that the laser cladding samples achieve the best crack resistance performance at laser power of 1400 W and laser scanning velocity of 10 mm/s. The fatigue life for the sample of cladding coating length of 50 mm is 2.93 times than that of the untreated sample. The linear pattern shows a better crack resistance performance than other patterns and the best crack resistance performance is achieved when the cladding angle of linear pattern is 0. The results demonstrate that the fatigue life of samples after being laser cladding treated is significantly higher than that of untreated samples, which benefits from the residual compressive stress induced by laser cladding process. The higher laser power or lower laser scanning velocity can improve the fatigue life of laser treated samples. The fatigue life of samples can be affected by laser parameters, laser cladding patterns and angles.

Automated summary

By laser cladding aluminum alloy structures, the crack resistance of aircraft skin can be effectively improved, where four main parameters affect the enhancement of fatigue life, manifested in different laser power, laser scanning velocity, laser cladding patterns, and angles.