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采用输出波长为1064 nm、脉冲宽度为20 ns的调Q钕玻璃激光,对2A02航空铝合金板表层进行了激光冲击,用透射电镜及其高分辨像的傅里叶过滤像分析了激光冲击后样品表面的微结构演变,研究了激光冲击诱导的纳晶化行为与形成机理及其对表面性能的影响。结果表明,激光冲击能在2A02航空铝合金板表面形成直径为～100 nm的纳米晶;表面纳晶层的硬度比基体提高54.5%。分析认为2A02铝合金表面纳晶化过程是激光冲击超高应变率和超高能量共同作用下由位错和空位等非平衡缺陷诱导的晶粒分化过程。
The Q02 neodymium glass laser with the output wavelength of 1064 nm and the pulse width of 20 ns was used to laser impact on the surface of 2A02 aviation aluminum alloy plate. After the laser shock was analyzed by the transmission electron microscope and its high-resolution Fourier filter, The microstructural evolution of the sample surface was investigated. The laser shock induced nanocrystallization behavior and formation mechanism and its effect on the surface properties were investigated. The results show that the laser shock energy can form nanocrystals with a diameter of ~ 100 nm on the surface of 2A02 aviation aluminum alloy plate. The surface nanocrystalline layer has a hardness of 54.5% higher than that of the matrix. It is concluded that the nanocrystallization process on the surface of 2A02 aluminum alloy is induced by the unbalanced defects such as dislocations and vacancies under the combined effect of ultrahigh strain rate and ultrahigh energy of laser shock.