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利用输出波长为1064 nm、脉冲宽度为20 ns的钕玻璃YAG激光,对2A02铝合金进行了表面冲击试验。通过对激光冲击处理试样的HREM高分辨像观察,分析了激光冲击2A02铝合金材料微结构中的空位现象。结果表明,考察区域在激光冲击超高应变率作用下,在形成大量位错的同时,伴随形成相应的空位;空位片成为激光冲击超高应变率形变条件下铝合金基体中的特征微结构;空位和位错的重组作用加剧了点阵畸变,引起的第三类内应力和纳晶化提高了激光冲击表面的硬度和残余压应力。
2A02 aluminum alloy was subjected to the surface impact test by using neodymium glass YAG laser with output wavelength of 1064 nm and pulse width of 20 ns. Through the HREM high-resolution image observation of the laser impact treatment sample, the vacancy phenomenon in the microstructure of 2A02 aluminum alloy by laser shock was analyzed. The results show that the investigation area is accompanied by the formation of a large number of dislocations with the formation of a large number of dislocations under the laser shock and ultrahigh strain rate. The vacancy slice becomes the characteristic microstructure in the aluminum alloy matrix under laser shock and ultrahigh strain rate deformation. The recombination of vacancies and dislocations aggravates the lattice distortion, and the third type of internal stress and nanocrystallization caused by this increase the hardness and residual compressive stress on the laser striking surface.