利用输出波长为1064 nm的钕玻璃YAG激光器，对固溶处理304 奥氏体不锈钢进行了激光冲击表面改性实验，用透电子显微镜、扫描电子显微镜分析技术和硬度测试方法分析了激光冲击表面改性组织的热致回归现象及其对力学性能的影响。实验结果表明，晶内形变微结构是激光冲击表面改性的主要强化机制，在固溶处理304 奥氏体不锈钢中主要表现为晶粒内部的层错与不全位错、位错网络与位错胞以及形变孪晶等。在高温再加热作用下，激光冲击诱导的微结构将发生回归，表现为层错消失、位错密度降低、孪晶退化等，表面硬度也随之恢复到基体硬度值。同时还观察到在内应力调整过程中形变孪晶的微损伤。固溶处理304奥氏体不锈钢激光冲击表面改性组织的热致回归系数约为0.35。

Experiments of laser-shocked surface modification of solution-treated 304 austenitic stainless steel specimens are carried out by means of NdYAG laser setup with 1064 nm output wavelength. The phenomenon of the thermo-induced regression and its effect on property of the laser-shocked surface are analyzed via transmission electron microscope, scanning electron microscope method and micro-hardness measurement. Experimental results show that deformation microstructure evolution in grains is the basic strengthening mechanism during the surface modification by laser shock processing. The microstructure in the deformed layer of the solution-treated 304 stainless steel consists of stacking faults and partial dislocations, dislocation networks and cells, and deformation twins. These deformation microstructures are liable to regress upon reheating. It is discovered that the regression process includes stacking faults disappearance, dislocation density decreasing and twins decomposition, and surface hardness of the laser-shocked layer returns to the original value of matrix. Meanwhile, micro-damage of deformation twins owing to the internal stress adjustment in the process is observed. Thermo-induced regression coefficient of about 0.35 is obtained for the laser-shocked surface modification of solution-treated 304 austenitic stainless steel.