采用输出波长1064 nm、脉冲宽度20 ns、光斑直径5 mm的调Q钕玻璃激光，对AISI-201不锈钢板表层进行激光冲击，用热场发射扫描电镜(TESEM)和透射电镜(TEM)分析了激光冲击后样品表面的微结构演变，分析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，在距表面300 μm的冲击区范围内，激光冲击在AISI-201奥氏体不锈钢表面形成了直径为20~50 nm的纳米晶，在纳米晶周围观察到非晶组织；表面纳晶层的硬度比基体提高36%。分析认为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的晶粒碎化与晶内缺陷交互作用的结果。

The stainless steel sheet of AISI-201 is shocked by means of Q-switched Ndglass laser setup with the 1064 nm output wavelength, 20 ns short pulse and 5 mm beam spot in diameter. The microstructure evolution of the shocked layer is analyzed by using the thermo-field emission scanning electron microscope (TESEM) and transmission electron microscope (TEM). The nano-crystallization behavior induced by laser shock and the mechanism are analyzed, as well as the effect on surface hardness. The experimental results demonstrate that the nano-crystalline grains with 20~50 nm in diameter are obtained on the surface layer up to the depth of 300 μm of the shocked stainless steel AISI-201, and the amorphous phase is also observed around some nano-crystalline grains. The hardness of the nano-crystallized surface is increased by 36% in comparison with the matrix of the stainless steel. It is considered that nano-crystallization process results from the co-action of grain′s smashing up and crystal′s defects of original austenite grains under the combination effect of the super strain rate and super-high power of laser shocking.