激光冲击是一种利用等离子冲击波效应的表面强化技术，该技术能显著提高金属材料抗疲劳、磨损、腐蚀等性能。简要阐述了激光冲击强化技术原理、特点及激光诱导的等离子体特性。从激光冲击强化后金属的疲劳行为、强化机理及疲劳延寿机制3个方面总结了国内外激光冲击强化在金属零部件抗疲劳性能方面的研究进展。激光冲击强化机理由最初的残余压应力强化机制转变为目前普遍接受的残余压应力和表面纳米化复合强化机制。冲击后的金属零部件表层硬度显著提高，由表层向内部引入较大的残余压应力，表层晶粒碎化至纳米级，而表面粗糙度基本保持不变，尤其适合表面粗糙度要求较高的最终零部件的强化。在总结疲劳性能研究及强化机理的基础上，对目前激光冲击强化研究中存在的问题进行探讨，并指出下一步研究的关键问题。
Laser shock processing(LSP)is an established surface cementing technology which utilizes plasma impulse wave to significantly improve anti-fatigue,wear-resistance and corrosion cracking of metallic materials.This paper briefly expounds the features and principle of laser shock processing,as well as peculiarity of plasma induced by laser.The research progresses including fatigue behavior after laser-shocking,strengthening mechanism and anti-fa-tigue theory on the anti-fatigue performance of metallic parts which is shock-processed by high intensity pulse laser ir-radiation at home and abroad are summarized.The initial reinforcement mechanism of laser shock processing is the re-sidual compressive stress consolidation,but it has transformed into residual compressive stress and surface nanocrystal-lization composite intensifying mechanism.After shock processing,surface hardness enhances distinctly,larger resi-dual stress is introduced from the surface to the internal,surface grain fragmented to nanoscale.However,surface roughness remained invariant,this approach can be applied to surface modification of ultimate metallic products. Eventually,on the basis of analysis on fatigue properties and strenghtening mechanism,the problems in laser shock processing are discussed,synchronously,the crucial points of henceforth exploration are illustrated.
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