激光喷丸技术及其应用

Technology of laser peening and its application

激光喷丸技术是一项新技术,它是用短脉冲(ns级)的强激光辐照在表面覆盖着能量吸收层和约束层的材料上产生冲击波,当激光冲击波诱导的应力波的峰值超过材料的动态屈服极限时,材料的表层将会发生塑性变形,不可回复的塑性变形导致靶材内残余应力的产生。激光喷丸的效果与脉冲的能量、光斑直径的大小、材料的力学性能等因素有关。激光喷丸不仅可以对材料表面进行改性,还可实现板材的塑性成形,并且表面留有有益残余的压缩应力,从而降低了材料的疲劳断裂和应力腐蚀的比率和延长其疲劳寿命。文章简要介绍了该技术在发达国家的应用,也指出该技术在我国走向实用化阶段必须要解决的关键问题。

Laser peening is an emerging modern technology that employs shock waves induced by short- duration intense laser illuminated on material coved with absorption insulation layer and tamping layer. When the peak of stress waves goes beyond the dynamic strength of material, plastic distortion in the surface occurs. Due to irrestored plastic deformation existing, residual stresses produce. The effect of laser peening is related to power of laser, spot size of laser, material mechanic property and so on. Laser peening not only change the microstructure in the surface of material, but also can form metals or alloys into precise shapes without their yielding, leaving their surfaces in a cracking resistant compressive state, which can reduce the rate of fatigue cracking and stress corrosion cracking in structural metals or alloys and extend their fatigue life. The paper introduces briefly its applications in developed countries and also points out some key problems to be resolved for its practical applications in our country.