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利用激光冲击波对304不锈钢表面进行了强化处理,用电子扫描电镜观察了激光强化处理后表面显微组织结构的变化,并测定了其显微硬度和残余应力,分析了激光冲击处理后显微硬度和残余应力的分布规律,并对残余应力产生的微观机理进行了讨论。实验结果表明:激光表面强化处理后,冲击区微观结构中产生了微塑性变形,显微硬度从基材的220 HV提高到冲击区的310 HV;用X射线分析仪测得冲击区残余压应力为-200 MPa以上,有利于提高其疲劳寿命;在激光冲击波作用下,材料表面发生的塑性变形不能完全恢复,是残余压应力产生的主要因素。
The surface of 304 stainless steel was strengthened by laser shock wave. The surface microstructure and microstructure after laser strengthening were observed by SEM. The microhardness and residual stress were measured. The microhardness And the distribution of residual stress, and discussed the microscopic mechanism of residual stress. The experimental results show that the micro-plastic deformation occurs in the microstructure of the impact zone after laser surface strengthening, and the microhardness increases from 220 HV to 310 HV in the impact zone. The residual compressive stress in the impact zone is measured by X-ray analyzer Is more than -200 MPa, which is beneficial to improve its fatigue life. Under the action of laser shock wave, the plastic deformation on the material surface can not be completely recovered, which is the main factor of residual compressive stress.