激光冲击对灰铸铁熔凝层组织和性能的影响  

Microstructures and Properties of Melted Layer of Gray Cast Iron with Laser Shock Processing

作　　者：万天一 崔承云[1] 彭希超 Wan Tianyi;Cui Chengyun;Peng Xichao(School of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]江苏大学机械工程学院,江苏镇江212013

出　　处：《稀有金属》2020年第9期967-973,共7页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51875267和51505198);江苏高校“青蓝工程”项目;江苏大学青年骨干教师计划项目资助。

摘　　要：对灰铸铁熔凝层表面进行激光冲击(LSP)处理,研究激光冲击前后灰铸铁熔凝层组织及性能的变化。结果表明,激光冲击后,灰铸铁熔凝层组织细化且产生大量的塑性变形,导致熔凝层深度方向残余拉应力转变为压应力,最大残余压应力出现在层深0.2 mm处,熔凝层残余压应力随着层深的增加而逐渐减小;激光冲击后灰铸铁的熔凝层上部马氏体组织、莱氏体组织发生细化,熔化区下部的相邻渗碳体间距减小,且部分渗碳体组织的尺寸减小,颗粒状珠光体转变为层片状珠光体;激光冲击对于熔凝层的熔化区及过渡区的显微硬度有强化作用,熔化区的平均显微硬度达到约HV0. 1843,相较于激光冲击前增幅约为15.96%,过渡区的平均显微硬度提高程度较小,相对于激光冲击前增幅约为9.35%;激光冲击后的灰铸铁熔凝层表面平均摩擦系数为0.11857,磨损量为0.072 g,相对于激光冲击前明显下降,熔凝层表面的耐磨性能提升。The melted layer surface of gray cast iron was treated by laser shock processing(LSP). The structure and property of the gray cast iron melted layer before and after LSP were studied. The results showed that after LSP,the microstructures of the gray cast iron melted layer refined and a large amount of plastic deformation occurred,resulting in the consequence that the residual tensile stress in the depth direction of the melted layer converted into compressive stress. The maximum residual compressive stress occurred at 0.2 mm depth,and the residual compressive stress of the melted layer decreased with the increase of the layer depth. After LSP,the refinement of martensite and ledeburite occurred at the top of melted zone. At the bottom of the melted zone,the distance between the adjacent cementite decreased and the size of part of the cementite reduced. The granular pearlite transformed into lamellar pearlite. Laser shock processing had a strengthening effect on the microhardness of the melted zone and transition zone of the melted layer. The average microhardness of melted zone reached about HV0.1843,which was about 15.96% higher than that before LSP. The average microhardness of transition zone improved slightly,which was about 9.35% higher than that before LSP. After LSP,the average friction coefficient and wear loss of the melted layer surface were 0.11857 and 0.072 g respectively,which were obviously lower than those before LSP,and the wear resistance of the melted layer surface improved.

关 键 词：灰铸铁 激光熔凝 激光冲击 微观组织 性能 

分 类 号：TG178[金属学及工艺—金属表面处理]