Si含量对316L不锈钢激光熔覆层凝固行为和显微组织的影响  

Effects of Si Content on Solidification Behavior and Microstructure of 316L SS Laser Cladding Layer

作　　者：古青 包海斌 王永强 冯敏敏 董刚[2,3,4] 尤涵潇 杨高林 姚建华 GU Qing;BAO Haibin;WANG Yongqiang;FENG Minmin;DONG Gang;YOU Hanxiao;YANG Gaolin;YAO Jianhua(Guoneng Zhejiang Beilun First Power Generation Co.,Ltd.,Zhejiang Ningbo 315800,China;Key Laboratory of Special Purpose Equipment and Advanced Processing Technology,Ministry of Education and Zhejiang Province,Hangzhou 310023,China;College of Mechanical Engineering,Zhejiang University of Technology,Hangzhou 310023,China;Institute of Laser Advanced Manufacturing,Zhejiang University of Technology,Hangzhou 310023,China)

机构地区：[1]国能浙江北仑第一发电有限公司,浙江宁波315800 [2]特种装备制造与先进加工技术教育部/浙江省重点实验室,杭州310023 [3]浙江工业大学机械工程学院,杭州310023 [4]浙江工业大学激光先进制造研究院,杭州310023

出　　处：《表面技术》2025年第5期167-175,共9页Surface Technology

基　　金：国家自然科学基金(52035014);浙江省公益技术应用研究项目(LGG22E050036);舟山科技计划(2023C13011)。

摘　　要：目的研究Si元素含量对316L不锈钢激光熔覆层凝固行为和显微组织的影响。方法利用LDF400-2000光纤耦合半导体激光器和ABB机械手组成的激光熔覆系统,在316L不锈钢基体上制备Si元素的质量分数分别为0.8%、1.6%的316L激光熔覆层。使用金相显微镜、扫描电镜(SEM)、电子背散射衍射(EBSD)、透射电镜(TEM)和维氏硬度计,分别从激光束扫描方向(SD)和切向(TD)分析熔覆层的微观组织、晶粒取向、织构和显微硬度。结果在SD方向,0.8%-Si熔覆层的中下部晶粒呈垂直于底部界面的柱状生长趋势,而顶部晶粒则呈胞状,1.6%-Si熔覆层晶粒的生长模式与0.8%-Si熔覆层类似,但取向更随机。在TD方向,0.8%-Si熔覆层晶粒呈外延状,取向为<100>方向,而1.6%-Si熔覆层则为<111>方向。与0.8%-Si熔覆层相比,1.6%-Si熔覆层内小角度晶界占比更高,超过了50%,在晶粒内部可见被位错缠绕的亚微米颗粒,其硬度也从0.8%-Si熔覆层的199.7HV0.3提升到212.2HV0.3。结论Si元素的含量对激光熔覆316L凝固行为和组织有着显著影响,改变了熔覆层的凝固模式,使组织结构由粗大外延生长的树枝晶转变为沿温度梯度方向生长的细小晶粒。In this study,the influence of different mass fractions of silicon(Si)on the solidification microstructure of 316L stainless steel during laser cladding process was investigated in details.A laser cladding system consisting of a LDF400-2000 fiber-coupled semiconductor laser and an ABB manipulator was utilized to deposit a cladding layer containing 0.8% and 1.6%Si on an 316L substrate.Multiple characterization techniques,such as optical microscopy,scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),transmission electron microscopy(TEM),and Vickers hardness testing were employed to assess the microstructure,formation mechanism,grain orientation,texture,and microhardness of the cladding layer both in the scanning direction(SD)and the tangential direction(TD).The results revealed clear differences in grain growth patterns depending on the Si content.In the SD direction,the cladding layer with 0.8%-Si displayed a columnar grain structure,with grains growing perpendicularly from the interface between the substrate and the cladding layer.The top regions of these grains exhibited a cellular morphology.For the 1.6%-Si cladding layer,although the grain growth pattern was still columnar at the bottom parts,the crystal orientation became more random,particularly in the top regions of the cladding.This indicated that higher Si content tended to reduce the alignment of grains,leading to more isotropic properties.In the TD direction,grain orientation was more strongly affected by the Si content.For the 0.8%-Si cladding layer,grain growth followed an epitaxial growth pattern with a strong<100>preferential orientation,meaning the grains continued growing in alignment with the crystallographic orientation of the substrate.This epitaxial growth was less prominent in the 1.6%-Si cladding layer,where the grains were influenced more by the thermal gradient created during solidification,resulting in a<111>preferential growth direction.This shift in grain orientation was significant because it suggested that higher

关 键 词：激光熔覆 SI元素 316L 凝固组织 晶粒细化 

分 类 号：TG174.4[金属学及工艺—金属表面处理] TG665[金属学及工艺—金属学]