激光熔覆304/TiC复合涂层组织研究  

Study on Microstructure of 304/TiC Composite Coating by Laser Cladding

作　　者：王永霞 陈林婷 张海曼 Wang Yongxia;Chen Linting;Zhang Haiman(School of Mechanical and Vehicle Engineering,Bengbu University,Bengbu 233030,Anhui,China;Anhui Additive Manufacturing Engineering Research Center,Bengbu 233030,Anhui,China;Anhui Raycham Laser Technology Co.,Ltd,Bengbu 233000,Anhui,China)

机构地区：[1]蚌埠学院机械与车辆工程学院,安徽蚌埠233030 [2]安徽省增材制造工程研究中心,安徽蚌埠233030 [3]安徽煜宸激光技术有限公司,安徽蚌埠233000

出　　处：《应用激光》2024年第6期37-45,共9页Applied Laser

基　　金：安徽省教育厅高校科研项目(2022AH051922);安徽省质量工程项目(2021jyxm0927)。

摘　　要：为了探究TiC对304不锈钢熔覆层组织形貌的影响,采用OM、SEM和EDS分析了304熔覆层和不同TiC含量的304熔覆层。结果表明,304不锈钢的凝固模型为FA模型,组织为奥氏体和铁素体,熔覆层从下至上依次为平面晶、柱状晶和等轴晶。TiC加入后以圆形和方形的小颗粒状分布为主,少量以团聚态存在。10%TiC熔覆层新增TiC和Cr23C6相,组织为等轴晶,下层和中层晶粒内部具有平行性较强的针状结构,上层晶粒发生粗化,针状平行关系不存在。20%和30%TiC熔覆层新增加α-Fe马氏体相,20%TiC熔覆层晶粒为大块岛状、粒状和杆状,从下到上,晶粒发生细化。30%TiC熔覆层组织形貌为粒状和杆状,从下到上,晶粒略微发生粗化。TiC对组织影响的机理:TiC加入能起到增加异质形核和抑制晶粒长大作用,使组织发生细化,熔覆层下层TiC含量相对较小,TiC为形核生长与未熔颗粒并存的形态,晶粒以熔解重新形核后的TiC和未熔化的TiC颗粒为晶核形成细小晶粒;熔覆层上层,TiC含量增加,晶粒依靠未熔化的TiC颗粒形核的比例增多,形成的晶粒比下层粗大,TiC粉末的加入改变了熔覆层晶粒形貌,随着TiC含量增多,熔覆层出现马氏体相,其含量和上层孔洞数量随着TiC的升高而增多。研究可为304/TiC复合涂层组织形貌改变原理增加资料。In order to investigate the effect of TiC on the microstructure of 304 stainless steel fusion cladding layers, 304 fusion cladding layers without and with varying TiC contents were analyzed by optical microscopy(OM), scanning electron microscopy(SEM), and energy dispersive spectroscopy(EDS). The results demonstrate that the solidification model of 304 stainless steel is the FA model. The 304 stainless steel microstructure is austenite and ferrite, and the cladding layer is composed of planar, columnar, and equiaxial crystals, from bottom to top. The TiC is primarily distributed in small round and square grains, with a minor amount present in the agglomerated state. The 10% TiC cladding layer comprises TiC and Cr_(23)C_6, with the grains arranged in an isometric crystal morphology. The lower and middle layer grains exhibit strong parallelism within the needle structure, while the upper layer grains display coarsening, however, the needle parallelism is not evident. The 20% and 30% TiC cladding layers have been observed to contain an α-Fe martensite phase. The grains of the 20% TiC cladding layer are observed to be large islands, granular, and rod-like, with the grains undergoing grain refinement from bottom to top. The morphology of the 30% TiC cladding layer is granular and rod-like, from the bottom to the top, the grains exhibit slight coarsening. The effect of TiC on the microstructure mechanism can be described as follows: TiC addition can facilitate heterogeneous nucleation and impede grain growth, thereby promoting microstructure refinement. The TiC content in the lower layer of the fusion cladding is relatively low, the TiC of re-nucleation after dissolution and unmelted TiC, which form fine grains as nuclei. In the upper layer of the cladding, the TiC content increases, the proportion of grains reliant on the nucleation of unmelted TiC particles increases, and the formation of grains is coarser than in the lower layer. The addition of TiC powder alters the morphology of the grains in the cladding. With an

关 键 词：304/TiC复合层 γ-Fe 重熔 异质形核 马氏体 

分 类 号：TG401[金属学及工艺—焊接]