稀土对WC颗粒增强铁基体复合涂层组织结构的影响

采用氩弧熔覆技术在45号钢表面制备一层稀土WC颗粒增强铁基体耐磨复合涂层。通过扫描电镜(SEM)、X射线衍射(XRD)和能谱仪(EDS)等测试分析手段研究了稀土的引入对复合涂层中基体组织及碳化物的影响,并与未加稀土进行了比较。结果表明:引入稀土后,一方面优化了熔覆层组织中碳化物颗粒分布,降低了熔覆层组织中碳化物颗粒的团聚、桥接,且颗粒分布均匀;另一方面改善了熔覆层的组织,细化晶粒,减弱了熔覆过程中产生的树状晶,抑制了WC颗粒的溶解和鱼骨状碳化物的生成。在熔覆层组织中碳化物颗粒相主要有三种存在形式:原始未熔WC颗粒、与基体形成的复式碳化物及在凝固过程中重新结晶的W2C(或WC)。

Effect of Rare Earth on Microstructure of WC Particles Reinforced Iron Matrix Composite Coating

RE/WC particles reinforced iron matrix composite coatings were prepared on the surface of 45 steel by means of argon arc cladding technique.The effect of microstructure of matrix and carbide with RE in the composite coating was investigated using SEM,XRD,EDS and other analysis tools,compared with and without RE.The results showed that the cladding layer with RE,on the one hand,the distribution of carbide particles was optimized,and the agglomeration and bridging of carbide particles in the cladding layer′s structure were reduced,and meanwhile their particles were distributed homogeneously.On the other hand,the microstructure of cladding layer was improved,grains were refined,the crystals were decreased in the process,and the dissolution of WC particles and the formation of fishbone-like interdendritic carbide were restrained.The carbide particles in the cladding layer existed mainly in three forms: no melted original WC particles,multiple carbides formed with matrix,and W2C(or WC) recrystallized during the solidification.