激光熔覆FeCr基Ni包B_4C复合涂层的组织性能

Microstructure and properties of Fe Cr-based composite coatings with Ni package B_4C laser cladding

利用3kW高功率半导体激光器,在45钢基体上制备不同含量的FeCr基Ni包B_4C复合涂层（10%-50%,质量分数）,分别用扫描电镜（SEM）、能谱仪（EDS）、X射线衍射（XRD）及摩擦磨损机对熔覆层的显微组织、成分分布、物相及耐磨性进行研究。结果表明：熔覆层与基体结合区组织为垂直于基体的胞状晶,中部为较粗大的柱状晶,上部为细小无方向的树枝晶;添加量为10%和20%的Ni包B4C时熔覆层的主要物相是α-Fe、Cr B、Cr23C6、B4C;添加量为30%-50%的Ni包B4C时熔覆层的主要物相是α-Fe、CrB、Cr23C6、B4C、（Fe,Ni）、Fe23（C,B）6、（Fe,Ni）23C6,同时还发现了未熔的B4C陶瓷颗粒;含量为30%时熔覆层显微硬度最高,可以达到1261 HV,约为基体（120 HV）的10倍,耐磨性能是基体45钢的41倍。

Fe Cr-based composite coatings with different Ni package B_4C contents were prepared on 45 steel substrate using a 3 k W high power diode laser. SEM,EDS,XRD,and friction wear testing machine were used to investigate the microstructure,composition,phase,and wear resistance of the coatings. The results show that the morphology at the bottom of lading layer is a cell structure,whose growth is perpendicular to the interface of cladding and substrate,the central is A bulky columnar crystal,the upper is tiny branch crystal which grows with random direction. The main phase of the laser cladding is α-Fe、CrB、Cr23C6、B4C,when the contents of Ni package B4C is10% and 20%; The main phase is α-Fe、CrB、Cr23C6、B4C、（ Fe,Ni） 、Fe23（ C,B）6、（ Fe,Ni）23C6,when the contents is 30% - 50% and B4C which are undissolved; The highest hardness is 1217 HV of the cladding layer is 10 times than that of matrix and it＇s wear resistance is 41 times than that of matrix,when the contents of Ni package B4C is 30%.