锆合金激光熔覆镍基复合层微观组织及界面特征  

Microstructure and interfacial characteristics of Ni-based composite coating on zirconium alloy substrate by laser cladding

作　　者：刘坤[1] 李亚江[1] 王娟[1] 马群双[1] 

机构地区：[1]山东大学材料液固结构演变与加工教育部重点实验室,济南250061

出　　处：《焊接学报》2016年第11期39-42,共4页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(51175303)

摘　　要：以Ni35自熔性合金粉末为熔覆材料,采用激光熔覆技术在锆合金表面原位生成了NiZr_2/陶瓷增强镍基涂层.利用金相显微镜、扫描电镜、X射线衍射仪等对熔覆界面附近的微观组织、物相组成及界面结合特征进行分析.结果表明,熔覆层基体组织为NiZr+Ni_(10)Zr_7,增强相NiZr_2以细针状均匀分布在熔覆层上部和底部,块状及棒状的陶瓷相Zr_5(Si_xNi_(1-x))_4/Zr(Si_xNi_(1-x))分布在熔覆层中部,熔覆层与基体间实现良好的熔焊冶金结合,界面结合区组织不均匀,分布有等轴状NiZr及晶间的α-Zr,熔覆层的显微硬度分布均匀,平均值约为1 100 Hv.The NiZr_2/ceramic reinforced Ni-based composite coating was in-situ synthesized by laser cladding using Ni35 self-fluxing powder on zirconium alloy substrate. The microstructure,phase constituents and interfacial characteristics were investigated by optical microscope,scanning electron microscope and X-ray diffraction method. Results indicated that the matrix of coating was mainly composed of NiZr + Ni_(10)Zr_7,fine needles NiZr_2 distributed at the top and the bottom,and blocky Zr_5( Si_xNi_(1-x))_4/Zr( Si_xNi_(1-x)) ceramic phase in the middle of the coating. Good metallurgical bonding between substrate and coating was obtained. Heterogeneous microstructure of interface zone was mainly compromised of equiaxial NiZ r phase and α-Zr at the grain boundary. The mean value of microhardness of the coating reached 1 100 HV.

关 键 词：锆合金 激光熔覆 增强相NiZr2 微观组织 界面特征 

分 类 号：TG156.99[金属学及工艺—热处理]