【摘要】 采用真空粉末熔覆工艺在镍基单晶高温合金表面制备了致密的NiCr-Cr₃C₂熔覆涂层,并采用SEM/EDS,XRD,EPMA等手段分析了熔覆层及界面的微观组织。结果表明,真空粉末熔覆层中主要由Ni₃Si,Cr₃Si,Cr₇C₃,γ-Ni,γ′-Ni₃Al及γ+γ′共晶组织组成,熔覆层显微硬度是基体硬度的2³倍。界面处附近由于元素互扩散,在靠近熔覆层侧生成了大量的MC型碳化物;而在靠近基体侧,由于枝晶轴与枝晶间组织与成分差异,析出了形态各异的碳化物,并分析了"十字花状"碳化物的演变过程。更多还原

【Abstract】 Compact NiCr-Cr₃C₂ composite cladding layer was prepared on nickel-based single crystal superalloy by vacuum powder brazing technology.The microstructure of the cladding layer and the interface was observed by OM,SEM/EDS,XRD,EPMA.The results reveal that the cladding layer is composed of Ni₃Si,Cr₃Si,Cr₇C₃,γ-Ni,γ′-Ni₃Al andγ+γ′eutectic,and microhardness of the cladding layer is1²times higher than that of the substrate.As a result of the interdiffusion,a large amount of MCtype carbides are precipitated from the cladding layer side at the interface,while on the substrate side,plenty of carbides with various morphologies are precipitated due to the differences of structure and composition between interdendrite regions and dendrite cores.In addition,the evolution mechanism of"cruciate flower"carbide was described.更多还原