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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-Cr_3C_2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Ni_3Si,Cr_3Si,Cr_7C_3,γ-Ni,γ′-Ni_3Al及γ+γ′共晶组织组成,熔覆层显微硬度是基体硬度的2~3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。
The dense NiCr-Cr_3C_2 coating was prepared on the surface of Ni-based single crystal superalloy by vacuum powder cladding. The microstructure of the coating and interface was analyzed by SEM, EDS, XRD and EPMA. The results show that the vacuum cladding layer consists mainly of Ni_3Si, Cr_3Si, Cr_7C_3, γ-Ni, γ’-Ni_3Al and γ + γ’eutectic microstructure. The microhardness of the cladding layer is 2-3 times of that of the matrix. In the vicinity of the interface, a large amount of MC-type carbides are generated near the cladding due to the mutual diffusion of elements. In the vicinity of the base side, due to the difference in microstructure and composition between the dendrite axis and the dendrite, carbides with different morphologies are precipitated , And analyzed the evolution of “cruciform ” carbides.