Abstract:The isothermal sections of Ni-Cr-Nb ternary system at 1 323 K and 1 423 K were determined by means of diffusion triple and energy spectrum analysis (ESA). By analyzing the diffusion layers in the diffusion couples, the compounds forming in this system were identified. There are three similar compounds found at these two temperatures: Ni₃Nb, NiNb and NbCr₂-R, and four similar three-phase regions are found: (Ni)+(Cr)+Ni₃Nb, Ni₃Nb+NbCr₂-R+NiNb, NbCr₂-R+(Cr)+Ni₃Nb, NbCr₂-R+NiNb+(Nb). The results show that no phase transformation happens between these tow temperatures. But the solid solubilities of the binary compounds at 1 423 K become bigger than those at 1 323 K, especially the solid solubility of NbCr₂-R. No ternary compound is observed.

Key words: Ni-Cr-Nb ternary system; diffusion triple; isothermal section