Determination of isothermal sections of Ni-Cr-Nb ternary system

The isothermal sections of Ni-Cr-Nb ternary system at 1323 K and 1423 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 1423 K become bigger than those at 1323 K, especially the solid solubility of NbCr2-R. No ternary compound is observed.