Phase equilibria in the Ni-V-Ta ternary system

Abstract

Two isothermal sections of the Ni-V-Ta ternary system at 1200°C and 1000°C have been experimentally established using X-ray diffraction, electron probe microanalysis, energy dispersive spectroscopy, and differential scanning calorimeter with equilibrated key alloys. The equilibrium composition of each phase is measured by electron probe microanalysis and energy dispersive spectroscopy. The results indicate that: (1) nine three-phase and eight three-phase regions were confirmed in the isothermal section at 1200°C and 1000°C, respectively; (2) the C14 phase with a large solubility of about 51.2 at. % Ni was observed at 1200°C, while it forms a single-phase region at 1000°C; (3) a small liquid region was confirmed at 1200°C, but disappeared at 1000°C.