Phase equilibria in Cu-Ni-(V,Nb,Ta,Mo) systems at 1275 K

Regularities of nickel effect on the character of solid-phase copper interaction with 5 group bcc metals and molybdenum are studied. Positions of three-phase equilibrium α+γ+MeNi (Me=V, Nb, Ta, Mo) and copper solubility in equiatomic nickel base compounds and corresponding refractory metals at 1275 K are determined. Due to atomic closeness in sizes, the electron concentration being 6.5-7.5, σ-phase on the base of VNi equiatomic compound is formed in Cu-Ni-V system, therewith the copper solubility in a phase is negligible (approximately 4.5 at.%). σ-phase is in equilibrium with nickel and copper base α-solid solution and vanadium base γ-solid solution. The limiting concentration of nickel in α-solid solution is approximately 4.0 at.%