The equilibrium diagram of the system molybdenum-nickel

The equilibrium diagram of the system molybdenum-nickel has been determined by a combination of thermal, microscopical, and X-ray methods. The system contains an intermediate γ-phase whose composition limits include the value corresponding to MoNi3; this phase has an orthorhombic structure. In contradiction to previous work, the composition of the intermediate δ-phase does not include the equiatomic ratio, and has a slight composition range centred at about 47 at.% Ni. The intermediate β-phase has a composition in the region of 80.5–81 at.% Ni, and does not include the exact ratio MoNi4; the structure is tetragonal and may be regarded as derived from a MoNi4 superlattice of the f.c.c. Ni solid solution. The lattice spacings of the terminal solid solutions have been determined. The equilibrium diagram of the systems Mo-Co and Mo-Ni show many similarities, and these are discussed.