Modeling of γ/γ' phase equilibrium in the nickel-aluminum system
Source InformationSeptember 1984, Volume32(Issue9) Page1519To1525
A theoretical model is proposed for the determination of phase equilibrium in alloys taking into consideration dissimilar lattice parameters. Volume dependent pair interactions are introduced by means of phenomenological Lennard-Jones potentials and the configurational entropy of the system is treated in the tetrahedron approximation of the cluster variation method. The model is applied to the superalloy relevant nickel-rich, γ/γ' phase region of the Ni-Al phase diagram. The model predicts reasonable values for the lattice parameters and the enthalpy of formation as a function of composition, and the calculated phase diagram closely approximates the experimental diagram.