Computer Estimation of the Eutectic Point for Ni3Ta - Ni3Al

The system Ni ₃ Ta-Ni ₃ Al, a superalloy, has been of interest recently for use as a high temperature material. Uses are suggested as a reinforced eutectoid composite. The phase diagram of this alloy is unknown but is believed to be similar to that of the Ni ₃ Al-Ni ₃ Nb. A computer method is applied utilizing a suitable program to evaluate the temperatures and compositions around the experimental T _e of 1633 K. The results of such a simulation show that the equilibrium composition of NiAl undergoes a substantial variation about this temperature, however the edge solutions differ from the theoretical stoichiometry possibly due to depletion of one or more components at the matrix-ppt ( γ', δ") interface which could result in misalignment of the phase boundaries. Addition of quaternary elements may improve this and also the corrosion resistance at elevated temperatures.