Restricted equilibrium phase diagram of nickel rich corner of quaternary system Ni-Cr-Fe-Mo

Abstract

The first partial restricted equilibrium phase diagram (RE diagram) for quaternary alloys (Ni rich corner of the Ni–Cr–Fe–Mo system) is calculated using an advanced numerical simulation program. In contrast to earlier diagrams, undercooling effects are considered in the calculations. Isothermal as well as temperature concentration sections of the predicted RE diagram are shown together with approximate equations for the concentration limits for complete solid solubility. In this system a single boundary line defines the limiting alloying content for a wide range of cooling rates (0·1 to 100 K mm⁻¹). It is demonstrated that calculations performed for a constant cooling rate of l0 K s^−l give reliable estimates for the maximum content of Cr, Fe, and Mo at which no topologically closed packed phases precipitate in nickel base alloys.