We can evaluate temperature-dependent phase stabilities in a wide alloying range: for instance, dissolution temperatures of gamma´ strengthening phase, calculated for more than 40 different technological Ni-base superalloys with our thermodynamic nickel database ME-Ni are in excellent agreement with experimental data. We predict the thermal stability limit of gamma’ phase with a mean deviation of 22°C

Figure1: Dissolution temperatures of γ’, calculated (red bars) for various technological Ni-base superalloys, compared with experiments (blue bars).

 

Relevant stable and metastable precipitate phases can be identified by thermodynamic calculations of phase fractions, employing thermodynamic Matcalc Engineering databases.

Figure2: Equilibrium calculation of phase fractions versus temperature in Ni-base superalloy IN718 (top). Metastable calculation, suspending thermodynamically stable δ-Ni3Nb phase (bottom) This calculation reveals the metastable stability of technologically relevant strengthening phase γ''-Ni3Nb.