Stronger and more resistant alloys are required in order to increase the performance and efficiency 11 of jet engines and gas turbines. This will eventually require planar faults engineering, or a complete 12 understanding of the effects of composition and temperature on the various planar faults that 13 arise as a result of shearing of the γ precipitates. In this work, a combined scheme consisting 14 of the density functional theory, the quasi-harmonic Debye model, and the axial Ising model, in 15 conjunction with a quasistatic approach are used to assess the effect of composition and temperature 16 of a series of pseudo-binary alloys based on the (N i 75−x X x)Al 25 system using distinct relaxation 17 schemes to assess observed differences. Our calculations reveal that the (111) superlattice intrinsic 18 stacking fault energies in these systems decline modestly with temperature between 0 K and 1000 K.