The use of superalloys is really meaningful because of its important mechanical properties in high temperature environment. We selected Inconel 718, which has over 50 wt% of nickel and chromium, niobium, molybdenum and titanium with significant weight percent between all the impurities atoms; to study its phase stability among a range of temperatures (from 500°C to approximately 1400°C). The thermodynamic modeling has a high importance to predict the behavior of alloys among equilibrium transition. The software named Thermo-Calc was used to calculate the microstructure of this system. The databases selected were: SSOL4 and TTNI6. Using this analysis it is possible to predict the phases presented, its compositions and amounts. And to confirm our theory, we compared with the results obtained experimentally after revealing its surface by MEV technique. Sustaining what we found, we can extend this analysis to any superalloy of interest, making it easier and faster.