Iron aluminide is a metal alloy with unique properties, including high strength and temperature resistance, making it suitable for applications in the aerospace, automotive, housing, and energy sectors. When compared to ferritic alloys, the FeAl alloy exhibits a higher specific modulus, a stronger strength-to-weight ratio, and better oxidation resistance. Furthermore, low-density steels based on FeAl systems have received a lot of attention due to the high demand for increasingly lighter materials with an optimal mix of structural and mechanical properties. In this work, we investigated the thermodynamic properties of the predicted ternary Fe1-XPtXAl systems in terms of their formation energies to better understand the effect of temperature and stability. The predicted phases Fe3PtAl4, FePtAl2, (FePt2Al3)2, and FePt3Al4 from cluster expansion demonstrated a good ductility quantified by Pugh ratio (B/G) and Poisson’s ratio. Values indicated B/G to be greater than 1.75 and Poisson’s ratio greater than 0.26. Further mechanical properties calculated, such as elastic moduli, Young’s modulus, Cauchy pressure, and Vickers’ hardness, signified stability. These phases showed increased stability in their binding energies with a temperature range of 1600 K, 1500 K, 1600 K, and 900 K, respectively. The FePtAl2 and (FePt2Al3)2 structures showed spontaneous reaction with a negative Gibbs free energy signifying thermodynamic stability, compared to FePt3Al4 and Fe3PtAl4 indication non-spontaneous reaction. These four phases showed that platinum substitution was more preferential in improving stability for the intrinsic and extrinsic properties of ß2 FeAl alloy. Consequently, with aluminium, a well adhered protective layer is designed with high adhesion capacity for component coating for superior protection.