Integrated Computational Materials Engineering Approach to Alloy Design for Elevated Temperature Service in Nigerian Gas Turbine Applications

This study applies an integrated computational materials engineering (ICME) framework to the design of nickel-based superalloy compositions optimised for elevated temperature service in industrial gas turbines of the type used in Nigerian power generation and upstream oil and gas compression. Nigeria's electricity sector is heavily dependent on gas turbines, and the cost and import dependence of nickel superalloy components are significant. An ICME workflow is established linking CALPHAD thermodynamic and kinetic calculations, physics-based creep and oxidation models, and finite element structural analysis into a systematic alloy composition optimisation loop. The design space explored spans Ni-Cr-Al-Co-Mo-Ti-Ta-W compositions within polycrystalline wrought alloy constraint boundaries. CALPHAD calculations using the TCNI10 database guide gamma prime volume fraction and gamma solvus predictions. A creep resistance merit index is formulated from the solid solution strengthening model of Fleischer and the gamma prime coarsening model of Lifshitz-Slyozov-Wagner, evaluated computationally across the design space. Oxidation resistance is assessed by the critical Al content criterion from Wagner's selective oxidation theory. Three optimised candidate compositions are synthesised, heat-treated, and characterised by SEM, XRD, and TEM. Creep tests at 850 degrees Celsius and 200 MPa are conducted. Results confirm that ICME-guided compositions achieve creep lives 25 to 40 percent longer than the reference IN718 benchmark. Keywords: ICME, nickel superalloy, alloy design, gas turbine, creep resistance.