Microstructure-property correlation in Ni-based superalloys

Abstract

This study explores the microstructure-property correlation in Ni-based superalloys through a synergistic computational and experimental approach, targeting applications in aerospace and high-temperature environments that demand materials capable of enduring slow or minimal deformation at temperatures exceeding 1000°C. Utilizing thermodynamic simulation techniques and machine learning (specifically a decision tree model that achieved an 89.5% accuracy and a 0.057 RMSE in cross-validation) for designing three Ni-based superalloys composed of Ni-Co-Cr-Ti-Al having densities 7.45, 7.48, 7.49 g/cm³ and two superalloys consisting of Ni-Nb-Ta-Ti- Al-W-Mo-Cr-Co exhibiting densities of 7.76 and 7.78 g/cm³. The experimental validation of these alloys was conducted using various characterization techniques, including FESEM, TEM, XRD, hardness testing, TG-DTA, HER and OER. The study also includes a comparative analysis with the conventional superalloy XH-67, which features both ordered and disordered FCC matrices, to highlight the structural and mechanical advantages of the newly developed alloys. Mechanical properties of conventional superalloys were further assessed under different strain rates and temperatures, revealing their enhanced performance and potential over traditional single-crystal nickel-based superalloys, thereby affirming their suitability for advanced engineering applications.