Research Projects

Despite decades of development, the operating temperature of Ni-based superalloys has plateaued at around 1100 °C due to the thermodynamic instability of the γʹ phase at elevated temperatures. These alloys derive their exceptional performance from a stable two-phase γ + γʹ microstructure, where ordered L1₂ precipitates are embedded within an FCC matrix. Given the interest in chemistries beyond Ni-based superalloys, Co-, Ir-, and Pt-based superalloys and multi-principal element alloys (MPEAs) have been explored as alternatives, however challenges related to phase stability, cost, and scalability persist. With poor room temperature ductility, the attention has drifted towards alloys featuring BCC matrices reinforced with ordered B2 precipitates, as they emulate the microstructures reported in Ni-based superalloys. Several promising BCC+B2 alloy systems have emerged, including refractory MPEAs, Ru-based systems, and low-density Al-containing alloys. However, a comprehensive understanding of the relationship between alloy composition, phase stability, APB energies, deformation behaviour, and mechanical properties remains limited. This project proposes a novel strategy to accelerate the design of BCC+B2 superalloys by decoupling complex multicomponent systems into pseudo-subsystems, separating matrix-forming and precipitate-forming elements. The alloy composition can be optimized to achieve coherent microstructures with desired precipitate morphology and lattice misfit. In this study, the focus will be on the Al-Ni-Co-Cr-Fe-Ti system, a complex compositional space that offers significant potential for high-temperature applications but remains underexplored. Thermodynamic modeling using CALPHAD methods will guide the identification of phase fields where stable B2 precipitates coexist with BCC phase. First-principles calculations based on density functional theory (DFT) will be employed to assess the effect of composition on structural parameters, phase stability, and defect properties, including antiphase boundary (APB) energies and elastic moduli. A high-throughput diffuse multi-layer fault (DMLF) model will be used to estimate APB energies in complex B2 systems. The mechanical performance of the proposed alloys will be modeled by integrating contributions from lattice friction, solid solution strengthening, coherency stresses, and interactions between dislocations and precipitates. The model predictions will be validated through melting select candidate alloys, followed by heat treatments to promote the formation of B2 precipitates. Structural and microstructural characterization using XRD, SEM, and TEM will verify phase constitution and coherency. Constant strain rate tests at room and elevated temperatures will be conducted in compression to evaluate strength and ductility. The dominant deformation mechanisms will be analyzed post-deformation. Experimental data will be integrated with computational predictions to refine models and optimize alloy design. The significance of this research lies in its potential to deliver a validated framework for the discovery of high-performance BCC+B2 superalloys for extreme environments such as aerospace propulsion systems, advanced power plants, and next-generation nuclear technologies. This project aims to accelerate materials discovery which possesses superior high-temperature strength, ductility, and durability by combining computational tools with experimental validation. Developing a defect-property database, including APB energies and elastic properties in multicomponent systems, will offer a critical resource for future alloy design. This work will contribute to the creation of stronger and more heat-resistant materials that can transform key sectors in energy and transportation.