Accelerated discovery of potential heat-resistant Al₈Cu₄X phases via high-throughput first-principles calculations

The Al₈Cu₄X phase has emerged as a promising heat-resistant strengthening candidate for Al-Cu alloys, mitigating the instability of Ω/θ′ precipitates at elevated temperatures. In this work, we employ high-throughput first-principles calculations to systematically investigate 57 Al₈Cu₄X compounds, focusing on their thermodynamic stability and phase transformation behavior. DFT calculations reveal negative formation energies for 53 compounds, and those containing rare earth elements, Ca, Sr, and Y are identified as favorable candidates for forming microscale phases at high temperatures. Phase transformation energies exhibit a pronounced periodic trend, with 33 compounds showing negative values, supporting the feasibility of forming nanoscale strengthening precipitates via high-temperature phase transformation. Symbolic regression analysis further identifies atomic volume as the primary descriptor governing the phase transformation energies, while bond order analysis demonstrates that the enhanced stability originates from a strengthened Al-Al bonding network and newly introduced Al-X bonds within the Al₈Cu₄X structures. Overall, this work provides a theoretical foundation for the future design and application of heat-resistant Al₈Cu₄X phases in aluminum alloys.