High temperature Nb-Si alloys using data science: optimization of fracture toughness and high-temperature strength.

Machine learning-guided design yields Nb-Si alloys with fracture toughness of 18.92 MPa·m^1/2 and high-temperature strength of 322 MPa at 1250°C, surpassing previous alloys.

• Why it matters: Achieving both high room-temperature fracture toughness and high-temperature strength in Nb-Si alloys is challenging due to their conflicting property requirements, limiting their practical applications.
• What they did: Using a three-step feature screening and SHAP analysis, six key descriptors were identified from 200 features, and a multi-objective optimization was performed with the NSGA-II algorithm on a specific alloy composition.
• The result: The optimized alloy's microstructure, featuring nanoscale γ'-Nb5Si3 phases and crack deflection at phase boundaries, explains its superior properties, demonstrating how machine learning accelerates high-temperature material discovery.