Insights into microscale crack propagation and fracture toughness in rare‐earth zirconates through high‐throughput molecular dynamics calculation

Abstract Rare‐earth zirconates (REZO) have emerged as next‐generation thermal barrier coating materials, owing to their exceptional phase stability, ultralow high‐temperature thermal conductivity, and high thermal expansion coefficient. However, their relatively low fracture toughness limits practical implementation. While numerous studies have documented fracture toughness measurements in REZOs at room temperatures, the intrinsic influences of rare‐earth element selection and order‐disorder phase transitions on fracture mechanisms at various temperatures remain insufficiently explored. This study integrates molecular dynamics simulations with high‐throughput calculations and experimental validation to systematically elucidate how rare‐earth cation configurations, crack propagation orientations, and order‐disorder transition govern fracture toughness and crack evolution in REZO systems. Our findings demonstrate brittle fracture behavior across all crystallographic orientations in REZOs, with maximum critical stress along (100) and minimum along (111). Fracture characteristics correlate not only with surface energy but also with geometric factors at crack tips. Molecular dynamics simulations reveal that structural disorder reduces fracture toughness without altering failure mechanisms. The integration of experimental and computational analyses for Nd 2 Zr 2 O 7 demonstrates that REZO exhibits lattice softening and reduced fracture toughness at elevated temperatures while maintaining brittle fracture characteristics. These findings establish critical experimental and theoretical foundations for advancing high‐toughness, long‐lifespan REZO‐based thermal barrier coating materials.