MD&MLR-informed design of Gd-Yb-La-Ce-Y co-doped ZrO₂: Ultra-low thermal conductivity and synergistic thermophysical performance optimization

To address the limitations of qualitative analysis-dominated and blind property regulation in traditional multi-rare-earth (RE) doping research, this study proposes a molecular dynamics (MD) and multiple linear regression (MLR)-guided strategy for developing low thermal conductivity multi- RE co-doped ZrO₂ TBC materials, and applies it to the development and validation of a Gd-Yb-La-Ce-Y co-doped zirconia TBC system. This strategy enables the accurate quantification of the regulatory effect of each RE component on the thermal conductivity, thereby enabling precise property tuning. MLR analysis of the MD simulation data confirmed that La3+ was the most dominant effective component for reducing the thermal conductivity of the material, followed by Gd3+ and Yb3+. Based on this quantitative law, three low thermal conductivity materials (Gd_0.01Yb_0.01La_0.03Ce_0.03Y_0.04Zr_0.88O_1.955, Gd_0.02Yb_0.02La_0.03Ce_0.03Y_0.02Zr_0.88O_1.955, and Gd_0.03Yb_0.03La_0.03Ce_0.03Y_0.01Zr_0.87O_1.95) were successfully prepared via solid-state synthesis in this work, with a comprehensive consideration of factors including ionic radius compatibility, oxygen vacancy concentration constraint (≤5 mol.%), and configurational entropy. The thermal conductivity results were highly consistent with the trends predicted by the theoretical model, verifying the prediction accuracy of the established MD&MLR-informed design strategy. Compared to conventional YSZ, Gd_0.03Yb_0.03La_0.03Ce_0.03Y_0.01Zr_0.87O_1.95 exhibits a 44% reduction in thermal conductivity at 1273 K, along with excellent phase stability (no monoclinic ZrO₂ after 50 h of isothermal aging at 1400 °C), and an optimized coefficient of thermal expansion (CTE), achieving a comprehensive property improvement. In summary, this study verified the theoretical model's reliability through “theoretical design-experimental verification”, highlighting the guiding value of MD&MLR for the precise design of multi-RE-doped ZrO₂ TBCs and providing solid theoretical and experimental support.