Research on component design strategy and anti-oxidation performance of high entropy carbide ultrahigh temperature ceramics

This article focuses on the bottleneck problem of antioxidant performance of high entropy carbide ultrahigh temperature ceramics in extreme environmental applications. Through interdisciplinary and innovative methods, a systematic study was conducted on component design strategies and performance optimization. Based on the concept of “material genetic engineering,” a full chain research system integrating machine learning, first principles calculations, and experimental verification has been constructed. At the theoretical level, a multi-objective optimization algorithm was designed to successfully screen high-performance component combinations such as (Ti0.15Zr0.2Hf0.3Nb0.15Ta0.2)C, which exhibited excellent thermodynamic stability in terms of configuration entropy (ΔSconf > 1.5R) and electronic structure properties (εd = −1.52 eV). By establishing a lattice distortion electronic structure coupling model, the microscopic mechanism of the synergistic effect of Hf/Ta in reducing the oxygen diffusion coefficient was revealed. In terms of the preparation process, innovative hydrogenation–dehydrogenation pretreatment combined with pulsed electromagnetic field assisted sintering technology was used to obtain bulk materials with a density of >98.5% and a grain size of 1.2 ± 0.3 μm. Multi-scale characterization confirms that Hf grain boundary segregation forms a nanoscale barrier layer, while Ta promotes the formation of the Ta2O5–ZrO2 eutectic phase, resulting in an 88% reduction in the oxidation rate of the material at 1800 °C compared to traditional TiC. The thermal mechanical oxygen coupling simulation shows that optimizing the composition reduces the crack propagation rate by 40% and increases the interfacial bonding energy to −3.2 J/m2. The “component structure performance” correlation model established in this study provides a new paradigm for the design of ultrahigh temperature protective materials, and the research results have demonstrated important potential application value in strategic fields such as aerospace thermal protection.