面向1600℃新型难熔高熵合金设计与包埋熔渗涂层的协同抗氧化机理

高温氧化已成为限制难熔高熵合金在航空航天领域发展应用的瓶颈问题。基于此，本项目重点研究难熔高熵合金的成分优化设计、高温氧化机理以及高温抗氧化性能调控。通过“合金组元改性”方法，形成高通量建模优化难熔高熵合金组分设计方法，建立合金的微观结构和力学性能预测模型，并结合实验验证，得到高温力学性能优异的新型难熔高熵合金。揭示合金在1600℃高温条件下初期选择性氧化机理，阐明初期选择性氧化对后续氧化反应的影响。通过包埋熔渗的“表面涂层改性”方法，在新型难熔高熵合金表面进一步可控制备耐高温-抗氧化-强结合的硅化物-硼化物复合梯度涂层，揭示复杂多元硅/硼化物涂层的成形与抗氧化机理。本项目为难熔高熵合金高温环境下的应用提供理论依据和技术支持。

High-temperature oxidation has become the bottleneck for development and application in aeronautics and astronautics of refractory high-entropy alloys. Therefore, the project focuses on the optimizing composition, high-temperature oxidation mechanism study and improvement of oxidation resistance of refractory high-entropy alloys. Through the “alloy component modification” method, a high throughput modeling method optimizing composition of refractory high-entropy alloys is achieved, and the prediction model of the alloy's microstructure and mechanical properties is established. Besides, combined with the corresponding experimental verification, the refractory high-entropy alloys with excellent high-temperature mechanical performance are prepared. Studying interfering factors will reveal the mechanism of the early selective oxidation and clarify how the early selective oxidation drives the following oxidation behavior under the high oxidation temperature of 1600 ℃. Through the “surface coating modification” method of embedding and infiltrating, a silicide-boride composite gradient coating is further prepared on the surface of the new refractory high-entropy alloy. And a high temperature resistance-oxidation resistance-strong bonding strength protective coating is prepared controllably. In addition, the formation and anti-oxidation mechanism of the complex multi-components silicon/boride coating is clearly revealed. This project will provide a reliable theoretical basis and technical support for the application under higher temperature of refractory high-entropy alloys.