MAX相陶瓷材料的空间环境带电粒子辐射损伤机理

Less research was conducted on the behavior, performance and damage mechanism of MAX-phase-based high-temperature ceramics applied to aerospace in radiation environment with charged particles in space. Low-earth orbit atomic oxygen erosion is one of the important environmental factors which affect the reliability of aircraft long-term service in orbits, besides high vacuum, solar ultraviolet radiation and heat cycle between high and low temperatures. While servicing in earth-synchronous orbit and polar orbit, radiation of high-energy charged particles becomes the primary reason of materials damage. Therefore, whether MAX-phase materials can meet the anti-erosion of space atomic oxygen and other functional requirement is also critical. Meanwhile, the dielectric properties of the material, which generate radiation induced conductivity effect and dynamic behavior of charge deposition when radiated by charged particles, is an important cause of many spacecraft problems and failures. This study is based on the optimal aerospace materials of Ti-Al-C system among MAX-phase-based ceramics. Researches are mainly focused on the physical mechanism of radiation damage effects in the space environment, on the relationship between the permanent damage and the microstructure in space radiation, and on the establishment of equivalent models of space radiation damage, degradation of main mechanical and thermal properties as well as other performance of the studied materials. A new way of in-orbit performance evaluation of MAX phase and other space materials will be provided based on the above research.

MAX相高温陶瓷应用于航空航天领域在空间辐射环境下的行为、性能及损伤机理研究几乎尚未开展。航空航天飞行器在轨长期可靠服役的影响因素除高真空、太阳紫外辐射及高低温热循环等环境因素外，低地球轨道下原子氧侵蚀是航天材料损伤的重要环境因素之一，而在地球同步轨道和极轨道服役时，高能带电粒子辐射则成为材料损伤的主要原因。因此，MAX相材料能否满足抗空间原子氧侵蚀及其它功能的需求也很关键。同时，材料的介电特性使得其在带电粒子辐射时产生辐致电导效应和电荷沉积动态行为，是许多航天器的故障和失效的重要原因。本研究拟以MAX相中最适为航天材料的Ti-Al-C系陶瓷为主，研究其在空间环境下辐照损伤效应的物理机制，明确空间辐照损伤与材料微观结构永久损伤之间的关系，建立在空间服役条件下该材料的辐射损伤及主要力学性能、热学性能及其它性能退化的等效模型及其等效评价模型，并为空间用MAX相及其它材料在轨性能评价提供新途径。

航空航天飞行器在轨服役期间，除了受到高真空、太阳紫外辐射及高低温热循环等环境因素影响，还受到空间辐照环境影响。带电粒子辐射时产生辐致电导效应和电荷沉积动态行为，是许多航天器的故障和失效的重要原因。MAX相高温陶瓷应用于航空航天领域在空间辐射环境下的行为、性能及损伤机理研究几乎尚未开展。因此，基于MAX相高温陶瓷开展辐照及损伤机理开展研究，具有重要的科学意义和工程价值。..本项目选取MAX相高温陶瓷体系中的Ti3AlC2陶瓷为研究对象，利用不同能量的电子束和质子束样品进行辐照，对辐照样品进行测试表征，分析样品在辐照前后微观组织、物相、结构化学态和性能变化规律，系统研究其在空间环境下辐照损伤效应的物理机制。Ti3AlC2陶瓷材料在质子和电子辐照后，其表面的性能也发生了改变，表面粗糙度会在材料辐照后有所下降而模量和硬度均会有所上升，并且两者的变化程度都会随着辐照能量的增加而变大。在电子辐照可以诱发Ti3AlC2陶瓷材料发生氧化。..本项目的实施，揭示了Ti3AlC2陶瓷的辐照行为与演变规律，建立了辐照参数与辐照诱发陶瓷微观组织结构变化的关联，为MAX相高温陶瓷在空间环境中的应用提供实验和科学依据，并为MAX相高温陶瓷的在轨性能评价提供新途径。