3-18. The characterization of thermal protective materials behavior under extreme service environment

Hua Jin*, Qingxuan Zeng, Wei Liang, Fajun Yi

National Key Laboratory of Science and Technology for National Defence on Advanced Composites in Special Environments, Harbin Institute of Technology

Abstract: The requirements of new generation near space hypersonic vehicles in wide speed range, long endurance and high maneuverability bring severe challenges to thermal protection materials / structures. The extreme service environment faced by thermal protective materials / structures is not only limited to the ablation behavior caused by high temperature, but also includes a series of environmental / material coupling effects caused by the real gas effect. However, the lack of ground simulation test in service environment has become the key to scientifically characterize the response of thermal protection materials and fine design of thermal protection structures. In view of this problem, this paper starting from the thermal itself brought by the extreme service environment, combined with the load characteristics of ablation, multi field thermal shock, oxidation under complex medium oxidant and catalytic recombination behavior of thermal protection materials in the actual service environment, established the thermal environment test and assessment platform based on the oxygen acetylene / propane gas jet, the multi physical field combined loading thermal shock test device, and ultra high temperature oxidation / catalysis device, respectively. The key response parameters such as the surface, back wall, internal temperature, strain, crack growth, surface morphology and concentration distribution of oxygen atoms on the surface of the material can be obtained online. On the one hand, these test devices can be directly used for the characterization and evaluation of candidate thermal protection materials for aircraft, on the other hand, they can obtain the behavior characteristics of materials under the simulated extreme service environment. At the same time, the response parameters obtained online can also provide the key parameters for the recognition of environmental / material coupling effect and the active control method for the design of cable thermal protection materials.

Keywords: Extreme service environment; ground simulation experiment; ablation; surface catalytic reaction; oxidation reaction; thermal shock performance

      超常服役环境下热防护材料行为表征研究

金华*，曾庆轩，梁伟，易法军
哈尔滨工业大学 特种环境复合材料国家级重点实验室 

摘要:新一代近空间高超声速飞行器宽速域、长航时、高机动的需求给热防护材料/结构带来了 严峻的挑战。热防护材料/结构面临的超常服役环境不仅仅限于高温带来的烧蚀行为，还包括真 实气体效应带来的一系列环境/材料耦合效应。然而，服役环境地面模拟测试的匮乏成为科学表 征热防护材料响应特征及热防护结构精细化设计的关键。本文针对这一问题，从超常服役环境 带来的热本身出发，结合实际服役环境中热防护材料面临的烧蚀、多场热冲击、复杂介质氧化 以及催化再结合行为的载荷特征，分别建立了基于氧-乙炔/丙烷燃气射流的热环境测试与考核平台、多物理场联合加载热冲击测试装置(可实现温度、压力、气氛及冷/热循环等多种加载模式)、 超高温氧化/催化测试方法与装置，可在线获取材料表面、背壁、内部温度、应变、裂纹扩展、 表面形貌以及催化再结合表面氧原子浓度分布等关键响应参量。这些测试装置一方面可直接用 于飞行器候选热防护材料的表征与评价，另一方面可获得模拟超常服役环境下的材料行为特征， 与此同时，在线获取的响应参量还可为认知环境/材料耦合效应，探索热防护材料设计的主动调 控方法提供关键参数。

关键词:超常服役环境;地面模拟实验;烧蚀;表面催化反应;氧化反应;热冲击性能