SiC-ZrB2改性C/C复合材料在非稳态超高温环境中的低温烧蚀机理研究

SiC-ZrB2改性C/C复合材料(C/C-SiC-ZrB2)有望用于速射武器身管内衬和高功率密度柴油机活塞等装备热端关重件，工作时超高温燃气以单次毫秒级短时加载、高频冲击且存在附壁燃烧等非正常焰流，形成材料表面平均温度远低于环境温度但剧烈震荡并伴随强烈粒子冲蚀的独特低温烧蚀环境。本项目针对改性C/C复合材料在上述工况中的失效机制尚不明确这一现状，通过化学气相渗透结合前驱体浸渍裂解法制备C/C-SiC-ZrB2，借助自研的氧乙炔燃气耦合刚玉砂冲蚀往复加载烧蚀测试装置，重点研究该材料在不同加载和燃烧环境中的低温烧蚀机理，探究SiC-ZrB2分布形态和微结构以及表面金属封填对烧蚀的影响规律与作用机制，以期阐明非稳态超高温环境参数、复合材料基体特性与材料烧蚀机理的内在联系，从而建立复合材料在非稳态超高温环境中的烧蚀模型，获得基体优化方法。

SiC-ZrB2 modified C/C composites (C/C-SiC-ZrB2) are promising candidates for key components as liner tube of fast-fire weapon barrel and piston of diesel engine with high-power density. The composite will be ablated by the high-frequency impacted flame at ultra high temperature cooperated with strong thermal shock and sand erosion in the course of using, while the surface temperature is much lower than the environment. The project is aimed at the failure mechanism of C/C composites in the conditions mentioned above. The C/C-SiC-ZrB2 will be prepared by chemical vapor infiltration combined precursor infiltration and pyrolysis. Testing under cyclic impact of oxyacetylene torch coupled corundum sand erosion on the self-developed device, the low-temperature ablation mechanism of the material in different loading and combustion environments, effect of SiC-ZrB2 distribution and microstructure and the surface metallization on the ablation will be mainly studied. And then the internal relations among parameters of ultra high temperature environment in unsteady state, microstructure of composite and ablation mechanism will be elucidated. Ablation model and optimization method of matrix should be finally obtained.