关键词: 陶瓷基复合材料, 反应熔渗工艺, 孔隙结构, 多物理场耦合

Abstract: Ceramic matrix composites combine the performance advantages of carbon/carbon materials and ceramic materials, and become important thermal structural materials in the aerospace field. The reactive melt infiltration method is the main process for the preparation of ceramic matrix composites, in which the high-temperature melt enters the carbon/carbon preform through capillary action, and the chemical reaction with the carbon matrix is formed into the ceramic phase and embedded in the pores, so as to achieve efficient densification. However, due to the high temperature and high activity and short-term intense thermophysicochemical interactions in the infiltration process, it is challenging to observe the experiment and control the process parameters. In this paper, based on the characteristics of the reactive infiltration process, considering the channeling characteristics between different pores, and distinguishing the microstructure characteristics of the precast with single-hole structure and two-hole structure, a multi-physics model of reactive infiltration is constructed that is closer to the pore structure of the real preform, and the error between the predicted temperature value and the experimental value of the model is within 3%, and the error between the predicted value and the experimental value in the early stage of the reaction is within 3%, and the overall prediction accuracy is much better than that of the Washburn equation and its modified form. Finally, the influence of the pore structure mode on the temperature distribution and reaction rate distribution of the reactive infiltration process is discussed, and it is found that the two-hole structure mode is more conducive to the infiltration of reactive melts. This study provides a multi-physics coupling method for the permeation process of reactive melt in porous carbon media, which provides a theoretical basis for the optimization of the reactive infiltration process of ceramic matrix composites.

Key words: Ceramic Matrix Composites, Reactive Infiltration Process, Pore Structure, Multiphysics Coupling