Guan Kang, Wu Jianqing, Cheng Laifei
School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China.
Science and Technology on Thermostructural Composite Materials Laboratory, Northwestern Polytechnical University, Xi'an 710072, China.
Materials (Basel). 2016 Dec 13;9(12):1011. doi: 10.3390/ma9121011.
The evolution of the thermal conductivities of the unidirectional, 2D woven and 3D braided composites during the CVI (chemical vapor infiltration) process have been numerically studied by the finite element method. The results show that the dual-scale pores play an important role in the thermal conduction of the CVI-densified composites. According to our results, two thermal conductivity models applicable for CVI process have been developed. The sensitivity analysis demonstrates the parameter with the most influence on the CVI-densified composites' thermal conductivity is matrix cracking's density, followed by volume fraction of the bundle and thermal conductance of the matrix cracks, finally by micro-porosity inside the bundles and macro-porosity between the bundles. The obtained results are well consistent with the reported data, thus our models could be useful for designing the processing and performance of the CVI-densified composites.
通过有限元方法对单向、二维编织和三维编织复合材料在化学气相渗透（CVI）过程中的热导率演变进行了数值研究。结果表明，双尺度孔隙在CVI致密化复合材料的热传导中起重要作用。根据我们的结果，开发了两种适用于CVI过程的热导率模型。敏感性分析表明，对CVI致密化复合材料热导率影响最大的参数是基体裂纹密度，其次是纤维束体积分数和基体裂纹的热导率，最后是纤维束内部的微孔率和纤维束之间的大孔率。所得结果与报道的数据吻合良好，因此我们的模型可用于设计CVI致密化复合材料的加工工艺和性能。
