激光脉冲法测试C/C复合材料比热容的影响因素分析

Factors affecting specific heat capacity results of carbon/carbon composites by laser flash method

实验探讨了试样轴径向比热容测试的差异性,获取了最佳测试方向,并在此基础上进一步研究了试样厚度对热损影响的程度,获得了最佳厚度值范围。结果表明,采用激光脉冲法进行比热容测试过程中,C/C复合材料内部传热非常复杂,具有非一维传热的特点,但在一定的试样条件下可以获得较好的测试效果;比热容测试时试样应选择热损小的方向,即毡基和轴编材料均应取纤维质量分数高且分布均匀的径向。

Differences between axial and radial specimens of carbon fiber reinforced carbon composites were studied. The most appropriate sampling direction was obtained. On basis of the results, affects of thickness on heat loss were studied, and the most appropriate specimen thickness was studied. Results indicated that the heat transfer in carbon/carbon composites was very complex during specific heat capacity tests. However, specific heat capacity values could be obtained at certain conditions. Directions of specimens should be benefit to decrease heat loss during tests. As for axial weaving reinforced carbon composites and felt reinforced composites, radial specimens were appropriate, which were high in fiber contents. Moreover, the fibers were uniformed distributed in radial specimens.