论文部分内容阅读
采用液相加压浸渗法将TaC渗入到三维针刺毡中,并结合反应熔体渗透法(RMI)制得C/SiC-TaC复合材料。采用热膨胀仪测量了热处理前后复合材料从室温到1400℃温度范围内的热膨胀系数(CTE),发现C/SiC-TaC的CTE数值较C/SiC的高。从材料内部热应力的变化、制备方法及添加物和基体的性能方面定性地分析了CTE的变化机制。研究表明,C/SiC-TaC复合材料的膨胀性能在各个温度段的变化机制不同,低温段(1100℃以下)CTE的不断上升主要由90°无纬布、TaC和SiC基体贡献,该阶段的起伏波动主要由复合材料的结构应力和孔隙分布不均及残余Si产生;高温段(1100℃以上)的热膨胀性能主要由0°无纬布和界面热应力决定。热处理降低了复合材料在1100℃以下的CTE,也改变了高温段的变化规律。
TaC was infiltrated into three-dimensional needle felt by liquid pressure impregnation method, and C / SiC-TaC composite was prepared by reactive melt infiltration (RMI). The CTE of C / SiC-TaC was higher than that of C / SiC. The CTE of C / SiC-TaC was higher than that of C / SiC. The change mechanism of CTE was qualitatively analyzed from the change of internal thermal stress, the preparation method, the properties of additive and matrix. The results show that the expansion mechanism of C / SiC-TaC composites varies in different temperature ranges. The rising of CTE in low temperature range (below 1100 ℃) is mainly contributed by 90 ° non-woven fabric, TaC and SiC matrix. Fluctuations and fluctuations are mainly caused by the structural stress and uneven distribution of pores and residual Si in the composites. The thermal expansion at high temperature (above 1100 ℃) is mainly determined by the 0 ° no-weave and the interfacial thermal stress. Heat treatment reduces the CTE of the composites below 1100 ° C, and also changes the high temperature section of the law.