Effects of carbon fiber architecture on the microstructure and mechanical property of C/C-SiC composites
首发时间:2009-10-21
Abstract:Carbon/carbon silicon carbide composites (C/C-SiC) were rapidly fabricated by a two-steps processing. Firstly a short-cut carbon fiber felt (SC) and a 2D carbon fiber felt (2D) were densified to C/C composites by a thermal gradient chemical vapor infiltration (CVI) method with vaporized kerosene as a precursor in 2h, 3h, 4h and 5h, respectively. Then the two types of the C/C composites were infiltrated and reacted with melting silicon at ~1600oC to obtain C/C-SiC composites. The influences of the fiber architectures and the CVI time on the microstructure and mechanical property of the C/C-SiC composites were investigated. The results show that, with increase of the CVI time, the densities of the two types of C/C-SiC composites decrease in the range of 2.28g/cm3 to 2.00g/cm3; their porosities increase ranging from 1.3% to 7.5%; the contents of the β-SiC and the unreacted Si phases in the composites decline. The flexural strength of the 2D_C/C-SiC composite is much higher than that of the SC_C/C-SiC composite when prepared in the same condition. The 2D_C/C-SiC (CVI time=4h) composite has the highest flexural strength, which is ~130MPa. The mechanism of how the carbon fiber architecture influences the Si infiltration and the mechanical property of the C/C-SiC composite was illuminated.
keywords: Carbon fiber SiC Chemical vapor infiltration Microstructure Mechanical property
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碳纤维结构对C/C-SiC复合材料显微结构和力学性能的影响
摘要:以短切碳毡(SC)和2D碳纤维碳毡为增强体,采用热梯度CVI结合反应熔融渗硅(RMI)的两步法快速制备了C/C-SiC复合材料,其中CVI的时间分别为2h, 3h, 4h 和5h, RMI的温度为~1600℃,并研究了纤维结构和CVI时间对C/C-SiC复合材料显微结构和力学性能的影响。结果表明,随着CVI时间的增加,两种类型的C/C-SiC复合材料的密度在2.28g/cm3 到2.00g/cm3的范围内呈下降趋势,气孔率则从1.3%升至 7.5%,基体中的β-SiC和未反应的Si的含量减少。相同制备工艺条件下,2D_C/C-SiC复合材料的弯曲强度比SC_C/C-SiC复合材料高很多,其中CVI时间为4h的2D_C/C-SiC复合材料的弯曲强度最高(~130MPa)。并深入分析了纤维结构影响液Si渗入和复合材料力学性能的机理。
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No.3599517967512561****
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