Papers by Author: Zhuo Xu

Abstract: C/C-SiC composites 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 C/C composites were infiltrated and reacted with melting silicon to obtain C/C-SiC composites. 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.

Abstract: C/C-SiC composites were rapidly fabricated using C/C with four different porosities in the range of 12.4%~45.7% and silicon by reactive-melt-infiltrated (RMI) method. The influence of the C/C porosity on the Si infiltration during the processing and on the microstructure and mechanical properties of the resulting C/C-SiC were investigated. The results show that β-SiC was formed by Si/C reaction and free Si remained in the composites. A higher porosity of C/C leads more Si infiltrating to the preform and produces higher density of C/C-SiC with lower porosity. The flexural strength of the composites was strong influenced by the matrix content and the interface between different phases. C/C-SiC derived from C/C with 24.8% porosity has the highest flexural strength (325.1MPa).