Microstructure and Compressive Behaviour of 3D Needled C/SiC Composites

2011 ◽  
Vol 194-196 ◽  
pp. 1599-1606 ◽  
Author(s):  
Shang Wu Fan ◽  
Li Tong Zhang ◽  
Lai Fei Cheng ◽  
Fang Xu

The 3D needled C/SiC composites were fabricated by chemical vapor infiltration combined with liquid melt infiltration. The microstructure and compressive behavior of 3D needled C/SiC composites were investigated. The results indicated that the 3D needled C/SiC composites were composed of the layers of 0 ° non-woven fiber cloth, short fiber web, 90 ° non-woven fiber cloth, and needle fibers. The materials were composed of carbon fiber, PyC, Si, and SiC. SiC and Si were mostly distributed in the short fiber web layers. Local C/C units (local carbon fiber reinforced PyC) were formed in the fiber bundles of non-woven fiber cloth. A great deal of pores and cracks existed in the 3D needled C/SiC composites. The pores less than 10 μm were generally located in the non-woven cloth layers, while the big pores were in the short fiber web layers. The cracks were regularly presented in the Si and SiC region of the composites and were normal to the axial direction of the fiber bundles. The compressive strengths perpendicular and parallel to the non-woven fiber cloth were about 118±18 MPa and 260±41 MPa, respectively. The compressive fractography revealed stepwise fracture along fiber layers direction.

2006 ◽  
Vol 11-12 ◽  
pp. 81-84 ◽  
Author(s):  
Dong Lin Zhao ◽  
Hong Feng Yin ◽  
Fa Luo ◽  
Wan Cheng Zhou

Three dimensional textile carbon fiber reinforced silicon carbide (3D textile C/SiC) composites with pyrolytic carbon interfacial layer were fabricated by chemical vapor infiltration. The microstructure and mechanical property of 3D textile C/SiC composites were investigated. A thin pyrolysis carbon layer (0.2 ± μm) was firstly deposited on the surface of carbon fiber as the interfacial layer with C3H6 at 850°C and 0.1 MPa. Methyltrichlorosilane (CH3SiCl3 or MTS) was used for the deposition of the silicon carbide matrix. The conditions used for SiC deposition were 1100°C, a hydrogen to MTS ratio of 10 and a pressure of 0.1 MPa. The density of the composites was 2.1 g cm-3. The flexural strength of the 3D textile C/SiC composites was 438 MPa. The 3D textile C/SiC composites with pyrolytic carbon interfacial layer exhibit good mechanical properties and a typical failure behavior involving fibers pull-out and brittle fracture of sub-bundle. The real part (ε′) and imaginary part (ε″) of the complex permittivity of the 3D-C/SiC composites are 51.53-52.44 and 41.18-42.08 respectively in the frequency range from 8.2 to 12.4 GHz. The 3D-C/SiC composites would be a good candidate for microwave absorber.


2007 ◽  
Vol 334-335 ◽  
pp. 145-148 ◽  
Author(s):  
Dong Mei Zhu ◽  
Fa Luo ◽  
Hong Na Du ◽  
Wan Cheng Zhou

A series of carbon fiber reinforced C-SiC dual matrix composites (C/C-SiC composites) were developed through precursor infiltration of polycarbosilane (PCS) and pyrolysis (PIP), using porous C/C composites with different density from chemical vapor infiltration (CVI) as the preform. The density, mechanical properties, and microstructure of the composites were investigated and the effects of the preform density and the PCS concentration of the infiltration solution on the final density and the mechanical properties of the composites were discussed in detail. The results show that the final density of the C/C-SiC composites prepared at the infiltration concentration of 50% is the highest, indicating that 50% is the proper PCS concentration of the PCS/ Xylene solution to prepare the C/C-SiC composites. The final densities of C/C-SiC composites were closely related to the preform density and the highest final density corresponds to the highest original preform density. For the composites prepared using infiltration solution of 50% PCS, the C/C-SiC composite whose preform density is 1.23 g/cm3 possesses the best mechanical properties while that whose preform density is 1.49 g/cm3 the worst mechanical properties.


2010 ◽  
Vol 658 ◽  
pp. 133-136 ◽  
Author(s):  
Ji Ping Wang ◽  
Jian Yong Lou ◽  
Zhuo Xu ◽  
Zhi Hao Jin ◽  
Guan Jun Qiao

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.


Author(s):  
Jun Lu ◽  
Dewei Ni ◽  
Chunjing Liao ◽  
Haijun Zhou ◽  
Youlin Jiang ◽  
...  

AbstractFiber damage and uniform interphase preparation are the main challenges in conventional short fiber reinforced ceramic matrix composites. In this work, we develop a novel processing route in fabrication of short carbon fiber reinforced ZrB2-SiC composites (Csf/ZrB2-SiC) overcoming the above two issues. At first, Csf preforms with oriented designation and uniform PyC/SiC interphase are fabricated via direct ink writing (DIW) of short carbon fiber paste followed by chemical vapor infiltration. After that, ZrB2 and SiC are introduced into the preforms by slurry impregnation and reactive melt infiltration, respectively. Microstructure evolution and optimization of the composites during fabrication are investigated in detail. The as-fabricated Csf/ZrB2-SiC composites have a bulk density of 2.47 g/cm3, with uniform weak interphase and without serious fiber damage. Consequently, non-brittle fracture occurs in the Csf/ZrB2-SiC composites with widespread toughening mechanisms such as crack deflection and bridging, interphase debonding, and fiber pull-out. This work provides a new opportunity to the material design and selection of short fiber reinforced composites.


2009 ◽  
Vol 24 (5) ◽  
pp. 939-942 ◽  
Author(s):  
Zhi-Xin MENG ◽  
Lai-Fei CHENG ◽  
Li-Tong ZHANG ◽  
Yong-Dong XU ◽  
Xiu-Feng HAN

2018 ◽  
Vol 44 (18) ◽  
pp. 22529-22537
Author(s):  
Yue Li ◽  
Zhaoke Chen ◽  
Ruiqian Zhang ◽  
Zongbei He ◽  
Haoran Wang ◽  
...  

Author(s):  
Bai Shuxin ◽  
Tong Yonggang ◽  
Ye Yicong ◽  
Zhang Hong

Carbon fiber reinforced ultra high temperature ceramic matrix composite (C/UHTC) is one of the most promising structural materials capable of prolonged operation in oxidizing environment at ultra high temperatures above 2000 ?C. Reactive melt infiltration (RMI) is a viable processing choice for C/UHTC composite. Compared with chemical vapor infiltration (CVI) and polymer impregnation and pyrolysis (PIP), RMI does not suffer from the drawbacks of time-consuming and high cost. It is viewed as a promising means of achieving near-net shape manufacturing with quick processing time and at low cost. Recently, great efforts have been made on RMI process for C/UHTC composite. Carbon fiber reinforced ZrC, HfC and TiC composites have been successfully fabricated by RMI. The aim of the following chapter is to introduce the RMI process and summarize the progress in RMI process for C/UHTC composite. In addition, future research directions of RMI are also proposed.


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