刘伟
,
刘荣军
,
曹英斌
,
杨会永
玻璃钢/复合材料
建立了C/C预制体孔隙率与C/SiC复合材料组成的关系模型,并通过表征不同孔隙率的C/C预制体气相硅浸渗制备的C/SiC复合材料的组成和力学性能对模型进行了验证.研究发现,实验结果与模型预测结果基本一致.随着C/C预制体孔隙率的增大,C/SiC复合材料的密度出现先上升后下降的规律,力学性能也遵从同样的规律.XRD分析和相含量测试结果均表明复合材料的相含量与模型预测结果基本一致.实验结果与模型预测结果产生偏差的主要原因是裂解碳反应不完全.
关键词:
C/C
,
C/SiC
,
孔隙率
,
模型
,
气相硅浸渗
张明瑜
,
黄启忠
,
朱建军
,
尹彩流
材料导报
总结了制备C/C的各种化学气相渗透方法,指出了其优缺点.缩短致密化时间、协调气相反应和表面沉积反应之间的竞争是快速致密化方法要解决的首要问题.介绍了热解炭的微观结构和石墨化度及其沉积机理的新发展.近期的研究集中在化学反应成分分析和数值模拟渗透过程上.展望了化学气相渗透研究的方向,探求热解炭沉积机理的必要性并指出了快速致密化方法是实现低成本、高效率制备高性能C/C的必由之路.
关键词:
化学气相渗透
,
C/C
,
热解炭
张会杰
,
孙乐民
,
上官宝
,
张永振
机械工程材料
在空气/氮气气氛下研究了电流、摩擦速度、载荷等试验参数对C/C复合材料载流磨损率和摩擦因数的影响,并对磨损表面的形貌和成分进行了观察和分析.结果表明:随着电流和摩擦速度增大,C/C复合材料的磨损率和摩擦因数均增大;相较于空气气氛,氮气气氛下的摩擦因数较高,磨损率较低;空气气氛中炭材料的氧化加剧了材料的磨损,使得磨损率较高,而摩擦过程中材料表面形成的氧化膜使得摩擦因数较低.
关键词:
C/C复合材料
,
摩擦因数
,
磨损率
Hanwei HE
,
Kechao ZHOU
材料科学技术（英）
A new method for preparation of TaC coating on C/C composite material is reported. The amorphous ethylate tantalum jellied as the precursor is prepared and spread densely on the surface of the C/C composite material so as to form a multilayer film. In a graphitization furnace the multilayer film is transformed into TaC coating at various temperatures. Ethylate tantalum film is characterized by FT-IR (Fourier transform infrared) spectra, XRD (X-ray diffraction) and SEM (scanning electron microscopy) and TaC coating is characterized by XRD and SEM. At 1200℃ the coating contained TaC and Ta¬2O5, and at above 1400℃ only TaC is formed. The coating formed at 1600℃ is a continuous stratum structure, and that formed at 1600℃ is a porous net structure. Analysis on thermodynamics and formation mechanism of TaC indicates that, after ethylate tantalum is decomposed, Ta2O¬5 is first produced and then transformed into Ta2C, and newly formed Ta2C is transformed into TaC by the sufficient C at last.
关键词:
C/C composite
,
composite
,
material
,
TaC
,
coating
,
ethyl
B.Wielage
材料科学技术（英）
The effects of fibre/matrix bonding, fabric density, fibre volume fraction and bundle size on microstructure, mechanical properties and failure mechanisms in carbon fibre reinforced composites (plastic and carbon matrix) have been investigated. The microstructure of unloaded and cracked samples was studied by optical microscopy and scanning electron microscopy (SEM), respectively whereas the mechanical behaviour was examined by 3-point bending experiments. Exclusively one type of experimental resole type phenolic resin was applied. A strong fibre/matrix bonding, which is needed for high strength of carbon fibre reinforced plastic (CFRP) materials leads to severe composite damages during the pyrolysis resulting in low strength, brittle failure and a very low utilisation of the fibres strain to failure in C/C composites. Inherent fabric parameters such as an increasing fabric density or bundle size or a reduced fibre volume fraction introduce inhomogenities to the CFRP0s microstructure. Results are lower strength and stiffness whereas the strain to failure increases or remains unchanged. Toughness is almost not affected. In C/C composites inhomogenities due to a reduced bundle size reduce strain to failure, strength, stiffness and toughness. Vice versa a declining fibre volume fraction leads to exactly the opposite behaviour. Increasing the fabric density (weight per unit area) causes similar effects as in CFRPs.
关键词:
CFRPs
,
null
,
null
,
null
,
null
