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Effect of Oxidation on Fracture Toughness of a Carbon/Carbon Composite 被引量:2
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作者 张程煜 郭永 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第5期944-947,共4页
The fracture toughness of a carbon/carbon composites oxidized at different temperature for 1 h was measured. The fracture surfaces were examined by scanning electron microscopy (SEM). The results indicate that oxida... The fracture toughness of a carbon/carbon composites oxidized at different temperature for 1 h was measured. The fracture surfaces were examined by scanning electron microscopy (SEM). The results indicate that oxidation temperature has significant effects on the fracture toughness. Fracture toughness decreases with the increase of the weight loss. The SEM images reveal that the decrease of fracture toughness was mainly attributed to the oxidation of the interface in the composite. 展开更多
关键词 c/c composite fracture toughness oxidation
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C/SiC/MoSi_2-SiC-Si multilayer coating for oxidation protection of carbon/carbon composites 被引量:5
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作者 张雨雷 李贺军 +2 位作者 胡志雄 李克智 张磊磊 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第7期2118-2122,共5页
C/SiC/MoSi2-SiC-Si oxidation protective multilayer coating for carbon/carbon (C/C) composites was prepared by pack cementation and slurry method. The microstructure, element distribution and phase composition of the... C/SiC/MoSi2-SiC-Si oxidation protective multilayer coating for carbon/carbon (C/C) composites was prepared by pack cementation and slurry method. The microstructure, element distribution and phase composition of the as-received coating were analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The results show that the multilayer coating was composed of MoSi2, SiC and Si. It could effectively protect C/C composites against oxidation for 200 h with the mass loss of 3.25% at 1873 K in static air. The mass loss of the coated C/C composites results from the volatilization of SiO2 and the formation of cracks and bubble holes in the coating. 展开更多
关键词 c/c composites c/SIc MOSI2 Sic MULTILAYER cOATING oxidation
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Bending properties and fracture mechanism of C/C composites with high density preform 被引量:9
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作者 张明瑜 苏哲安 +1 位作者 李建立 黄启忠 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第8期1795-1800,共6页
C/C composites with banded structure pyrocarbon were fabricated by fast chemical vapor infiltration(CVI),with C3H6 as carbon source,N2 as carrier gas,and three-dimensional(3D) 12K PAN-based carbon fabric with high... C/C composites with banded structure pyrocarbon were fabricated by fast chemical vapor infiltration(CVI),with C3H6 as carbon source,N2 as carrier gas,and three-dimensional(3D) 12K PAN-based carbon fabric with high density of 0.94 g/cm3 as preform.Experimental results indicated that the fracture characteristics of C/C composites were closely related to the frequency of high-temperature treatment(HTT) at the break of CVI process.According to the load?displacement curves,C/C composites showed a pseudoplastic fracture after twice of HTT.After three times of HTT,load?displacement curves tended to be stable with a decreasing bending strength at 177.5 MPa.Delamination failure and intrastratal fiber fracture were observed at the cross-section of C/C composites by scanning electronic microscope.Because the content of pyrocarbon and fibers has a different distribution in layers,the C/C composites show different fracture characteristics at various regions,which leads to good toughness and bending strength. 展开更多
关键词 c/c composites chemical vapor infiltration(cVI) high density preform bending properties fracture mechanism
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Fabrication of Y_2Si_2O_7 coating and its oxidation protection for C/SiC composites 被引量:3
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作者 马青松 蔡利辉 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第2期390-396,共7页
Yttrium silicate (Y2Si2O7) coating was fabricated on C/SiC composites through dip-coating with silicone resin + Y2O3 powder slurry as raw materials. The synthesis, microstructure and oxidation resistance and the an... Yttrium silicate (Y2Si2O7) coating was fabricated on C/SiC composites through dip-coating with silicone resin + Y2O3 powder slurry as raw materials. The synthesis, microstructure and oxidation resistance and the anti-oxidation mechanism of Y2Si2O7 coating were investigated. Y2Si2O7 can be synthesized by the pyrolysis of Y2O3 powder filled silicone resin at mass ratio of 54.2:45.8 and 800 °C in air and then heat treated at 1400 °C under Ar. The as-fabricated coating shows high density and favorable bonding to C/SiC composites. After oxidation in air at 1400, 1500 and 1600 °C for 30 min, the coating-containing composites possess 130%-140% of original flexural strength. The desirable thermal stability and the further densification of coating during oxidation are responsible for the excellent oxidation resistance. In addition, the formation of eutectic Y-Si-Al-O glassy phase between Y2Si2O7 and Al2O3 sample bracket at 1500 °C is discovered. 展开更多
关键词 c/Sic composites yttrium silicate cOATING oxidation resistance
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Fracture mechanism of 2D-C/C composites with pure smooth laminar pyrocarbon matrix under flexural loading
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作者 曹伟锋 李贺军 +3 位作者 郭领军 张守阳 李克智 邓海亮 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第7期2141-2146,共6页
Using natural gas as carbon source, 2D needle felt as preform, 2D-C/C composites were prepared by thermal gradient chemical vapor infiltration. Their microstructures were observed under polarized light microscope (PL... Using natural gas as carbon source, 2D needle felt as preform, 2D-C/C composites were prepared by thermal gradient chemical vapor infiltration. Their microstructures were observed under polarized light microscope (PLM) and scanning electron microscope (SEM), and the flexural behaviors before and after heat-treatment were studied with a universal mechanical testing machine. The fracture mechanism of the composites was discussed in detail. The results show that, carbon matrix exhibits pure smooth laminar (SL) characteristic including numerous wrinkled layered structures and some inter-laminar micro-cracks. With the decreasing density, the strength of the composites decreases and the toughness increases slightly; after 2500 °C heat-treatment, the inter-laminar micro-cracks in matrix increase, the strength decreases, and the toughness obviously increases. The fracture mode of the composites changes from brittle to pseudo-plastic characteristic due to more crack deflections in SL matrix. 展开更多
关键词 c/c composites PYROcARBON fracture flexural behavior
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W-Mo-Si/SiC Oxidation Protective Coating for Carbon/Carbon Composites 被引量:3
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作者 Dangshe HOU Kezhi LI Hejun LI Qiangang FU Jian WEI Yulei ZHANG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2007年第4期559-562,共4页
A W-Mo-Si/SiC double-layer oxidation protective coating for carbon/carbon (C/C) composites was prepared by a two-step pack cementation technique. XRD (X-ray diffraction) and SEM (scanning electron microscopy)res... A W-Mo-Si/SiC double-layer oxidation protective coating for carbon/carbon (C/C) composites was prepared by a two-step pack cementation technique. XRD (X-ray diffraction) and SEM (scanning electron microscopy)results show that the coating obtained by the first step pack cementation was a thin inner buffer layer of SiC with some cracks and pores, and a new phase of (WxMo1-x)Si2 appeared after the second step pack cementation. Oxidation test shows that, after oxidation in air at 1773 K for 175 h and thermal cycling between 1773 K and room temperature for 18 times, the weight loss of the W-Mo-Si/SiC coated C/C composites was only 2.06%. The oxidation protective failure of the W-Mo-Si/SiC coating was attributed to the formation of some penetrable cracks in the coating. 展开更多
关键词 c/c composites cOATING MIcROSTRUcTURE oxidation
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OXIDATION RESISTANCE AND SELF-SEALING PROPERTY OF CERAMIC COATINGS FOR C/C COMPOSITES 被引量:3
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作者 曾燮榕 李贺军 +1 位作者 杨峥 朱小旗 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1999年第2期49-52,共4页
The oxidation behavior and damage mechanism of modifiers and compounds of many types of ceramic coatings were investigated experimentally. A MoSi 2/SiC coating was produced by infiltration process. The oxidation beha... The oxidation behavior and damage mechanism of modifiers and compounds of many types of ceramic coatings were investigated experimentally. A MoSi 2/SiC coating was produced by infiltration process. The oxidation behavior of the coated C/C composites was studied at various temperatures below 1650℃. The oxidation results showed that the MoSi 2/SiC coating for thermal protection of C/C composites has high oxidation resistance at temperature up to 1650℃. In the present work, a new model of an oxidation protective, self sealing multi layer coating system was proposed for C/C composites. The multi layer coating possessing the self sealing property was obtained by pack cementation and infiltration process. The protection coating system for C/C composites consists of an inner layer of SiC and an outer layer of porous refractory oxides filled by modified SiO 2 glass. Isothermal and cyclic thermal oxidation tests showed the multi layer coating was capable of protecting the C/C composites in an oxidizing atmosphere at temperature up to 1800℃. 展开更多
关键词 c/c composite oxidation protection coating self sealing
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Oxidation behavior of CVI,MSI and CVI+MSI C/SiC composites 被引量:2
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作者 闫志巧 陈峰 +3 位作者 熊翔 肖鹏 张红波 黄伯云 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第4期590-596,共7页
The oxidation behavior of chemical vapor infiltration(CVI),molten silicon infiltration(MSI)and CVI+MSI C/SiC composites at 500-1 400℃was studied.The oxidation below 900℃increased successively for CVI,CVI+MSI and MSI... The oxidation behavior of chemical vapor infiltration(CVI),molten silicon infiltration(MSI)and CVI+MSI C/SiC composites at 500-1 400℃was studied.The oxidation below 900℃increased successively for CVI,CVI+MSI and MSI composites.However,the oxidation of CVI composite above 1 000 ℃was much faster thanthat of MSI and CVI+MSI composites. As active carbon atoms produced by siliconization of fibers during MSI process were oxidized first and decreased initial oxidation temperature.The initial oxidation temperature of MSI,MSI+CVI and CVI composites was 526,552 and 710℃,respectively.New active carbon atoms were generated due to the breaking of 2D molecular chains during oxidation,so the activation energy of three C/SiC composites was decreased gradually at 500-800℃with oxidation process,exhibiting a self-catalytic characteristic. 展开更多
关键词 chemical vapor infiltration(cVI) molten silicon infiltration(MSI) c/Sic composites oxidation
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Oxidation Behavior of C/C-SiC Gradient Matrix Composites 被引量:6
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作者 Jingyi DENG, Wenchuan LIU, Haifeng DU, Huiming CHENG and Yiyi LI Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第5期543-546,共4页
Oxidation behavior of C/C-SiC gradient matrix composites and C/C composites were compared in stationary air. The results show that oxidation threshold of C-SiC materials increases with the amount of SiC particles in t... Oxidation behavior of C/C-SiC gradient matrix composites and C/C composites were compared in stationary air. The results show that oxidation threshold of C-SiC materials increases with the amount of SiC particles in the codeposition matrix. Oxidation rate of C/C-SiC gradient matrix composites is significantly lower than that of C/C material. The micro-oxidation process was observed by SEM. 展开更多
关键词 oxidation Behavior of c/c-Sic Gradient Matrix composites SIc SIc
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Effects of Temperature Induced Thermal Expansion and Oxidation on the Charpy Impact Property of C/C Composites 被引量:1
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作者 米应映 燕青芝 +3 位作者 LI Xianhui HONG Ming CAO Meiqi ZHANG Xiaoxin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2015年第3期473-477,共5页
C/C composites are the emerging materials of choice for aero-engine hot-end components that will bear impact loading in thermal-oxidizing environments. For the components run for extended periods, the safe operation o... C/C composites are the emerging materials of choice for aero-engine hot-end components that will bear impact loading in thermal-oxidizing environments. For the components run for extended periods, the safe operation of components depends on how to evaluate damages under a dynamic load. In this study, Charpy impact tests at a temperature range of 25 to l 200 "C were carried out on C/C composites to verify the effects of temperature induced thermal expansion and oxidation on their impact performance. Below 800 ℃, oxidation was negligible and composites expanding played a leading role, resulting in the remarkable increase in fiber/ matrix interface strength and impact energy. However, when the temperature was above 800 ℃, the release of CO or CO2 due to oxidation resulted in a lower impact energy. 展开更多
关键词 c/c composites impact property thermal expansion oxidation
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Oxidation behavior of oxidation protective coatings for C/C-SiC composites at 1500 ℃ 被引量:5
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作者 闫志巧 熊翔 +3 位作者 肖鹏 陈峰 张红波 黄伯云 《中国有色金属学会会刊:英文版》 CSCD 2009年第1期61-64,共4页
Porous carbon/carbon preforms were infiltrated with melted silicon to form C/C-SiC composites. Three-layer Si-Mo coating prepared by slurry painting and SiC/Si-Mo multilayer coating prepared by chemical vapor depositi... Porous carbon/carbon preforms were infiltrated with melted silicon to form C/C-SiC composites. Three-layer Si-Mo coating prepared by slurry painting and SiC/Si-Mo multilayer coating prepared by chemical vapor deposition(CVD) alternated with slurry painting were applied on C/C-SiC composites, respectively. The oxidation of three samples at 1 500 ℃ was compared. The results show that the C/C-SiC substrate is distorted quickly. Three-layer Si-Mo coating is out of service soon due to the formation of many bubbles on surface. The mass loss of coated sample is 0.76% after 1 h oxidation. The sample with SiC/Si-Mo multilayer coating gains mass even after 105 h oxidation. SiC/Si-Mo multilayer coating can provide longtime protection for C/C-SiC composites and has excellent thermal shock resistance. This is attributed to the combination of dense SiC layer and porous Si-Mo layer. Dense SiC layer plays the dual role of physical and chemical barrier, and resists the oxidation of porous Si-Mo layer. Porous Si-Mo layer improves the thermal shock resistance of the coating. 展开更多
关键词 c/c-SIc复合材料 防氧化涂层 氧化性能 金属防护层 金属腐蚀
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Oxidation mechanisms of C-SiC-TaC-C composites prepared by chemical vapor infiltration 被引量:2
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作者 陈招科 熊翔 +4 位作者 黄伯云 李国栋 肖鹏 王雅雷 王琼 《中国有色金属学会会刊:英文版》 CSCD 2007年第A01期145-149,共5页
To improve the oxidation-resistance properties,SiC and TaC species were introduced in C/C composites by chemical vapor infiltration(CVI) methods. The oxidation-resistance properties of C-SiC-TaC-C composites were stud... To improve the oxidation-resistance properties,SiC and TaC species were introduced in C/C composites by chemical vapor infiltration(CVI) methods. The oxidation-resistance properties of C-SiC-TaC-C composites were studied by X-Ray diffractometry(XRD),JEOL-6360LV scanning electronic microscopy(SEM) and AdventurerTM electronic balance with precision of 0.1 mg. The results show that,1) the oxidation rate of the composites increases continuously with time at all experimental temperatures;2) The oxidation rate increases with temperature within 700-1 100 ℃,slowly in 700-800 ℃,acutely in 800-1 100 ℃;it reaches a maximum value at 1 100 ℃,then decreases within 1 100-1 400 ℃;3) The relationship curve of oxidation rate with temperature can be divided into three regions. The oxidation rate is controlled by reactivity in region Ⅰ,the mixed effects of reactivity and gas diffusion in region Ⅱ,gas phase diffusion in region Ⅲ;4) The composites exhibit a higher oxidation onset temperature in low temperature region and a lower oxidation rate at high temperature due to the oxidation of TaC to(Ta,O) and the formation of the dense SiO2-Ta2O5 oxide layer respectively. With the addition of SiC/TaC species,the oxidation-resistant properties of C/C composites can be improved effectively. 展开更多
关键词 碳化合物 化学特性 抗氧化性 合金
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Microstructure of a Mo-Si-C-N multi-layered anti-oxidation coating on carbon/carbon composites by fused slurry 被引量:1
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作者 LAI Zhonghong MENG Songhe +1 位作者 ZHU Jingchuan JEON Jaeho 《Rare Metals》 SCIE EI CAS CSCD 2009年第5期460-464,共5页
A Mo-Si-C-N multi-layered anti-oxidation coating was in-situ fabricated by introducing nitrogen atmosphere during the fused sintering of Mo-Si slurry pre-layer on carbon/carbon composites. The phase composition and mi... A Mo-Si-C-N multi-layered anti-oxidation coating was in-situ fabricated by introducing nitrogen atmosphere during the fused sintering of Mo-Si slurry pre-layer on carbon/carbon composites. The phase composition and microstructure of the Mo-Si-C-N coating were characterized by X-ray diffractometry, optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The Mo-Si-C-N coating exhibited a three-layered structure. Besides the MoSi2/Si main-layer and the SiC bonding-layer, a surface layer of about 10 μm in thickness was synthesized on the coating surface. The surface layer mainly consisted of SiC nanowires and contained some Si3N4 and Si phases. SiC nanowires of 10 to 200 nm in diameter presented a terrace and distortion structure. Transmission electron microscopy indicated that the SiC nanowires grew along the preferred 〈111〉 direction. During oxidation test, SiC nanowires transmuted into SiO2 glass, which can play an important role in improving the oxidation resistance of C/C composites. 展开更多
关键词 c/c composites cOATING MIcROSTRUcTURES ANTI-oxidation
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Preparation and Anti-oxidation Mechanism of Mullite/Yttrium Silicate Coatings on C/SiC Composites 被引量:3
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作者 马青松 cai lihui 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第6期1284-1288,共5页
In order to enhance the oxidation resistance of C/Si C composites, mullite/yttrium silicate coatings were fabricated on C/Si C composites through dip-coating route. Al_2O_3-SiO_2 sol with high solid content was select... In order to enhance the oxidation resistance of C/Si C composites, mullite/yttrium silicate coatings were fabricated on C/Si C composites through dip-coating route. Al_2O_3-SiO_2 sol with high solid content was selected as the raw material for mullite and "silicone resin + Y_2O_3 powder" slurry was used to synthesize yttrium silicate. The microstructure and phase composition of coatings were characterized, and the investigation on oxidation resistance and anti-oxidation mechanism was emphasized. The as-fabricated coatings consisting of SiO_2-rich mullite phase and Y_2Si_2O_7 phase show high density and favorable bonding to C/Si C composites. After oxidized at 1 400 ℃ and 1 500 ℃ for 30 min in static air, the coating-containing C/Si C composites possess 91.9% and 102.4% of the original flexural strength, respectively. The desirable thermal stability of coatings and the further densification of coatings due to viscous flow of rich SiO_2 and Y-Si-Al-O glass are responsible for the excellent oxidation resistance. In addition, the coating-containing composites retain 99.0% of the original flexural strength and the coatings exhibit no cracking and desquamation after 12 times of thermal shock from 1 400 ℃ to room temperature, which are ascribed to the combination of anti-oxidation mechanism and preferable physical and chemical compatibility among C/Si C composites, mullite and Y_2Si_2O_7. The carbothermal reaction at 1 600 ℃ between free carbon in C/Si C substrate and rich SiO_2 in mullite results in severe frothing and desquamation of coatings and obvious degradation in oxidation resistance. 展开更多
关键词 anti-oxidation coatings mullite yttrium silicate c/Sic composites
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Effect of Plastic Deformation and H_2S on Dynamic Fracture Toughness of High Strength Casing Steel 被引量:1
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作者 曾德智 ZHANG Naiyan +3 位作者 TIAN Gang HU Junying ZHANG Zhi SHI Taihe 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2015年第2期397-403,共7页
The effects of plastic deformation and H2 S on fracture toughness of high strength casing steel(C110 steel) were investigated. The studied casing specimens are as follows: original casing, plastic deformation(PD)... The effects of plastic deformation and H2 S on fracture toughness of high strength casing steel(C110 steel) were investigated. The studied casing specimens are as follows: original casing, plastic deformation(PD) casing and PD casing after being immersed in NACE A solution saturated with H2S(PD+H2S). Instrumented impact method was employed to evaluate the impact behaviors of the specimens, meanwhile, dynamic fracture toughness(JId) was calculated by using Rice model and Schindler model. The experimental results show that dynamic fracture toughness of the casing decreases after plastic deformation. Compared with that of the original casing and PD casing, the dynamic fracture toughness decreases further when the PD casing immersed in H2 S, moreover, there are ridge-shaped feature and many secondary cracks present on the fracture surface of the specimens. Impact fracture mechanism of the casing is proposed as follows: the plastic deformation results in the increase of defect density of materials where the atomic hydrogen can accumulate in reversible or irreversible traps and even recombine to form molecular hydrogen, subsequently, the casing material toughness decreases greatly. 展开更多
关键词 sour gas fields high strength casing c110 steel plastic deformation H2S fracture toughness
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FRACTURE MODE AND PROCESS OF SiCw+B4Cp/MB15 MAGNESIUM MATRIX COMPOSITE
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作者 Su, Ying Zhang, Guoding +2 位作者 Wang, Huimin Zhang, Di Qin, Jining 《中国有色金属学会会刊:英文版》 EI CSCD 1997年第3期109-113,共5页
FRACTUREMODEANDPROCESSOFSiCw+B4Cp/MB15MAGNESIUMMATRIXCOMPOSITE①SuYing,ZhangGuoding,WangHuimin,ZhangDi,QinJin... FRACTUREMODEANDPROCESSOFSiCw+B4Cp/MB15MAGNESIUMMATRIXCOMPOSITE①SuYing,ZhangGuoding,WangHuimin,ZhangDi,QinJiningStateKeyLabofM... 展开更多
关键词 MAGNESIUM composites SIc WHISKERS B 4c PARTIcLES fracture
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Anti-oxidation mechanism of SiC-B_4C-C composites
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作者 刘其城 徐协文 +1 位作者 黄启忠 黄伯云 《中国有色金属学会会刊:英文版》 EI CSCD 2005年第6期1346-1350,共5页
Mixture of green petroleum coke, B4C and SiC together with short carbon fiber were employed as starting materials, the mixture was press-formed without any binder after grinding, dense and homogeneous binderless SiC-B... Mixture of green petroleum coke, B4C and SiC together with short carbon fiber were employed as starting materials, the mixture was press-formed without any binder after grinding, dense and homogeneous binderless SiC-B4C-C(carbon/ceramic) composites were then obtained after sintering. Composites thus prepared possess excellent anti-oxidation property, that is, mass loss less than 1% within the temperature range from 900 to 1100℃ for 10h. Anti-oxidation mechanism was also discussed from the viewpoint of thermodynamics, excellent anti-oxidation property of materials thus prepared can be discribed to 1) solid SiO2 formed from SiC, which restrains the filtering of oxygen and simultaneously, its volume expansion brought about by the reaction takes roles both walling up the (original) pores and making the material more compact; 2) liquid B2O3 from the reaction of B4C not only makes the combination with C, B4C and SiC tighter through forming solid solution, but also effect of reaction SiC(s)+2CO(g)=SiO2(s)+3C(s) is an expansive process, which improves the microstructure of the material. 展开更多
关键词 c-c复合材料 SIc B4c 石油焦 抗氧化机制
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Property and Oxidation Behaviours of (Mo,Cr)Si2 + ZrO2 Composite Produced by Pressure-Less Sintering
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作者 Yiming Yao Erik Ström +1 位作者 Xin-Hai Li Qin Lu 《Journal of Materials Science and Chemical Engineering》 2016年第7期15-21,共7页
A composites of (Mo<sub>0.9</sub>Cr<sub>0.1</sub>)Si<sub>2</sub> + 15vol% ZrO<sub>2</sub> was prepared with powder metallurgy and Pressure- Less Sintering (PLS) method, ... A composites of (Mo<sub>0.9</sub>Cr<sub>0.1</sub>)Si<sub>2</sub> + 15vol% ZrO<sub>2</sub> was prepared with powder metallurgy and Pressure- Less Sintering (PLS) method, aiming at applications of high temperature structural materials. Mechanical properties of the composites were assessed with hardness, indentation fracture toughness K<sub>c</sub> and K<sub>IC</sub> tested using SEVNB, flexure strength at room temperature and 1200?C, and isothermal oxidation at 1400?C. The results showed that the native silica oxide and molybdenum-oxides on the silicide feedstock surface were significantly reduced in terms of Cr-alloying. (Mo<sub>0.9</sub>Cr<sub>0.1</sub>)Si<sub>2</sub> and its composite also exhibited improved sinterability and grain growth, owing to the presence of (Cr, Mo)<sub>5</sub>Si<sub>3</sub> at grain boundaries. Fracture toughness of the composite was increased by a factor of 1.6 to that in the monolithic silicide. Mechanical property of the composite at high temperature was not affected by Cr addition. However, the high temperature oxidation resistance was greatly improved in the (Mo<sub>0.9</sub>Cr<sub>0.1</sub>)Si<sub>2</sub> + 15vol% ZrO<sub>2</sub> compared with the non Cr-alloyed counterpart. The Cr-alloying effects on the microstructure, fracture behaviour, and high temperature oxidation resistance were discussed. 展开更多
关键词 MOSI2 composite fracture toughness Mechanical Property Microstructure High Temperature oxidation
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Influence of additives on oxidation resistance of binderless C/C composite
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作者 周声劢 刘其城 胡晓凯 《中国有色金属学会会刊:英文版》 CSCD 2003年第1期162-164,共3页
Experiment of adding B 4C, SiC, and Si powders to improve oxidation resistance of the C/C composites was carried out. The results show that the increase of oxidation resistance is remarkable when the contents of B 4C,... Experiment of adding B 4C, SiC, and Si powders to improve oxidation resistance of the C/C composites was carried out. The results show that the increase of oxidation resistance is remarkable when the contents of B 4C, SiC, and Si powders are 10%, 10%, and 5% in the composites, respectively. The regularities and mechanism of the effects of the ceramic powders on the oxidation resistance of the composites were also discussed. 展开更多
关键词 抗氧化性 无粘合剂 c/c复合材料
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Effect of fiber characteristics on fracture behavior of C_f/SiC composites
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作者 何新波 杨辉 张新明 《中国有色金属学会会刊:英文版》 CSCD 2002年第1期30-33,共4页
C f/SiC composites were prepared by precursor pyrolysis hot pressing, and the effect of fiber characteristics on the fracture behavior of the composites was investigated. Because the heat treatment temperature of fibe... C f/SiC composites were prepared by precursor pyrolysis hot pressing, and the effect of fiber characteristics on the fracture behavior of the composites was investigated. Because the heat treatment temperature of fiber T300 (below 1?500?℃) was much lower than that of fiber M40JB (over 2?000?℃), fiber T300 had lower degree of graphitization and consisted of more impurities compared with fiber M40JB, suggesting that T300 exhibits higher chemical activity. As a result, the composite with T300 showed a brittle fracture behavior, which is mainly ascribed to a strongly bonded fiber/matrix interface as well as the degradation of fibers during the preparation of the composite. However, the composite with M40JB exhibits a tough fracture behavior, which is primarily attributed to a weakly bonded fiber/matrix interface and higher strength retention of the fibers. 展开更多
关键词 光纤特性 断裂性能 cf/Sic合成物 光纤增强陶瓷合成物
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