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| 1 | 预制体孔隙结构对炭/炭复合材料ICVI制备工艺的影响显示文摘研究了预制体孔隙结构对ICVI工艺致密化过程及基体热解炭微观结构的影响。结果表明:2D针刺炭毡致密化速度高于炭布叠层预制体,1K炭布叠层预制体的致密化速度高于3K炭布叠层;在致密化过程中,热解炭均匀沉积在纤维表面,预制体AS/VR比值变化是导致热解炭微观结构发生改变的根本原因。 | 白瑞成 李贺军 付业伟 王兰英 卢锦花 | 2005 | 炭素技术2005,24,3: | 9 |
| 2 | 前驱体对C/C复合材料的致密化和性能的影响显示文摘研究了分别以甲烷和丙烯为前驱体对制备C/C复合材料的新型ICVI工艺致密化速率及组织结构和力学性能的影响。考察了密度与致密化时间之间的变化规律和密度分布,采用偏光显微镜和扫描电镜观察材料的组织结构和试样的断口形貌,利用三点弯曲实验测定材料的弯曲强度。实验结果表明:在致密化时间100h前,以甲烷为前驱体,C/C复合材料的致密化速率比丙烯为前驱体时低,100h后致密化速率发生逆转;以甲烷为前驱体所得C/C复合材料的密度梯度小,组织结构为粗糙层,弯曲强度为250.87MPa,模量为29.29GPa;而以丙烯为前驱体所得C/C复合材料的密度梯度大,组织结构为光滑层,弯曲强度为102.75MPa,模量为11.42GPa。因此,相对而言甲烷作为制备C/C复合材料的前驱体优于丙烯。 | 徐国忠 李贺军 白瑞成 陈拂晓 黄敏 | 2007 | 材料工程2007,35,6: | 8 |
| 3 | Modeling of CVI process in fabrication of carbon/carbon composites by an artificial neural network显示文摘The chemical vapor infiltration(CVI) process in fabrication of carbon-carbon composites is very complex and highly inefficient, which adds considerably to the cost of fabrication and limits the application of the material. This paper tries to use a supervised artificial neural network(ANN) to model the nonlinear relationship between parameters of isothermal CVI(ICVI) processes and physical properties of C/C composites. A model for preprocessing dataset and selecting its topology is developed using the Levenberg-Marquardt training algorithm and trained with comprehensive dataset of tubal C/C components collected from experimental data and abundant simulated data obtained by the finite element method. A basic repository on the domain knowledge of CVI processes is established via sufficient data mining by the network. With the help of the repository stored in the trained network, not only the time-dependent effects of parameters in CVI processes but also their coupling effects can be analyzed and predicted. The results show that the ANN system is effective and successful for optimizing CVI processes in fabrication of C/C composites. | 李爱军 李贺军 李克智 顾正彬 | 2003 | Science China(Technological Sciences)2003,46,2: | 5 |
| 4 | 单向碳/碳复合材料ICVI致密化机理研究显示文摘通过把致密化进程中热解碳作为分散相和连续相两种情况进行统一处理,研究了圆柱形单向碳/碳复合材料的化学气相渗透过程。着重讨论了致密化的均匀性问题,分析了预制体纤维体积分数对致密进程的影响及预制体内贯穿大孔洞对致密化的增进作用。研究结果表明,预制体纤维体积分数越低,致密化后期所能达到的密度越高,致密化的均匀程度也越好;贯穿大孔洞的存在,大大提高了丙烯气体在预制体内的传输能力,使内部的致密化效果有了很大改善。 | 侯向辉 李贺军 刘应楼 康沫狂 | 1999 | 西北工业大学学报1999,17,2: | 5 |
| 5 | ICVI制备炭/炭复合材料流场模拟显示文摘为探讨制备炭/炭复合材料等温化学气相渗透工艺渗透过程,用Navier-Stokes方程耦合Brinkman方程成功地模拟了混合前驱体在沉积炉内流场。分析了该流场的特征,讨论了流场与沉积炉入口尺寸和初始流速的关系。为保证混合前驱体在自由流动空间内为层流,当入口尺寸为0.01m时,初始速度应该为0.4m/s。 | 杨锦 李贺军 李克智 张守阳 | 2008 | 科学技术与工程2008,8,11: | 3 |
| 6 | 正丙醇ICVI制备C/C复合材料的组织结构及力学性能显示文摘以正丙醇为前驱体,N2为载气和稀释气体,采用等温化学气相渗透(ICVI)工艺,沉积温度为1050、1100、1150℃,压力为6kPa,对初始密度为0.43g/cm3的2D针刺炭毡进行致密化,沉积96h制备出表观密度分别为1.64、1.68和1.69/cm3的C/C复合材料.考察了密度随沉积时间的变化规律,利用三点弯曲测试了材料的弯曲强度,采用偏光显微镜、扫描电子显微镜观察了材料的组织结构和断口形貌.结果表明:以正丙醇为前驱体,采用ICVI工艺在1050和1150℃下制备的试样组织为高织构和中织构的混合组织,1100℃制备的试样基体组织为均一的高织构,其弯曲强度可达199.24MPa.在本实验条件下,并未发现正丙醇中的氧元素在高温下对炭纤维的腐蚀作用,正丙醇可以作为前驱体制备高性能C/C复合材料. | 刘志成 张守阳 李贺军 李伟 | 2011 | 无机材料学报2011,26,2: | 3 |
| 7 | 正丁醇等温CVI工艺制备C/C复合材料显示文摘以正丁醇为前躯体,N2为载气和稀释气,以2D炭毡为预制体,在负压和沉积温度为1 150℃的实验条件下,采用等温化学气相渗透(ICVI)工艺制备出C/C复合材料制品,讨论了沉积时间与密度的变化规律以及预制体内部密度分布规律。利用三点弯曲测定了材料的弯曲强度,采用偏光显微镜、扫描电镜观察了材料的组织结构和断口形貌。结果表明,试样的组织结构以具有靠近纤维部分为中织构热解炭组织,外部为高织构热解炭组织特征,断裂方式为假塑性断裂,并且具有优异的力学性能。研究表明丁醇中氧元素的存在并未在高温下对炭纤维产生腐蚀破坏作用,正丁醇可以作为前躯体中的一种组分用于CVI工艺热解制备高性能C/C复合材料。 | 李伟 张守阳 李贺军 任俊杰 刘志成 | 2010 | 固体火箭技术2010,33,6: | 2 |
| 8 | ICVI法制备C/SiC复合材料构件的数值模拟显示文摘根据C/SiC复合材料的结构特点及等温化学气相浸渗法的工艺特点,建立了C/SiC复合材料ICVI致密化过程的数学模型,并将该模型应用于C/SiC复合材料构件制备过程的数值模拟中。利用有限单元法,对航空发动机用C/SiC复合材料小喉衬的ICVI致密化行为进行了数值计算和分析。为了验证计算结果,设计并进行了相应的对比实验,对致密化后的喉衬构件进行了密度测量和CT断层扫描无损检测。实验结果与模拟结果呈现出相同的变化规律并且两者之间偏差较小,表明本文作者所建立的模型可以很好地描述C/SiC复合材料的ICVI过程。利用该数学模型,计算了ICVI过程中喉衬构件的密度分布及其演变规律,为ICVI法制备C/SiC复合材料构件的进一步研究打下基础,对ICVI工艺的优化具有一定的指导意义。 | 魏玺 成来飞 张立同 徐永东 | 2006 | 复合材料学报2006,23,5: | 2 |
| 9 | Densification and microstructure of carbon/carbon composites prepared by chemical vapor infiltration using ethanol as precursor显示文摘Chemical vapor infiltration of carbon fiber felts with uniform initial bulk density of 0.47 g·cm-3 was investigated at the ethanol partial pressures of 5-20 kPa,as well as the temperatures of 1050,1100,1150 and 1200°C.Ethanol,diluted by nitrogen,was employed as the precursor of pyrolytic carbon.Polarized light microscopy(PLM),scanning electron microscopy and X-ray diffraction were adopted to study the texture of pyrolytic carbon deposited at various temperatures.A change from medium-to high-textured pyrolytic carbon was observed in the sample infiltrated at 1050°C.Whereas,homogeneous high-textured pyrolytic carbons were deposited at the temperatures of 1100,1150 and 1200°C.Extinction angles of 19°-21° were determined for different regions in the samples densified at the temperatures ranging from 1100 to 1200°C.Scanning electron microscopy of the fracture surface after bending test indicated that the prepared carbon/carbon composite samples exhibited a pseudo-plastic fracture behavior.In addition,fracture behavior of the carbon/carbon samples was obviously effected by their infiltration temperature.The fracture mode of C/C composites was transformed from shearing failure to tensile breakage with increasing infiltration temperature. Results of this study show that ethanol is a promising carbon source to synthesize carbon/carbon composites with homogeneously high-textured pyrolytic carbon over a wide range of temperatures(from 1100 to 1200°C). | LI Wei,ZHANG ShouYang ,YAN XiaFeng,LI HeJun&LI KeZhi State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China | 2010 | Science China(Technological Sciences)2010,53,8: | 1 |