热处理温度对高导热3DC/C复合材料性能的影响  

Effect of heat treatment temperature on properties of high thermal conductivity 3D C/C composites

作　　者：阮家苗 李红[1] 姚彧敏 杨敏[1] 任慕苏[1] 孙晋良[1] RUAN Jia-miao;LI Hong;YAO Yu-min;YANG Min;REN Mu-su;SUN Jin-liang(Research Center of Composite Materials,School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学材料科学与工程学院复合材料研究中心,上海200444

出　　处：《材料工程》2021年第9期128-134,共7页Journal of Materials Engineering

基　　金：上海市教育发展基金会和上海市教育委员会“曙光计划”(18SG34);科技委项目(2017-JCJQ-ZD-035)。

摘　　要：通过化学气相渗透和前驱体浸渍裂解复合工艺对三向碳纤维织物进行致密化,获得密度为1.95 g/cm^(3)的高导热3D C/C复合材料。利用SEM,XRD,导热系数测试,线膨胀系数测试和三点弯曲实验,研究2350,2550,2850℃不同热处理温度对3D C/C复合材料微观形貌、结构、导热系数、线膨胀系数和弯曲性能的影响。结果表明:随着热处理温度的升高,中间相沥青基碳纤维石墨片层结构更加明显,均匀包裹在碳纤维周围的热解碳片层排列的有序度提高,且片层之间排列更加致密;3D C/C复合材料的石墨化度和导热系数提高;在测试温度250~1400℃区间,线膨胀系数随着测试温度的升高略微增大,不同热处理温度后的3D C/C复合材料线膨胀系数均在-1×10^(-6)~2×10^(-6)℃^(-1),表现出良好的“零膨胀性”。此外,当热处理温度升高,3D C/C复合材料的碳纤维与基体的结合减弱,导致材料的弯曲强度和弯曲模量降低,2850℃高温热处理后的材料弯曲断裂面出现大量长纤维拔出,总体来说,3种不同热处理温度后的断裂均表现出“假塑性”断裂特征。The three-dimensional carbon fiber fabric was densified by chemical vapor infiltration and precursor impregnation cracking composite process,and the high thermal conductivity 3D C/C composite material with density of 1.95 g/cm^(3) was obtained.Using SEM,XRD,thermal conductivity test,linear expansion coefficient test and three-point bending experiment to study the effect of different heat treatment temperatures of 2350,2550,2850℃on the microscopic morphology,structure,thermal conductivity,linear expansion coefficient and bending performance of 3D C/C composites.The results show that with the increase of the heat treatment temperature,the mesophase pitch-based carbon fiber graphite sheet structure becomes more obvious,the order of the pyrolytic carbon sheets evenly wrapped around the carbon fiber increases,and the arrangement between the sheets becomes more dense;the graphitization and thermal conductivity of 3D C/C composite materials improve;in the test temperature range of 250-1400℃,the linear expansion coefficient increases slightly with the increase of the test temperature,and the 3D C/C composite after different heat treatment temperatures.The linear expansion coefficient of the materials is-1×10^(-6)-2×10^(-6)℃^(-1),showing good“zero expansion”.In addition,when the heat treatment temperature increases,the bonding of the carbon fiber and the matrix of the 3D C/C composite materials are weakened,resulting in the decrease in the bending strength and flexural modulus of the materials.A large number of long fibers are pulled out on the bending fracture surface of the materials after the high temperature heat treatment at 2850℃.In general,the fracture after three different heat treatment temperatures shows“pseudoplastic”fracture characteristics.

关 键 词：3D C/C复合材料 热处理温度 微观形貌 导热系数 弯曲性能 

分 类 号：TB332[一般工业技术—材料科学与工程]