【摘要】 利用热膨胀仪测定了炭/炭复合材料从室温到1300℃的热膨胀系数,研究了热处理温度、炭纤维取向和环境温度对炭/炭复合材料热膨胀性能的影响。结果表明由于热解炭是以层状的方式围绕炭纤维生长,所以其热膨胀各向异性,垂直于纤维方向的热膨胀大于平行于纤维方向的热膨胀。随着热处理温度的升高,炭/炭复合材料中具有乱层石墨结构的晶体有序度增加,石墨化度增大,石墨片层间的范德华作用力增强,热膨胀系数减小。随着环境温度的升高热膨胀系数先增大后减小,在1200℃有最大值。更多还原

【Abstract】 The thermal expansion of carbon/carbon composite from room temperatur to 1300℃ was measured by using a Netzsch DIL 402C dilatometer.The influences of heat treatment,the preform architecture and the environmental temperature on thermal expansion were investigated.The results show that the graphitic flat-layered structure crystallites of pyrocarbon are arranged on the surface of the carbon fiber,and grow around the carbon fiber in the form of a ringed multilayer structure.Therefore,the thermal expansion is anisotropic and is higher in perpendicular direction than parallel direction to fiber.The graphitization degree of carbon/carbon composite is enhanced with the increasing of the heat treatment temperature,at the same time,the space between graphite crystallite layers decreases and van der Waals forces between the layers increase.The coefficient of thermal expansion decreases with the heat treatment temperature increasing.With the environmental temperature increasing,the coefficient of thermal expansion increases first and then decreases with a peak value at 1200℃.更多还原