空气氧化处理的中间相沥青基炭/炭复合材料的组织和弯曲性能

Microstructures and Bending Property of Mesophase Based C/C Composites with Air Oxidation Process

通过引入225℃空气氧化处理,在较短周期内采用常压浸渍炭化工艺制备了中间相沥青基炭/炭复合材料.采用偏光显微镜、万能力学试验机及扫描电镜等检测手段研究了炭/炭复合材料微观组织和弯曲力学性能.研究结果表明,225℃空气氧化处理后,炭化收率显著提高,经过四次常压浸渍-炭化循环后炭/炭复合材料密度达到了1.73g/cm3,弯曲强度为152.39MPa,比未经过空气氧化处理的试样提高了62.87%.空气氧化处理制备的试样呈现典型的假塑性断裂特征,而未经空气氧化处理制备的试样主要从层间断裂,其弯曲强度较低.通过偏光显微分析,未经空气氧化处理的炭/炭复合材料组织大部分为小域组织,只有少量的镶嵌型组织和广域组织,而经过225℃空气氧化处理后的试样,以广域型组织为主,并在其间夹着流线型组织和小域组织.

Carbon-carbon composites were fabricated in short period by LPIC（low pressure impregnation car-bonization） process with 225 ℃ air oxidation using mesophase pitch as precursor.The microstructures were ob-served by PLM（polarizing microscope）.The bending property and fracture surface were tested by universal testing machine and SEM（scanning electron microscope）,respectively.The results show that the carbon yield is improved remarkably with 225℃ air oxidation compared with the samples without air-oxidation.After four cycles of LPIC,the density of C/C composites reaches 1.73 g/cm3.Its bending property is 152.39MPa,which is increased 62.87% compared with the samples without air oxidation process.It is concluded that the C/C composites with air oxidation exhibit pseudo-plastic failure behavior and the samples without air-oxidation rupture from interlays with low bend-ing strength.The microstructures of C/C composites without air oxidation are mainly small domains with few mo-saic and domain textures.Nevertheless,the composites with 225℃ air oxidation present domain textures mainly with small domain and flow domain.