Effect of Heat-treatment Temperature on Mechanical Properties of Pyrocarbon and Carbon/Carbon Composites
Effect of Heat-treatment Temperature on Mechanical Properties of Pyrocarbon and Carbon/Carbon Composites
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DOI：
10.3724/sp.j.1077.2010.00315
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发表时间：
2010-03
影响因子：
1.7
通讯作者：
Yu Shouquan;Zhang Weigang
中科院分区：
文献类型：
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作者：
Yu Shouquan;Zhang Weigang
以丙烷为碳源，采用等压等温化学气相渗透法制备了碳/碳复合材料。采用X射线衍射仪、偏光显微镜、扫描电子显微镜、纳米压痕和三点弯曲试验研究了2500℃以下的热处理温度对热解碳和碳/碳复合材料微观结构和力学性能的影响。显微组织分析表明，随着热处理温度的升高，样品的层间距明显减小，石墨化程度也随之提高，偏光显微镜观察到局部应力诱导的石墨化产生了明显的同心裂纹，裂纹的数量和宽度随着热处理温度的升高而增加。对热解碳进行的纳米压痕实验表明，热解碳的压痕行为是纯弹性的，但加载和卸载曲线并不重叠，有大量的能量耗散，随着热处理温度的升高，热解碳的弹性模量增加。另一方面，随着热处理后纤维强度的降低和纤维/基体界面的脱粘，碳/碳复合材料的弯曲强度和弹性模量下降。
Carbon/carbon composites were infiltrated by isobaric, isothermal chemical vapor infiltration using propane as the carbon source. Effects of heat-treatment temperature up to 2500 degrees C on the microstructure and the mechanical properties of pyrocarbon and carbon/carbon composites were investigated by X-ray diffractometry, polarized light microscope, scanning electron microscope, nanoindentation, and three points bending tests. The microstructural investigations of samples reveal a pronounced decreased of the interlayer spacing with a simultaneous enhance of the graphitization degree, and polarized light microscope results exhibit distinct concentric cracks due to local stress induced graphitization, the number and width of cracks increase with the increase of heat-treatment temperature. Nanoindentation carried out on the pyrocarbon shows the indentation behavior is purely elastic, but the curves of loading and unloading do not overlap with significant amount of energy dissipation, the elastic modulus of pyrocarbon increases with the increase of heat-treatment temperature. On the other hand, with the decrease of fiber strength and the debonding of fiber/matrix interface after heat-treatment, the flexural strength and modulus of the carbon/carbon composites decrease.