In order to explore the dependence of mechanical properties on the microstructure of high-textured (HT) pyrolytic carbon (PyC), the microstructure and properties of HT PyC specimens prepared by isothermal isobaric chemical vapor infiltration (ICVI) and thermal gradient chemical vapor infiltration (TCVI) processes were investigated. The HT PyC of ICVI was uniform and exhibited a more distinct long-range order compared to that of TCVI. Besides, a spatial gradient in texture existed within the HT PyC of TCVI, demonstrating the micro-nonuniformity of the whole matrix. The orientation angle (OA) of HT layers in TCVI increased gradually from the fiber surface to outside, whereas the OA of HT layers in ICVI with better microcrystalline was nearly similar. According to the results of three-point bending and micro-indentation, the flexural strength, interfacial fracture strength, and micro-hardness of TCVI specimens were slightly higher than those of ICVI specimens. Furthermore, the residual thermal stress distribution of TCVI specimens was complex owing to the spatial gradient in temperature of TCVI process, while the residual thermal stress distribution of ICVI specimens was relatively uniform. This work provides meaningful guidance for the process selection and industrial applications of C/C composites.

为了探索机械性能对高结构（HT）热解碳（PyC）微观结构的依赖性，通过等温等压化学气相渗透（ICVI）和热梯度化学气相渗透制备的HT PyC标本的微观结构和性能（ TCVI）过程进行了调查。与TCVI相比，ICVI的HT PyC是均匀的，并且显示出更明显的远程顺序。此外，TCVI的HT PyC内部存在纹理的空间梯度，这说明了整个矩阵的微观不均匀性。TCVI中HT层的取向角（OA）从纤维表面到外部逐渐增大，而具有较好微晶的ICVI中HT层的OA几乎相似。根据三点弯曲和微压痕的结果，弯曲强度 TCVI试样的界面断裂强度和显微硬度略高于ICVI试样。此外，由于TCVI过程温度的空间梯度，TCVI样品的残余热应力分布复杂，而ICVI样品的残余热应力分布相对均匀。这项工作为C / C复合材料的工艺选择和工业应用提供了有意义的指导。