热处理温度对中间相沥青基碳/碳复合材料力学性能的影响

通过三点弯曲实验,并借助XRD,SEM断口形貌分析,研究了最终热处理温度对中间相沥青基碳/碳复合材料微观结构与力学性能的影响,并对其断裂机制进行了探讨.结果表明:随着最终热处理温度的升高,材料的石墨化度增大,层间距d002减小,微晶尺寸Lc增大;材料未经热处理时,纤维与基体间界面结合较强,抗弯强度较高,弯曲断口较为平整,具有脆性断裂特征;随着热处理温度的升高,基体收缩,纤维与基体间界面结合减弱,抗弯强度减小,弯曲断口纤维拔出较长,材料具有韧性断裂特征.

Effects of Heat Treatment Temperature on Mechanical Properties of Mesophase Pitch-based C/C Composites

The effects of final heat treatment temperature on the microstructure, mechanical properties and fractured surface image of mesophase pitch-based 2D C/C composites were studied by three-point bending, XRD and SEM test, and the fracture mechanism was investigated. The results show that the graphitization degree and microcrystal size (L_c) increase, interlayer distance (d_ 002 ) decrease with the increase of final heat treatment temperature of the C/C composites. The interface bonding strength weakens with the increase of heat treatment temperature. The flexural strength of composites after heat treatment is lower than that of untreated, the fracture characters of composites are changed from the brittle fracture to like-tough.