Effect of stress level on fatigue behavior of 2D C/C composites

应力水平对二维炭/炭复合材料疲劳行为的影响(英文)

Laminated carbon fiber clothes were infiltrated to prepare carbon fiber reinforced pyrolytic carbon （C/C） using isothermal chemical vapor infiltration （CVI）. The bending fatigue behavior of the infiltrated C/C composites was tested under two different stress levels. The residual strength and modulus of all fatigued samples were tested to investigate the effect of maximum stress level on fatigue behavior of C/C composites. The microstructure and damage mechanism were also investigated. The results showed that the residual strength and modulus of fatigued samples were improved. High stress level is more effective to increase the modulus. And for the increase of flexural strength, high stress level is more effective only in low cycles. The fatigue loading weakens the bonding between the matrix and fiber, and then affects the damage propagation pathway, and increases the energy consumption. So the properties of C/C composites are improved.

采用等温化学气相浸渗法制备二维炭布叠层炭/炭复合材料。进行了两种应力水平下的弯曲疲劳测试,测定剩余弯曲强度及模量,以表征不同应力水平对炭/炭复合材料疲劳行为的作用。结果表明:疲劳加载后试样的剩余弯曲强度及模量均有提高,在高应力水平下剩余弯曲模量的增强作用更显著,但在疲劳循环超过105次后,低应力水平下的剩余强度更高。分析了炭/炭复合材料的疲劳强化与损伤机理。疲劳加载会弱化基体与纤维之间的结合,改变损伤扩展路径,从而改善炭/炭复合材料的性能。