高温老化对T700/HT280双马来酰亚胺复合材料疲劳性能的影响

Effect of high temperature aging on the fatigue property of the T700/bismaleimide composites

以多向铺层碳纤维增强双马来酰亚胺(T700/HT280)复合材料和双马来酰亚胺(HT280)树脂为研究对象,采用刚度降的方法研究高温老化对复合材料抗疲劳性能的影响。测量了复合材料和树脂的质损率,并利用FTIR、超声C扫描和动态力学热分析仪(DMA)对高温老化前后材料的化学结构、内部损伤、动态力学行为进行了分析。实验结果表明,随着高温老化时间的延长,两种材料的质损率均呈现先迅速增加后缓慢增加的变化规律。经历长期高温老化后,树脂发生了热氧老化。HT280树脂动态力学性能的变化归因于后固化与热老化效应,T700/HT280复合材料则归因于后固化、热老化和界面脱粘的综合作用。高温老化后T700/HT280复合材料刚度下降的速率与幅度明显小于原始态,表明高温老化后复合材料的后固化与热老化的强化效应明显,导致其抗疲劳性能有一定的提高。

The fatigue property of T700/HT280 composite and HT280 resin in high temperature environment were studied via the stiffness reduction theory.The mass loss rate of composite and resin was measured.The chemical construction,interior damage and dynamic mechanical behavior were analyzed by FTIR,ultrasonic C-scanning and DMA.The results indicate that the mass loss rate T700/HT280 composite and HT280 resin increases rapidly at the initial aging stage and then increases slowly with further aging.After the long-term exposure to high temperature,thermal-oxidative aging can be seen in HT280 resin.The change of dynamic mechanical properties of HT280 resin is attributed to the post-curing and thermal aging,while for T700/HT280 composite,it is attributed to the synthetic action of the post-curing,thermal aging and interface debonding.The stiffness decline rate of treated composite is less than the original one.It indicates that the strengthening effect of post-curing and thermal aging is obvious after exposuring to high temperature.Therefore,a certain improvement in the fatigue-resistance of T700/HT280 composite can be obtained.