航空用国产碳纤维/双马树脂复合材料湿热力学性能

Hygrothermal mechanical properties of domestic carbon fiber/bismaleimide resin composites for aviation application

用一种航空用国产T700级碳纤维和4种双马树脂分别制备复合材料,采用三种湿热条件(100℃水煮、70℃水浸、70℃/85%相对湿度)对复合材料层板进行湿热处理,研究室温和150℃下与界面和基体相关的复合材料湿热力学性能。结果表明:湿热处理后复合材料的力学性能有所降低,尤其是对复合材料高温力学性能影响显著,其中90°拉伸性能、0°压缩强度、弯曲强度、开孔压缩强度对吸湿和温度较敏感,而0°压缩模量、弯曲模量和开孔拉伸强度对吸湿和温度不敏感。对比不同湿热条件处理后复合材料力学性能的变化,发现100℃水煮后力学性能衰减幅度较大,认为这与其平衡吸湿率较高有关。结合90°拉伸断面的扫描电镜分析,认为界面湿热性能是决定国产碳纤维复合材料湿热性能的关键因素。

The composites were separately prepared by a domestic T700-grade carbon fiber used for aviation and four types of bismaleimide resin.The composite laminates were treated by three hygrothermal conditions,including 100℃boiling water,70℃water immersion and 70℃/85%relative humidity to study the hygrothermal mechanical properties of the composite laminates related to interface and matrix under ambient temperature and 150℃.The results show that the moisture absorption decreases the mechanical properties of composites,and the effect on mechanical properties under high temperature is significant.Furthermore,90o tensile property,0o compressive strength,flexural strength and open-hole compressive strength are sensitive to moisture absorption and temperature,while the sensitivities of 0o compressive modulus,flexural modulus and open-hole tensile strength are small.By comparing the changes of the mechanical properties of composite after different hygrothermal treatment conditions,it is found that the degree of degradation after 100℃boiling water is larger,which is believed to be related to its higher equilibrium moisture absorption rate.Based on fracture morphology of composite after 90o tensile testing using scanning electron microscope,it is considered that the hygrothermal property of interface is the critical factor to determine the hygrothermal property of domestic carbon fiber composite.