空间环境下碳纤维/双马树脂基复合材料的性能演化及损伤机理

Property Evolution and Damage Mechanism of CF/BMI Composite in Space Environment

目的基于碳纤维/双马树脂基(CF/BMI)复合材料在航天结构材料中广泛的应用前景,研究其性能演化及损伤机理,为评估与预测其在空间环境下的服役性能及寿命提供理论依据。方法利用地面试验装置模拟不同的空间环境因素包括真空热循环、质子辐照和电子辐照,利用动态力学分析(DMA)、热重分析(TGA)、X射线光电子能谱(XPS)、热膨胀分析、原子力显微镜(AFM)和力学性能测试等手段系统地研究CF/BMI复合材料在空间环境下的性能变化及损伤行为。结果真空热循环能够引发复合材料产生脱气行为与界面脱粘效应,使其横向拉伸强度退化,弯曲强度和层间剪切强度受到热循环初期固化交联作用的影响,呈现先升高后降低的变化趋势。质子辐照导致材料表面层化学键断裂及碳化,使力学性能及热性能受到一定程度的损伤。电子辐照能够引发辐照交联和辐照降解作用,在较高束流量辐照下降解作用占据主导地位成为复合材料力、热性能退化的决定性因素。结论预期研究成果为CF/BMI复合材料在空间环境下的服役性能及寿命的评估与预测提供了必要的理论依据。

Objective To study the evolution performance and damage mechanism of carbon fibers/bismaleimide （CF/BMI） composites used as structure materials in spacecrafts and provide basis for forecasting and assessing its service performance and life in space environment used on its broad application. Methods Ground facilities were used to simulate different space envi-ronment factors involving vacuum thermal cycling, proton and electron irradiation. Properties and corresponding damage mechanisms of CF/BMI composite in space environment were investigated by dynamic mechanical analysis （DMA）, thermal gravimetric analysis （TGA）, X-ray photoelectron spectroscopy （XPS）, thermal expansion analysis, atomic force microscopy （AFM） and mechanical tests, respectively. Results Vacuum thermal cycling could induce matrix outgassing and interfacial debonding, which resulted in the reduction in the transverse tensile strength. While the flexural strength and ILSS increased firstly and then fell back to a plateau value, which were affected by a crosslinking effect in the early stage. Proton radiation could cause molecular bond breakage in surface layer of the composites, thereby leading degradation of thermal and mechanical performance. Electron radiation could introduce both degradation and cross-linking effect in the irradiation process, while the degradation effect played a dominant role at higher fluences and thus became a decisive factor for degradation of thermal and mechanical performance. Conclusion The expected results would provide a useful theoretical foundation for assessing and forecasting the service performance and service life of CF/BMI composites applied in space environment. KE