湿热/干燥环境交替作用下碳纤维复合材料的吸湿/脱湿特性

Moisture absorption/desorption characteristics of carbon fiber composite under hygrothermal/dry alternation environment

研究了湿热/干燥环境交替作用下碳纤维复合材料的吸湿/脱湿特性。完成了复合材料层合板的六次高温高湿/干燥环境交替作用试验。通过观察复合材料基体和界面微观形貌,分析环境损伤的特征和演化规律。研究结果表明:在湿热/干燥环境交替作用下,复合材料的吸湿扩散速率逐渐变大,平衡吸湿量有所增加,脱湿时间明显增大。这表明材料特性和微观结构发生了一些变化;使用多项式拟合吸湿/脱湿试验数据精度较好,并依据Fick定律推导出多次吸湿-脱湿方程;观察第四、六次吸湿后复合材料的界面微观形貌差异不大,界面破坏基本达到“饱和”;最后提出“总损伤”和“残留损伤”来描述湿热/干燥交替作用而产生的环境损伤,为损伤表征和性能预测提供新思路。

The moisture absorption/desorption characteristics of carbon fiber composite under hygrothermal/dry alternation environment were studied.Six times high temperature and high humidity/dry environment alternation test of composite laminates were finished.By observing the microstructure of matrix and interface,the characteristics and evolution of environmental damage were analyzed.The results show that moisture absorption diffusion coefficient increased gradually,the balanced moisture content increased,and desorption time increased significantly under hygrothermal/dry alternation environment.It shows that there are some changes in material properties and microstructure.The accuracy of fitting moisture absorption/desorption test data by polynomial was good,and the equations of multiple moisture absorption/desorption were derived according to Fick′s law.The micro morphology of composite interface after the fourth and sixth moisture absorption was slightly different,which indicated that interface failure of composite basically reached"saturation".Finally,"total damage"and"residual damage"were proposed to describe the environmental damage caused by hygrothermal/dry alternation environment,which provided a new idea for damage characterization and performance prediction.