基于纳米压痕技术的碳纤维/环氧树脂复合材料各组分原位力学性能测试

In situ characterization of carbon fiber/epoxy composites by nanoindentation

基于纳米压痕技术对碳纤维/环氧树脂复合材料各组分的原位硬度、弹性模量和蠕变性能进行了测试,实验得到了基体、纤维和微小厚度界面层的力学性能。结果表明,从环氧树脂基体到碳纤维过渡过程中,硬度和弹性模量有明显的梯度变化,并且纤维和树脂基体的原位弹性模量平均值与其非原位性能有一定的变化,实验得到纤维的原位弹性模量有所下降,环氧树脂的弹性模量有所增加。试件制备过程中的机械研磨对其表面产生的残余应力和复合后两种材料的相互影响是组分材料原位性能变化的主要原因。各组分的蠕变性能呈现出明显的差异。

The in situ properties of components including the epoxy matrix, the carbon fiber and the interlayer of the carbon fiber/epoxy composites were examined by the nanoindentation. The hardness, Young’s modulus and creep behavior of the components in the composites were obtained. The results show that the hardness and Young’s modulus have a gradient variation from the epoxy matrix to carbon fiber. Compared with the intrinsical value, the in situ Young’s modulus of the fiber has a decline, and the Young’s modulus of the matrix exhibits an enhancement. The in situ properties are influenced by the surface residual stress due to mechanical grinding of the specimen and the interaction of the components of the composites. Moreover, a remarkable change of creep behavior at the transition zone from the fiber to the epoxy matrix is found in the present nanoindentation tests.