基于纳米压痕法的民机复合材料胶接维修界面微区力学性能研究

胶接维修是民机碳纤维增强树脂基复合材料(CFRP)结构的重要维修方式,而胶接界面微观结构及微区力学性能几乎决定了胶接维修效果及耐久性。以共固化胶接维修试样为基础,以维修试样的界面微区为研究对象,采用扫描电镜(SEM)对界面微区形貌进行分析;采用纳米压痕仪对界面微区的微观力学性能进行测试,主要表征界面微区不同位置的微观硬度、模量及加载-卸载曲线。研究结果表明,胶接维修界面存在过渡区域,其宽度约为2μm;维修母体与补片中纤维的微观力学性能并无太大差异;但由于固化成型工艺不同(母体为热压罐工艺,补片及胶膜为真空袋工艺),母体树脂的硬度与弹性模量略高于补片树脂。

Research on Microzone Mechanical Properties of Bonded Repair Interface of Civil Aircraft Composite Materials Based on Nano-indentation Method

Bonding repair has been one of the foremost ways of CFRP structure maintenance. In a sense, the repair effectiveness and durability of bonding repair has been determined by microstructure and micro-mechanical properties of adhesive interface. Based on the interface micro-area of co-curing bonding repair samples, this paper analyzed the interface micro-area morphology by SEM. Using nano-indenter apparatus, the microcosmic mechanics performance was evaluated, including the micro hardness, modulus and loading-unloading curve. The results show that a ~2 microns transitional area exists in the bonding repair interface. No much difference of micro mechanical properties has been found for the fibers in repair matrix and patch. While, for the reason of differences of curing process (autoclave for repair matrix and vacuum bag for patch), the micro hardness and elastics modulus in the matrix were slightly higher than those of patch.