Hierarchical microstructure design of CFRP/Al interface with ZnO-nanostructures and Modified resin Pre-Coating: Nano-mechanical interlocking

This study designs novel hierarchical microstructures of CFRP/Al interface with ZnO-NanoStructures (ZnO-NS) and Modified Resin Pre-Coating (RPC) to in-situ form nano-mechanical interlocking . ZnO-NSs with different growth times are fabricated by hydrothermal method , while the traditional RPC technology is modified by mixing resin-hardener-acetone with different ratios. Combining ZnO-NS and modified-RPC, difficultly infiltrated nanogaps among ZnO-NSs can be fully filled with resin to form flawless interface. Results show that the shear force firstly increases and then decreases with increasing growth time. As compared with no-ZnO-NS, 6 h-ZnO-NS presents a 207.5% higher shear force. When using ZnO-NS with RPC, an obvious reduction confirms that nanogaps are difficult to be infiltrated even through RPC technology. It is interesting that the shear property of sample with the modified RPC firstly increases and then decreases as the ratio changes. An improvement around 275.0% in shear force is identified for the modified-RPC with the ratio of resin, acetone and hardener (3:1:0.6) due to in-situ formed stronger nano-mechanical interlocking. The strengthening mechanisms are analyzed based on failure modes with different ZnO-NS-bridging length. The proposed method is of significance in lightweight material joining technology.