Abstract The interfacial native oxide layer always acts as barriers preventing effective interfacial bonding and load transfer in carbon nanotube reinforced aluminum (CNT/Al) composites. In this work, annealing-controlled reaction between the interfacial native oxide layer and Mg element was attempted to improve interfacial bonding in CNT/Al Mg composite, and mechanical interfacial bonding featured with direct CNT-Al contact and well-reserved CNTs was achieved in the 1 h annealed composite. For the 2 h annealed composite, chemical interfacial bonding featured with interfacial aluminum carbide (Al4C3) was established due to progressive interfacial reaction. Further tensile tests and numerical analysis revealed that, owing to barrier-free load path and increased interfacial friction stress, the mechanical interfacial bonding significantly enhanced CNT load transfer effect from 30.9 MPa to 59.4 MPa, which was close to shear-lag model prediction of 59.9 MPa. While, the chemical interfacial bonding led to a combined strengthening effect of 58.8 MPa from CNT-Al4C3 hybrid as a comprised outcome of Al4C3 strengthening and CNT damage. Thus, the design of mechanical interfacial bonding should be a superior strategy for improving interfacial bonding and enhancing mechanical performance in CNT/Al composites, considering its effective protection of CNT structure integrity and suppressed formation of hydrolysable Al4C3 phase.

中文翻译：

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通过设计碳纳米管增强铝复合材料中的机械界面结合来增强载荷传递

摘要 在碳纳米管增强铝 (CNT/Al) 复合材料中，界面天然氧化物层始终充当阻碍有效界面结合和负载转移的屏障。在这项工作中，界面天然氧化物层与镁元素之间的退火控制反应试图改善碳纳米管/铝镁复合材料中的界面结合，并在碳纳米管中实现了以碳纳米管-铝直接接触和保留良好的碳纳米管为特征的机械界面结合。 1 小时退火复合材料。对于 2 小时退火的复合材料，由于界面反应的进行，建立了以界面碳化铝 (Al4C3) 为特征的化学界面键合。进一步的拉伸试验和数值分析表明，由于无障碍载荷路径和增加的界面摩擦应力，机械界面结合显着增强了 CNT 负载转移效果，从 30.9 MPa 到 59.4 MPa，接近剪切滞后模型预测的 59.9 MPa。同时，化学界面结合导致 CNT-Al4C3 杂化物产生 58.8 MPa 的综合强化效果，这是 Al4C3 强化和 CNT 损伤的综合结果。因此，机械界面结合的设计应该是改善界面结合和提高 CNT/Al 复合材料机械性能的优越策略，考虑到其有效保护 CNT 结构完整性和抑制可水解 Al4C3 相的形成。来自 CNT-Al4C3 混合体的 8 MPa 作为 Al4C3 强化和 CNT 损伤的综合结果。因此，机械界面结合的设计应该是改善界面结合和提高 CNT/Al 复合材料机械性能的优越策略，考虑到其有效保护 CNT 结构完整性和抑制可水解 Al4C3 相的形成。来自 CNT-Al4C3 混合体的 8 MPa 作为 Al4C3 强化和 CNT 损伤的综合结果。因此，机械界面结合的设计应该是改善界面结合和提高 CNT/Al 复合材料机械性能的优越策略，考虑到其有效保护 CNT 结构完整性和抑制可水解 Al4C3 相的形成。