Abstract In the present work, we studied the effect of the aspect ratio of carbon nanotubes (CNTs) on strengthening aluminum metal matrix composites (Al MMCs). To this end, Al samples reinforced with CNTs of various aspect ratios were produced via three different powder metallurgy methods. Microstructural examination revealed that the CNTs were uniformly dispersed in the materials with a range of aspect ratios from 6.5 to 55. The tensile results showed that the CNTs exhibited a strong strengthening effect in the composites regardless of their aspect ratios. However, the post-loading examination and quantitative analysis indicated that there was a strengthening mechanism transition for CNTs, which was closely associated with the aspect ratio or length of CNTs. The origin of such transition was explored from the viewpoint of dislocation-CNTs interaction under loading. The findings may provide a new insight in understanding the strengthening behaviors of CNT-reinforced MMCs.

中文翻译：

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碳纳米管的长度对金属基复合材料强化机制的影响

摘要 在目前的工作中，我们研究了碳纳米管 (CNT) 的纵横比对增强铝金属基复合材料 (Al MMC) 的影响。为此，通过三种不同的粉末冶金方法生产了用各种纵横比的碳纳米管增强的铝样品。微观结构检查表明，碳纳米管均匀地分散在纵横比范围为 6.5 至 55 的材料中。拉伸结果表明，无论纵横比如何，碳纳米管在复合材料中都表现出很强的强化作用。然而，加载后检查和定量分析表明，碳纳米管存在强化机制转变，这与碳纳米管的纵横比或长度密切相关。从负载下位错-碳纳米管相互作用的角度探索了这种转变的起源。这些发现可能为理解 CNT 增强的 MMC 的强化行为提供新的见解。