Abstract The carbon nanotubes reinforced 6061Al composites (CNT/6061Al) with CNTs uniformly dispersed were fabricated by flake powder metallurgy process. The mechanical properties of composites, with and without artificial heat-treatment, were compared to the unreinforced 6061Al alloy. It was found that higher content of oxygen was introduced with increasing CNTs and consumed the magnesium element, which had a negative effect on the precipitation strengthening mechanism. Thus, the strength improvement of CNT/6061Al composites by heat treatment was less significant than the monolithic 6061Al alloy. However, the T6-aged CNT/6061Al composites still exhibited enhanced yield strength and ultimate tensile strength than the monolithic 6061Al alloy. This was attributed to the synergistic strengthening of multi-mechanisms, such as precipitation strengthening, grain refinement strengthening, load transfer behavior of CNTs and especially, CNT-induced back stress strengthening and the strain hardening. As results, the aged CNT/6061Al composites with 1.5 wt% CNTs had balanced tensile strength of 469 MPa and uniform elongation of 6%.

中文翻译：

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片状粉末冶金制备的CNT/6061Al复合材料的热处理行为及强化机制

摘要 采用片状粉末冶金工艺制备了碳纳米管均匀分散的碳纳米管增强6061Al复合材料（CNT/6061Al）。将经过和未经人工热处理的复合材料的机械性能与未增强的 6061Al 合金进行比较。结果表明，随着 CNTs 的增加，引入更高含量的氧并消耗镁元素，这对沉淀强化机制产生负面影响。因此，CNT/6061Al 复合材料通过热处理的强度提高不如整体 6061Al 合金显着。然而，T6 时效 CNT/6061Al 复合材料仍表现出比整体 6061Al 合金更高的屈服强度和极限拉伸强度。这归功于多机制的协同加强，如沉淀强化、晶粒细化强化、碳纳米管的载荷传递行为，特别是碳纳米管诱导的背应力强化和应变硬化。结果，具有 1.5 wt% CNT 的老化 CNT/6061Al 复合材料具有 469 MPa 的平衡拉伸强度和 6% 的均匀伸长率。