Fabrication of Carbon Nanotube-Reinforced Aluminum Matrix Composites by SPS Pre-sintering and Hot Extrusion

采用放电等离子烧结和热挤压相结合的方法制备了铝/碳纳米管(CNT)复合材料。采用纳米分散的方法将碳纳米管很好地分散在Al颗粒上。采用放电等离子烧结和热挤压相结合的方法制备了高致密碳纳米管复合材料。光学显微镜、场发射扫描电子显微镜和高分辨电子显微镜的微观结构观察证实，烧结的Al/CNT致密和挤压块体材料具有良好的定向碳纳米管的分散性。拉曼光谱表明，处理对碳纳米管的损伤起到了抑制作用。在SPS烧结过程中，生成了少量的过渡铝液相，这可能有助于碳纳米管的致密化，也有利于碳纳米管与铝基体的良好接触。结果表明，复合材料的抗拉强度是纯铝的三倍，这是因为有效的载荷从基体传递到碳纳米管。

Aluminum/carbon nanotube (CNT)composites have been fabricated by a combination of spark plasma sintering and hot-extrusion processes. The CNTs were well dispersed onto Al particles by nanoscale dispersion method. The highly densified CNT composites were prepared by spark plasma sintering and subsequent hot extrusion. Microstructural observations by optical, fieldemission scanning electron and high-resolution transmission electron microscopies confirmed that the sintered Al/CNT compact and extruded bulk material has a good dispersion of oriented CNTs. Raman spectroscopy showed that the processing restrained damage to the CNTs. A small amount of transient Al liquid phase was formed during SPS sintering, which may assist the densification as well as good contact between CNT and aluminum matrix. As a result, the composites exhibited three times larger tensile strength than pure aluminum because of the effective load transfer from the matrix to the CNTs.