Processing of CNTs reinforced al-based nanocomposites using different consolidation techniques

In this work, the development of two types of Al-based alloys with different concentrations of Si reinforced with MWCNT's at 0.5-2.0 wt% is presented. Sonication of the CNT's in ethyl alcohol was carried out for dispersion, and the mixtures were ball milled for 1, 3, and 5 hrs. SEM/EDS were used to study the morphology and the effects of changing milling parameters in addition to changes caused due to increasing concentration of the CNT's. Furthermore, three sintering techniques, namely, Spark Plasma Sintering (SPS), Microwave Sintering (WS), and Hot Isostatic Press Sintering (HIP) were employed to consolidate the ball milled powders at varying temperatures of 400, 450, and 500°C. It was found that SPS consolidated samples showed the most promising results amongst the three with the highest hardness values; around 100% densification, as well as the finest microstructure. On the other hand, microwave sintered samples showed the least appealing results, this could be attributed to the poor temperature distribution and the pressureless nature of the technique. A sintering temperature of 500°C was found to be the most suitable for these types of alloys.