Role of synthesis method on microstructure and mechanical properties of graphene/carbon nanotube toughened Al<inf>2</inf>O<inf>3</inf> nanocomposites
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The effects of hot-pressing (HP) and spark plasma sintering (SPS) methods on the grain size, microstructural features, and mechanical behaviour of graphene nanoplatelet/carbon nanotubes (GNTs) reinforced Al<inf>2</inf>O<inf>3</inf> nanocomposites were comprehensively studied. Different graphene nanoplatelet to carbon nanotube ratios were selected as the overall reinforcement content of composites prepared using HP and SPS. Highly densified samples (>98%) were obtained at 1650°C under 40MPa in Ar atmosphere, with dwell times of 1h and 10min for HP and SPS respectively. Both types of sample showed a mixture of inter- and transgranular fracture behaviour. A 50% grain size reduction was observed for samples prepared by HP compared to SPS samples. Both types of samples achieved a high flexural strength and fracture toughness of >400MPa and 5.5MPam<sup>1/2</sup>, whilst SPS samples peaked at relatively lower GNT contents than those for the HP samples. Based on analyses of the morphology, grain sizes and fracture mode, similar toughening mechanisms for both types of sample were observed, involving the complex characteristics of the combined GNT fillers.
AuthorsYazdani, B; Porwal, H; Xia, Y; Yan, H; Reece, MJ; Zhu, Y
- College Publications