Effect of graphite intercalation compounds in the interfacial zone on the mechanical and thermal properties of unidirectional carbon fiber reinforced spodumene composite

The interface in unidirectional carbon-fiber-reinforced beta-spodumene matrix composite (UD-Cf/beta-spodumene) significantly affected the thermal conductivity characteristics and mechanical properties due to the presence of a multi-layer interface. The mechanical and thermal properties of UD-Cf/beta-spodumene composites with and without a multi-layer interface have been studied. The measured thermal conductivities, flexural strength and fracture toughness of composites with a multi-layer interface were much better than those composites with a clear interface. Interfacial layers with a multi-layer morphology originated from the diffusion of lithium from the beta-spodumene matrix to the surface of the carbon fiber, which led to the formation of graphite intercalation compounds. The mechanical properties and thermal conductivity of UD-Cf/beta-spodumene hot pressed at 1350 and 1400 degrees C were enhanced due to the textured interfacial microstructure and high thermal conductivity of graphite intercalation compounds. The textured interface decomposed at 1450 degrees C, resulting in the formation of a strong interface. Inevitably, the mechanical properties and thermal conductivity decreased. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.