Heat transfer characteristics in discontinuous silicon carbide-reinforced aluminum multiphase composites containing nano-graphene additives: a micromechanics-based multistep technique

摘要

A nested micromechanical technique is proposed to predict thermal conductivities of discontinuous silicon carbide (SiC)/graphene nanoplatelet (GNP)-reinforced aluminum matrix multiphase composites (AMMCs). Agglomeration and waviness of GNPs and interfacial thermal resistance (ITR) between the nanofiller and metal matrix are considered to perform a more realistic simulation process. The present predictions are compared with experimental measurements to verify the validity of the micromechanics approach. The effects of volume fraction, waviness, size and nonuniform distribution of GNPs, graphene/metal ITR, volume fraction, length and diameter of discontinuous SiC and SiC/matrix ITR on the AMMC thermal conductivities in the axial and transverse directions are investigated. The results show that heat in discontinuous SiC/metal composites is better transferred by a uniform distribution of GNPs in the metal matrix. The increase in graphene volume fraction leads to an enhancement in the heat transfer capacity for the metal-based multiphase composites. It is found that GNP with higher length and thickness can significantly improve the AMMC thermal conductivities. However, a great decrease in the thermal conductivities is observed by the ITRs and waviness of nano-graphene. Also, formation of GNP agglomeration drastically reduces the AMMC heat transfer capacity. Increasing the length of discontinuous SiC up to a certain value significantly increases the AMMC thermal conductivity in the axial direction, however, it has a negative effect on the transverse thermal conductivity.