Influence of the factors on thermal conductivity of carbonaceous fiber reinforced aluminum composites

For improving the electrical efficiency of a hybrid car, relationship between microstructure and thermal properties of carbon nanotube, carbon fiber reinforced aluminum composites were examined as heat sink plate. In this study, influence of interfacial thermal resistance between fiber and binder, fiber diameter and binder volume fraction on thermal conductivity of the composites were examined. Firstly, in order to examine the effectivity for binding the fibers by the binder, the interfacial thermal resistance between fiber and binder was compared with that between fiber and matrix. In order to examine the influence of fiber diameter, the thermal conductivity of multi walled carbon nanotube preforms was compared with that of carbon fiber preforms. As the result, interfacial thermal resistance between fiber and binder was lower than that between fiber and matrix. Secondly, it was revealed that the larger fiber diameter leads to the higher thermal conductivity of the composite. Finally, the binder volume fraction was influenced by the microstructure so that the simply increasing and decreasing tendency was not found for thermal conductivity of the composites. By means of simulation for thermal conductivity, it was suggested that highly constricted fiber+binder part would deteriorate the thermal conductivity of the composites.