WITHDRAWN (NO REG) 5/20/2024 CH01.08.04 Effect of Particle Shape on Microstructure and Thermal Conductivity of Al/Graphite Materials by Spark Plasma Sintering

The Al particle shapes which are spherical, irregular and flake shape were mixed with flake type graphite. The Al–50 vol.% Gr. powders, mixed by shaking mixer, were sintered under the following process conditions; sintering temperature of 550^oC, sintering pressure of 60 MPa and duration of 2 minutes at the temperature of 550^oC. The relative density of the sintered body reached its highest value of 99% when the shape of the Al particles was irregular. On the other hand, the lowest value was 92% when Al particle were flake-shaped. Pores were formed due to the wettability at the Al and Gr interface, which varied with the shape of the Al powder, thereby affecting the relative density. The hardness of the Al-Gr sintered body were investigated by vickers hardness analysis depending on the Al particle type. The results showed that the hardness value increased as the relative density became higher. The propagation of micro-cracks was further extended by the pores, which are assumed to have influenced the hardness. Moreover, the results of thermal conductivity as a function of the particle type, the most important indicator of this study, demonstrated the importance of porosity and the orientation of graphite.