SPS 成形したAl/SiC 複合材料の熱物性に及ぼすSiC のバイモーダルな粒度分布の影響

概要

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Silicon carbide (SiC)-particle-dispersed-aluminum (Al) matrix composites were fabricated in continuous solid-liquid co-existent state by Spark Plasma Sintering (SPS) process from the mixture of SiC powders, Al powders and Al - 5 mass% Si alloy powders. As the SiC powders, two kind of powders, monomodal SiC powders of 109.8 µm in diameter and a bimodal SiC powder mixture of 109.8 µm and 14.3 µm in diameter, were used. The microstructures and thermal conductivities of the composites fabricated were examined. These composites were all well consolidated by heating at a temperature range between 798 K and 876 K for 1.56 ks during SPS process. No reaction at the interface between the SiC particle and the Al matrix was observed by scanning electron microscopy for the composites fabricated under the sintering conditions employed in the present study. Although the relative packing density of the monomodal composite decreased from 99.8 % to 95.1 % with increasing SiC volume fraction between 55 % and 65 %, that of the bimodal composite was higher than 97 % in a SiC volume fraction range up to 70 %. The thermal conductivity of the bimodal composite was higher than that of the monomodal composite in a SiC volume fraction range higher than 60 %. The coefficient of thermal expansion of the composites falls in the upper line of Kerner's model, indicating strong bonding between the SiC particle and the Al matrix in the composite.