Journal of Materials Science, Vol.29, No.24, 6439-6444, 1994
Production of SiC Particulate-Reinforced Aluminum Composites by Melt-Spinning
Melt spinning is successfully used for the preparation of a rapidly solidified SiC particle reinforced AlSi7Mg0.3 alloy. The composites are prepared by introducing SiC particles in a semi-solid matrix slurry (SiC volume fractions up to 0.15, particle size 10 or 20 mum). Duralcan material (SiC volume fraction 0.20, particle size 12 mum) was also used. After stirring in the semi-solid state the composites are heated above the liquidus temperature and subsequently melt-spun. Featureless, columnar and dendritic zones can be identified in the ribbons. A finer dendritic structure is found around the SiC particles. The SiC particles tend to segregate to the air side of the ribbons and the segregation effect is influenced by particle size and volume fraction. As interface velocities are higher than the critical velocities predicted by models on interface pushing, it is concluded that fluid flow in the melt puddle is responsible for the segregation effect.