Abstract:The experimental and analytical approaches were taken to investigate the non-dendritic microstructure formation and evolution of AlSi9Cu3 alloy during rheocasting. The results show that the globular primary α(Al) particles free of entrapped eutectic form after rheocasting for 3 s, and could be morphologically stabilized during subsequent growth. The fine and globular particles underwent a coarsening process under quiescently continuous cooling in which the particle density decreases, the solid fraction increases, the average particle size increases with the increase of solidification time at a rate that closely followed the classical Ostwald ripening.

Key words: AlSi9Cu3 alloy; microstructure evolution; rheocasting; interface instability; growth; coarsening