Characterization of hypereutectic Al-Si powders solidified under far-from equilibrium conditions

TitleCharacterization of hypereutectic Al-Si powders solidified under far-from equilibrium conditions
Publication TypeJournal Article
Year of Publication2007
AuthorsKalay YE, Chumbley LS, Anderson IE, Napolitano RE
Journal TitleMetallurgical and Materials Transactions a-Physical Metallurgy and Materials Science
Volume38A
Pages1452-1457
Date PublishedJul
Type of ArticleProceedings Paper
ISBN Number1073-5623
Accession NumberISI:000248511300010
Keywordsalloys, DROPLETS, EUTECTIC GROWTH, rapid solidification
Abstract

The rapid solidification microstructure of gas-atomized Al-Si powders of 15, 18, 25, and 50 wt pet Si were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In order of increasing particle size, the powders exhibited microcellular Al, cellular/dendritic Al, eutectic Al, and primary Si growth morphologies. Interface velocity and undercooling were estimated from measured eutectic spacing based on the Trivedi-Magnin-Kurz (TMK) model, permitting a direct comparison with theoretical predictions of solidification morphology. Based on our observations, additional conditions for high-undercooling morphological transitions are proposed as an extension of coupled-zone predictions.

DOI10.1007/s11661-007-9168-8
Alternate JournalMetall. Mater. Trans. A-Phys. Metall. Mater. Sci.