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

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 38; no. 7; pp. 1452 - 1457
• Main Authors: KALAY, Y. E, CHUMBLEY, L. S, ANDERSON, I. E, NAPOLITANO, R. E
• Format: Conference Proceeding Journal Article
• Language: English
• Published: New York, NY Springer 01-07-2007; Springer Nature B.V
• Subjects: Alloys; ALUMINIUM; Applied sciences; CHEMICAL ANALYSIS; EUTECTICS; Exact sciences and technology; MATERIALS SCIENCE; Metallurgy; Metals. Metallurgy; Microstructure; POWDERS; SILICON; SOLIDIFICATION; Transmission electron microscopy
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-007-9168-8

The rapid solidification microstructure of gas-atomized Al-Si powders of 15, 18, 25, and 50 wl pct 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. [PUBLICATION ABSTRACT]