Structure of molten Al and eutectic Al-Si alloy studied by neutron diffraction

TitleStructure of molten Al and eutectic Al-Si alloy studied by neutron diffraction
Publication TypeJournal Article
Year of Publication2013
AuthorsDahlborg U, Kramer MJ, Besser M, Morris JR, Calvo-Dahlborg M
Journal TitleJournal of Non-Crystalline Solids
Volume361
Pages63-69
Date Published02
Type of ArticleArticle
ISBN Number0022-3093
Accession NumberWOS:000315557400010
Keywordsal-si, crystallization behavior, electron-ion correlation, glasses, HEAT-TREATMENT, liquid-aluminum, magnetic-properties, mechanical-properties, melt, melt superheating treatment, metallic, neutron diffraction, PHYSICAL-PROPERTIES, structure, Superheat, x-ray-diffraction
Abstract

The structure of molten eutectic Al87.8Si12.2 alloy has been studied by neutron diffraction during a temperature cycle. For comparison measurements were performed on pure molten Al. The measurements show that the alloy after heating above the liquidus contains particles of two kinds, aluminum-rich and silicon-rich. The silicon-rich particles are partly dissolved after a further heating. Earlier published data obtained by the gamma-ray absorption technique of the density of the molten eutectic Al-Si alloy had demonstrated the existence of two temperatures above the liquidus temperature: A dissolution temperature T-d, at which the microstructure of the melt inherited from the ingot starts to dissolve and a branching temperature, T-b, at which the melt reaches a fully mixed state. The highest temperature that was possible to reach during the neutron experiments lies between T-d and T-b. The obtained results support these conclusions that molten alloys after melting are inhomogeneous up to a temperature well above the liquidus. Moreover, the difference in shape between the static structure factors measured by neutron and X-ray diffraction on molten aluminum is observed and is found to be more accentuated and to extend to larger wavevectors than in earlier works. (C) 2012 Elsevier B.V. All rights reserved.

URL<Go to ISI>://WOS:000315557400010
DOI10.1016/j.jnoncrysol.2012.10.027