Halo formation in directional solidification

Autor:	David H. StJohn, Arne K. Dahle, M. D. Nave
Rok vydání:	2002
Předmět:	Materials science Polymers and Plastics Metals and Alloys Thermodynamics Liquidus Electronic Optical and Magnetic Materials Physics::Fluid Dynamics Grain growth Crystallography Dendrite (crystal) Phase (matter) Ceramics and Composites Halo Supercooling Eutectic system Directional solidification
Zdroj:	Acta Materialia. 50:2837-2849
ISSN:	1359-6454
DOI:	10.1016/s1359-6454(02)00104-0
Popis:	A new model of halo formation in directional solidification is presented. The model describes halo formation in terms of competitive growth between the halo phase and coupled eutectic in liquid with a nominal composition that follows the primary phase liquidus extension with decreasing temperature. The model distinguishes between the effects of constitutional, capillarity and (where applicable) kinetic undercooling and avoids a number of theoretical inconsistencies associated with previous models. The critical growth rate for halo formation in directionally solidified hypereutectic Al-Si alloys is calculated using the model in conjunction with models of primary phase and coupled eutectic growth from the literature. The calculated result agrees reasonably well with the experimental result of Yilmaz and Elliott (Met. Sci. 18 (1984) 362), given the use of a relatively simple isolated dendrite tip model to calculate the growth undercooling of the halo tip. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::d6aa5b33f96d86aed5d8d812fe22d9a4 https://doi.org/10.1016/s1359-6454(02)00104-0 Zobrazit plný text záznamu Full Text from ScienceDirect