The roles of Eu during the growth of eutectic Si in Al-Si alloys

Li, J., Hage, F., Wiessner, M., Romaner, L., Scheiber, D., Sartory, B., Ramasse, Q. and Schumacher, P. (2015) The roles of Eu during the growth of eutectic Si in Al-Si alloys. Scientific Reports, 5, 13802. (doi: 10.1038/srep13802) (PMID:26328541) (PMCID:PMC4557128)

Abstract

Controlling the growth of eutectic Si and thereby modifying the eutectic Si from flake-like to fibrous is a key factor in improving the properties of Al-Si alloys. To date, it is generally accepted that the impurity-induced twinning (IIT) mechanism and the twin plane re-entrant edge (TPRE) mechanism as well as poisoning of the TPRE mechanism are valid under certain conditions. However, IIT, TPRE or poisoning of the TPRE mechanism cannot be used to interpret all observations. Here, we report an atomic-scale experimental and theoretical investigation on the roles of Eu during the growth of eutectic Si in Al-Si alloys. Both experimental and theoretical investigations reveal three different roles: (i) the adsorption at the intersection of Si facets, inducing IIT mechanism, (ii) the adsorption at the twin plane re-entrant edge, inducing TPRE mechanism or poisoning of the TPRE mechanism, and (iii) the segregation ahead of the growing Si twins, inducing a solute entrainment within eutectic Si. This investigation not only demonstrates a direct experimental support to the well-accepted poisoning of the TPRE and IIT mechanisms, but also provides a full picture about the roles of Eu atoms during the growth of eutectic Si, including the solute entrainment within eutectic Si.

• Item Type: Articles
• Additional Information: J. L. gratefully acknowledges the access to TEM at the Erich Schmid Institute of Materials Science of the Austrian Academy of Sciences and the financial support from the Major International (Regional) Joint Research Project (No. 51420105005) from China.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hage, Dr Fredrik Sydow
• Authors: Li, J., Hage, F., Wiessner, M., Romaner, L., Scheiber, D., Sartory, B., Ramasse, Q., and Schumacher, P.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Scientific Reports
• Publisher: Nature Publishing Group
• ISSN: 2045-2322
• ISSN (Online): 2045-2322
• Copyright Holders: Copyright © 2015 The Authors
• First Published: First published in Scientific Reports 5: 13802
• Publisher Policy: Reproduced under a Creative Commons License