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Advances in Materials Science and Engineering
Volume 2014 (2014), Article ID 798479, 4 pages
http://dx.doi.org/10.1155/2014/798479
Research Article

Surface Crystallization in Mg-Based Bulk Metallic Glass during Copper Mold Casting

School of Material Science and Engineering, Hebei University of Technology, Dingzigu Road, Hongqiao District, Tianjin 300130, China

Received 21 March 2014; Accepted 18 April 2014; Published 6 May 2014

Academic Editor: Yang Shao

Copyright © 2014 Xin Wang. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The localized crystallization of Mg54Cu28Ag7Y11 bulk metallic glass (BMG) in the injection casting process using a copper mold was investigated. It has been found that several crystalline phases were formed close to the as-cast surface but did not exist in the internal part of the BMG plate. It is abnormal that the as-cast surface is partially crystallized with higher cooling rate than that of inside. Overheating of the melt and nucleation induced by the surface of copper mold play key roles in the abnormal crystallization. It is suggested that the function of copper mold to trigger heterogeneous nucleation cannot be totally ignored, although it provides the high cooling rate for the glass formation during casting.