Observation and prediction of the hot tear susceptibility of ternary Al-Si-Mg alloys

Easton, Mark A. and Wang, Hao and Grandfield, John and Davidson, Cameron J. and StJohn, David H. and Sweet, Lisa D. and Couper, Malcolm J. (2012) Observation and prediction of the hot tear susceptibility of ternary Al-Si-Mg alloys. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science , 43 (9). pp. 3227-3238. ISSN 1073-5623

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Abstract

An investigation into the hot tear susceptibility of ternary Al-Si-Mg alloys has been made using direct crack observation, measurement of load response, and predictions made by a modified Rappaz-Drezet-Gremaud (RDG) hot tearing model. A peak in both the hot tear susceptibility and the load at solidus occurred at approximately 0.2Si and 0.15Mg, and then the hot tear susceptibility decreased as the total solute content increased. In general, a good correlation was found among the observation of cracks, the load at solidus, and the predictions of the RDG hot tearing model, although it was shown that correlation with the RDG model depended critically on the fraction solid at which solid coalescence was assumed to occur. A combination of these approaches indicated that when the total Si+Mg content and the Si:Mg ratio increased toward four, a decrease occurred in the hot tear susceptibility because of an increase in the amount of final eutectic formed. At the lowest Si:Mg ratio of 0.25, the RDG model also predicted a lower relative hot tear susceptibility than that measured by the load at solidus. In these alloys, the final stages of solidification are predicted to occur over a large temperature range, and hence, both the predictions of the RDG model and the measurement of the load were dependent on which fraction solid was chosen for grain coalescence. In the alloys studied in this article, the formation of small amounts of the ternary eutectic Al+Mg 2Si+Si caused the highest hot tear susceptibility.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published online 4 May 2012. © The Mineral, Metals & Materials Society. This publication is copyright. It may be reproduced in whole or in part for the purposes of study, research, or review, but is subject to the inclusion of an acknowledgment of the source.
Depositing User: Dr Hao Wang
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - No Department
Date Deposited: 03 Aug 2012 05:22
Last Modified: 11 Aug 2014 05:03
Uncontrolled Keywords: alloys; hot tear; aluminum casting
Fields of Research (FOR2008): 03 Chemical Sciences > 0303 Macromolecular and Materials Chemistry > 030307 Theory and Design of Materials
09 Engineering > 0912 Materials Engineering > 091202 Composite and Hybrid Materials
09 Engineering > 0912 Materials Engineering > 091207 Metals and Alloy Materials
Socio-Economic Objective (SEO2008): E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
Identification Number or DOI: 10.1007/s11661-012-1132-6
URI: http://eprints.usq.edu.au/id/eprint/21245

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