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Advances in Materials Science and Engineering
Volume 2013 (2013), Article ID 512606, 9 pages
http://dx.doi.org/10.1155/2013/512606
Research Article

High Temperature Deformation Behavior of 8090 Al-Li Alloy

1Department of Civil Engineering, Gangneung-Wonju National University, 120 Gangneung-Daehangno, Gangneung, Gangwon 210-702, Republic of Korea
2Department of Advanced Metal and Materials Engineering, Gangneung-Wonju National University, 120 Gangneung-Daehangnu, Gangneung, Gangwon 210-702, Republic of Korea

Received 25 March 2013; Accepted 17 June 2013

Academic Editor: S. Miyazaki

Copyright © 2013 Woo Young Jung and Tae Kwon Ha. 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

High temperature deformation behavior, especially the superplasticity of an 8090 Al-Li alloy, was studied within the recent framework of the internal variable theory of structural superplasticity. In this study, a series of load relaxation tests were conducted at various temperatures ranging from 200°C to 530°C to obtain the flow curves of log  versus log . The effect of grain size was also examined by varying the grain sizes through a proper thermomechanical treatment. The flow curves were found to be composite curves consisting of contributions from grain boundary sliding (GBS) and grain matrix deformation (GMD) at superplastic temperatures. The activation energy obtained for GMD was 124.9 kJ/mole in the temperature range from 470°C to 530°C, very similar to that for self-diffusion in pure Al.