期刊
ACTA MATERIALIA
卷 60, 期 19, 页码 6842-6850出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.actamat.2012.08.058
关键词
Portevin-Le Chatelier effect; Dislocation dynamics; Acoustic methods; Self-organization; Synchronization
资金
- Centre National de la Recherche Scientifique [55561]
- Russian Academy of Sciences [55561]
- Agence Nationale de la Recherche [ANR 2010 JCJC 0914 01]
The acoustic emission (AE) accompanying jerky flow in dilute alloys, the so-called Portevin-Le Chatelier effect, is usually considered to be composed of discrete bursts associated with the motion of large dislocation ensembles giving rise to stress serrations, which are superimposed on continuous AE generated during macroscopically smooth plastic flow. The data streaming technique which allows continuous AE recording is used to investigate the jerky flow of an AlMg alloy on different timescales. The apparent behavior, discrete or continuous, of AE is found to depend on the period of observation and the characteristic surveyed. However, it is proved that AE has a burst-like character during both stress serration and smooth flow. This behavior, revealed on timescales proper to the given strain rate, reflects the inherently intermittent, avalanche-like nature of collective dislocation dynamics, and unifies the concept generally applied to jerky flow with the similar approach to macroscopically uniform deformation flow, based on recent studies of AE during plastic deformation of pure materials. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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