The acoustic emission from moving dislocations in aluminium

Abstract

The acoustic emission during tensile tests is investigated for several types of aluminium alloys. It is found that the mean square amplitude of the continuous emission is proportional to strain rate and sample length. It is assumed that the continuous emission is generated by dislocation loops, which are created continuously at Frank-Read sources. According to this model the mean square amplitude of the continuous emission U2 is proportional to the total length of the mobile dislocations L and the size of the loops l: \documentclass{article}\pagestyle{empty}\begin{document}$ \overline {U^2 } $\end{document} ∼LI. Information about l was taken from Kuhlmann and Wilsdorf's observations of slip lines at the surface of deformed aluminium single crystals.