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Invited Lecture

Transient Strain Aging in Al-Mg and Al-Mg-Cu alloys

Wednesday (06.11.2019)
17:00 - 17:20
Part of:

While dynamic strain aging of Al-Mg alloys is well appreciated, evidence for static strain aging in such alloys is less apparent. Commercial Al-Mg alloy sheet typically are given a tension leveling treatment prior to forming so as to avoid the appearance of Luders bands, suggesting static stain aging similar to the behaviour of steels. Unlike steels which will re-develop Luders behaviour if left for short times at room temperature following tension leveling, Al-Mg alloys can be left for weeks at room temperature without the reappearance of Luders bands. In this study we have examined the aging response of binary Al-Mg alloys and low Cu containing Al-Mg-Cu alloys following pre-strain. We show that there is a notable effect of strain aging which appears to effect not only the yield strength but also the work hardening rate. An extension of the phenomenological Kocks-Mecking work hardening law, including the effects of low dislocation density will be presented and shown to predict the observed behaviour for the studied conditions. This effect is included in the analysis of mechanical properties arising from precipitation pardonable Al-Mg-Cu alloys.

Prof. Chad Sinclair
University of British Columbia