Attenuation of the dynamic yield point of shocked aluminum using elastodynamic simulations of dislocation dynamics

When a metal is subjected to extremely rapid compression, a shock wave is launched that generates dislocations as it propagates. The shock wave evolves into a characteristic two-wave structure, with an elastic wave preceding a plastic front. It has been known for more than six decades that the ampli...

Full description

Saved in:
Bibliographic Details
Published in:Physical review letters 2015-05, Vol.114 (17), p.174301-174301, Article 174301
Main Authors: Gurrutxaga-Lerma, Beñat, Balint, Daniel S, Dini, Daniele, Eakins, Daniel E, Sutton, Adrian P
Format: Article
Language:English
Subjects:
Aluminum
Decay
Dislocations
Dynamics
Elastic waves
Precursors
Shock waves
Yield point
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:When a metal is subjected to extremely rapid compression, a shock wave is launched that generates dislocations as it propagates. The shock wave evolves into a characteristic two-wave structure, with an elastic wave preceding a plastic front. It has been known for more than six decades that the amplitude of the elastic wave decays the farther it travels into the metal: this is known as "the decay of the elastic precursor." The amplitude of the elastic precursor is a dynamic yield point because it marks the transition from elastic to plastic behavior. In this Letter we provide a full explanation of this attenuation using the first method of dislocation dynamics to treat the time dependence of the elastic fields of dislocations explicitly. We show that the decay of the elastic precursor is a result of the interference of the elastic shock wave with elastic waves emanating from dislocations nucleated in the shock front. Our simulations reproduce quantitatively recent experiments on the decay of the elastic precursor in aluminum and its dependence on strain rate.
ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.114.174301