Article abstract
Nature Materials 5, 875 - 880 (2006)
Published online: 22 October 2006 | doi:10.1038/nmat1765
Subject Categories: Metals and alloys | Mechanical properties | Computation, modelling and theory
A predictive mechanism for dynamic strain ageing in aluminium–magnesium alloys
William A. Curtin1, David L. Olmsted1,3 & Louis G. Hector, Jr2
Abstract
Dynamic strain ageing (DSA) is the phenomenon in which solute atoms diffuse around dislocations and retard dislocation motion, leading to negative strain-rate sensitivity (nSRS) and thus to material instabilities during processing, an important issue in commercial metal alloys. Here, we show the mechanism of DSA and nSRS on experimental strain-rate, temperature and stress scales for Al–Mg to be single-atomic-hop motion of solutes from the compression to the tension side of a dislocation core. We derive an analytic expression for the strengthening versus strain rate and temperature that justifies widely used phenomenological forms, provides specific dependences of the parameters on material properties and is supported by atomistic kinetic Monte Carlo simulations. Using literature material properties, the predicted strengthening quantitatively agrees with the experimentally derived behaviour of Al–2.5% Mg at 300 K, and qualitatively agrees with the strain rate and temperature ranges of DSA and nSRS in Al–Mg alloys. The analyses herein show a clear path for multiscale design, from quantum to continuum mechanics, of solute strengthening in face-centred-cubic metal alloys.
- Division of Engineering, Brown University, Providence, Rhode Island 02912, USA
- General Motors Technical Center, 30500 Mound Rd., Warren, Michigan 48090-9055, USA
- Current address: Sandia National Laboratories, Albuquerque, New Mexico 87185-1411, USA
Correspondence to: William A. Curtin1 e-mail: curtin@engin.brown.edu
MORE ARTICLES LIKE THIS
These links to content published by NPG are automatically generated.
RESEARCH
Connecting atomistic and mesoscale simulations of crystal plasticityNature Letters to Editor (12 Feb 1998)
Quantitative insight into dislocation nucleation from high-temperature nanoindentation experimentsNature Materials Article (01 Aug 2005)
Dynamic transitions from smooth to rough to twinning in dislocation motionNature Materials Article (01 Mar 2004)
Novel Ti-base nanostructure?dendrite composite with enhanced plasticityNature Materials Article (01 Jan 2003)
X-ray microbeam measurements of individual dislocation cell elastic strains in deformed single-crystal copperNature Materials Letter (01 Aug 2006)
