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Deformation mechanisms of an Ω precipitate in a high-strength aluminum alloy subjected to high strain rates

Published online by Cambridge University Press:  17 February 2011

K. Elkhodary ,
W. Lee ,
L.P. Sun ,
D.W. Brenner  and
M.A. Zikry
K. Elkhodary
Affiliation:
Department of Mechanical & Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695-7910
W. Lee
Affiliation:
Department of Mechanical & Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695-7910
L.P. Sun
Affiliation:
Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27587-7907
D.W. Brenner
Affiliation:
Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27587-7907
M.A. Zikry*
Affiliation:
Department of Mechanical & Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695-7910
*
a)Address all correspondence to this author. e-mail: [email protected]
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Abstract

The objective of this study was to identify the microstructural mechanisms controlling Ω precipitates’ contribution to the high strength and ductility of Al–Cu–Mg–Ag alloys subjected to high impact loading conditions. Three interrelated approaches were used: (i) HRTEM imaging of deformed Ω precipitates in ballistically impacted Al–Cu–Mg–Ag plates, (ii) microstructurally based finite element (FE) analysis based on specialized crystalline plasticity formulations, and (iii) molecular dynamics (MD) simulations of dislocation nucleation and emission. The FE and MD simulations detail the evolution of dislocation densities and dislocations at the Al/Ω interface, which are consistent with the experimentally observed multiplicity of shear cutting of thin Ω precipitates. Furthermore, the FE results indicate that unrelaxed tensile strains at the Al/Ω interface can inhibit localized deformation in the alloy.

Keywords

AlMicrostructureNanoscale
Type
Invited Feature Paper
Information
Journal of Materials Research , Volume 26 , Issue 4 , 28 February 2011 , pp. 487 - 497
Copyright
Copyright © Materials Research Society 2011

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Footnotes

This paper has been selected an as Invited Feature Paper.

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