Effect of the Strain Rate and Microstructure on Damage Growth in Aluminum

Materials used in soldier protective structures, such as armor, vehicles and civil infrastructures, are being improved for performance in extreme dynamic environments. Nanocrystalline metals show significant promise in the design of these structures with superior strengths attributed to the dislocat...

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Bibliographic Details
Published in:Computers, materials & continua materials & continua, 2013, Vol.36 (3), p.231-255
Main Authors: Valisetty, R R, Dongare, A M, Rajendran, A M, Namburu, R R
Format: Article
Language:English
Subjects:
Aluminum
Armored vehicles
Computer simulation
Crystal structure
Crystallinity
Damage
Dynamical systems
Dynamics
Embedded atom method
Evolution
Grain size
Microstructure
Molecular dynamics
Nanocrystals
Optimization
Plastic deformation
Protective structures
Single crystals
Strain rate
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Summary:Materials used in soldier protective structures, such as armor, vehicles and civil infrastructures, are being improved for performance in extreme dynamic environments. Nanocrystalline metals show significant promise in the design of these structures with superior strengths attributed to the dislocation-based and grain-boundary-based processes as compared to their polycrystalline counterparts. An optimization of these materials, however, requires a fundamental understanding of damage evolution at the atomic level. Accordingly, atomistic molecular dynamics simulations are performed using an embedded-atom method (EAM) potential on three nano-crystalline aluminum atom systems, one a Voronoi-based nano-crystalline system with an average grain size of 10 nm, and the other two single crystals. These simulations are performed under the condition of uniaxial expansion at several strain rates ranging from 106s-1 to 1010s-1. Results for the effective stress are discussed with the aim of establishing the role of the strain rate and microstructure on the evolution of the plastic strain and void volume fraction and the eventual loss of stress carrying capability of the atom systems.
ISSN:1546-2218
1546-2226
DOI:10.3970/cmc.2013.036.231