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Title: A comparative study on shock compression of nanocrystalline Al and Cu: Shock profiles and microscopic views of plasticity

Shock compressions of nanocrystalline (nc) metals Al and Cu with the same grain size and texture are studied by using molecular dynamics simulations. Results have revealed that the shock front of both Al and Cu can be divided into three stages: elastic, grain-boundary-mediated, and dislocation-mediated plastic deformation. The transition planes among these three stages are proven to be non-planar by two-dimensional shock response analysis, including local stress, shear, temperature, and atom configuration. The difference between shocked Al and Cu is that the rise rate of the elastic stage of Cu is slightly higher than that of Al, and that the shock-front width of Al is wider than Cu at the same loading conditions. For the plastic stage, the dislocation density of shocked Al is lower than Cu, and the contribution of grain-boundary-mediated plasticity to shock front and strain for nc Al is more pronounced than for nc Cu. These results are explained through intrinsic material properties and atomistic analysis of the plastic process. In the case of the shocked Al sample, partial dislocations, perfect dislocations, and twins are observed, but few evidence of perfect dislocations and twins are observed in the shocked Cu.
Authors:
;  [1] ;  [2]
  1. Department of Physics, College of Science, National University of Defense Technology, Changsha 410073 (China)
  2. National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-111, Mianyang 621900 (China)
Publication Date:
OSTI Identifier:
22217874
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 16; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM; COPPER; DEFORMATION; DISLOCATIONS; GRAIN BOUNDARIES; GRAIN SIZE; NANOSTRUCTURES; PLASTICITY; PLASTICS; SHEAR; SHOCK WAVES; SIMULATION; STRAINS; STRESSES; TEXTURE