Date of Award

2010-01-01

Degree Name

Master of Science

Department

Physics

Advisor(s)

Dr. Ramon J. Ravelo

Abstract

Large-scale atomistic simulations of shock-wave propagation in single crystals exhibit large anisotropies in the elastic-plastic and solid-liquid transitions. Characteristic of this type of simulations are the large strains at which the crystal yields plastically, regardless of crystal orientation. At these large strains, uniaxial deformations, such as those produced in planar shock loading generate dynamical instabilities. We have investigated the directional anisotropy of the elastic limit in bcc crystals, in particular Tantalum (Ta), employing molecular dynamics (MD) simulations. We show that the elastic - plastic transition in BCC defect-free crystals is caused by the appearance of soft-phonon modes and not via homogenous nucleation of extended defects.

Language

en

Provenance

Received from ProQuest

File Size

92 pages

File Format

application/pdf

Rights Holder

Oscar Guerrero

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