Open AccessFinal Report LDRD 04-ERD-021
Author(s) -
Eduardo M. Bringa
Publication year - 2007
Language(s) - English
Resource type - Reports
DOI - 10.2172/902248
Subject(s) - nanoindentation , nanocrystalline material , materials science , transmission electron microscopy , strain rate , constitutive equation , diffraction , deformation (meteorology) , molecular dynamics , deformation mechanism , composite material , crystallography , thermodynamics , nanotechnology , optics , microstructure , physics , chemistry , finite element method , computational chemistry
In this project, we performed experiments and simulations to establish constitutive models for plastic behavior and to determine the deformation mechanism of nanocrystalline materials at different grain sizes (<100 nm) and high strain rates (>10{sup 6}/s). The experiments used both laser-induced shocks and isentropic compression to investigate, for the first time, the high-strain-rate deformation of nanocrystalline Ni. Samples were characterized using transmission electron microscopy, nanoindentation, profilometry, and x-ray diffraction before and after loading. We validated constitutive models using both atomistic molecular dynamics and continuum simulations performed at the boundary of their current computational possibilities to match experimental scales