24-10-2012, 11:35 AM
Dislocation Density-Based Constitutive Model for the Mechanical Behavior of Irradiated Cu
ABSTRACT
Performance degradation of structural steels in nuclear environments results from the development of a high number
density of nanometer scale defects. The defects observed in copper-based alloys are composed of vacancy clusters in the form
of stacking fault tetrahedra and/or prismatic dislocation loops, which impede dislocation glide and are evidenced in
macroscopic uniaxial stress-strain curves as increased yield strengths, decreased total strain to failure, decreased work
hardening and the appearance of a distinct upper yield point above a critical defect concentration (neutron dose). In this paper,
we describe the development of an internal state variable model for the mechanical behavior of materials subject to these
environments. This model has been developed within an information-passing multiscale materials modeling framework, in
which molecular dynamics simulations of dislocation--radiation defect interactions, inform the final coarse-grained continuum
model.