Accession Number:

ADA523966

Title:

The Activated State for Cross-Slip at Screw Dislocation Intersections in Face-Centered Cubic Nickel

Descriptive Note:

Journal article (preprint)

Corporate Author:

UES INC DAYTON OH

Report Date:

2010-04-01

Pagination or Media Count:

38.0

Abstract:

We extend our recent work where a screw dislocation in FCC Ni was found to spontaneously attain a low-energy partially cross-slipped configuration upon intersecting a forest dislocation. Using atomistic molecular statics simulations with embedded atom potentials, we evaluate the activation barrier for a dislocation to transform from fully residing on the glide plane to fully residing on the cross-slip plane intersecting a forest dislocation. The activation energies were obtained by determining equilibrium configurations energies when variable pure tensile or compressive stresses are applied along the direction on the partially cross-slipped state. We show that the activation energy is a factor of 3 - 6 lower than that for cross slip in isolation via the Escaig process. Further, the activation barrier for cross-slip at these intersections is shown to be linearly proportional to dblndb, as in the Escaig process, where d is the Shockley partial dislocation spacing and b is the Burgers vector of the screw dislocation. These results suggest that cross-slip should be preferentially observed at selected screw dislocation intersections in FCC materials.

Subject Categories:

  • Inorganic Chemistry
  • Physical Chemistry
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE