THE INTERACTION OF HELIUM ATOMS WITH EDGE DISLOCATIONS IN alpha-Fe

Book · Fri Dec 31 04:00:00 EST 2004

OSTI ID:985089

Heinisch, Howard L; Gao, Fei; Kurtz, Richard J; Le, E A

Formation energies, binding energies, and migration energies of interstitial He atoms in and near the core of an a/2<111>{110} edge dislocation in alpha-Fe are determined in atomistic simulations using conjugate gradient relaxation and the Dimer method for determining saddle point energies. Results are compared as a function of the proximity of the He to the dislocation core and the excess interstitial volume in regions around the dislocation. Interstitial He atoms have negative binding energy on the compression side of the dislocation and strong positive binding energy on the tension side. Even at low temperatures, interstitial He atoms in the vicinity of the dislocation easily migrate to the dislocation core, where they form crowdion interstitials oriented along the close-packed slip direction, with binding energies in excess of 2 eV. Crowdion interstitial He atoms diffuse along the core, transverse to the crowdion direction, with a migration energy of 0.4-0.5 eV.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 985089
• Report Number(s): PNNL-SA-46385; AT6020100
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ATOMS
BINDING ENERGY
COMPRESSION
CROWDIONS
DIMERS
DISLOCATIONS
EDGE DISLOCATIONS
HELIUM
INTERSTITIALS
RELAXATION
SLIP