Accession Number:

ADA244223

Title:

Effect of Interstitials on the Trapping of Hydrogen in Iron-Single Crystals

Descriptive Note:

Final rept. 21 Jan 1985-20 Jul 1991

Corporate Author:

NORTHWESTERN UNIV EVANSTON IL DEPT OF MATERIALS SCIENCE

Personal Author(s):

Report Date:

1991-11-01

Pagination or Media Count:

41.0

Abstract:

A non destructive method of determining the densities of edge and screw dislocations was developed. Using it, thermal elimination of dislocation was shown to be a binary and two stage process for both a cold-rolled and b metallographically polished specimens. The process involves the glide of dislocation dipoles rather than vacancy migration and climb. A method of extracting kinetic information from isochronal runs was developed and tested with isothermal runs. The strong effect of surface dislocations on reducing the diffusion of hydrogen and deuterium in iron single crystals was demonstrated. Positron lifetime results were then used to determine dislocation densities and the results were verified using transmission electron microscopy TEM and etch pit techniques on the same crystals. A few confirmatory experiments were made on annealed and on twisted iron whiskers. Internal friction measurements to show the effects of trapped hydrogen were also made on annealed, cold-worked, and charged high-purity single-crystal iron specimens.

Subject Categories:

  • Crystallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE