Effect of Interstitials on the Trapping of Hydrogen in Iron-Single Crystals
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1991
- Accession Number
- ADA244223
Entities
People
- James T. Weaver
Organizations
- Northwestern University