Hydrogen Effects on Crystal Dislocations and Stacking-Fault Energy
Ferreira, Paulo Jorge
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/82867
Description
Title
Hydrogen Effects on Crystal Dislocations and Stacking-Fault Energy
Author(s)
Ferreira, Paulo Jorge
Issue Date
1997
Doctoral Committee Chair(s)
Birnbaum, Howard K.
Department of Study
Materials Science and Engineering
Discipline
Materials Science and Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Engineering, Materials Science
Language
eng
Abstract
The mechanisms of hydrogen shielding the interaction of dislocations with other elastic centers are outlined. In-situ straining transmission electron microscope experiments show that the effect of hydrogen on the interaction between dislocations is reversible, whereas in systems where significant levels of impurities exist, the effect of hydrogen is to decrease the interaction between dislocations and solute atoms. Both observations strongly support the HELP mechanism to account for the observed hydrogen-enhanced dislocation mobility. In addition, the effect of hydrogen on the nature (screw vs. edge) of dislocations in high-purity aluminum are discussed. Hydrogen stabilizes the edge dislocation segments which results in a decreased ability of dislocations to cross-slip. It suggests that hydrogen has a tendency to promote slip planarity. Finally, the effect of hydrogen on the stacking-fault energy of an austenitic stainless steel is presented. Measurements done on dislocation nodes reveal a reduction of approximately 19% when comparing the stacking fault energies in vacuum and 40 torr of hydrogen.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.