Files in this item

FilesDescriptionFormat

application/pdf

application/pdf9717273.pdf (5MB)Restricted to U of Illinois
(no description provided)PDF

Description

Title:Hydrogen Effects on Crystal Dislocations and Stacking-Fault Energy
Author(s):Ferreira, Paulo Jorge
Doctoral Committee Chair(s):Birnbaum, Howard K.
Department / Program:Materials Science and Engineering
Discipline:Materials Science and Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Engineering, Materials Science
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.
Issue Date:1997
Type:Text
Language:English
Description:169 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1997.
URI:http://hdl.handle.net/2142/82867
Other Identifier(s):(MiAaPQ)AAI9717273
Date Available in IDEALS:2015-09-25
Date Deposited:1997


This item appears in the following Collection(s)

Item Statistics