Author
Hahn, Henry N.
Other Contributors
Duquette, David J.; Aikens, David A.; Doremus, R. H.; Judd, Gary; Stoloff, N. S.;
Date Issued
1977-05
Subject
Metallurgy
Degree
PhD;
Terms of Use
This electronic version is a licensed copy owned by Rensselaer Polytechnic Institute, Troy, NY. Copyright of original work retained by author.;
Abstract
Transmission electron microscopy of near surface areas of copper single crystals shows that dissolution disrupts the normal fatigue generated dislocation substructure in these regions. Increased slip offset heights and blunted slip bands are also observed for copper single crystals.; High cycle fatigue of high purity polycrystalline copper, single crystals of copper, single crystals of copper-aluminum and polycrystalline copper-nickel-chromium alloys in the aged and solutionized conditions has been investigated. Specimens were tested in laboratory air, 0.5N NaCl, and 0.5N NaCl with applied anodic currents or potentials.; Preferential attack of slip bands and grain boundaries is observed. A shift in crack initiation and propagation mode from predominantly transgranular in air to predominantly intergranular in aqueous solutions is also observed.; A large decrease in life occurred when the aged coppernickel-chromium alloy was tested in 0.5N NaCl. However, accelerated dissolution caused the same loss in life of polycrystalline copper or solutionized copper-nickel-chromium alloy. Cathodic currents restored fatigue life to that observed in air. Exposure of single crystals of copper or single crystals of copper-aluminum to a corrosive environment during fatigue results in a large increase in life.; A model of cooperative interaction between emerging strained metal associated with dislocations and the dissolution process is suggested to explain observed results.;
Description
May 1977; School of Engineering
Department
Dept. of Materials Engineering;
Publisher
Rensselaer Polytechnic Institute, Troy, NY
Relationships
Rensselaer Theses and Dissertations Online Collection;
Access
Restricted to current Rensselaer faculty, staff and students. Access inquiries may be directed to the Rensselaer Libraries.;
