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Title: Effects of thin anodic films on cyclic deformation of tungsten

Abstract

The dynamics of edge and screw dislocation motion as a function of temperature play a decisive role in the mechanical response of bcc metals. Cyclic deformation over a range of plastic-strain levels was used to investigate many aspects of the cyclic stress-strain response of tungsten single crystals at room temperature. The results of this investigation fully support a two-dislocation model of deformation for bcc metals at low homologous temperatures (T less than or equal to 0.15T/sub m/). The occurrence of stress asymmetry and cyclic stress-strain behavior which fits a two-dislocation model are demonstrated in crystals of several orientations. The results indicate that the nearly isotropic elastic response of tungsten produces the nearly ideal stress asymmetry expected for bcc crystals. Thin anodic films (approx. 80 nm) were utilized to determine the effects of surface modification on the cyclic stress-strain behavior of tungsten. At cyclic microstrains, the anodization of tungsten produces a large reversible hardening effect. At cyclic macrostrains the anodization of tungsten produces a smaller, less reversible softening effect. These two effects are explained in terms of dislocation multiplication and annihilation processes

Authors:
Publication Date:
Research Org.:
Michigan Univ., Ann Arbor (USA)
OSTI Identifier:
5289314
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; TUNGSTEN; DEFORMATION; ANODIZATION; BCC LATTICES; DISLOCATIONS; ELASTICITY; FILMS; MONOCRYSTALS; STRAINS; STRESS ANALYSIS; CHEMICAL COATING; CORROSION PROTECTION; CRYSTAL DEFECTS; CRYSTAL LATTICES; CRYSTAL STRUCTURE; CRYSTALS; CUBIC LATTICES; DEPOSITION; ELECTROCHEMICAL COATING; ELECTROLYSIS; ELEMENTS; LINE DEFECTS; LYSIS; MECHANICAL PROPERTIES; METALS; SURFACE COATING; TENSILE PROPERTIES; TRANSITION ELEMENTS; 360103* - Metals & Alloys- Mechanical Properties

Citation Formats

Bowman, K J. Effects of thin anodic films on cyclic deformation of tungsten. United States: N. p., 1987. Web.
Bowman, K J. Effects of thin anodic films on cyclic deformation of tungsten. United States.
Bowman, K J. 1987. "Effects of thin anodic films on cyclic deformation of tungsten". United States.
@article{osti_5289314,
title = {Effects of thin anodic films on cyclic deformation of tungsten},
author = {Bowman, K J},
abstractNote = {The dynamics of edge and screw dislocation motion as a function of temperature play a decisive role in the mechanical response of bcc metals. Cyclic deformation over a range of plastic-strain levels was used to investigate many aspects of the cyclic stress-strain response of tungsten single crystals at room temperature. The results of this investigation fully support a two-dislocation model of deformation for bcc metals at low homologous temperatures (T less than or equal to 0.15T/sub m/). The occurrence of stress asymmetry and cyclic stress-strain behavior which fits a two-dislocation model are demonstrated in crystals of several orientations. The results indicate that the nearly isotropic elastic response of tungsten produces the nearly ideal stress asymmetry expected for bcc crystals. Thin anodic films (approx. 80 nm) were utilized to determine the effects of surface modification on the cyclic stress-strain behavior of tungsten. At cyclic microstrains, the anodization of tungsten produces a large reversible hardening effect. At cyclic macrostrains the anodization of tungsten produces a smaller, less reversible softening effect. These two effects are explained in terms of dislocation multiplication and annihilation processes},
doi = {},
url = {https://www.osti.gov/biblio/5289314}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1987},
month = {1}
}

Thesis/Dissertation:
Other availability
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