Mechanisms of deformation in beta-brass single crystals
type: CreativeWork
description: The investigation reported in this thesis is an extension of an earlier investigation of the stress/strain behaviour of β-brass single crystals under static and dynamic loading. It was aimed at elucidating the mechanisms of deformation, using optical microscopy to examine slip habits and transmission electron microscopy to examine dislocation substructures. Marked differences were observed in the stress/strain response, slip behaviour, and the substructural rearrangements of single crystals of β-brass when widely different rates of uninterrupted compressive loading were used. Under static loading (strain rates = 10-4 sec-1) the crystals workhardened in a parabolic manner, slip being confined to either of the two (101) [111] or (211) [111] systems. Cross-slip in the statically deformed crystals was evidenced by the wavy appearance of the slip traces. Under dynamic loading (strain rates > 103 sec-1) the crystals exhibited large yield drops followed by a linear rate of work-hardening which was lower than the static work-hardening rate. Slip on the four (-101) [111], (-110) [111], (101) [-11l] and (110) [-111] systems occurred simultaneously. The traces on any one dynamically deformed specimen were both coarser and finer than those observed on specimens statically deformed. The coarse traces belonging to a given {110} <111> slip system always bounded the finer traces of another {110} <111> system. No wavy slip was observed on the dynamically deformed specimens. The substructures present in the statically deformed crystals were consistent with a single mode of slip and exhibited features indicative of high rates of hardening on the active slip planes. The important features of the statically induced substructures were as follows:- (a) There was a predominance of dislocations with Burgers vectors of a[111]. Many of these lay in non-screw high-energy orientations, consistent with the occurrence of cross-slip and the observed high hardening rates of the crystals. (b) Strong…
abstract: The investigation reported in this thesis is an extension of an earlier investigation of the stress/strain behaviour of β-brass single crystals under static and dynamic loading. It was aimed at elucidating the mechanisms of deformation, using optical microscopy to examine slip habits and transmission electron microscopy to examine dislocation substructures. Marked differences were observed in the stress/strain response, slip behaviour, and the substructural rearrangements of single crystals of β-brass when widely different rates of uninterrupted compressive loading were used. Under static loading (strain rates = 10-4 sec-1) the crystals workhardened in a parabolic manner, slip being confined to either of the two (101) [111] or (211) [111] systems. Cross-slip in the statically deformed crystals was evidenced by the wavy appearance of the slip traces. Under dynamic loading (strain rates > 103 sec-1) the crystals exhibited large yield drops followed by a linear rate of work-hardening which was lower than the static work-hardening rate. Slip on the four (-101) [111], (-110) [111], (101) [-11l] and (110) [-111] systems occurred simultaneously. The traces on any one dynamically deformed specimen were both coarser and finer than those observed on specimens statically deformed. The coarse traces belonging to a given {110} <111> slip system always bounded the finer traces of another {110} <111> system. No wavy slip was observed on the dynamically deformed specimens. The substructures present in the statically deformed crystals were consistent with a single mode of slip and exhibited features indicative of high rates of hardening on the active slip planes. The important features of the statically induced substructures were as follows:- (a) There was a predominance of dislocations with Burgers vectors of a[111]. Many of these lay in non-screw high-energy orientations, consistent with the occurrence of cross-slip and the observed high hardening rates of the crystals. (b) Strong…
author: Broom, Neil, professor.
language: en
license: https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm
date published: 1971
date modified: 2026-07-24T01:06:29Z
provider: University of Auckland
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: ResearchSpace@Auckland

PropertyValue
property ID: Handle
value: https://hdl.handle.net/2292/2529