Masters Theses

Abstract

"The data collected in an attempt to evaluate the pressure dependency of the mechanical properties of extruded AZ31B-F magnesium alloy are presented herein. This information was compiled from the results of compression tests run in hydraulic fluid environments pressurized to 50,000 psi, and tension tests run in the atmosphere. Specimen axial load and longitudinal strain were recorded and converted to effective stress and effective strain parameters for presentation. The term pressure is defined, in this report, as the negative average of the principal stresses or, essentially, the negative of the hydrostatic component of stress. The effective stress and strain, at yield and fracture, which were achieved at various hydrostatic stress levels are plotted against the hydrostatic stress levels at which they occurred. It has been shown that the strength and ductility of this extruded alloy, measured at fracture, are increased by an increase in the hydrostatic stress component that exists at the time of fracture. In addition, the effective stress, at yield, is increased and the effective strain is decreased by an increase in the current pressure. An exception to the above seems to be the effective stress achieved at yield in uniaxial tension which is substantially greater than the highest effective yield stress obtained in compression at any fluid environment pressure. This anomaly is due to the fact that the specimen material was cold formed. The aforementioned graphs are combined to form a three dimensional yield and fracture model based on the parameters of effective stress, effective strain and pressure. This model shows the pressure dependent properties of the particular magnesium alloy under investigation. It is, however, incomplete since bi-axial tension tests run at various fluid pressure environments are needed to better define the tensile pressure region of the model, and compression tests conducted in higher fluid pressure environments are needed to determine the pressures required to obtain infinite ductility"--Abstract, page ii-iii.

Advisor(s)

Davis, Robert L.

Committee Member(s)

Lehnhoff, T. F., 1939-
Hansen, Peter G.
Davidson, Robert F., 1911-1971

Department(s)

Mechanical and Aerospace Engineering

Degree Name

M.S. in Engineering Mechanics

Publisher

University of Missouri at Rolla

Publication Date

1968

Pagination

vii, 42 pages

Note about bibliography

Includes bibliographical references (leaf 45).

Rights

© 1968 Joseph George Hoeg, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Library of Congress Subject Headings

Magnesium -- Mechanical properties
Strains and stresses

Thesis Number

T 2117

Print OCLC #

5995608

Electronic OCLC #

803605343

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