Degree Type

Thesis

Date of Award

2017

Degree Name

Master of Science

Department

Materials Science and Engineering

Major

Materials Science and Engineering

First Advisor

Peter C. Collins

Abstract

Magnesium alloys are of more and more interest in engineering applications because they have low density, good machinability and great damping capacity. However, the application of Mg alloys at their present stage has been restricted by their poor formability and limited room temperature ductility because of their hcp crystal structure. Therefore, many attempts have been made to improve the mechanical properties of Mg. Grain refining is considered an effective way of increasing strength, though there is less well-established understanding of how microstructural refinement influences other properties, including fatigue.

In this research, the Equal Channel Angular Pressing (ECAP) process was used to develop an ultra-fine grained AZ31 Mg alloy. Materials with ECAPed process have very small grain size, typically less than 1 μm, thus improve their tensile strength and hardness with fairly large ductility. Fatigue properties of AZ31 Mg alloy are measured using a four point bending fatigue testing configuration. The effect of texture on fatigue properties is studied. The fractography of the specimen is discussed. The strengthening mechanisms are also investigated.

Copyright Owner

Muchen Li

Language

en

File Format

application/pdf

File Size

56 pages

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