Masters Theses

Author

Ang Li

Abstract

"Ultra-high temperature ceramics are being investigated for future use in aerospace applications due to their superior thermo-mechanical properties, as well as oxidation resistance, at temperatures above 2000°C. However, their brittle properties make them susceptible to thermal shock failure. Components fabricated as functionally graded materials (FGMs) can combine the superior properties of ceramics with the toughness of an underlying refractory metal by fabricating graded composites. This paper discusses the grading of two materials through the use of a Freeze-form Extrusion Fabrication (FEF) system to build FGMs parts consisting of zirconium carbide (ZrC) and tungsten (W). Aqueous-based colloidal suspensions of ZrC and W were developed and utilized in the FEF process to fabricate test bars graded from 100%ZrC to 50%W-50%ZrC (volume percent). Following FEF processing the test bars were co-sintered at 2300°C and characterized to determine their resulting density and micro-structure. Four-point bending tests were performed to assess the strength of test bars made using the FEF process, compared to test bars prepared using conventional powder processing and isostatic pressing techniques, for five distinct ZrC-W compositions. Scanning electron microscopy (SEM) was used to verify the inner structure of composite parts built using the FEF process"--Abstract, page iii.

Advisor(s)

Leu, M. C. (Ming-Chuan)

Committee Member(s)

Hilmas, Greg;Landers, Robert G.

Department(s)

Mechanical and Aerospace Engineering

Degree Name

M.S. in Manufacturing Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2013

Pagination

vii, 34 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2013 Ang Li, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Library of Congress Subject Headings

Solid freeform fabrication
Ceramics -- Extrusion
Zirconium carbide
Tungsten
Sintering
Powder metallurgy

Thesis Number

T 10294

Electronic OCLC #

853280654

Included in

Manufacturing Commons

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