Preparation, microstructure and properties of silicon carbide-dysprosia composites

Composites of silicon carbide with up to 30 vol% dysprosia (Dy$\sb2$O$\sb3$) were fabricated by hot pressing and hot isostatic pressing. Dy$\sb2$O$\sb3$, one of the lanthanide sesquioxides (or rare-earth oxides), undergoes a displacive (monoclinic to cubic) phase transformation with volume expansion during cooling from high temperatures ($\approx$1850$\sp\circ$C). The effects of Dy$\sb2$O$\sb3$ additions on the microstructure and on selected mechanical properties of the composites were investigated. The phase analysis and microstructure of the composites were investigated using X-ray diffraction, SEM and TEM. Processing parameters influencing composite density and the retention of monoclinic dysprosia in a silicon carbide matrix were identified. Some of the mechanical properties evaluated for the composites were: modulus of elasticity, hardness, flexure strength and fracture toughness. The hardness of the composites was determined using the Vickers indentation method. Elastic properties were determined by the ultrasonic pulse echo technique. Flexure strengths were determined using four point bend testing. Fracture toughness was determined by both the three point, single-edge notched beam test and by the microindentation methods.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Materials Science and Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Kim, Shin

Contributors dc:contributor

• Kriven, Waltraud M.

• Engineering, Metallurgy
• Engineering, Materials Science

Statement dc:rights

• Copyright 1991 Kim, Shin

Language dc:language

eng

Identifier

AAI9210869
(UMI)AAI9210869

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/20033