Transition metal diboride matrix composites. Final technical report 1 Jun 1969--30 Nov 1970. [TiB/sub 2/ and ZrB/sub 2/ with graphite, SiC, or ZrO/sub 2/ reinforcement fibers]
Titanium diboride and zirconium diboride composites containing 'Thornel' 50 graphite fibers, silicon carbide whiskers, and 'Zircar' zirconium oxide fibers were fabricated by hot-pressing. In all composites fabricated to near theoretical density, degradation of the fibrous component occurred. The degradation is a recrystallization process, rather than a chemical interaction between the fibers and the matrix components. Recrystallization took place in each of the types of fibers, including 'Thornel' 50 fibers coated with TiC and TiB/sub 2/. In diboride composites containing SiC whiskers, the recrystallization of the whiskers was greatly reduced by using large diameter (>5 micrometers) whiskers. The strength of composites containing the undegraded SiC whiskers, however, was less than that of the unreinforced diboride matrix. The strongest zirconium diboride composites were fabricated with 'Zircar' stabilized zirconia fibers. The average strength of the strongest 'Zircar'--ZrB/sub 2/ composite was 81,000 psi. The composition of the strongest composite was 64 volume percent ZrB/sub 2/ powder, 16 volume percent SiC powder, and 20 volume percent 'Zircar' ZrO/sub 2/ fibers. (auth)
- Research Organization:
- Union Carbide Corp., Parma, OH (USA). Carbon Products Div.
- OSTI ID:
- 7313802
- Report Number(s):
- AD-888888
- Country of Publication:
- United States
- Language:
- English
Similar Records
Characterization of hot-pressed short ZrO{sub 2} fiber toughened ZrB{sub 2}-based ultra-high temperature ceramics
Zirconium-diboride silicon-carbide composites: A review
Related Subjects
360301* -- Composite Materials-- Preparation & Fabrication-- (-1987)
360303 -- Composite Materials-- Mechanical Properties-- (-1987)
BORIDES
BORON COMPOUNDS
CARBIDES
CARBON
CARBON COMPOUNDS
CHALCOGENIDES
COMPOSITE MATERIALS
CRYSTALS
ELEMENTS
FABRICATION
FIBERS
GRAPHITE
HOT PRESSING
MATERIALS WORKING
MECHANICAL PROPERTIES
MONOCRYSTALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PRESSING
RECRYSTALLIZATION
SILICON CARBIDES
SILICON COMPOUNDS
TENSILE PROPERTIES
TITANIUM BORIDES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
WHISKERS
ZIRCONIUM BORIDES
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES