Reaction paths and microstructural evolution during transient plastic phase processing of titanium carbide -- Titanium boride composites

Book · Tue Aug 01 04:00:00 EDT 1995

OSTI ID:77953

Brodkin, D; Kalidindi, S; Barsoum, M; Zavaliangos, A ^[1]

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1. Drexel Univ., Philadelphia, PA (United States). Dept. of Materials Engineering

Transient Plastic Phase Processing (TPPP) was used to fabricate fully dense, ultra-refractory ceramic-ceramic composites of different microstructures in the Ti-B-C system. The attainment of the full density was related to the presence of a substoichiometric titanium carbide (TiC{sub 0.5}) that was formed in situ or chosen as a reactant. Two starting compositions, that correspond to the same point in the ternary diagram, namely: 4:1 (molar) Ti/B{sub 4}C and 1:1 TiC{sub 0.5}/ TiB{sub 2} were examined. The final microstructures were dramatically different, with Ti{sub 3}B{sub 4} nucleating and growing as platelets when the reactants were 4:1Ti/B{sub 4}C and as equiaxed grains when the starting powders were 1:1 TiC{sub 0.5}/TiB{sub 2}. Interrupted runs have shown that the formation of the platelets was linked to the presence of the intermediate phase TiB. For both starting compositions fully dense composites with good mechanical properties were produced. The superior mechanical properties of 4:1Ti/B{sub 4}C composite is believed to be due to the platelet morphology of the Ti{sub 3}B{sub 4} phase and associated specific mechanisms of platelet-crack interactions.

• OSTI ID: 77953
• Report Number(s): CONF-950201--; ISBN 0-87339-283-3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BULK DENSITY
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
COMPOSITE MATERIALS
EXPERIMENTAL DATA
FABRICATION
FLEXURAL STRENGTH
HARDNESS
HOT PRESSING
MECHANICAL PROPERTIES
MICROSTRUCTURE
POWDERS
SCANNING ELECTRON MICROSCOPY
TITANIUM BORIDES
TITANIUM CARBIDES
X-RAY DIFFRACTION