Reduced-temperature processing and consolidation of ultra-refractory Ta4HfC5

TitleReduced-temperature processing and consolidation of ultra-refractory Ta4HfC5
Publication TypeJournal Article
Year of Publication2013
AuthorsGaballa O, Cook BA, Russell AM
Journal TitleInternational Journal of Refractory Metals & Hard Materials
Date Published11
Type of ArticleArticle
ISBN Number0263-4368
Accession NumberWOS:000325840700045
Keywordsboron-carbide, ceramics, densification, electronic-structure, hafnium, hfc-based composites, Hot press, mechanical-properties, OXIDATION BEHAVIOR, powder processing, tac, tantalum carbide, Tantalum hafnium carbide, tungsten carbide, Ultra-refractory materials

TaC, HfC, and WC powders were subjected to high-energy milling and hot pressing to produce Ta4HfC5, a composite of Ta(4)HfC5 + 30 vol.% WC, and a composite of Ta4HfC5 + 50 vol.% WC. Sub-micron powders were examined after four different milling intervals prior to hot pressing. XRD was used to verify proper phase formation. SEM, relative density, and hardness measurements were used to examine the resulting phases. Hot pressed compacts of Ta4HfC5 showed densification as high as 98.6% along with Vickers hardness values of 21.4 GPa. Similarly, Ta4HfC5 + 30 vol.% WC exhibited 99% densification with a Vickers hardness of 22.5 GPa. These levels of densification were achieved at 1500 degrees C, which is lower than any previously reported sintering temperature for Ta4HfC5. Microhardness values measured in this study were higher than those previously reported for Ta4HfC5. The WC additions to Ta4HfC5 were found to improve densification and increase microhardness. (C) 2013 Elsevier Ltd. All rights reserved.

URL<Go to ISI>://WOS:000325840700045