Effect of applied pressure on densification of monolithic ZrCxceramic by reactive hot pressing
| Autor: | Tamoghna Chakrabarti, Rajaguru Kannan, Vikram Jayaram, Lingappa Rangaraj |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Materials science
chemistry.chemical_element 02 engineering and technology Hot pressing 01 natural sciences Carbide 0103 physical sciences Relative density General Materials Science Ceramic Composite material 010302 applied physics Zirconium Mechanical Engineering Metallurgy Materials Engineering (formerly Metallurgy) 021001 nanoscience & nanotechnology Condensed Matter Physics Microstructure chemistry Mechanics of Materials visual_art Volume fraction visual_art.visual_art_medium 0210 nano-technology Stoichiometry |
| Zdroj: | Journal of Materials Research. 31:506-515 |
| ISSN: | 2044-5326 0884-2914 |
| DOI: | 10.1557/jmr.2016.30 |
| Popis: | The effect of applied pressure on reactive hot pressing (RHP) of zirconium (Zr):graphite (C) in molar ratios of 1:0.5, 1:0.67, 1:0.8, and 1:1 was studied at 1200 degrees C for 60 min. The relative density achievable increased with increasing pressure and ranged from 99% at 4 MPa for ZrC0.5 to 93% for stoichiometric ZrC at 100 MPa. The diminishing influence of pressure on the final density with increasing stoichiometry is attributed to two causes: the decreasing initial volume fraction of the plastically deforming Zr metal which leads to the earlier formation of a contiguous, stress shielding carbide skeleton and the larger molar volume shrinkage during reaction which leads to pore formation in the final stages. A numerical model of the creep densification of a dynamically evolving microstructure predicts densities that are consistent with observations and confirm that the availability of a soft metal is primarily responsible for the achievement of such elevated densification during RHP. The ability to densify nonstoichiometric compositions like ZrC0.5 at pressures as low as 4 MPa offers an alternate route to fabricating dense nonstoichiometric carbides. |
| Databáze: | OpenAIRE |
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