The aim of this study was to understand the processing – structure – property relationships in spark plasma sintered (SPS) boron carbide (B4C) and B4C-titanium diboride (TiB2) ceramic composites. SPS allowed for consolidation of both B4C and B4C-TiB2 composites without sintering additives, residual phases, e.g., graphite, and excessive grain growth due to long sintering times. A selection of composite compositions in 20% TiB2 feedstock powder increments from 0% to 100%, was sintered at 1900°C for 25 minutes hold time. A homogeneous B4C-TiB2 composite microstructure was determined with excellent distribution of TiB2 phase, while achieving ~99.5% theoretical density. An optimum B4C-23 vol.% TiB2 composite composition with low density of ~3.0 g/cm3 was determined that exhibited ~30-35% increase in hardness, fracture toughness, and flexural bend strength compared to commercial armor-grade B4C. This is a result of a) no residual graphitic carbon in the composites, b) interfacial microcrack toughening due to thermal expansion coefficient differences placing the B4C matrix in compression and TiB2 phase in tension, and c) TiB2 phase aids in crack deflection thereby increasing the amount of intergranular fracture. Collectively, the addition of TiB2 serves as a strengthening and toughening agent, and SPS shows promise for the manufacture of hybrid ceramic composites.
| Identifer | oai:union.ndltd.org:unt.edu/info:ark/67531/metadc1157631 |
| Date | 05 1900 |
| Creators | Rubink, William S. |
| Contributors | Scharf, Thomas W., Reidy, Richard F., Du, Jincheng |
| Publisher | University of North Texas |
| Source Sets | University of North Texas |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
| Format | ix, 50 pages, Text |
| Rights | Public, Rubink, William S, Copyright, Copyright is held by the author, unless otherwise noted. All rights Reserved. |
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