Composition Modification and Mechanical Properties of Solidified TiB₂-Based Ceramic Prepared by Combustion Synthesis in Ultra-High Gravity Field

Abstract:

The solidified TiC-TiB₂ ceramics with excessive Ti mole content were prepared through adjusting the Ti additional agent in combustion system with ultra-high-gravity of 2000 g, and the ceramics were comprised of TiB₂ primary phases, irregular TiC_1-x secondary phases, a few of Al₂O₃ inclusions and Cr-Ti-Al metallic phases. The additional Ti content resulted in not only the rapidly-reduced Al₂O₃ inclusions but also the refined microstructure and the improved homogeneity in the solidified microstructure. As the Ti additional agent was increased, more and more Ti atoms could participate in the formation of nonstoichiometric TiC_1-x phases and Cr-Ti-Al metallic phases. The maximum fracture toughness of 18.5 ± 1.0 MP · m^0.5 in current solidified TiC-TiB₂composite was achieved because of the less Al₂O₃ inclusions, the refined microstructure and the Ti-rich Cr-Ti-Al metallic phases obtained in the near-full-density composite. The high fracture toughness contributed from not only mechanism of crack deflection, crack-bridging and pull-out by a large number of fine TiB₂ platelets, but also the ductile fracture toughening result from plastic deformation of Cr-Ti-Al metallic phases.

• Periodical: Key Engineering Materials (Volume 591)
• Pages: 79-83
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.591.79
• Online since: November 2013
• Authors: Xue Gang Huang, Zhong Min Zhao, Long Zhang
• Keywords: Composition Modification, Homogeneity, TiC-TiB₂ Composite, Toughening

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