[T14] High Temperature Materials

[15F-T14-05] Keynote: Deformation-Resistant Multipurpose Ultra-High Temperature Ceramics with Superior Hardness, Toughness, and Flexural Strength

*O. Vasylkiv¹ (1.National Institute for Materials Science, Japan)

キーワード：SPS, Deformation resistance, UHTC

The request for new multipurpose ultra-high temperature transition-metal carbide and boride ceramics causes the worldwide demand for a new class of composites with sufficient balance of high toughness, hardness, and superior flexural strength up to 2000°C. Deformation resistivity of reaction-driven SPSed boron carbide, TiB₂ with stiff skeleton of B₄C, Ta_0.2Hf_0.8C, Zr-Ta boride composite with artificially created hierarchical superstructure, tantalum mono-boride, medium-entropy Zr-Ta-Nb diboride, and TaB₂-ZrB₂-TiB₂-HfB₂ to be addressed. With RT to 1800 °C mean strength of 650 MPa, boron carbide exhibits ultrahigh flexural strength far exceeding 1000 MPa accompanied by a change in the deformation mechanism from brittle fracture to plastic deformation at 2000 °C. Ultra-strength of boron carbide through the mechanism of ultra-high temperature flexure & strain-driven amorphization to be discussed.