Reactive Wetting of HF Alloy Melts into B4C Packed Bed Forming Ceramic Composites
Abstract
This proposal will investigate the reactive wetting of Hf-Ti-Nb-Ta alloy melts with B4C to form (Hf, Ti, Nb, Ta)B2-(Hf, Ti, Nb, Ta)C composites. Although the ultimate goal of the research endeavor is to enhance significantly the oxidation resistance of ultra-high temperature ceramic composites (UHTCC), the processing of these reactive metals will optimize the toughness of the composite core to control the eventual development of the oxide layers on the near-surface. The objective of the proposed research is to study the (Hf-Ti-Nb-Ta)Liq/B4C processing driven by the computational thermodynamics and computational fluid dynamics (CFD) through the following integrated research thrusts: • Investigate the impact of surface tensions for liquid Hf-Ti-Nb-Ta alloys to predict their infusion into a B4C packed bed by computational fluid dynamics at 2800 K; • Investigate the effect of the temperature gradient on the fluid dynamics, as well as the stable and metastable phases within the boride-carbide composite. • Investigate the demixing of components in (Hf-Ti-Nb-Ta)Liq/B4C composite through the microstructures formed at temperatures greater than 2800 K. The surface tension of the alloy melt will be linked to the depth of melt penetration and the segregation of the alloying elements (i.e., Hf, Ti, Nb, and Ta) within the pores. The segregation can then be exploited to place elements for developing a ceramic composite for toughness and oxidation resistance. With an understanding of the fluid dynamics of the Hf alloy melt through varying-spatial pore channels, the elemental components should segregate the carbide and boride phases creating a directional microstructure causing a tactical development of the near-surface region.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 21, 2022
- Source ID
- FA95502210018XX0
Entities
People
- Arturo Bronson
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Texas at El Paso