
Structure-Process-Property-Performance Relations of Tungsten and Molybdenum Refractory Alloys with Hafnium Carbide Additions Fabricated via Field Assisted Sintering Technology (FAST)
Refractory elements and respective alloys can satisfy the high temperature mechanical and phase stability requirements of materials for harsh thermomechanical environments, such as reusable hypersonic flight. It has been demonstrated that altering refractory alloy composition enables greater control of the microstructure and mechanical performance, while maintaining phase stability. This study utilizes Field Assisted Sintering Technology (FAST) to rapidly consolidate refractory metals to high densities with minimal grain growth. The research then examined the effect of hafnium carbide (HfC) as a grain refiner in low concentrations (1, 3, 5 wt. %) by characterizing the microstructure and mechanical properties of W and Mo post sintering. It was found that HfC in additions of 5 wt. % reduces average grain size from 53.54 μm in to 2.52 μm in W and from 8.23 μm to 2.14 μm in Mo due to grain boundary pinning. This reduction in grain size, coupled with compositional influences, caused Vickers hardness and flexural strength to increase in tandem. Both W-HfC and Mo-HfC saw an increase in Vickers hardness by 27.1 % and 16.3 %, respectively. Similarly, HfC was found to increase the yield flexural strength of both materials, increasing yield flexural strength by 98.2 % in W-HfC and by 31.1 % in Mo-HfC.
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Work Title | Structure-Process-Property-Performance Relations of Tungsten and Molybdenum Refractory Alloys with Hafnium Carbide Additions Fabricated via Field Assisted Sintering Technology (FAST) |
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License | No Copyright - U.S. |
Work Type | Research Paper |
Publication Date | July 2022 |
Deposited | October 10, 2023 |