Solid solution synthesis of tantalum carbide‐hafnium carbide by spark plasma sintering |
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| Authors: | Cheng Zhang Ankur Gupta Sudipta Seal Benjamin Boesl Arvind Agarwal |
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| Affiliation: | 1. Plasma Forming Laboratory, Department of Mechanical and Materials Engineering, Florida International University, Miami, Florida;2. AMPAC, NSTC, University of Central Florida, Orlando, Florida |
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| Abstract: | Solid solutions of Tantalum carbide (TaC) and Hafnium carbide (HfC) were synthesized by spark plasma sintering. Five different compositions (pure HfC, HfC‐20 vol% TaC, HfC‐ 50 vol% TaC, HfC‐ 80 vol% TaC, and pure TaC) were sintered at 1850°C, 60 MPa pressure and a holding time of 10 min without any sintering aids. Near‐full density was achieved for all samples, especially in the HfC‐contained samples. The porosity in pure TaC samples was caused by the oxygen contamination (Ta2O5) on the starting powder surface. The addition of HfC increased the overall densification by transferring the oxygen contamination from TaC surface and forming ultrafine HfO2 and Hf‐O‐C grains. With the increasing HfC concentration, the overall grain size was reduced by 50% from HfC‐ 80 vol% TaC to HfC‐20 vol% TaC sample. The solid solution formation required extra energy, which restricted the grain growth. The lattice parameters for the solid solution samples were obtained using X‐ray diffraction which had an excellent match with the theoretical values computed using Vegard's Law. The mechanical properties of the solid solution samples outperformed the pure TaC and HfC carbides samples due to the increased densification and smaller grain size. |
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| Keywords: | HfC solid solution spark plasma sintering TaC Vegard's law |
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