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Recrystallization Characteristics of Mo-W-Re-HfC Alloys for Thermionic Applications
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Abstract
Microstructural evolution of a Mo-10W-2Re-0.5HfC alloy was studied in the temperature range of 298 K to 2200 K. The typical characteristics of the microstructure were curly deformation bands, with nucleation at boundaries and subgrain coalescence. The recrystallization temperature of the Mo-10W-2Re-0.5HfC alloy was determined to be near 1950 K, which is comparable with 2125 K for W-4Re-0.35 HfC and 2000 K for W-0.35 HfC. Microhardness tests were performed before and after 1 hour of vacuum annealing and the results indicate that the mechanical strength of Mo-10W-2Re-0.5HfC is lower than that of W-4Re-0.35 HfC or W-0.35 HfC. X-ray diffraction and pole figures indicate that this particular alloy exhibits the primary texture (110) and secondary texture (112) which is normally observed in B.C.C. metals such as Molybdenum. The creep strengths of W-4Re-0.35HfC, TZM-Mo, and W-25Re-30Mo were evaluated and compared at the same stress level. The W-4Re-0.35HfC alloy was found to have the superior creep strength. The creep strength of the Mo-10W-2Re-0.5HfC alloy is comparable to that of TZM-Mo or W-25Re-30Mo making it a suitable alternative for thermionic electrode materials.
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Citation
Tsao, B., Ramalingam, M., Donovan, B., and Lamp, T., "Recrystallization Characteristics of Mo-W-Re-HfC Alloys for Thermionic Applications," SAE Technical Paper 929302, 1992, https://doi.org/10.4271/929302.Also In
References
- Davison H.W. “Preliminary Analysis of Accident in a Lithium-Cooled Space Nuclear Plant” NASA TMX-1937 1970
- Buckman R.W. Begg L.L. “the Production of W-0.35HfC (mol%) Wire Bar By Arc Melting and High Energy Rate Extrusion of Small Diameter Ingots,” Proceedings of the 25th IECEC 2 412 419 Reno, Nevada August 12-17 1990
- ASM Handbook Committee Metal Handbook 8th 211 232 American Society for Metals
- Tsao B. H. Chen B. L. Tang D. Jacobson D. L. “Recrystallization Behavior of W-4Re-0.35HfC Alloys,” Proceedings of the Space Nuclear Power Symposium 309 314 Jan. 7-10 1990
- Tsao B.H. Ramalingam M.L. Donovan B.D. Lamp T.R. “W-Re-HfC as an Emitter Material with Long Life for Thermionic Fuel Element Application,” Proceedings of 26th IECEC 3 154 159 Boston, MA Aug. 4-9 1991
- Tsao B.H. Ramalingam M.L. Tang D. Chen B.L. Jacobson D.L “The Effect of ThO 2 and HfC on the Recrystallization of W-Re Alloys” TMS Annual Meeting New Orleans, Louisiana Feb. 17-22 1991