Hafnium carbide strengthening in a tungsten-rhenium matrix at ultrahigh temperatures

Luo, Anhua; Shin, Kwang Seon; Jacobson, D. L.

doi:10.1016/0956-7151(92)90141-z

Cited by 30 publications

(9 citation statements)

References 17 publications

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“…Zirconium carbide belongs to the family of ultra high‐temperature ceramic (UHTC) compounds that are known for their excellent thermomechanical properties, hardness, and wear resistance . These include the Group IVB carbides along with Ta and W, which demonstrate applications in extreme environments of thermal protection systems, field emitters, thermal coatings, and creep strengthening of refractory metals …”

Section: Introductionmentioning

confidence: 99%

“…1 These include the Group IVB carbides along with Ta and W, which demonstrate applications in extreme environments of thermal protection systems, field emitters, thermal coatings, and creep strengthening of refractory metals. [2][3][4][5][6][7][8] Conventional powder synthesis of metal carbides generally involves reduction of milled powder oxides in an environment rich in carbon that is sourced from gas phases, resins, or powdered carbon. [9][10][11][12] In all cases, high temperatures are required for carbon self-diffusion, resulting in extended isotherms and large carbide particle size.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and Evolution of Zirconium Carbide via Sol–Gel Route: Features of Nanoparticle Oxide–Carbon Reactions

et al. 2013

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A sol–gel route was used to synthesize nanocrystalline zirconium carbide (ZrC). The starting materials were zirconium propoxide, with carbon introduced by furfuryl alcohol (FA). A block copolymer surfactant was used to homogenize the oxide and carbon components. ZrC was produced at a low temperature of 1250°C and complete conversion achieved at 1450°C. The powder was nanocrystalline size less than 100 nm. Phase changes were studied using X‐ray diffraction and Raman spectroscopy. Rietveld analysis followed the changes in crystallite size and lattice parameters of the phases during carbothermal reduction. Morphology changes were observed using nitrogen gas sorption. High‐resolution TEM and EDS were used to image the carbide lattice, surface oxides, and graphene‐like carbons. The results indicate that nanoparticle carbothermal synthesis involves agglomeration and necking as the most viable mode of mass transport to complete the carbothermal reduction.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis and Evolution of Zirconium Carbide via Sol–Gel Route: Features of Nanoparticle Oxide–Carbon Reactions

et al. 2013

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“…The homogenized matrix composition can be estimated by EDS spot analyses (Table 6) and the differences between the Hf and Ta contents in alloy and the contents in Hf and Ta in measured in the matrix can be exploited to estimate the volume fractions of the MC carbides. After conversion using the volume masses of matrix (average with chromium carbides if any; about 9 g/cm 3 ) and of the MC carbides (13 g/cm 3 ), one can The difference of oxide spallation behavior was, thus, confirmed by the metallographic characterization of the oxidized samples. The XRD runs and SEM/SE observations showed that chromia had spalled from the surface of the T alloy while it remained partially over the H alloy.…”

Section: Oxidation Tests: Evolution Of the Microstructures In The Bulkmentioning

confidence: 89%

“…This is the case for HfC. Used for several decades in some alloys based on refractory metals (such tungsten [3]), hafnium monocarbides may be currently found in ceramics [4,5] and high temperature composites [6,7]. Recently used as efficient reinforcing particles in nickel-based superalloys [8], HfC must be present in high quantities to lead to an interesting creep resistance [9], and this may lead to high production costs if such alloys must be produced at an industrial scale.…”

Section: Introductionmentioning

confidence: 99%

Oxidation and Microstructural Behaviors of Ni-Based Alloys Strengthened by (Ta, Hf)C Carbides at 1250 °C in Air

2021

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Two alloys based on nickel and designed to be reinforced by MC carbides thanks to the presence of Hf and Ta were produced by casting. They were subjected to 50 h-long isothermal exposure at 1250 °C in synthetic air with thermogravimetric monitoring of the oxidation progress. In the as-cast state, they contain both significant quantities of (Hf,Ta)C carbides. Their verified melting start temperatures, close to 1300 °C, allowed performing the planned oxidation test. The two alloys demonstrated a chromia-forming behavior with limited mass gain rates. However, they also showed a rather low resistance to oxide spallation at cooling, which is in proportion with the Ta/Hf ratio. After 50 h at 1250 °C, the morphology of the carbides had significantly evolved, from their initial script-like shape to a fragmented and coalesced state. The results are promising, but the use of these alloys at 1250 °C needs further improvements on the mechanical level.

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“…It is used as a 1-2% addition in the superalloys used for cast vanes and turbine blades placed in the hottest stages following the combustion zone of jet aircraft engines. Small additions of hafnium and carbon react to form second-phase dispersions in tantalum, molybdenum, and tungsten alloys (38)(39)(40), including the tantalum alloys T-111, T-222, and Astar 811C, and the molybdenum alloy MHC.…”

Section: Usesmentioning

confidence: 99%

Hafnium and Hafnium Compounds

Nielsen¹

2004

Kirk-Othmer Encyclopedia of Chemical Technology

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Hafnium, Hf, is in Group 4 (IVB) of the Periodic Table, as are the lighter elements zirconium and titanium. Hafnium is a heavy gray‐white metallic element never found free in nature. It is always found associated with the more plentiful zirconium. The two elements are almost identical in chemical behavior. Hafnium is obtained as a by‐product of the production of hafnium‐free nuclear‐grade zirconium. Hafnium is used in nuclear control rods, nickel‐based superalloys, nozzles for plasma arc metal cutting, and high temperature ceramics. Hafnium is a hard, heavy, somewhat ductile metal having an appearance slightly darker than that of stainless steel. Hafnium's aqueous chemistry is characterized by a high degree of hydrolysis, the formation of polymeric species, a very slow approach to true equilibrium, and the multitude of complex ions that can be formed. Hafnium is a highly reactive metal. Most hafnium compounds have been of slight commercial interest aside from intermediates in the production of hafnium metal. However, hafnium oxide, hafnium carbide, and hafnium nitride are quite refractory and have received considerable study as the most refractory compounds of the Group 4 (IVB) elements.

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Hafnium carbide strengthening in a tungsten-rhenium matrix at ultrahigh temperatures

Cited by 30 publications

References 17 publications

Synthesis and Evolution of Zirconium Carbide via Sol–Gel Route: Features of Nanoparticle Oxide–Carbon Reactions

Synthesis and Evolution of Zirconium Carbide via Sol–Gel Route: Features of Nanoparticle Oxide–Carbon Reactions

Oxidation and Microstructural Behaviors of Ni-Based Alloys Strengthened by (Ta, Hf)C Carbides at 1250 °C in Air

Hafnium and Hafnium Compounds

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