Observations on the evolution of potassium bubbles in tungsten ingots during sintering

Bewlay, B. P.; Lewis, N.; Lou, K.

doi:10.1007/bf02660859

Cited by 13 publications

(12 citation statements)

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“…In doped tungsten, aluminosilicate particles have been found to decompose more rapidly than potassium aluminosilicates at temperatures above 1900 ЊC. [13,14,15] The data described in the present article suggest that this may also be the case for doped molybdenum.…”

Section: Introductionmentioning

confidence: 64%

“…Dissolution of aluminum, silicon, and oxygen into the tungsten matrix during sintering plays little role in potassium bubble formation. [13,14] Figure 4 suggests that bubble generation occurs in three stages, as follows.…”

Section: Introductionmentioning

confidence: 99%

“…The micrograph shows the sintered tungsten ingots. [13,14] This is a result of the lower molybdenum matrix and the amorphous dopant particles sintering temperatures that were employed for the molybdethat were observed inside the reduced molybdenum powder num ingot; the potassium aluminosilicate dopant particles particles prior to sintering. The molybdenum matrix around had not fully decomposed to potassium bubbles.…”

Section: Introductionmentioning

confidence: 99%

“…First, the potassium aluminosilicates experipore was probably generated by partial decomposition of a ence little decomposition because they are relatively stable at dopant particle during sintering; a potassium bubble would 1800 ЊC, as indicated by the present TEM data and previous probably have been generated after full decomposition of the data. [13,14,15] Second, the decomposition products can readily potassium aluminosilicate and dissolution of the aluminum, dissolve in the molybdenum matrix because, at these relasilicon, and oxygen into the molybdenum matrix. tively low temperatures, there is extensive solubility in the The pores generated in the sintered ingot have sizes in molybdenum matrix for aluminum, silicon, and oxygen.…”

Section: Introductionmentioning

confidence: 99%

“…the highest temperatures that are employed for sintering However, this is not such an important consideration for tungsten ingots, [4][5][6]13,14] where the final sintering temperamolybdenum, because lower sintering temperatures are tures can be higher than 2800 ЊC. At 2800 ЊC, the decomposition kinetics of the potassium aluminosilicates are very employed.…”

Section: Introductionmentioning

confidence: 99%

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Dopant particle characterization and bubble evolution in aluminum-potassium-silicon-doped molybdenum wire

Iorio

Bewlay

Larsen

2002

Metall Mater Trans A

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The present article describes the creation of dopant inclusions in aluminum-potassium-silicon (AKS)-doped molybdenum powder and the generation of potassium bubbles in doped molybdenum wire. Molybdenum wire is used extensively in the incandescent lamp industry for coiling mandrels, filament support wires, and foil seals. The AKS-doped molybdenum wire is an important product, because it possesses greater high-temperature strength and a higher recrystallization temperature than undoped molybdenum; both of these properties are important for structural applications in lamps. The AKSdoped molybdenum wire is produced in a similar manner to AKS-doped tungsten wire, but lower processing temperatures are typically used for the production of molybdenum wire. Previous studies on AKS-doped tungsten wire have shown that the dispersion which provides the interlocking grain structure in recrystallized tungsten wire is bubbles of elemental potassium; these enhance incandescent lamp filament life. However, there is little previous work on the potassium-containing dispersion in AKS-doped molybdenum wire. In AKS-doped molybdenum, the dispersion can be either potassium bubbles, or solid oxide particles, depending on the processing method. This article will describe a series of analyses of doped molybdenum wire and its precursors, namely, doped powder and sintered ingots. The roles of high-and low-temperature sintering are also described.

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Section: Introductionmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Dopant particle characterization and bubble evolution in aluminum-potassium-silicon-doped molybdenum wire

Iorio

Bewlay

Larsen

2002

Metall Mater Trans A

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Tungsten Wire—From Lamp Filaments to Reinforcement Fibers for Composites in Fusion Reactors

Riesch,

Fuhr,

Almanstötter

2024

Adv Eng Mater

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The use of drawn tungsten wire marked a breakthrough in electric lighting which led to a significant advancement in human society and technology. Nowadays, thermal light sources using tungsten filaments are being more and more replaced by semiconductor‐based light‐emitting diodes (LEDs). Despite the lower visibility of incandescent lamps in everyday life, new markets and applications for drawn tungsten wires are opening up, which makes this complex material a highly‐studied subject. One of these applications is the use of heavily drawn tungsten wires as high‐performance reinforcement fibers for new composites that can withstand the extreme environment present in a nuclear fusion reactor. The main advantage of tungsten wires for this class of composites is their ductility and high strength. It can be used to increase the high‐temperature strength of copper‐based heat sink materials as well as the fracture toughness of bulk tungsten considered for the use of highly loaded reactor wall components. These new applications for tungsten wire has also given new impetus to the study of their fundamental properties.

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Potassium bubbles in tungsten wire

Briant

1993

Metall Trans A

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Observations on the evolution of potassium bubbles in tungsten ingots during sintering

Cited by 13 publications

References 8 publications

Dopant particle characterization and bubble evolution in aluminum-potassium-silicon-doped molybdenum wire

Dopant particle characterization and bubble evolution in aluminum-potassium-silicon-doped molybdenum wire

Tungsten Wire—From Lamp Filaments to Reinforcement Fibers for Composites in Fusion Reactors

Potassium bubbles in tungsten wire

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