Preparation of a large-scale molybdenum single-crystal sheet by means of secondary recrystallization

Fujii, Tadayuki; Watanabe, Ryoji; Hiraoka, Yutaka; Okada, Masatoshi

doi:10.1016/0022-5088(84)90208-x

Cited by 39 publications

(6 citation statements)

References 5 publications

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“…• There is considerable interest in the production of large-scale molybdenum single crystal ,.. sheets for electric components, and as blanket materials for controlled thermonuclear reactors [35][36][37][38]." Secondary recrystallization processing has been used to produce single crystal sheets.…”

Section: Molybdenum *Tomentioning

confidence: 99%

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Recent Advances and Developments in Refractory Alloys

Nieh

Wadsworth

1993

MRS Proc.

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Refractory metal alloys based on Mo, W, Re, Ta, and Nb (Cb) find applications in a wide range of aerospace applications because of their high melting points and high-temperature strength. In this paper, we present recent progress in the understanding and applications of these alloys. Recent studies to improve the oxidation and mechanical behavior of refractory metal alloys, and particularly Nb alloys, will also be discussed. Some Re structures, for extremely high temperature applications (> 2000°C), made by CVD and P/M processes, are also illustrated. Interesting work on the development of new W alloys (W-HfC-X) and the characterization of some commercial refractory metals, e.g., K-doped W, TZM, and Nb-l%Zr, continues. Finally, recent developments in high temperature composites reinforced with refractory metal filaments, and refractory metal-based intermetallics, e.g., Nb3A1, Nb2Be17, and MoSi2, are briefly described.

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Section: Molybdenum *Tomentioning

confidence: 99%

“…The rolled sheet is annealed above 2100°C to induce secondary recrystallization. Using the above technique, single-crystal Mo sheets of dimensions 2 mm x 49 mm x 180 mm have been made successfully [36].…”

Section: Molybdenum *Tomentioning

confidence: 99%

Recent Advances and Developments in Refractory Alloys

Nieh

Wadsworth

1993

MRS Proc.

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“…In extreme cases, abnormal grains can consume the entire microstructure to produce a uniformly coarse grain size or even a single crystal [2][3][4][5][6][7]. AGG is thus of interest for producing single crystals in the solid state, a capability demonstrated in the laboratory for molybdenum (Mo) [8][9][10][11][12][13][14] and tantalum (Ta) [15]. For grain-oriented silicon steels, AGG is desired and necessary to produce the coarse, highly-textured microstructures required for optimal performance in electrical transformers [16].…”

Section: Introductionmentioning

confidence: 99%

“…For the case of commercial-purity Mo sheet materials, DAGG was observed at approximately 1773 K (1500 • C) and has been repeatedly produced at 1923 K (1650 • C) [10][11][12]. SAGG, however, has only been observed in Mo at temperatures of 2073 K (1800 • C) and higher [8,24]. Important features of DAGG are illustrated in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Growth of preexisting abnormal grains in molybdenum under static and dynamic conditions

Noell

Worthington

Taleff

2017

Materials Science and Engineering: A

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This investigation compares the growth rates of preexisting abnormal grains under both static and dynamic conditions. Abnormal grains several millimeters in length were produced in two commercial-purity molybdenum (Mo) materials by tensile straining at temperatures from 1923 to 2073 K (1650 to 1800 • C). This process is termed dynamic abnormal grain growth (DAGG) because it produces abnormal grains during concurrent plastic straining. DAGG creates abnormal grains at much lower temperatures than does static abnormal grain growth (SAGG). Abnormal grains created through DAGG were characterized with their surrounding microstructures and were then subjected to annealing treatments. Only one-third of the preexisting abnormal grains subsequently grew by SAGG. Among these, SAGG occurred only in those specimens that required the largest strains to initiate DAGG when creating the abnormal grain(s). The rates of boundary migration observed for SAGG were approximately two orders of magnitude slower than those for DAGG. When DAGG in one specimen was interrupted by extended static annealing, it did not recur when straining resumed. The dislocation substructure developed during hot deformation, which includes subgrains typical of five-power creep, is critically important to both DAGG and SAGG of preexisting abnormal grains under the conditions examined.

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“…The present authors recently developed a new method for preparing large-scale single crystals of molybdenum (1).…”

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confidence: 99%

Crack Generation and Propagation Characteristics of Molybdenum Single Crystals

et al. 1985

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Tensile tests at 77, 173 and 293 K were performed on molybdenum single crystals having axial-orientations near the <011>-direction, which had been prepared by the secondary recrystallization method. The effect of "island grains" at the crystal surface and/or in the bulk, and the effect of test temperature on the crack generation and propagation characteristics were investigated.At 77 and 173 K, cracks were generated from "island grains" for all of annealed or polished specimens and for most of carburized specimens. The plane on which the cracks propagated was initially the {011}-plane and afterwards changed to the {112}-and/or {001}-planes, though the {011}-plane component just around the crack generation sites tended to diminish or vanish in polished or carburized specimens. The fracture strength of annealed or polished specimens depends on the size of "island grain" from which the crack was generated. On the other hand, the strength of carburized specimens was appreciably enhanced by addition of a small amount of carbon and was apparently not size-dependent.At 293 K, cracks which were not propagated were observed at the interfaces between the "island grains" and the matrix in annealed or polished specimens. However, any "island grains" were not responsible at all for the final failure of the crystals. All the specimens failed after having shown considerably high ductility.

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Preparation of a large-scale molybdenum single-crystal sheet by means of secondary recrystallization

Cited by 39 publications

References 5 publications

Recent Advances and Developments in Refractory Alloys

Recent Advances and Developments in Refractory Alloys

Growth of preexisting abnormal grains in molybdenum under static and dynamic conditions

Crack Generation and Propagation Characteristics of Molybdenum Single Crystals

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