Influence of initial ingot breakdown on the microstructural and textural development of high-purity tantalum

Clark, J. B.; Garrett, R. K.; Jungling, T. L.; Asfahani, R. I.

doi:10.1007/bf02650255

Cited by 42 publications

(20 citation statements)

References 4 publications

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“…* This find-*Combining Eqs. [4] and [19] into a new constitutive relation was done recently by Zerilh and Armstrong. I47] ing is consistent with the fact that the deformation mechanisms in both bcc and fcc materials are dominated by thermally activated processes under the currently studied deformation conditions.…”

Section: B Comparison Of Constitutive Modeling Resultsmentioning

confidence: 99%

“…Neither Eq. [4] nor Eq. [19] can, however, satisfactorily represent the mechanical response of the Ta-10W shown in Figure 13.…”

Section: B Comparison Of Constitutive Modeling Resultsmentioning

confidence: 99%

“…0-= Co+ C,.exp(-C3"T+ Ca'T'lnk) + C5" ep" [4] where Co, C1, C3, C4, C5, and n are constants for this model. The athermal stress term Co can be replaced with a Hall-…”

Section: B Za Model For Bce Materials T16jmentioning

confidence: 99%

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Constitutive behavior of tantalum and tantalum-tungsten alloys

Chen

Gray

1996

Metall Mater Trans A

238

120

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The effects of strain rate, temperature, and tungsten alloying on the yield stress and the strainhardening behavior of tantalum were investigated. The yield and flow stresses of unalloyed Ta and tantalum-tungsten alloys were found to exhibit very high rate sensitivities, while the hardening rates in Ta and Ta-W alloys were found to be insensitive to strain rate and temperature at lower temperatures or at higher strain rates. This behavior is consistent with the observation that overcoming the intrinsic Peierls stress is shown to be the rate-controlling mechanism in these materials at low temperatures. The dependence of yield stress on temperature and strain rate was found to decrease, while the strain-hardening rate increased with tungsten alloying content. The mechanical threshold stress (MTS) model was adopted to model the stress-strain behavior of unalloyed Ta and the Ta-W alloys. Parameters for the constitutive relations for Ta and the Ta-W alloys were derived for the MTS model, the Johnson-Cook (JC), and the Zerilli-Armstrong (ZA) models. The results of this study substantiate the applicability of these models for describing the high strain-rate deformation of Ta and Ta-W alloys. The JC and ZA models, however, due to their use of a power strain-hardening law, were found to yield constitutive relations for Ta and Ta-W alloys that are strongly dependent on the range of strains for which the models were optimized.

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Section: B Comparison Of Constitutive Modeling Resultsmentioning

confidence: 99%

“…Neither Eq. [4] nor Eq. [19] can, however, satisfactorily represent the mechanical response of the Ta-10W shown in Figure 13.…”

Section: B Comparison Of Constitutive Modeling Resultsmentioning

confidence: 99%

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Constitutive behavior of tantalum and tantalum-tungsten alloys

Chen

Gray

1996

Metall Mater Trans A

238

120

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“…However, the application of traditional plastic working techniques to tantalum, such as rolling and extrusion, generate relatively coarse-grained microstructures [6,7]. With reference to the Hall-Petch relationship [8,9], it is reasonable to anticipate that the strength and performance of tantalum will be significantly improved if it is possible to produce an ultrafine-grained (UFG) or a nanostructured material.…”

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confidence: 99%

A critical examination of pure tantalum processed by high-pressure torsion

Maury

Zhang

Huang

et al. 2015

Materials Science and Engineering: A

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Tantalum, a common refractory metal with body-centred cubic (BCC) crystalline structure, was processed by high-pressure torsion (HPT) at room temperature through different numbers of rotations. Significant grain refinement and high strength were achieved with a reduction in grain size from ~60 m to ~160 nm and an increase in strength from ~200 to >1300 MPa. Hardness measurements revealed a high level of homogeneity after 10 turns of HPT but the hardness after 10 turns was slightly lower than after 5 turns indicating the occurrence of some recovery. Tensile testing at a strain rate of 1.0  10 -3 s -1 gave high strengths of ~1200 MPa but little or no ductility after processing through 1, 5 and 10 turns.The introduction of a short-term (15 min) anneal immediately after HPT processing led to significant ductility in all samples and a reasonable level of strength at ~800 MPa.

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“…11-14 A (111) type texture in wrought tantalum has been correlated to a fine, uniform grain structure; conversely, (100) orientations in tantalum have been associated with microstructural and textural inhomogeneities about the thickness of the wrought product. 11,12,18 It is also well documented that wrought tantalum planar mill forms contain a texture gradient that varies from a (100)-type at and near the surface to (111) ͗uvw͘ or (111) ͗112͘ about the midplane of the plate. [15][16][17]19 In addition, grains of similar orientations may not be randomly dispersed in wrought tantalum, but instead exist as "orientation clusters" within the microstructure.…”

Section: Background Orientation and Grain Size Influences On Sputteringmentioning

confidence: 97%

Correlating discrete orientation and grain size to the sputter deposition properties of tantalum

Michaluk

2002

Journal of Elec Materi

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Recent findings indicate that the erosion behavior of tantalum sputtering targets varies across regions of different discrete crystal orientation. Specifically, bands of sharp, localized (100) texture amid the microstructure and aligned parallel to the sputtering surface of planar tantalum targets have been shown to resist erosion. Referencing theoretical models and characterization studies of wrought tantalum, this paper explores the relationship between discrete crystallographic texture and grain size of tantalum with respect to the physical erosion behavior of tantalum sputtering targets. The findings demonstrate that both grain size and preferred orientation contribute to the deposition behavior of tantalum. Also, controlling both the microstructural and textural homogeneity are key to assuring the reliability of Ta targets and the subsequent integrity of the sputter-deposited thin films.

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Influence of initial ingot breakdown on the microstructural and textural development of high-purity tantalum

Cited by 42 publications

References 4 publications

Constitutive behavior of tantalum and tantalum-tungsten alloys

Constitutive behavior of tantalum and tantalum-tungsten alloys

A critical examination of pure tantalum processed by high-pressure torsion

Correlating discrete orientation and grain size to the sputter deposition properties of tantalum

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