Tensile Tests of Niobium Material for SRF Cavities

Wu, G.; Dhanaraj, N.; Cooley, L. D.; Hicks, D. G.; Hahn, Eric N.; Burk, D.; Muranyi, W.; Foley, M.; Edwards, H.; Harms, E.; Champion, M.; Baars, D.; Compton, C.; Weisend, J. G.

doi:10.1063/1.3422440

Cited by 6 publications

(2 citation statements)

References 2 publications

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“…All the welded joints showed lower tensile strength than the base metal. This result is consistent with that of Wu [ 43 ] and mainly attributed to the fine grains in the base metal referring to the Hall–Petch relationship [ 41 ] and no phase transition in the weld. The tensile and yield strength of the joints with no oscillation is the highest among all the joints.…”

Section: Resultssupporting

confidence: 92%

Influence of Different Beam Oscillation Patterns in Electron Beam Welding of Niobium Sheets with Different Thickness

Tao

Liu

et al. 2022

Materials

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The electron beam welding of the tubes and the half-cells for our 1.3 GHz single-cell superconducting radiofrequency (SRF) cavities is complex due to the different thicknesses of the tubes and the half-cells in the iris region. However, the mechanical properties and microstructure of the iris welds in niobium SRF cavities have barely been explored in previous studies. For high-quality iris welds, welding experiments of niobium sheets of 2 mm and 2.8 mm were carried out under different oscillating conditions. The results show that welding with no oscillation or sinusoidal oscillation may not be applied in actual welding owing to the large misalignment of the bottom surface. The weld grains were not significantly refined through beam oscillation. The joints with infinity oscillation had a higher elongation than circular oscillation, which exhibited a brittle fracture in the tensile tests at 77 K. Nevertheless, the texture of the weld with infinity oscillation implies poor formability, so the feasibility of infinity oscillation in actual welding needs verification in future study.

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Section: Resultssupporting

confidence: 92%

Influence of Different Beam Oscillation Patterns in Electron Beam Welding of Niobium Sheets with Different Thickness

Tao

Liu

et al. 2022

Materials

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“…The situation is even more complicated when considering ingot Nb material, for which tensile test samples typically only have 1-2 grains which results in a large variability in tensile test results, depending on the crystal orientation of the samples [12,[17][18][19]. Furthermore, the Nb material is subjected to a plastic deformation during the deep-drawing into half-cells and, as a result of the subsequent annealing of the entire Nb cavity, the behavior of the material under mechanical loading can, in general, be different than for the case of flat tensile test samples which have no initial plastic deformation [20].…”

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confidence: 96%

Mechanical properties of niobium radio-frequency cavities

Ciovati

Dhakal

Matalevich

et al. 2015

Materials Science and Engineering: A

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a b s t r a c tRadio-frequency cavities made of bulk niobium are one of the components used in modern particle accelerators. The mechanical stability is an important aspect of cavity design, which typically relies on finite-element analysis simulations using material properties from tensile tests on sample. This contribution presents the results of strain and resonant frequency measurements as a function of a uniform pressure up to 620 kPa, applied to single-cell niobium cavities with different crystallographic structure, purity and treatments. In addition, burst tests of high-purity multi-cell cavities with different crystallographic structures have been conducted up to the tensile strength of the material. Finite-element analysis of the single-cell cavity geometry is in good agreement with the observed behavior in the elastic regime assuming a Young's modulus value of 88.5 GPa and a Poisson's ratio of 0.4, regardless of crystallographic structure, purity or treatment. However, the measured yield strength and tensile strength depend on crystallographic structure, material purity and treatment. In particular, the results from this study show that the mechanical properties of niobium cavities made from ingot material with large crystals are comparable to those of cavities made of fine-grain niobium.

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Effect of Oscillating Patterns on the Weld Formation, Microstructure, and Tensile Properties of 1.7-mm Recrystallized Niobium Sheets

Tao

Liu

et al. 2022

Trans Indian Inst Met

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Tensile Tests of Niobium Material for SRF Cavities

Cited by 6 publications

References 2 publications

Influence of Different Beam Oscillation Patterns in Electron Beam Welding of Niobium Sheets with Different Thickness

Influence of Different Beam Oscillation Patterns in Electron Beam Welding of Niobium Sheets with Different Thickness

Mechanical properties of niobium radio-frequency cavities

Effect of Oscillating Patterns on the Weld Formation, Microstructure, and Tensile Properties of 1.7-mm Recrystallized Niobium Sheets

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