On the micromechanics of multifilamentary superconducting composites

Cogan, Stuart F.; Holmes, Douglas; Puffer, I.; Eagar, T. W.; Rose, Robert M.

doi:10.1109/tmag.1979.1060125

Cited by 6 publications

(1 citation statement)

References 4 publications

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“…Wire properties as a function of stress/strain, including the residual one, have been related to variables such as component ratio in the composite (e.g. bronze to Nb [1,2]), Nb 3 Sn to residual Nb in the filament [3][4][5], voids at the filament/matrix interface [6][7][8], crystallographic texturing [9], architecture of the wire [7], type of the component materials, work-hardening of some of the components (e.g. bronze), and grain size, morphology and composition [3][4][5][10][11][12] of Nb 3 Sn and of component materials (e.g.…”

Section: Introductionmentioning

confidence: 99%

Relationship between architecture, filament breakage and critical current decay in Nb₃Sn composite wires repeatedly in-plane bent at room temperature

Badica

Awaji

Oguro

et al. 2006

Supercond. Sci. Technol.

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Six Nb 3 Sn composite wires with different architectures ('central and near-the-edge reinforcement') were repeatedly in-plane bent at room temperature (in-plane 'pre-bending'). Breakage behaviour was revealed from scanning electron microscopy observations by semi-quantitative analysis of the filament crack formation and evolution. Cracks are formed in the transversal and longitudinal directions. Transversal cracks show some tolerance to the applied bending strain due to the fact that filaments are composite materials; residual Nb core can arrest development of a partial transversal crack initiated in the Nb 3 Sn outer part of the filament. Together with the density of cracks C and the evolution of this parameter with pre-bending strain, ε pb , in different regions of the wire, R-ε pb curves are important to understand breakage behaviour of the wires. R is the ratio (number of full transversal cracks)/(number of full transversal cracks + number of partial transversal cracks). Parameters C and R allow us to reveal and satisfactorily understand the wire architecture-breakage-critical current decay relationship when pre-bending treatment is applied. As a consequence, breakage criteria necessary to minimize I c decay were defined and the positive influence of the reinforcement in preventing breakage was observed. It was also found that, in this regard, more Nb in the CuNb reinforcement, for the investigated wires, is better, if the heat treatment for the wire synthesis is performed at 670 • C for 96 h. A different heat treatment, 650 • C for 240 h, is less efficient in preventing filament breakage. Our results suggest the possibility of control and improvement of the breakage susceptibility of the filaments in the wires and, hence, of the bending I c decay, through the wise design of the wire architecture (i.e. by correlating design with the choice of composing materials and heat treatments).

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Section: Introductionmentioning

confidence: 99%

Relationship between architecture, filament breakage and critical current decay in Nb₃Sn composite wires repeatedly in-plane bent at room temperature

Badica

Awaji

Oguro

et al. 2006

Supercond. Sci. Technol.

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Stress Effects in an Nb3Sn Conductor Proposed for use in the Magnetic Fusion Energy Program

Easton

Kroeger

Specking

et al. 1980

Advances in Cryogenic Engineering Materials

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Crystallographic texturing in Nb3Sn multifilamentary superconducting composites

Cogan

Rose

1980

Journal of Applied Physics

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Crystallographic texturing in Nb3Sn composites, fabricated by both the external diffusion and the commercial bronze processes, has been investigated. In the external-diffusion-processed composite the as-drawn texture of the copper matrix contained ca. 55% 〈111〉 and 45% 〈100〉; after recrystallization at 650 °C for 16 h this changed to 70% 〈111〉 and 30% 〈100〉. Tin plating and reaction heat treatment for 40 h at 650 °C eliminated most of the texturing. In a commercial bronze-processed composite a 〈211〉 or 〈221〉 texture was obtained in the as-drawn bronze matrix, and after a reaction heat treatment at 700 °C for 30 h a diffuse 〈100〉 texture was developed. In both composites the Nb3Sn reaction layer exhibited no preferred orientation.

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On the micromechanics of multifilamentary superconducting composites

Cited by 6 publications

References 4 publications

Relationship between architecture, filament breakage and critical current decay in Nb₃Sn composite wires repeatedly in-plane bent at room temperature

Relationship between architecture, filament breakage and critical current decay in Nb₃Sn composite wires repeatedly in-plane bent at room temperature

Stress Effects in an Nb3Sn Conductor Proposed for use in the Magnetic Fusion Energy Program

Crystallographic texturing in Nb3Sn multifilamentary superconducting composites

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On the micromechanics of multifilamentary superconducting composites

Cited by 6 publications

References 4 publications

Relationship between architecture, filament breakage and critical current decay in Nb3Sn composite wires repeatedly in-plane bent at room temperature

Relationship between architecture, filament breakage and critical current decay in Nb3Sn composite wires repeatedly in-plane bent at room temperature

Stress Effects in an Nb3Sn Conductor Proposed for use in the Magnetic Fusion Energy Program

Crystallographic texturing in Nb3Sn multifilamentary superconducting composites

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Product

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Relationship between architecture, filament breakage and critical current decay in Nb₃Sn composite wires repeatedly in-plane bent at room temperature

Relationship between architecture, filament breakage and critical current decay in Nb₃Sn composite wires repeatedly in-plane bent at room temperature