Internal stresses in cold-deformed Cu-Ag and Cu-Nb wires
The co-deformation of Cu-Ag or Cu-Nb composite wires used for high-field magnets has a number of important microstructural consequences, including the production of very-fine-scale structures, the development of very high internal surface-area-to-volume ratios during the drawing, and the storage of...
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Published in | Philosophical magazine (Abingdon, England) Vol. 84; no. 24; pp. 2579 - 2593 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Abingdon
Taylor & Francis Group
21.08.2004
Taylor and Francis |
Subjects | |
Online Access | Get full text |
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Summary: | The co-deformation of Cu-Ag or Cu-Nb composite wires used for high-field magnets has a number of important microstructural consequences, including the production of very-fine-scale structures, the development of very high internal surface-area-to-volume ratios during the drawing, and the storage of defects at interphase interfaces. In addition, the fabrication and co-deformation of the Cu and Ag or Nb, which differ in crystal structure, thermal expansion, elastic modulus and lattice parameter, lead to the development of short-wavelength internal stresses in both composites. In this paper, these internal stresses are characterized by neutron diffraction and transmission electron microscopy as a function of the imposed drawing strain. The internal stresses lead to important changes in the elastic-plastic response, which is related to both magnet design and service life. The second derivative ∂
2
σ/∂
2
ε of the stresses with respect to strain is used to describe the low-strain anelasticity of the composites. The internal stresses in Cu-Nb are higher than in Cu-Ag and, consequently, the absolute values of (∂
2
σ/∂
2
ε)
Cu-Nb
are higher than those of (∂
2
σ/∂
2
ε)
Cu-Ag
at low strains. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 1478-6435 1478-6443 |
DOI: | 10.1080/14786430410001689981 |