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Title: Investigation of Bonding Generation during the Drawing of Multifilamentary Wires

Abstract

Experimental shear tests and Finite Element Modeling (FEM) have been used to study the generation of bonding during the multi-pass drawing of multifilamentary wire, focusing on the experimental conditions and materials of interest to composite superconductor manufacture. The wires were of two kinds: (1) a simple cylindrical monocore arrangement consisting of a Nb7.5%Ta core inside a Cu can (or sleeve), (2) a six-around-one restack of the monocores. For the modeling a thermo-mechanical, elasto-plastic, finite-element model was employed. Two kinds of simulations were performed: (1) the initial state of the billet was assumed to be without bonding. The FEM simulation was then performed, and from this the normal pressure, deformation, and temperature at the core/sleeve interface were calculated; (2) a pressure welding model was used to estimate the bonding stress generated at the interface by the multi-pass drawing process. On the experimental side, the Cu-clad Nb monocore 'billet' was drawn to certain size, restacked into a Cu can to form a 7 restack multifilamentary billet, and then drawn to small size. High resolution scanning electron microscopy was used to observe the characteristics of the Nb/Cu and Cu/Cu interfaces and mechanisms for the observed interfacial bonding were proposed. Furthermore, specially designed shearmore » tests were carried out to determine the interfacial shear load. The results of these led to calculations of the interfacial shear stress (i.e. the bonding stress at the interfaces), the results of which were compared with the FEM predictions in order to establish the validity of the FEM model.« less

Authors:
 [1];  [2]; ;  [3];  [4]
  1. LASM, Department of Materials Science and Engineering, Ohio State University, Columbus, OH, 43210 (United States)
  2. (United States)
  3. LASM, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210 (United States)
  4. Hyper Tech Research Inc., Columbus, OH, 43212 (United States)
Publication Date:
OSTI Identifier:
20800182
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 824; Journal Issue: 1; Conference: Cryogenic engineering conference, Keystone, CO (United States), 29 Aug - 2 Sep 2005; Other Information: DOI: 10.1063/1.2192400; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; BONDING; COMPUTERIZED SIMULATION; COPPER; CYLINDRICAL CONFIGURATION; DEFORMATION; DRAWING; FINITE ELEMENT METHOD; INTERFACES; NIOBIUM; RESOLUTION; SCANNING ELECTRON MICROSCOPY; SHEAR; SHEAR PROPERTIES; STRESSES; SUPERCONDUCTORS; TANTALUM; TESTING; WIRES

Citation Formats

Peng, X., Hyper Tech Research Inc., Columbus, OH, 43212, Sumption, M. D., Collings, E. W., and Tomsic, M. Investigation of Bonding Generation during the Drawing of Multifilamentary Wires. United States: N. p., 2006. Web. doi:10.1063/1.2192400.
Peng, X., Hyper Tech Research Inc., Columbus, OH, 43212, Sumption, M. D., Collings, E. W., & Tomsic, M. Investigation of Bonding Generation during the Drawing of Multifilamentary Wires. United States. doi:10.1063/1.2192400.
Peng, X., Hyper Tech Research Inc., Columbus, OH, 43212, Sumption, M. D., Collings, E. W., and Tomsic, M. Fri . "Investigation of Bonding Generation during the Drawing of Multifilamentary Wires". United States. doi:10.1063/1.2192400.
@article{osti_20800182,
title = {Investigation of Bonding Generation during the Drawing of Multifilamentary Wires},
author = {Peng, X. and Hyper Tech Research Inc., Columbus, OH, 43212 and Sumption, M. D. and Collings, E. W. and Tomsic, M.},
abstractNote = {Experimental shear tests and Finite Element Modeling (FEM) have been used to study the generation of bonding during the multi-pass drawing of multifilamentary wire, focusing on the experimental conditions and materials of interest to composite superconductor manufacture. The wires were of two kinds: (1) a simple cylindrical monocore arrangement consisting of a Nb7.5%Ta core inside a Cu can (or sleeve), (2) a six-around-one restack of the monocores. For the modeling a thermo-mechanical, elasto-plastic, finite-element model was employed. Two kinds of simulations were performed: (1) the initial state of the billet was assumed to be without bonding. The FEM simulation was then performed, and from this the normal pressure, deformation, and temperature at the core/sleeve interface were calculated; (2) a pressure welding model was used to estimate the bonding stress generated at the interface by the multi-pass drawing process. On the experimental side, the Cu-clad Nb monocore 'billet' was drawn to certain size, restacked into a Cu can to form a 7 restack multifilamentary billet, and then drawn to small size. High resolution scanning electron microscopy was used to observe the characteristics of the Nb/Cu and Cu/Cu interfaces and mechanisms for the observed interfacial bonding were proposed. Furthermore, specially designed shear tests were carried out to determine the interfacial shear load. The results of these led to calculations of the interfacial shear stress (i.e. the bonding stress at the interfaces), the results of which were compared with the FEM predictions in order to establish the validity of the FEM model.},
doi = {10.1063/1.2192400},
journal = {AIP Conference Proceedings},
number = 1,
volume = 824,
place = {United States},
year = {Fri Mar 31 00:00:00 EST 2006},
month = {Fri Mar 31 00:00:00 EST 2006}
}
  • The mechanical properties of multifilamentary Nb{sup 3}Sn wires have an important role in their application in large scale magnetic systems. The influence of heat treatment schedules and design factors on the mechanical properties of rectangular and round section bronze route wires was investigated. Ultimate tensile strength, yield strength and elongation of stabilized and nonstabilized wires 0.4 mm x 4 mm in section and 0.8--1.5 mm in dia containing 4000--14,000 Nb filaments before and after heat treatment were studied. It was shown that a change of the wire design, volume fraction of copper, heat treatment regimes influence strongly on strength andmore » plasticity of wires. The level of the mechanical properties of stabilized wires depends on the volume fraction and location of stabilizer in the section of Nb{sub 3}Sn wire.« less
  • Cold drawing is an effective process to increase the strength of fully pearlitic steels with an acceptable level of ductility. Microstructural changes and deformation behavior of the pearlite during wire drawing are closely related to the initial microstructure of the pearlite. The main features of the changes while increasing drawing strain are a progressive alignment of lamellae along the drawing axis, a reduction of interlamellar spacing and a thinning of the lamellar cementite. Likewise, the behavior of the cementite dissolution would be influenced by microstructural features of the pearlite before drawing such as interlamellar spacing, colony size, etc. However, itmore » is hard to find a report investigating the effect of microstructural features on the cementite dissolution during drawing. The purpose of this investigation is to examine the effect of microstructural features such as interlamellar spacing and colony size on the cementite dissolution during wire drawing, using Moessbauer spectroscopy, for fully pearlitic eutectoid steels.« less