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Microstructure and Superconductive Property of MgB₂/Al Based Composite Materials

Tokimasa KAWABATA, Daisuke TOKAI¹⁾, Katsuhiko NISHIMURA, Yoshimitsu HISHINUMA²⁾, Shigeki AOYAMA³⁾, Susumu IKENO⁴⁾ and Kenji MATSUDA

Graduate School of Science and Engineering for Research, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan

1)

Graduate School of Science and Engineering for Education, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan

2)

National Institute for Fusion Science, Toki, Gifu 509-5292, Japan

3)

Nikkei Niigata Co., Ltd., Niigata 950-3101, Japan

4)

Hokuriku Polytechnic College, Uozu, Toyama 937-0856, Japan

(Received 1 December 2011 / Accepted 2 July 2012 / Published 22 November 2012)

Abstract

MgB₂ superconducting wires are interesting as the alternative conductors of Nb-based superconducting wires applied for the advanced nuclear fusion reactor because of the decay time of the induced radioactivity. However, MgB₂ is difficult for practical use because of its unworkable and lower critical current density (J_C) in a high magnetic field than Nb-based superconductivematerials. We have developed the original method of three-dimensional penetration casting (3DPC) to fabricate the MgB₂/Al composite materials. In the composite materials we made, MgB₂ particles dispersed in the matrix uniformly. This makes these composite materials can be processed by machining, extrusion and rolling. And the T_C of the made composite materials was determined by electrical resistivity and magnetization to be 37∼39 K. In this work, we made composite materials with ground MgB₂ particles with the purpose of extruding thinner wires of composite material. Furthermore, we successfully produced φ1 mm wires and also changed the matrix from pure Al to Al-In alloy. J_C of composite materials with the matrix of Al-In alloy was calculated with the width of the magnetic hysteresis based on the Extended Bean Model. The result was better than that of MgB₂/Al composite material without Indium. Microstructures of these samples had been confirmed by SEM observation.

Copyright (c) 2012 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

composite material, aluminum, MgB₂, superconductor, superconductive wire, critical current density

DOI: 10.1585/pfr.7.2402150

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This paper may be cited as follows:

Tokimasa KAWABATA, Daisuke TOKAI, Katsuhiko NISHIMURA, Yoshimitsu HISHINUMA, Shigeki AOYAMA, Susumu IKENO and Kenji MATSUDA, Plasma Fusion Res. 7, 2402150 (2012).