Improvement in microstructure and superconducting properties of single-filament powder-in-tube MgB2 wires by cold working with a swaging machine

Yusuke Saito, Masato Murakami, Akiyoshi Matsumoto, Hiroaki Kumakura

Research output: Research - peer-reviewArticle

Abstract

We investigated the influence of the mechanical deformation method of wire fabrication on the microstructure and superconducting properties of single-filament in situ powder-in-tube (PIT) MgB2 wires. We employed three deformation methods to fabricate the wires: only swaging, groove rolling + roller drawing, and groove rolling + conventional drawing. We found that cold working by swaging has three advantages over the groove rolling + drawing method: (1) improved uniformity of the MgB2 core along the longitudinal direction; (2) higher mass density of the Mg + B (MgB2) core before (after) heat treatment (HT); and (3) well-developed fiber structures of Mg (MgB2) before (after) HT. These three factors greatly enhanced the critical current density (J c) values of PIT MgB2 wires. The highest J c values were obtained through mechanical deformation by swaging for both pure and carbon-doped wires. A J c value of 3.5 ×104 A cm-2 and an engineering critical current density (J e) of 1.1 ×104 A cm-2 were recorded at 4.2 K and 10 T for a swaged wire of 4.5%-carbon-coated boron powder heat-treated at 600 °C for 1 h.

LanguageEnglish
Article number065005
JournalSuperconductor Science and Technology
Volume30
Issue number6
DOIs
StatePublished - 2017 May 16

Fingerprint

swaging
cold working
filaments
wire
tubes
microstructure
Swaging machines
Cold working
Powders
Wire
Microstructure
grooves
Drawing (graphics)
Swaging
critical current
heat treatment
current density
carbon
Carbon
Heat treatment

Keywords

  • carbon doping
  • critical current density
  • MgB
  • powder-in-tube (PIT)
  • swaging

ASJC Scopus subject areas

  • Ceramics and Composites
  • Condensed Matter Physics
  • Metals and Alloys
  • Materials Chemistry
  • Electrical and Electronic Engineering

Cite this

Improvement in microstructure and superconducting properties of single-filament powder-in-tube MgB2 wires by cold working with a swaging machine. / Saito, Yusuke; Murakami, Masato; Matsumoto, Akiyoshi; Kumakura, Hiroaki.

In: Superconductor Science and Technology, Vol. 30, No. 6, 065005, 16.05.2017.

Research output: Research - peer-reviewArticle

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