The Nb_3Al superconducting wire fabricated by the Rapid-Quenching and Transforming process exhibits excellent superconducting properties at high magnetic fields: Jc of 153 A/mm~2 at 21 T, 4.2 K. We fabricated a small solenoid coil using this wire 0.5 mm in diameter and 137 m in length. The coil generated an incremental field of 0.68 T in 21 T backup field. The resulting total field of 52.68 T is the highest record of the field which is generated by low Tc superconducting coil. As a next step, w wire with a large current capacity was produced. The diameter of this was 1.25mm and the wire matrix ratio was 0.8. The Ic was 117 A at 21 T, 4.2K and the Jc was 171.6 a/mm~2 at 21 T, 4.2K. These results confirmed that we now have a wire of a great potential to high field applications. Rapid-quenching and transforming process enables the formation of a nearly-stoichiometric A15 Nb_3Al phase, while the conventional heat-treatment process at low temperature deivates the composition from stoichiometry.
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