Properties of low-cost MgB2 superconducting wires fabricated by high reduction cold rolling

Abstract

Magnesium Diboride (MgB2) is a high-potential material for medical and electrical applications with zero resistance and high efficiency. In this study, the raw materials of Mg powder with a purity of 98 % and low-cost B amorphous with a purity of 95 %, were mixed using a high-energy ball mill, and subsequently compacted and inserted into stainless steel (SS) tube by powder-in tube (PIT). The SS tube was previously cleaned by ultrasonication. The sintering process was carried out using a muffle furnace at a temperature of 800 °C for 1 h, followed by cold wire rolling with a 3-phase gradual reduction. This study aimed to investigate the reduction size of deformation wire on to mechanical properties, microstructure, and superconductivity behavior. The samples were characterized for their mechanical properties using Vickers microhardness and an ultimate tensile test machine. Surface morphologies of samples were observed using an SEM-EDAX and superconducting properties were measured with the cryogenic magnet R-T measurement. The result shows that the highest hardness value of 373.7 HV was achieved at a 60 % size reduction and the ultimate tensile strength of 1896 KN/mm. The results of the morphological observation showed homogeneous deformation without any cracks, with the grain shape being crystalline form. The superconductivity test showed zero resistance at a critical temperature of 39.86 K at a 3.1 mm diameter wire.