Measurement of Irreversible External-Compressive Strain at RT and Enhancing Strain Tolerance at RT on MgB2 Multifilament Wire

The strain tolerance of magnesium dioboride (MgB2) wire should be enhanced at room temperature for fabricating MgB2 coils by using the react and wind method. The irreversible external-compressive strain of MgB2 filaments was measured by evaluating the critical current degradation of bent sample wires. From the results, MgB2 filaments can accept -1.77% strain, and the pre-compressive strain should be -0.88% at room temperature to minimize its reversible bending radius. A stainless-steel reinforced 18-filament MgB2 wire was fabricated and its strain tolerance was evaluated through bending and tensile tests at room temperature. The irreversible strain of this wire is 0.60%, and this wire seems to be suitable for the react and wind method. The filling factor of MgB2 of this wire is 17%, so this wire has both suitable strain tolerance for the react and wind method and higher engineering current density.

Automated summary

The strain tolerance of magnesium dioboride (MgB2) wire and its impact on coil fabrication were investigated. Results showed that MgB2 wire can tolerate a certain amount of strain at room temperature. A stainless-steel reinforced MgB2 wire was fabricated and found to have suitable strain tolerance for the react and wind method, as well as higher engineering current density.