Mechanical properties of superconducting MgB₂ wire

This study aims at examining the mechanical properties of MgB₂ wires fabricated with PIT method by studying the effect of tensile and bending stresses on their current carrying capacity. Wires are mounted on a tensile machine and are subjected to different load increments within both the elastic and the plastic regions. The current carrying capacity is measured for each load and the behavior of I_c versus stress/strain is studied. Microstructures of MgB₂ core are studied for different loads by using SEM. For bending tests, two cases are examined. The first case is to anneal MgB₂ wires then wind them on mandrels with different diameters, while the second case is to wind un-annealed wires on the same mandrels with different diameters then anneal the winded wires. A comparison between both cases is made using SEM for all different diameters and measuring the corresponding I_c. The behavior of I_c versus bending strain is studied. This whole study aims at giving a clear picture of the optimum loading, bending and processing conditions at which MgB₂ wires will possess a high current carrying capacity for practical applications.