Abstract
This work describes the performance of several MgB2 composite wires when subjected to tensile stress at 4.2 K. Electromechanical properties of these wires are influenced by the composite elements encasing the filament and also by the filament's mechanical strength. A linear increase in critical current by tension up to ≈20% was measured due to compensation of the precompression effect caused by different thermal expansions of composite elements. Final heat treatment influences the electromechanical characteristics of composite wires due to stress recovery and also by interface reactions among the composite elements. Results showed that the highest irreversible strain εirr = 0.9 % was obtained for MgB2 wires reinforced by stainless steel, which has more than doubled εirr in comparison to commercially available MgB2/Nb/Cu/Monel wires with the same filament number.

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