The mechanical properties of filamentary niobium tin composites

Abstract

The mechanical properties of filamentary Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn superconducting composites have been investigated. The effect of reaction conditions and variation of component dimensions on the strain which can be accommodated before loss of current carrying capacity occurs has been determined, Critical strains to failure lie within the range 1-3%. The failure mechanism of Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn layers is discussed in terms of the fracture mechanics of composite materials. Commercial types of composite consisting, typically, of 1500 filaments in bronze were found to withstand repeated stressing to 3.6 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sup> Nm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> in liquid helium without degradation of superconductivity.