Electromechanical behaviour of PIT Nb$_{3}$Sn wires for NED

The critical current vs. axial tensile strain and transverse compressive force for two PIT Nb$_{3}$Sn conductors, manufactured by SMI (now EAS), has been investigated. In addition, the distribution of the critical temperature has been determined by specific heat measurements. After identical reaction heat treatments wire #B207 has a slightly broader Tc distribution than wire #B215 and less volume fraction of Nb$_{3}$Sn. The behaviour under axial tensile strain is as expected, although the strain for maximum current, 􀀁m, is relativly low. However the studied wires are rather sensitive to transverse compressive forces. For instance at 10 kN and 15 T the critical current is reduced to 48% of its initial value and recovers only partially after unloading.