CRITICAL-CURRENT DEGRADATION IN NB3AL WIRES DUE TO AXIAL AND TRANSVERSE STRESS

Effects of axial and transverse stress on the critical current of Nb-tube processed multifilamentary Nb3Al wires have been studied. The degradations of the critical current due to axial or transverse stress for these Nb3Al wires are much smaller than those for Nb3Sn wires. The microstructures and stress states of the Nb3Al wires have been investigated to understand the stress dependences of the critical current through the microscopic observations and the elastic theory. From an engineering standpoint, the importance of mechanical strength of the matrix material where superconducting filaments are embedded has been found especially for transverse stress effects.