Recently, superconducting devices are getting larger as can be seen in magnets for plasma containment in CTR, MHD generator and energy storage. Multifilamentary composites consisting of superconducting Nb-Ti filaments in a normal metal matrix are hopeful for such large scale applications because of good superconducting properties and workability of Nb-Ti alloy. The mechanical and electrical behaviour of Nb-Ti superconductor itself and composites at ambient and low temperatures should be understood for the successful use of superconducting wires in large magnets. From this stand point, this paper reviews the current research on stress effects in superconducting Nb-Ti wires as follows.
(1) mechanical properties of Nb-Ti superconducting alloy
(2) tensile and fatigue properties and characteristic behaviour of Nb-Ti multifilamentary composite wires
(3) critical current degradation under several stresses and resultant strains
(4) proposed mechanism of the critical current degradation
(5) influence of stress effects on coil performances
(6) effect of cyclic stress (strain) on electrical resistivity of matrix metals as stabilizer
Problem areas have been cleared but much research needs to be done.
