Influences of tensile and bending strains on the critical current in multifilamentary Nb3Sn composites processed by Nb tube method

The critical current degradation of multifilametary Nb3Sn superconducting composites strained mechanically at room temperature has been investigated. The experimental results show that the effects of the Nb3Sn layer thickness and the specimen wire structure, such as monolithic and stranded cable on critical current degradation, are appreciable for the specimens strained by bending stress, but are not for specimens strained by tensile stress. The results of the critical current degradation by tensile strain were discussed, based on the stress-strain characteristics of the composites. It was clarified that the critical strain in the case of applying tensile bending stresses simultaneously at room temperature lay around the line which was drawn from the point of the critical tensile strain to that of the critical bending strain, when the ordinate was tensile strain and the abscissa was bending strain. 10 ref.--AA