RELATIONSHIP BETWEEN STRAIN EFFECT AND MARTENSITIC-TRANSFORMATION IN MULTIFILAMENTARY NB3SN WIRES

For bronze-processed multifilamentary pure Nb3Sn and 2.3 at. % Ti added (Nb,Ti)3Sn wires, which were prepared under the condition of the same wire parameters such as the filament size, filament number, and bronze ratio, the strain effects on the critical current density were measured. The large difference of the residual strain between Nb3Sn and (Nb,Ti)3Sn wires was obtained. It was found that the martensitic transformation for Nb3Sn compound largely contributes to the residual strain through the variation of the elastic modulus in bronze-processed multifilamentary Nb3Sn wires. It was verified that the ternary element addition of Ti surely suppresses the martensitic transformation in the bronze processed multifilamentary Nb3Sn wire.