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

For bronze-processed multifilamentary pure Nb3Sn and 2.3 at. % Ti adde d (Nb,Ti)3Sn wires, which were prepared under the condition of the sam e wire parameters such as the filament size, filament number, and bron ze ratio, the strain effects on the critical current density were meas ured. The large difference of the residual strain between Nb3Sn and (N b,Ti)3Sn wires was obtained. It was found that the martensitic transfo rmation for Nb3Sn compound largely contributes to the residual strain through the variation of the elastic modulus in bronze-processed multi filamentary Nb3Sn wires. It was verified that the ternary element addi tion of Ti surely suppresses the martensitic transformation in the bro nze processed multifilamentary Nb3Sn wire.