Mechanical properties of Ti–6 at.% Mo–4 at.% Sn alloy wires and their application to medical guidewire

Effects of heat treatment conditions on mechanical and superelastic properties of Ti–6 at.% Mo–4 at.% Sn alloy were investigated mainly by cyclic tensile testing. The cold-drawn wires were heat-treated in the temperature range of 773–1273 K for 300 s. Youngʹs modulus and ultimate tensile strength of the wires heat-treated at over 823 K decreased with increasing heat treatment temperature, while premature failure was observed in the wire heat-treated at 773 K. A maximum recovery strain of about 4%, including both genuine elastic and superelastic strain, was obtained in the wires heat-treated in the temperature range of 1073–1273 K. On the other hand, the wire heat-treated at 823 K showed a high Youngʹs modulus of 77 GPa and a high tensile strength of 1698 MPa. Given these characteristics, it is expected that a new class of Ni-free Ti-based guidewire possessing mechanical properties graded from the tip to the end can be developed.