Effect of prestrain on martensitic transformation in a Ti46.4Ni47.6Nb6.0 superelastic alloy and its application to medical stents.
The effect of applied strain on martensitic transformation in a superelastic Ti(46.4)Ni(47.6)Nb(6.0) alloy at room temperature was investigated by tensile tests, differential scanning calorimetry measurements, and X-ray diffraction. Reverse transformation starting (A(s)) and finishing (A(f)) temperatures increased with the application of tensile-strain over 13%, the undeformed specimen showing A(s) = -29.2 degrees C and A(f) = 17.9 degrees C, while the 13% predeformed alloy exhibited A(s) = 37.1 degrees C and A(f) = 40.2 degrees C. Furthermore, the values of the A(s) and A(f) for the predeformed alloy almost recovered to those of the undeformed alloy when heated to about 42 degrees C and then showed superelasticity again at room temperature. This characteristic is significant for application in sensors, actuators, and medical devices. Especially, medical stents with such qualities show promise as a new class of self-expandable stents with both excellent mountability and deliverability.
Takagi
T
T
Management of Science and Technology, Graduate School of Engineering, Tohoku University, Aoba-yama 04, Sendai 980-8579, Japan. takamitsu.takagi@most.tohoku.ac.jp
Sutou
Y
Y
Kainuma
R
R
Yamauchi
K
K
Ishida
K
K
D000497:Alloys; D008422:Materials Testing; D009532:Nickel; D009556:Niobium; D015607:Stents; D014025:Titanium
D000497:Alloys; D009556:Niobium; D009532:Nickel; D014025:Titanium