Superelastic guiding member

An elongated superelastic body formed of a NiTi alloy in an austenite phase which is stable at temperatures up to body temperature, which has residual stress at a relatively uniform level, which will transform to a martensite phase upon the application thereto of a stress at a relatively constant level above about 70 ksi and which exhibits a recoverable strain of about 2 to about 8% upon the application of sufficient stress to induce the transformation of the austenite phase to the martensite phase, said body exhibiting a straight memory resulting from cold working, followed by heat treating at a temperature from about 350.degree. to about 600.degree. C. and straightening.

An elongated tubular body suitable for use in a medical device within a human body having a cylindrical wall defining an inner lumen therein which is formed at least in part of a NiTi superelastic alloy in an austenite phase which is stable at a temperature below body temperature, which will transform to a martensite phase upon the application of stress, which will exhibit a recoverable strain of about 2 to about 8% upon the application of stress at a level which transforms the austenite phase to the martensite phase, which has residual stresses therein at relatively uniform level and which has a straight memory resulting from cold working and then heat treating at a temperature from about 350.degree. to about 600.degree. C. and straightening.

An elongated body for intravascular devices having a straight memory and residual stress at relatively uniform levels and being formed of a NiTi superelastic alloy in an austenite phase which is stable at a temperature below body temperature, which will transform upon the application of stress at a relatively constant level from the austenite phase to a martensite phase, which exhibits a strain of about 2 to about 8% upon the application of stress at a level sufficient to transform the austenite phase to the martensite phase and which has a straight memory resulting from cold working and then heat treating at a temperature between about 350.degree. and 600.degree. C. while being subjected to a longitudinal tension of up to 50% of the ultimate tensile strength thereof.

A superelastic elongated tubular member having an inner lumen extending therein which is formed of a NiTi alloy, which is in an austenite phase at a temperature at or below body temperature, which at body temperature will transform from the austenite phase to a martensite phase and exhibit a recoverable strain of about 2 to about 8% upon the application of stress above 50 ksi, and which has a straight memory resulting from cold working and then heat treating at a temperature between about 350.degree. and 600.degree. C. while being subjected to a longitudinal tension of up to 50% of the ultimate tensile strength thereof.