Ultra-elastic guide member

PURPOSE: To provide an improved guide member having a peculiar combination of ultra-elastic characteristics for allowing a catheter to advance through a lumen of the body. CONSTITUTION: An ultra-elastic alloy material has a compsn. consisting of titanium and nickel and pref. contains one or more element selected from a group consisting of iron, cobalt, vanadium and copper. This alloy material is subjected to cold processing and subsequently heat-treated at temp. equal to or higher than austenite-martensite transformation temp. and, at the time of this heat treatment, longitudinal stress equal to about 5-50% of yield temp. at room temp. is applied to apply straight memory to a metal. The guide member using this improved material generates stress derived austenite-martensite phase transformation in exceptionally high constant yield strength of at least 90 ksi with respect to a solid member and 70 ksi with respect to a tubular member and generates recoverable strain of a wide range of at least about 4% during phase transformation. COPYRIGHT: (C)1992,JPO