Production method of spinal fixation titanium alloy rod low modulus with excellent fatigue strength

摘要

A spinal fixation titanium alloy rod fixes a plurality of spinal-fixing screws embedded and fixed in vertebrae of a human body. The rod is cylindrically shaped, has a sufficient length for coupling with the spinal-fixing screws, and has a diameter adjusted to 4 to 7 mm. In the titanium alloy constituting the rod, Nb content is 25 to 35 percent by weight, Ta content is such that the Nb content+0.8×Ta content ranges from 36 to 45 percent by weight, Zr content is 3 to 6 percent by weight, and the remainder is Ti and unavoidable impurities, excluding vanadium. The titanium alloy is manufactured by swaging processing at a cross-sectional reduction rate of at least 90%, and aging the swaged titanium alloy by heating at a temperature of 600 to 800K, preferably 700 to 800K, for 43.2 ks to 604.8 ks.