Optimization of a thermomechanical treatment of superelastic Ti-Zr-Nb alloys for the production of bar stock for orthopedic implants

Ti-19Zr-14 Nb (at%) shape memory alloy was subjected to low- and high-temperature thermomechanical treatments to fabricate long-length bar stock for the production of load-bearing orthopedic implants. The phase composition, structure, texture, uniaxial tensile and three-point bending fatigue behavior were studied. Low-temperature thermomechanical treatment (LTMT), combining cold rotary forging and post-deformation annealing at 550 °C led to the formation in the peripheral zone of the bar cross-section of a statically recrystallized fine-grained structure with a relatively strong [001] crystallographic texture and of a mixed statically recrystallized and polygonized substructure, in the central zone of the cross-section. In this state, the alloy exhibited an excellent combination of the static functional and mechanical properties: relatively high strength (UTS=680 MPa), low Young’s modulus (E