Influence of aging heat treatment on mechanical properties of biomedical Ti-Zr based ternary alloys containing niobium

Titanium-zirconium based alloys containing a small amount of niobium were i nvestigated in order to evaluate their possible use as biomedical materials . Zirconium, which belongs to the IVa group, is known to have good corrosio n resistance and biocompatibility similar to titanium. As the titanium-zirc onium system shows a complete solid solution, a wide variation of alloy des ign is available and large quantities of solid-solution hardening must be p ossible. Niobium, having a beta-phase stabilizing effect, was chosen as a t ernary element in order to control desirably the microstructure. There have been no reports which suggest its harm to a living body. The alloys contai ning 2% or 3% niobium showed the highest hardness value after aging heat tr eatment at 773 K. In contrast to this, no alteration of hardness was seen i n specimens aged at 1073 K. Through conventional X-ray diffractometry and i n situ X-ray analysis using a hot stage, beta-phase precipitation in the a matrix was identified. From the above results, it is concluded that alloys containing 2%-3% niobium are hopeful candidates for new kinds of biomedical alloys, when they are heat treated under suitable conditions. (C) 1998 Klu wer Academic Publishers.