Effect of Nb on Microstructural Characteristics of Ti-Nb-Ta-Zr Alloy for Biomedical Applications

Abstract

The effects of several commonly used heat treatment schemes on the microstructures of two Ti-Nb-Ta-Zr alloys aimed at biomedical applications were studied in this work using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The specimens were water quenched from 790 • C and then aged at temperatures between 300 • C and 600 • C. The experimental results showed that α and ω phase precipitated from the metastable β matrix in Ti-29Nb-13Ta-4.6Zr alloy during isothermal ageing. But for Ti-39Nb-13Ta-4.6Zr, the precipitation reaction was more sluggish than that in Ti-29Nb-13Ta-4.6Zr because of high amount of β stabilizing elements in the former alloy. As a result the α phase was unable to precipitate during short time ageing treatment. After longer time (12 days) ageing treatment at 500 • C or 400 • C, recognizable α precipitates were observed in the aged samples. It is concluded that Ti-29Nb-13Ta-4.6Zr can be heat treated to obtain different microstructures and is better than Ti-39Nb-13Ta-4.6Zr in terms of age hardenability.

Evolution of Microstructure and Texture during Recrystallization of the Cold-Swaged Ti-Nb-Ta-Zr-O Alloy

“…[10][11][12] It has been suggested that these curly grain or swirled structures result from a favorable plane strain elongation of the grains for bcc metals under tensile-dominated applied stress. [13,14] where the elements in square brackets denote their mass percent concentration in the alloy. The b transus temperature of the alloy is about 635°C.…”

Aging response of the Ti–35Nb–7Zr–5Ta and Ti–35Nb–7Ta alloys

“…Thus, there is an effort in order to develop new titanium alloys with non-toxic elements [2]. There are several potential alloys and considerable attention has been paid to other additions, among them Nb, Zr and Ta [3][4][5][6][7]. One who deals with structural materials, aiming implant applications, faces the necessity of getting a low Young's modulus alloy on one hand, and a high strength alloy on the other, since the implant should present the modulus close to that of the bone [3,4,8] and high strength [3,8,9].…”

Fatigue Property of Super-Elastic Ti–Ni Alloy Dental Castings

“…30) Consequently, beta type titanium alloys with low elastic modulus as well as high strength have been recently designed and developed for biomedical use. [31][32][33] On the other hand, mechanically functional properties like super-elasticity of metallic materials are utilized in dental devices. Ti-Ni alloy shows low elastic modulus, 5) and the small continuous force delivered in the process of shape recovery is ideal for orthodontic arch wires, 34,35) while the flexibility to trace curved root canals is utilized in endodontic files.…”