Composition/Phase Structure and Properties of Titanium-Niobium Alloys

Abstract

This study attempts to develop Ti-Nb alloys with elastic moduli that approach that of human bone. The experimental results reveal that the microstructure of a Ti-Nb alloy that contains 14 mass% Nb consists of and phases, with phase being the dominant one. The proportion of the phase decreases gradually as the Nb content increases, and the microstructure becomes completely the phase when the Nb content exceeds 34 mass%. Moreover, the ! phase can be detected using XRD and TEM in alloys with a Nb content from 30 to 34 mass%. Over the Nb range studied (14 to 40 mass%), the elastic modulus decreases from 14 to 26 mass% Nb, and then increases to a maximum at 34 mass% Nb, before falling again as Nb content is increased further. The elastic modulus of the Ti-Nb alloys is closely related to the microstructure (or Nb content) of the alloys. The fall in the elastic modulus with the increasing Nb content from 14 to 26 mass% is associated with a gradual decrease in the proportion of the phase in the microstructure, while the precipitation of the ! phase accounts for the increase in the elastic modulus over the intermediate range of Nb (30 to 34 mass%). The tensile strength of Ti-Nb alloys increases slightly from 14 to 26 mass% Nb, and then increases markedly with a Nb content of up to 34 mass%, before falling drastically as Nb content is increased further. A similar pattern was obtained for 0.2% proof stress, while the elongation vs. %Nb curve was just the reverse of the T.S. vs. %Nb curve, as expected. A Ti-Nb alloy with a relatively high Nb content (above 36 mass%) is preferred to other compositions for use in medical implants with a reduced stress shielding effect.

Imprecise knowledge based design and development of titanium alloys for prosthetic applications

“…It is worth here that the reason for the variations of the elastic modulus due to different processing need to be explored. The presence of other phases, such as αc, αcc and Z, is known to have a strong influence on the modulus [11,15,60]. Thus, the analysis of the microstructural constituents may provide clues as to the behavior of the alloys at different processing conditions.…”

Selective Laser Melting of Ti-45Nb Alloy

“…It can be observed that the yield strength as well as the compression strength at 35% increases with increasing energy input and the density of the samples. A highest compressive strength at 35% strain of ~723 MPa is observed for the sample with the highest energy input of 257 J/mm 3 However, the compressive modulus was observed to be ~30-50 GPa higher than the Ti-45Nb alloy prepared by other conventional routes [6,28,29], which might be attributed to the fine microstructure. Thanks to the advantage of such additive manufacturing processes, modification in the modulus can be incorporated in the form of introducing structures in the samples instead of the bulk samples.…”

Enhancement of Biocompatibility on Bioactive Ti-Nb-Based Alloy by High-Density Plasma Modification

“…16,18) Some researchers reported that higher amounts of protein present on the implant surface can provide better tissue healing and hence better osseointegration. 18) The present authors have developed certain Ti-Nb-based alloys, 2) e.g., Ti-40Nb-1Hf, which has been shown to exhibit excellent properties combination of relatively high strength and low modulus (UTS: 893 MPa, 0.2% Proof stress: 841 MPa and E: 65 GPa), and can be considered quite suitable for implant applications. Therefore, this study chose Ti-40Nb-1Hf alloy as the subject alloy, and was conducted with the following two objectives: Firstly, to investigate the effect of surface treatment or modification by employing glow discharge plasma treatment (Ar-and O 2 -plasma) on the surface characteristics of Ti-40Nb-1Hf alloy.…”

“…Among them, Ti-Nb-based alloy is one of the commonly applied implant biomaterials. [1][2][3] Due to the fact that the implant surface will contact the host tissue directly, the surface characteristic will play an important role in determining implants' biocompatibility. However, the surface characteristics of biomaterials may change or degrade with time, mainly due to contamination.…”