Mechanical Strength and Biocompatibility of Meta-Stable ^|^beta; Type Ti-5Fe-3Nb-3Zr for Biomedical Applications

Abstract

Ti 29Nb 13Ta 4.6Zr (TNTZ) is a very attractive material for biomedical applications because of its low Young's modulus. However, this alloy contains a certain amount of rare metals elements. In this study, Ti Fe Nb Zr system alloys were developed by substituting Fe for Ta as the low cost b stabilizer, and the mechanical properties and biocompatibility of these alloys were investigated forˆve diŠerent compositions through thermo mechanical treatments. The micro Vickers hardness of the Ti Fe Nb Zr system alloy decreases with Fe addition up to 7 mol because of the suppression of the v phase precipitate. Subsequently, it increases by further Fe addition due to solid solution strengthening. Ti 5Fe 3Nb 3Zr (Ti 5 3 3) subjected to solution treatment (ST) shows the lowest Young's modulus among the other composition. In addition, the tensile strength of Ti 5 3 3 subjected to ST is higher than those of the annealed Ti 6Al 4V ELI and TNTZ subjected to ST. The specimens of the alloy implanted in the femoral epicondyle of rabbit are surrounded by new bone tissue formed with direct contact after 24 and 48 weeks from the implantation. It is considered that Ti 5 3 3 has relatively good biocompatibility with contact osteo genesis as compared with those of Ti 6Al 4V ELI and SUS316L stainless steel.

Effect of Thermomechanical Treatments on the Mechanical Properties of New Low-Cost Ti-Fe-Nb-Zr Alloys

“…The present alloys were designed based on the electronic structure calculations by the DV-Xα cluster method, which is one of the simple alloy design methods for Fe, Ni, and Ti alloys [3]. The designed Ti-alloys used in this study are located in the β-type zone of the 𝐵𝐵𝐵𝐵 ���� -𝑀𝑀𝑀𝑀 ����� phase map, as shown in figure 1 [4]. Detailed information about this alloy design method is presented in Ref.…”

“…Therefore, the following question is raised by the scientists: Is it possible to use alternative common elements (like Fe and Mn) as β -stabilizers, instead of high melting point rare metals (Nb, W and Ta) and maintains the high biocompatibility and mechanical properties without deterioration? [4,5]. Alternatively, reducing the amount of those rare alloying elements makes the manufacturing process and its cost much lower and is able to propose low cost-type metallic biomaterials [6,7].…”

“…Therefore, there are many trials to develop new Ti-alloys composed of the common β-stabilizing elements (such as; Fe, Mn, Cr,..) to replace totally or partially the high melting point and rare βstabilizing elements without much reduction in the targeted biocompatibility and mechanical properties [6]. Among these trails, new Ti-Fe-Zr-Nb alloys are developed and showed very promising biocompatibility as confirmed by mechanical and invivo tests [4,8].…”

Change in Mechanical Strength and Bone Contactability of Biomedical Titanium Alloy with Low Young’s Modulus Subjected to Fine Particle Bombarding Process

“…Table 2 shows the bone formation ratio, the bone contact ratio and relative bone contact ratio on average. 13,14) The relative bone contact ratio of SW/FPB is around 80%, much higher than that of SW/mirror (around 13%), although their bone formation ratios are nearly equal. Some kinds of cells have different favorable surface morphologies for expansion and growth.…”

“…1. 13,14) The image was converted into the rectangle shape for easily analyzing the level of gray value obtained from implant surface to distance of around 50 µm thick. The lower limit of gray value between those was defined as the bone contact threshold (BCT) although BCT was different value in each sample.…”