Characterization of Ti‐Ta Alloys Synthesized by Cold Crucible Levitation Melting

Abstract

Titanium alloys offer an excellent combination of high mechanical properties and outstanding corrosion resistance in a wide variety of environments. For example, titanium and titanium alloys are well suited as clinically used biomaterials because their biological, mechanical and physical properties play significant roles in the longevity of the prostheses and implants. [1][2][3] The Ti-6Al-4V alloy, currently used in aircraft industry, was one of the first titanium biomaterials introduced in implantable components and devices. Although this alloy is still widely used in medicine, some concern has been recently expressed over its use since it appears that small amounts of vanadium, released in the human body, induce possible cytotoxic effect. Thus, toxicity of V has required the development of new titanium alloys with non-toxic elements such as Zr, Nb, Fe, Mo, Ta. [4][5][6][7][8][9][10] Among the different alloying elements used, tantalum is considered as one of the best biocompatible in human body. [11,12] This is related to the fact that pure tantalum presents an excellent corrosion resistance in almost all acid solutions. It was recently pointed out that, due to the relatively high cost of Ta, Ti-Ta alloys are also promising materials in a severe chemical environment as they present a higher corrosion resistance than pure Ti in reducing acid. [13,14] Thus, the Ti-Ta alloys are potentially interesting for many applications including chemistry industries, marine environment and biomedical devices.Titanium and tantalum are however difficult to alloy in usual furnaces because they are very reactive metals having a great difference in melting point and specific gravity. To synthesize alloys from the Ti-Ta system with a wide range of composition, we have developed the cold crucible levitation melting (CCLM) technique, which is well known to be an efficient method in order to melt metals with a high melting point and to obtain uniform chemical composition without contamination. [14] In the present work, the microstructure and the mechanical properties (microhardness measurements and compression tests) of stable Ti-Ta alloys synthesized by CCLM in the whole range of composition are presented. As these alloys are potentially interesting for biomedical applications, electrochemical experiments in a simulated body fluid were carried out. The results are compared with those obtained on the Ti-6Al-4V alloy taken as reference in this study. Materials and MethodsIn this study, the 7 following alloy compositions were prepared: Ti-10Ta, . The different characteristics of the Ti and Ta metals used for the synthesis are presented in Table 1. The Ti-Ta alloys were synthesized by the cold crucible levitation melting (CCLM) technique in a CELES induction furnace under a pure Ar atmosphere, which was introduced after several cycles of high vacuum pumping. Each melted alloy was cast into a cylindrical copper mould by removing the copper cold finger situated at the bottom of the cold crucible. Once the generator switched off, the melt ...

Comparative corrosion study of Ti–Ta alloys for dental applications

“…The Ti-Ta alloys have also a (a + b) biphasic structure, but a-phase morphology is quite different in regard to that of Ti-6Al-7Nb alloy (Fig. 2a-d) [52,53]. It is noteworthy that the volume fraction of b-phase increases along with the increase of alloy Ta content.…”

“…The XRD phase analysis showed that all the titanium alloys has a (a + b) biphasic structure with different (a/b) ratio values [52]. The Ti-6Al-7Nb alloy has a (a + b) duplex microstructure which consists of an equiaxed primary a (light) in a matrix of transformed b (dark) containing fine acicular a (light) (Fig.…”

Effect of Mo content on electrochemical behaviour of TiMo alloys for dental applications

“…The TiMo alloys were synthesized by the CCLM technique in a CELES induction furnace under a pure Ar atmosphere, which was introduced after several cycles of high vacuum pumping [42,43].…”

Investigation of processing effects on the corrosion resistance of Ti20Mo alloy in saline solutions

“…Unfortunately, titanium and molybdenum are difficult to alloy through a conventional melting-casting process due to the big difference in melting point and specific gravity between the two metals. New fabrication procedures were thus developed, particularly powder sintering [10,[18][19][20] and cold crucible levitation melting [21] are efficient methods for the synthesis of Ti-Mo alloys in a wide range of compositions. Though similar composition ranges are achieved with the two kinds of Page 4 of 41 A c c e p t e d M a n u s c r i p t procedures, their fabrication procedures are significantly different and produce materials with variations in the microstructure as revealed by the major difference in porosity that is observed.…”