J0401-3-3 Mechanical properties of Ti-29Nb-13Ta-4.6Zr alloy with different oxygen contents for biomedical applications

Geng, Feng; Niinomi, Mtsuo; Nakai, Masaya; Akahori, Toshikazu; Tsutsumi, Harumi; Ogawa, Michiharu

doi:10.1299/jsmemecjo.2009.6.0_283

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“…A TNTZ alloy including 0.1-0.7 mass % oxygen could be employed for a variety of applications. 19 Therefore, when producing TNTZ by our approach, it was concluded that the reduction and deoxidation proceeded sufficiently and the targeted residual oxygen concentration had been achieved.…”

Section: E118mentioning

confidence: 82%

Direct Production of Ti–29Nb–13Ta–4.6Zr Biomedical Alloy from Oxide Mixture in Molten CaCl[sub 2]

Osaki

Sakai

Suzuki

2010

J. Electrochem. Soc.

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A process based on the principle of the Ono-Suzuki process involving electrolysis and the calciothermic coreduction of an oxide mixture consisting of TiO 2 , Nb 2 O 5 , Ta 2 O 5 , and ZrO 2 for producing Ti-29Nb-23Ta-4.6Zr ͑TNTZ͒ was proposed. Ca was produced by the electrolysis of CaO in molten CaCl 2 by applying a voltage of 3.2 V between a carbon anode and Ti cathode at 1173 K. The residual oxygen concentration in the obtained powder decreased monotonically with an increase in the supplied electric charge. An oxygen concentration of 0.19 mass % was attained by supplying the electrical charge around 3 times larger than that necessary to generate the stoichiometrically required amount of Ca. This sample consisted of a Ti-based body-centered cubic solid solution and a small amount of hexagonal close-packed ͑hcp͒ solid solution. The inhomogeneity in the composition was suppressed to a relatively low level so that it could be easily improved by heat-treatment. After sintering at 1300 K for 54 ks, for example, the Tiand Zr-rich hcp phase disappeared and the composition achieved the targeted value. The results of this study indicate that the OS process can be applied to directly produce TNTZ alloy from an oxide mixture. © 2010 The Electrochemical Society. ͓DOI: 10.1149/1.3435302͔ All rights reserved. In recent years, new processes for producing Ti or Ti-based alloys have been investigated. The Ono-Suzuki ͑OS͒ process is one such process.1-6 A schematic representation of the OS process is shown in Fig. 1. The OS process involves calciothermic reduction and Ca recycling. Ca is produced by the electrolysis of CaO in molten CaCl 2 electrolyte; Ca has a strong reducing capacity, and therefore, it can reduce various types of oxides. When a carbon anode and Ti cathode are used, the electrolysis reactions at the electrodes are expressed as follows At the anode:At the cathode:The overall reaction is expressed as followsThe calciothermic reduction of a metal oxide ͑for example, TiO 2 ͒ is expressed as followsCaO that is formed as a by-product immediately dissolves in the molten CaCl 2 , where CaO is electrolyzed again. These reactions permit the recycling of Ca used as a reducing agent and the continuous reduction of oxides in the same molten CaCl 2 bath. Because of the wide solubility of CaO, the dissolution of O 2− from the oxide at the cathode was also studied as the direct electro-deoxidation, 7-10 which has been applied to TiO 2 using CaCl 2 melt especially applying a low electrochemical potential such as 2.0 V.At a voltage higher than the theoretical decomposition voltage of CaO, the OS process has been successfully applied to the reduction of single oxides such as TiO 2 1-6 and V 2 O 5 . 11 Recently, the principle of the OS process was applied to the synthesis of Ti-V-Cr hydrogen-storage alloy 12 and Ti-6Al-4V aerospace alloy. 13 In this study, we attempted to directly produce Ti-29Nb-13Ta-4.6Zr ͑TNTZ͒ alloy from an oxide mixture, as shown in Fig. 1.TNTZ alloy is a newly developed alloy that is used for biomedical purp...

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Section: E118mentioning

confidence: 82%