2015-Sustainable Industrial Processing Summit
SIPS 2015 Volume 1: Aifantis Intl. Symp. / Multiscale Material Mechanics
| Editors: | Kongoli F, Bordas S, Estrin Y |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2015 |
| Pages: | 300 pages |
| ISBN: | 978-1-987820-24-9 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Biomedical β-type titanium alloys: Nanostructuring and biofunctinality
Hakan Yilmazer1; Bunyamin Aksakal2;1YILDIZ TECHNICAL UVIVERSITY, Istanbul, Turkey; 2DEPARTMENT OF METALLURGICAL AND MATERIALS ENGINEERING, YILDIZ TECHNICAL UNIVERSITY, Istanbul, Turkey;
Type of Paper: Regular
Id Paper: 440
Topic: 1
Abstract:
The main challenge of this paper is the development of a titanium implant having both favorable bulk and surface functionalities not only to certify the long-standing stability of the implant but also to moderate interactions between cells and substrate. Recently, ultrafine/nanostructured materials fabricated by severe plastic deformation (SPD) exhibits promising bulk and surface properties. Therefore, microstructural refinement and its effect on mechanical and surface functionalities of β-type titanium alloys through severe plastic deformation (SPD) processing are investigated in this study. A novel β-type titanium alloy, Ti–29Nb–13Ta–4.6Zr (TNTZ), composing of non-toxic and non-allergic Nb, Ta, and Zr alloying elements, has been subjected to high-pressure torsion (HPT). Solutionized TNTZ (TNTZST) at 1063K for 1 hour was subjected to cold rolling (TNTZCR) at reduction ratio of over 80 % and aging treatment (TNTZAT) at 723 K for 3 hours. While TNTZST and TNTZCR show coarse-grained single β structure, TNTZAT exhibits a coarse-grained β matrix and precipitated needle like α phase. TNTZCR and TNTZAT subjected to HPT processing (TNTZCHPT and TNTZAHPT) show a homogeneous microstructure consisting of nanostructured elongated β grains. The β grains exhibit nanostructured subgrains having non-uniform morphologies distorted by severe torsional deformation. Furthermore, the β grains and subgrains are surrounded by blurred and wavy boundaries in a non-equilibrium state. In addition, the needle-like α precipitates are totally refined to a nanostructure with a diameter of approximately 12 nm. TNTZCHPT and TNTZAHPT show enhanced mechanical biocompatibility, which is a greater tensile strength and a higher hardness than those of TNTZST, TNTZCR, TNTZAT, and Ti-6Al-4V ELI while maintaining relatively low Young's modulus. Furthermore, TNTZCHPT and TNTZAHPT exhibit an enhanced combination of great corrosion performance and improved cellular response in comparison to TNTZST, TNTZCR, TNTZAT, and Ti-6Al-4V ELI.