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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Application of coupled substrate aging and TiO2 nanotube crystallization heat treatments in cold-rolled Ti-Nb-Sn alloys

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Author(s):
Cremasco, A. [1, 2] ; Lopes, E. S. N. [1] ; Bertazzoli, R. [1] ; Caram, R. [1]
Total Authors: 4
Affiliation:
[1] Univ Estadual Campinas, Sch Mech Engn, Rua Mendeleyev 200, BR-13083860 Campinas, SP - Brazil
[2] Univ Estadual Campinas, Sch Appl Sci, Rua Pedro Zaccaria 1300, BR-13484350 Limeira, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Journal of Materials Science; v. 51, n. 13, p. 6389-6399, JUL 2016.
Web of Science Citations: 2
Abstract

Among titanium alloys, the beta-type is the most indicated for orthopedic implants due to the reduced elastic modulus compared with alpha + beta alloys. To improve osseointegration, the growth of a self-ordered titania nanotube layer onto the surface of titanium alloy implant pieces is a strategy used to accelerate bone growth. In this paper, the effects of heat treatment for titania nanotube crystallization on Ti-Nb and Ti-Nb-Sn alloys on the phase transformation, the Vickers hardness, and the elastic modulus of the substrate were investigated. TiO2 layers were grown onto cold-rolled Ti alloy substrates by anodization, and crystallization to anatase was followed by glazing-angle high-temperature X-ray diffraction with a heating ramp of 288 K/min to 623 K, where the samples were held for up to 4 h. The dynamic of the alpha- and omega-phase formation/dissolution was followed by X-ray diffraction. Transmission electron microscopy was used to confirm the presence of the alpha- and omega-phases and their volumes and dimensions. As a result of the TiO2 crystallization heat treatment, a continuous increase in the hardness was observed for the Ti-35Nb and Ti-35Nb-2Sn alloys, which is attributed to dissolution of alpha aEuro(3) and the formation of omega precipitates. The same feature was observed for the elastic modulus. In the Ti-35Nb-4Sn alloy, the reverse decomposition of martensite resulted in the beta phase and later in alpha phase precipitation. The aging of this alloy resulted in a homogeneous distribution of a high volumetric fraction of fine and dispersed alpha phase, which resulted in a hardness increase from 220 to 270 HV. This coupled heat treatment resulted in high hardness, low elastic modulus, and a nanotube with an anatase crystal phase. (AU)

FAPESP's process: 14/00159-2 - Electrochemical study of beta metastable titanium alloys coated with TiO2 nanostructured films
Grantee:Alessandra Cremasco
Support Opportunities: Regular Research Grants