Effect of contact pressure on fretting fatigue behavior of Ti-1023

With a new test facility, we have investigated fretting fatigue properties of Ti-1023 titanium alloy at different contact pressure. Both fatigue fracture and fretting scar were analyzed by scanning electron microscopy (SEM). Moreover, the depth of crack initiation area in fatigue fracture has been analyzed quantitatively, to investigate the relationship between the depth of crack initiation area and the fretting fatigue strength. The changing trends of the depth of crack initiation area and fretting fatigue strength with the increase of contact pressure show obvious opposite correlations. The depth of crack initiation area increases rapidly with the increase of contact pressure at low contact pressure (smaller than 10 MPa), and the fretting fatigue strength drops rapidly. At the contact pressure of 10–45 MPa, both the depth of crack initiation area and the fretting fatigue strength do not vary significantly. Contact pressure influences fatigue strength through influencing the initiation of fatigue crack. The main damage patterns are fatigue flake and plow.

Histomorphologic evaluation of Ti-13Nb-13Zr alloys processed via powder metallurgy. A study in rabbits

This study presents the in-vivo evaluation of Ti-13Nb-13Zr alloy implants obtained by the hydride route via powder metallurgy. The cylindrical implants were processed at different sintering and holding times. The implants` were characterized for density, microstructure (SEM), crystalline phases (XRD), and bulk (EDS) and surface composition (XPS). The implants were then sterilized and surgically placed in the central region of the rabbit`s tibiae. Two double fluorescent markers were applied at 2 and 3 weeks, and 6 and 7 weeks after implantation. After an 8-week healing period, the implants were retrieved, non-decalcified section processed, and evaluated by electron, UV light (fluorescent labeling), and light microscopy (toluidine blue). BSE-SEM showed close contact between bone and implants. Fluorescent labeling assessment showed high bone activity levels at regions close to the implant surface. Toluidine blue staining revealed regions comprising osteoblasts at regions of newly forming/formed bone close to the implant surface. The results obtained in this study support biocompatible and osseoconductive properties of Ti-13Nb-13Zr processed through the hydride powder route. (c) 2007 Published by Elsevier B.V.

Obtaining of Nanoapatite in Ti-7.5Mo Surface After Nanotube Growth

Titanium and their alloys have been used for biomedical applications due their excellent mechanical properties, corrosion resistance and biocompatibility. However, they are considered bioinerts materials because when they are inserted into the human body they are cannot form a chemical bond with bone. In several studies, the authors have attempted to modify their characteristic with treatments that changes the material surface. The purpose of this work was to evaluate obtaining of nanoapatite after growing of the nanotubes in surface of Ti-7.5Mo alloy. Alloy was obtained from c.p. titanium and molibdenium by using an arc-melting furnace. Ingots were submitted to heat treatment and they were cold worked by swaging. Nanotubes were processed using anodic oxidation of alloy in electrolyte solution. Surfaces were investigated using scanning electron microscope (SEM), FEG-SEM and thin-film x-ray diffraction. The results indicate that nanoapatite coating could form on surface of Ti-7.5Mo experimental alloy after nanotubes growth.

Fractal analysis of eroded surfaces by digital image processing

Jet impingement erosion test rig has been used to erode titanium alloy specimens (Ti-4Al-4V). Eroded surface profiles have been obtained by vertical sectioning method for light microscopy observation. Mixed fractals have been measured from profile images by a digital image processing and analysis technique. The use of this technique allows glimpsing a quantitative correlation among material properties, fractal surface topography and erosion phenomena. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Fibroblast functionality on novel Ti-30Ta nanotube array

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

High-pressure assisted sintering of Ti-20Si-10B and Ti-10Si-5B powders

This work presents the structural characterization of Ti-10Si-5B and Ti-20Si-10B (at-%) alloys produced by high-pressure assisted sintering. Sintering was performed in air at 1100 and 1200°C for 60 s using pressure levels of 5 GPa. Structural evaluation of sintered samples was conducted by means of scanning electron microscopy and energy dispersive spectrometry. Samples were successfully consolidated after sintering, which presented theoretical density values higher than 99%. The microstructures of the sintered Ti-10Si-5B and Ti-20Si-10B alloys revealed the presence of the TiSS, TiB, TiB2, Ti5Si3, Ti5Si4, TiSi, and TiSi2.phases. A small amount of Ti6Si2B was formed after high-pressure assisted sintering of the Ti-20Si-10B alloy (5GPa, 1100°C for 60 s) indicating that equilibrium structures were not achieved during short sintering times. No oxygen and carbon contamination was detected in structures of Ti-Si-B alloys after high-pressure sintering at 1100 and 1200°C without controlled atmosphere. © (2012) Trans Tech Publications, Switzerland.

Growth of TiO2 nanotubes by anodization of Ti-7.5Mo in NH 4F solutions

Titanium and its alloys are widely used as biomaterials due to their mechanical, chemical and biological properties. To enhance the biocompatibility of titanium alloys, various surface treatments have been proposed. In particular, the formation of titanium oxide nanotubes layers has been extensively examined. According to the literature, it is possible to induce the growth of TiO2 on the surface of titanium, employing the aqueous anodizing electrolyte. This Ti-7.5Mo alloy was anodized in glycerol electrolytes containg 0.25 wt% of NH4F, with variations in time, voltage and calcinations temperature. After anodization, the sample surfaces were analyzed with a field emission scanning electron microscopy, DRX and contact angle measurements. It was possible to observe the formation of TiO2 on the surface and these findings represent a simple surface treatment for Ti alloys that has high potential for biomedical applications. Copyright © 2013 American Scientific Publishers. All rights reserved.

Avaliação de implantes dentários da liga experimental Ti-30Ta após tratamento de superfície biomimético e imobilização com bisfosfonato

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Processamento e caracterização mecânica da liga à base de titânio (Ti-7,5Mo) para confecção de prótese ortopédica

Pós-graduação em Engenharia Mecânica - FEG

Crescimento da nanoapatita na liga Ti-30Ta, para aplicações odontológicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Preparação de superfície bioativa na Liga Ti-7,5Mo para uso em Odontologia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito do tratamento de superfície na osseointegração de implantes dentários da liga TI-7,5Mo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Crescimento de nanotubos de TiO2 na superfície da liga Ti-7,5Mo empregando oxidação anódica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Interstitial oxygen's influence on the corrosion behavior of Ti-9Mo alloys

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da biocompatibilidade da liga Ti-6AI-7Nb e titânio de grau 2 em tíbia de coelhos

Pós-graduação em Biopatologia Bucal - ICT