Spatially resolved X-ray diffraction phase mapping and α → β → α transformation kinetics in the heat-affected zone of commercially pure titanium arc welds

1998 ◽  
Vol 29 (11) ◽  
pp. 2761-2773 ◽  
Author(s):  
John W. Elmer ◽  
Joe Wong ◽  
Thorsten Ressler
2015 ◽  
Vol 365 ◽  
pp. 232-236 ◽  
Author(s):  
Roman S. Laptev ◽  
Andrey M. Lider ◽  
Yuriy S. Bordulev ◽  
Viktor N. Kudiiarov ◽  
Georgy V. Garanin ◽  
...  

This paper presents the results of a defect structure investigation in commercially pure titanium alloy after hydrogen charging in a gaseous atmosphere at the temperature of 873 K up to the concentration of 5.1 at. %. Structure of samples was studied by positron lifetime, Doppler broadening and X-ray diffraction spectrometry. Several processes, corresponding to the different ranges of hydrogen concentrations were revealed. It was shown that hydrogen, penetrating in the material, expands its crystal lattice, initiates formation of vacancy-like defects of different dimensions and reacts with the last ones, forming the defect-hydrogen complexes.


2007 ◽  
Vol 12 (3) ◽  
pp. 525-531 ◽  
Author(s):  
E. Gemelli ◽  
N.H.A. Camargo

The aim of this work was to perform thermal characterization of commercially pure titanium in dry air to determine its oxidation kinetics and the structure of the oxide. The oxidation kinetics were determined thermogravimetrically under isothermal conditions in the temperature range 300 to 750 ºC for 48 hours and the structure of the oxides was determined by differential thermal analyses and X-ray diffraction in the temperature range room temperature - 1000ºC. The oxidation rate of titanium increased with increase in temperature. It was high in the initial stages of oxidation and then decreased rapidly with time, especially up to 600 ºC. The kinetic laws varied between inverse logarithmic at the lower temperatures (300 and 400 ºC) and parabolic at the higher temperatures (650, 700 and 750 ºC). Evidences from X-ray diffraction and differential thermal analyses data revealed that the passive oxide film formed at room temperature crystallized into anatase at about 276 ºC. The crystallized oxide formed in the range 276 - 457 ºC consisted of anatase, in the range 457 - 718 ºC consisted of anatase and rutile sublayers, and at temperatures beyond 718 ºC consisted of a layer of pure rutile. Scanning electron microscopy observations reveled that the oxidized surfaces were crack-free and the surface roughness increased steadily with oxidation temperature.


2008 ◽  
Vol 368-372 ◽  
pp. 1201-1202
Author(s):  
Q. Ma ◽  
Y.J. Wang ◽  
Cheng Yun Ning ◽  
Hai Mei Cheng ◽  
Zhao Yi Yin

Porous bioactive thin film on commercially pure titanium substrate was prepared by micro-arc oxidation (MAO) in electrolytic solution, which contained calcium acetate, β-glycerol phosphate disodium salt pentahydrate (β-GP) and lanthanum nitrate. The phases and microstructure of the bioactive films were examined by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectrometer and electron probe microanalysis. The results showed that: (1) porous bioactive films with about 10μm were formed on titanium substrate by MAO; (2) phases of the thin films were hydroxyapatite, anatase and rutile; (3) elements of Ca, P, and Ti of films were identified by EDS.


2017 ◽  
Vol 23 (2) ◽  
pp. 135
Author(s):  
Shijing Lu ◽  
Kunxia Wei ◽  
Yan Wang ◽  
Jing Hu

<p class="AMSmaintext">Commercially pure titanium (CP-Ti) was subjected to thermal oxidation at different temperatures and times for determining the optimum oxidation conditions to obtain the optimum corrosion resistance. The phase constituents of the samples were determined by X-ray diffraction (XRD), the morphology of the surface was observed by SEM, and the corrosion behavior was investigated using immersion test by exposing the samples in HCl solutions with a concentration of 37%. The results showed that Rutile TiO<sub>2</sub> layer was formed on the surface of CP-Ti after thermal oxidation and the thickness of the TiO<sub>2</sub> layer increased with the treating temperature. Meanwhile, It was found that the optimum corrosion resistance to HCl was obtained while oxidizing at 700℃ for 330min~500min.</p>


2014 ◽  
Vol 880 ◽  
pp. 93-100 ◽  
Author(s):  
Yuriy S. Bordulev ◽  
Roman S. Laptev ◽  
Viktor N. Kudiiarov ◽  
Andrey M. Lider

In this work the goal was to study the behavior of titanium-hydrogen system with hydrogen concentration of 1 wt. % at high temperature vacuum annealing by means of positron lifetime (PL) spectroscopy and electrical resistivity measurements. The range of hydrogen concentrations under investigation requires the γ phase formation. The study is related with the X-ray diffraction (XRD) and thermal desorption spectra (TDS) analysis. The registered positron lifetime spectra were analyzed by multiexponential decomposition into two components. Correlation of changes of the parameters of the PL spectrum and the electrical resistivity is revealed in this paper.


2010 ◽  
Vol 442 ◽  
pp. 152-157 ◽  
Author(s):  
M. Mansoor ◽  
J. Lu

In the domain of incremental nanotechnology, surface mechanical attrition treatment is a technique which can transform superficial structure of a material to nanocrystalline without changing the chemical composition. This study is a part of the development and implementation of the technique by using ultrasonic vibrations. The material used is pure titanium in rolled and annealed condition. The nanocrystalline structure is characterized using X-ray diffraction (XRD), and transmission electron microscopy (TEM). The measured grain size is in the order of 5~60 nm. A correlation in the results of XRD and TEM is also discussed.


2007 ◽  
Vol 330-332 ◽  
pp. 333-336 ◽  
Author(s):  
Xiao Xiao Cai ◽  
Ping Gong ◽  
Yi Man ◽  
Zhi Qing Chen ◽  
Gang He

This research was aimed at the construction and characterization of nano-FHA bioceramic coating on titanium surface. Nano-FHA coating was constructed on the surface of commercially pure titanium by sol-gel route. X-ray diffraction (XRD), scanning electromicroscope (SEM) and dissolution test was employed to characterize the obtained coating. In vitro cellular responses of osteoblasts to the coating were also evaluated by MTT assay, ALP assay and SEM observation. Conventional HA coatings and commercially pure titanium (cpTi) were taken as control. Results show the nano-FHA bioceramic coating has good crystallization and homogeneous, nano-scale surface morphology. The dissolution rate of the coating is favorable. The in vitro osteoblasts culture exhibits satisfactory bioactivity.


2018 ◽  
Vol 15 (3) ◽  
pp. 253-261
Author(s):  
Baghdad Science Journal

Commercially pure titanium (cpTi) is widely used as dental implant material although it was found that titanium exhibited high modulus of elasticity and the lower corrosion tendency in oral environment. Niobium(Nb) was chosen for this study as an alternative to cpTi implant material due to its bioinert behavior and good elastic modulus and moderate cost in addition to corrosion resistance. This study was done to evaluate the effect of biomimetic coating on the surface properties of the commercially pure titanium and niobium implants by in vitro and in vivo experiments. The in vitro study was involved etching the samples of each material in HCl then soaking in 10M NaOH aqueous solution. These samples were then immersed in a 5 times concentrated simulated body fluid for 14 days. Scanning Electron Microscope, Energy Dispersive X-ray, and X-Ray Diffraction tests were done to analyze surface changes. The in vivo study was done by the implantation of screw-shaped implants (two from each material, uncoated and the other was biomimetically coated) in the tibias of New Zealand rabbits. After 2 and 4 weeks of healing period, 20 rabbits were sacrificed for each period. A removal torque was done for ten animals in each group, whereas the other ten were used for histological testing and histomorphometric analysis with optical microscope.The in vitro experiments showed that the use of 14 days immersion in a concentrated simulated body fluid produced a layer of calcium phosphate on metal surfaces. The removal torque values and new bone formation were increased significantly in Nb than Ti, in coated than uncoated screws, and in 4 weeks than 2 weeks healing periods. The Nb implants had better biomechanical and biological properties than the commercially pure titanium implants and can be used as an alternative dental implant.


Sign in / Sign up

Export Citation Format

Share Document