scholarly journals Characterization of the Microstructure, Local Macro-Texture and Residual Stress Field of Commercially Pure Titanium Grade 2 Prepared by CONFORM ECAP

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1000 ◽  
Author(s):  
Gergely Németh ◽  
Klaudia Horváth ◽  
Charles Hervoches ◽  
Petr Cejpek ◽  
Jan Palán ◽  
...  

The paper investigated the residual strain and stress distribution, microstructure, and macro-texture along the transverse direction of commercially pure titanium grade 2 samples prepared by the CONFORM ECAP technique. This method belongs to the severe plastic deformation methods; hence, it could be assumed that residual stress fields would be present in the work-pieces. Residual stresses cannot be directly measured; thus, neutron diffraction measurements, Electron back-scatter diffraction (EBSD) investigations, and local X-ray macro-texture measurements were performed in different regions of the sample to determine the data for the residual stress calculation. The calculation was based on the modified Kröner model. Neutron diffraction strain scans and residual stress calculations revealed that symmetrical residual strain and stress gradients with compression character were present in the axial and hoop direction after one and two passes. Asymmetric distribution of the residual strains and stresses remained after the third pass of the CONFORM ECAP. EBSD investigations showed that after the first pass, significant grain refinement occurred; however, further passes did not cause any dramatic grain refinement. X-ray texture measurements revealed that local macro-texture was dependent on the number of passes of the CONFORM ECAP and on the investigated area in the samples.

Alloy Digest ◽  
2020 ◽  
Vol 69 (6) ◽  

Abstract UPM CP Titanium Grade 3 (UNS R50550) is an unalloyed commercially pure titanium that exhibits moderate strength (higher strength than that of Titanium Grade 2), along with excellent formability and corrosion resistance. It offers the highest ASME allowable design stress of any commercially pure grade of titanium, and can be used in continuous service up to 425 °C (800 °F) and in intermittent service up to 540 °C (1000 °F). This datasheet provides information on composition, physical properties, and elasticity. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ti-167. Producer or source: United Performance Metals.


2015 ◽  
Vol 60 (3) ◽  
pp. 1895-1900 ◽  
Author(s):  
K. Dyja ◽  
W. Więckowski

Abstract An important factor in the possibility of obtaining correct drawn parts with the desired functional properties is the friction between the stamped sheet and the tool. The article discusses the impact of technological lubricants developed according to our own formulas, based on vegetable oils, on the stamping process taking into account the strain distributions in the drawn parts. Biodegradable lubricants based on rapeseed oil with an addition of stearic acid or boric acid were used. The results of the friction coefficient in a strip drawing test and the numerical analysis results of the stamping process of a spherical cap from sheet metal: aluminium 2024, commercially pure titanium Grade 2, steel 5604 in dry friction and lubrication conditions, are presented. Strain distributions and changes in the drawn part wall thickness were analysed.


Author(s):  
Gry Hulsart-Billström ◽  
Oscar Janson ◽  
Håkan Engqvist ◽  
Ken Welch ◽  
Jaan Hong

Abstract The release of growth factors from platelets, mediated by the coagulation and the complement system, plays an important role in the bone formation around implants. This study aimed at exploring the thromboinflammatory response of H2O2-alkali soaked commercially pure titanium grade 2 discs exposed to whole human blood, as a way to assess the bioactivity of the discs. Commercially pure titanium grade 2 discs were modified by soaking in H2O2, NaOH and Ca(OH)2. The platelet aggregation, coagulation activation and complement activation was assessed by exposing the discs to fresh whole blood from human donors. The platelet aggregation was examined by a cell counter and the coagulation and complement activation were assessed by ELISA-measurements of the concentration of thrombin-antithrombin complex, C3a and terminal complement complex. The modified surface showed a statistically significant increased platelet aggregation, coagulation activation and complement activation compared to unexposed blood. The surface also showed a statistically significant increase of coagulation activation compared to PVC. The results of this study showed that the H2O2-alkali soaked surfaces induced a thromboinflammatory response that indicates that the surfaces are bioactive.


2017 ◽  
Vol 1 (88) ◽  
pp. 5-11 ◽  
Author(s):  
J. Palán ◽  
L. Maleček ◽  
J. Hodek ◽  
M. Zemko ◽  
J. Dzugan

Purpose: At present, materials research in the area of SPD (severe plastic deformation) processes is very intensive. Materials processed by these techniques show better mechanical properties and have finer grain when compared to the input feedstock. The refined microstructure may be ultrafine-grained or nanostructured, where the grain size becomes less than 100 nm. One of the materials used for such processes is CP (commercially pure) titanium of various grades, which is widely used for manufacturing dental implants. The article deals with one of the technologies available for the production of ultrafine-grained titanium: Conform technology. CP titanium processed by CONFORM technology exhibits improved mechanical properties and very favourable biocompatibility, due to its fine-grained structure. The article presents the current experience in the production of ultrafine CP titanium using this technology. The main objective of this article is describing the behaviour of CP titanium during forming in the Conform device and its subsequent use in dental implantology. Design/methodology/approach: In the present study, commercially pure Grade 2 titanium was processed using the CONFORM machine. The numerical simulation of the process was done using FEM method with DEFORMTM software. The evaluation was performed by simple tensile testing and transmission electron microscopy. The first conclusions were derived from the determined mechanical properties and based on analogies in available publications on a similar topic. Findings: This study confirmed that the SPD process improves mechanical properties and does not impair the ductility of the material. The CONFORM process enables the continuous production of ultrafine-grained or nanostructured materials. Research limitations/implications: At the present work, the results show the possible way of continuous production of ultrafine-grained or nanostructured materials. Nevertheless, the further optimization is needed in order to improve the final quality of wires and stabilize the process. As these factors will be solved, the technology will be ready for the industry. Practical implications: The article gives the practical information about the continuous production of ultrafine-grained pure titanium Grade 2 and the possibility of use this material for dental implants. Originality/value: The present paper gives information about the influence of the CONFORM technology on final mechanical and structural properties with the emphasis on technological aspects


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.


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.


2020 ◽  
Vol 321 ◽  
pp. 09005
Author(s):  
La Chance LEPEMANGOYE ◽  
Nicolas CRETON ◽  
Virgil OPTASANU ◽  
Elise DELOYE ◽  
Tony MONTESIN ◽  
...  

In this article, we study the impact of rolling conditions on the texture of the commercially pure titanium grade 2. In a previous work, NEOTISS in collaboration with ICB laboratory, shown that the texture highly influences the precipitation of hydrides in Titanium. In order to create different textures, Titanium sheets grade 2 are cold rolled asymmetrically and symmetrically with or without lubricant. The inverse pole figures and direct pole figures obtained allow us to deduce that symmetrical cold rolling does not change the grains orientation but generates a rotation of grains along c-axis (normal to basal plan). However, asymmetrical cold rolling leads to the formation of a new crystallographic texture, which could limit the formation of the hydrides in titanium grade 2 submitted to a hydrogen-rich environment. Key words: asymmetrical rolling, symmetrical rolling, titanium, hydriding, texture


2016 ◽  
Vol 61 (4) ◽  
pp. 2177-2182 ◽  
Author(s):  
T. Moskalewicz ◽  
A. Babkiewicz ◽  
B. Dubiel ◽  
M. Kot ◽  
A. Radziszewska ◽  
...  

Abstract Porous hydroxyapatite doped SiO2 coatings were electrophoretically deposited (EPD) on commercially pure titanium. The influence of EPD parameters on coatings quality was investigated. Microstructural observation was done using transmission and scanning electron microscopy as well as X-ray diffractometry. The coatings consisted of spherical micro and nanocrystalline hydroxyapatite (HAp) as well as amorphous SiO2 nanoparticles. The coatings exhibited open porosity with pore diameter up to 1 μm and due to presence of nanoparticles high surface development. It was found that application of SiO2/HAp coating increase corrosion resistance of titanium in Ringer’s solution.


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