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Sample records for plasma-nitrided titanium alloy

  1. Plasma nitriding of titanium alloy: Effect of roughness, hardness, biocompatibility, and bonding with bone cement.

    Science.gov (United States)

    Khandaker, Morshed; Riahinezhad, Shahram; Li, Yanling; Vaughan, Melville B; Sultana, Fariha; Morris, Tracy L; Phinney, Lucas; Hossain, Khalid

    2016-11-25

    Titanium (Ti) alloys have been widely used in orthopedics and orthodontic surgeries as implants because of their beneficial chemical, mechanical, and biological properties. Improvement of these properties of a Ti alloy, Ti-6Al-4V Eli, is possible by the use of plasma nitriding treatment on the Ti alloy. The novelty of this study is the evaluation of a DC glow discharge nitrogen plasma treatment method on the surface, mechanical and biological properties of Ti alloy. Specifically, this study measured the chemical states, roughness, hardness, and biocompatibility of plasma nitride treated Ti-6Al-4V Eli as well as determined the effect of plasma treatment on the fracture strength between the Ti alloy and bone clement. This study hypothesized that DC glow discharge nitrogen plasma treatment may alter the surface chemical and mechanical states of the Ti alloy that may influence the fracture strength of implant/cement interfaces under static load. This study found that plasma nitride treatment on Ti alloy does not have effect on the roughness and biocompatibility (P value > 0.5), but significantly effect on the hardness and fracture strength of Ti-bone cement interfaces compared to those values of untreated Ti samples (P value plasma treated Ti alloy can potentially be used for orthopedic applications.

  2. Mesenchymal stem cell adhesion and spreading on microwave plasma-nitrided titanium alloy.

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    Clem, William C; Konovalov, Valery V; Chowdhury, S; Vohra, Yogesh K; Catledge, Shane A; Bellis, Susan L

    2006-02-01

    Improved methods to increase surface hardness of metallic biomedical implants are being developed in an effort to minimize the formation of wear debris particles that cause local pain and inflammation. However, for many implant surface treatments, there is a risk of film delamination due to the mismatch of mechanical properties between the hard surface and the softer underlying metal. In this article, we describe the surface modification of titanium alloy (Ti-6Al-4V), using microwave plasma chemical vapor deposition to induce titanium nitride formation by nitrogen diffusion. The result is a gradual transition from a titanium nitride surface to the bulk titanium alloy, without a sharp interface that could otherwise lead to delamination. We demonstrate that vitronectin adsorption, as well as the adhesion and spreading of human mesenchymal stem cells to plasma-nitrided titanium is equivalent to that of Ti-6Al-4V, while hardness is improved 3- to 4-fold. These in vitro results suggest that the plasma nitriding technique has the potential to reduce wear, and the resulting debris particle release, of biomedical implants without compromising osseointegration; thus, minimizing the possibility of implant loosening over time. (c) 2005 Wiley Periodicals, Inc.

  3. Evaluation of plasma nitriding efficiency of titanium alloys for medical applications

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    T. Frączek

    2009-04-01

    Full Text Available The surface layers obtained on selected titanium alloys, used in medicine, by the nitriding under glow discharge condition were investigated. The results concern of: α- titanium alloy Grade 2 and α + β alloys Grade 5 and Grade 5 ELI nitrided in temperature below 873 K. The nitriding experiments were performed in a current glow-discharge furnace JON-600 with assisting of unconventional methods. After nitriding surface layers were characterised by surface microhardness measurements, chemical depth profiles, microhardness depth profiles and wear resistance tests.

  4. [Experimental study on the corrosion behavior of a type of oral near β-type titanium alloys modified with double glow plasma nitriding].

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    Wen, Ke; Li, Fenglan

    2015-12-01

    To study the electrochemical corrosion performance of a type of biomedical materials near beta titanium alloy(Ti-3Zr-2Sn-3Mo-25Nb, TLM) in artificial saliva before and after nitride changing, and to provide clinical basis for clinical application of titanium alloy TLM. The double glow plasma alloying technology was used to nitride the surface of titanium alloy TLM. The surface properties of the modified layer were observed and tested by optical microscope, scanning electron microscope, glow discharge spectrum analyzer, X-ray diffraction and micro hardness tester. Then, electrochemical measurement system was used to test and compare titanium alloy TLM's electrochemical corrosion in artificial saliva before and after its surface change. Finally, the surface morphology of the original titanium alloy and the modified layer was compared by scanning electron microscope. By the technology of double glow plasma nitriding, the surface of the titanium alloy TLM had been successfully nitrided with a modified layer of 4-5 µm in thickness, uniform and compact. Its main compositions were Ti and Ti(2)N. The Microhardness of modified layer also had been improved from (236.8 ± 5.4) to (871.8 ± 5.2) HV. The self-corrosion potential in electrochemical corrosion tests had been increased from -0.559 V to -0.540 V, while the self- corrosion current density had been reduced from 2.091 × 10(-7) A/cm(2) to 7.188 × 10(-8) A/cm(2). Besides, alternating-current impedance(AC Impedance) had also been increased. With the scanning electron microscope, it's obvious that the diameter of corrosion holes on modified layer were approximately 10 µm. As to the diameter and number of corrosion holes on modified layer, they had been decreased comparing with the original titanium alloy. The type of near beta titanium alloy TLM can construct a nitriding modified layer on its surface. Meanwhile, the performance of its anti- corrosion in artificial saliva has been improved, comparing to the original

  5. Microbial adherence to a nonprecious alloy after plasma nitriding process.

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    Sonugelen, Mehmet; Destan, Uhmut Iyiyapici; Lambrecht, Fatma Yurt; Oztürk, Berran; Karadeniz, Süleyman

    2006-01-01

    To investigate the microbial adherence to the surfaces of a nonprecious metal alloy after plasma nitriding. The plasma-nitriding process was performed to the surfaces of metals prepared from a nickel-chromium alloy. The microorganisms were labeled with technetium-99m. After the labeling procedure, 60 metal disks were treated with a microorganism for each use. The results revealed that the amount of adherence of all microorganisms on surfaces was changed by plasma-nitriding process; adherence decreased substantially (P plasma nitriding time were not significant (P> .05) With the plasma-nitriding process, the surface properties of nonprecious metal alloys can be changed, leading to decreased microbial adherence.

  6. [Initial osteoblast functions on a type of near β-type titanium alloys surfaces modified by the double glow plasma nitriding technology].

    Science.gov (United States)

    Qu, Y H; Li, F L; Wen, K; Wang, W

    2017-02-09

    Objective: To evaluate the adhesion, proliferation, alkaline phosphatase (ALP) activity and the expression of osteogenesis-related genes and osteoprotegerin (OPG)/receptor activator of NF-κB ligand (RANKL) of osteoblast-like cells on a type of near β-type titanium alloys (Ti-5Zr-3Sn-5Mo-15Nb, TLM) surfaces modified by the double glow plasma nitriding technology, and to investigate the effect of the modified surfaces on the initial functions of osteoblast-like cells. Methods: The surfaces of TLM were modified by the double glow plasma nitriding technology. TLM surfaces without modification were used as control. Cell morphology was observed with scanning electron microscopy (SEM). Methyl thiazolyl tetrazolium (MTT) method was used to measure cell proliferation. Cell ALP activity was evaluated by using reagent kits. The mRNA expression of Runt-related transcription factor-2 (RUNX2), typeⅠcollagen alpha 1 chain (COLⅠ α1) and OPG/RANKL were examined by quantitative real-time PCR(qRT-PCR). Results: Four hour following cell alture, cells on modified surfaces extend filopodia and intercellular junction was tight. Three days later, cell proliferation (0.277±0.007) was significantly higher than that in control group (0.249±0.004) (Pplasma nitriding technology has a positive effect on osteoblasts initial adhesion, proliferation and differentiation, and it can also improve expression of OPG mRNA and has an inhibitory effect on RANKL mRNA expression of osteoblasts.

  7. Surface modification of titanium by plasma nitriding

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    Kapczinski Myriam Pereira

    2003-01-01

    Full Text Available A systematic investigation was undertaken on commercially pure titanium submitted to plasma nitriding. Thirteen different sets of operational parameters (nitriding time, sample temperature and plasma atmosphere were used. Surface analyses were performed using X-ray diffraction, nuclear reaction and scanning electron microscopy. Wear tests were done with stainless steel Gracey scaler, sonic apparatus and pin-on-disc machine. The obtained results indicate that the tribological performance can be improved for samples treated with the following conditions: nitriding time of 3 h; plasma atmosphere consisting of 80%N2+20%H2 or 20%N2+80%H2; sample temperature during nitriding of 600 or 800 degreesC.

  8. Plasma Nitriding of Low Alloy Sintered Steels

    Institute of Scientific and Technical Information of China (English)

    Shiva Mansoorzadeh; Fakhreddin Ashrafizadeh; Xiao-Ying Li; Tom Bell

    2004-01-01

    Fe-3Cr-0.5Mo-0.3C and Fe-3Cr-1.4Mn-0.5Mo-0.367C sintered alloys were plasma nitrided at different temperatures. Characterization was performed by microhardness measurement, optical microscopy, SEM and XRD. Both materials had similar nitriding case properties. 1.4% manganese did not change the as-sintered microstructure considerably.It was observed that monophase compound layer, γ, formed with increasing temperature. Compound layer thickness increased with increasing temperature while nitriding depth increased up to a level and then decreased. Core softening was more pronounced at higher temperature owing to cementite coarsening.

  9. In-Vitro Biocompatibility Studies of Plasma-Nitrided Titanium Alloy β-21S Using Fibroblast Cells

    Science.gov (United States)

    Mohan, L.; Raja, M. D.; Uma, T. S.; Rajendran, N.; Anandan, C.

    2016-04-01

    In the present work, titanium alloy β-21S was nitrided in a low-pressure RF plasma with 100% nitrogen and 20% hydrogen-diluted nitrogen at 800 °C for 4 h and the samples were evaluated for in-vitro biocompatibility by using NIH 3T3 fibroblast cell line. Cellular behavior was evaluated in terms of cell morphology and its viability. FESEM was exploited to observe the morphology of the cells fixed over the surface of the implant. Fibroblasts were seemed to be well distributed over the surface with its characteristic spindle-like shape. Over all, the results indicate that nitriding provided a compatible surface for cell attachment and cell growth. Cell viability and proliferation was assessed by using standard MTT assay. Compared with substrate, the nitrided samples exhibited high-percentage cell viability demonstrating their increased biocompatibility. In addition, the nitrided samples facilitate bone-like apatite formation and exhibited a gradual increase of apatite formation after immersion in Hanks' solution.

  10. Osteoblastlike cell adhesion on titanium surfaces modified by plasma nitriding.

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    da Silva, Jose Sandro Pereira; Amico, Sandro Campos; Rodrigues, Almir Olegario Neves; Barboza, Carlos Augusto Galvao; Alves, Clodomiro; Croci, Alberto Tesconi

    2011-01-01

    The aim of this study was to evaluate the characteristics of various titanium surfaces modified by cold plasma nitriding in terms of adhesion and proliferation of rat osteoblastlike cells. Samples of grade 2 titanium were subjected to three different surface modification processes: polishing, nitriding by plasma direct current, and nitriding by cathodic cage discharge. To evaluate the effect of the surface treatment on the cellular response, the adhesion and proliferation of osteoblastlike cells (MC3T3) were quantified and the results were analyzed by Kruskal-Wallis and Friedman statistical tests. Cellular morphology was observed by scanning electron microscopy. There was more MC3T3 cell attachment on the rougher surfaces produced by cathodic cage discharge compared with polished samples (P Plasma nitriding improves titanium surface roughness and wettability, leading to osteoblastlike cell adhesion.

  11. Precipitate-Accommodated Plasma Nitriding for Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Patama Visittipitukul; Tatsuhiko Aizawa; Hideyuki Kuwahara

    2004-01-01

    Reliable surface treatment has been explored to improve the strength and wear resistance of aluminum alloy parts in automotives. Long duration time as well as long pre-sputtering time are required for plasma nitriding of aluminum or its alloys only with the thickness of a few micrometers. New plasma inner nitriding is proposed to realize the fast-rate nitriding of aluminum alloys. Al-6Cu alloy is employed as a targeting material in order to demonstrate the effectiveness of this plasma nitriding. Mechanism of fast-rate nitriding process is discussed with consideration of the role of Al2Cu precipitates.

  12. Bone tissue response to plasma-nitrided titanium implant surfaces

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    Emanuela Prado FERRAZ

    2015-02-01

    Full Text Available A current goal of dental implant research is the development of titanium (Ti surfaces to improve osseointegration. Plasma nitriding treatments generate surfaces that favor osteoblast differentiation, a key event to the process of osteogenesis. Based on this, it is possible to hypothesize that plasma-nitrided Ti implants may positively impact osseointegration. Objective The aim of this study was to evaluate the in vivo bone response to Ti surfaces modified by plasma-nitriding treatments. Material and Methods Surface treatments consisted of 20% N2 and 80% H2, 450°C and 1.5 mbar during 1 h for planar and 3 h for hollow cathode. Untreated surface was used as control. Ten implants of each surface were placed into rabbit tibiae and 6 weeks post-implantation they were harvested for histological and histomorphometric analyses. Results Bone formation was observed in contact with all implants without statistically significant differences among the evaluated surfaces in terms of bone-to-implant contact, bone area between threads, and bone area within the mirror area. Conclusion Our results indicate that plasma nitriding treatments generate Ti implants that induce similar bone response to the untreated ones. Thus, as these treatments improve the physico-chemical properties of Ti without affecting its biocompatibility, they could be combined with modifications that favor bone formation in order to develop new implant surfaces.

  13. Bone tissue response to plasma-nitrided titanium implant surfaces.

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    Ferraz, Emanuela Prado; Sverzut, Alexander Tadeu; Freitas, Gileade Pereira; Sá, Juliana Carvalho; Alves, Clodomiro; Beloti, Marcio Mateus; Rosa, Adalberto Luiz

    2015-01-01

    A current goal of dental implant research is the development of titanium (Ti) surfaces to improve osseointegration. Plasma nitriding treatments generate surfaces that favor osteoblast differentiation, a key event to the process of osteogenesis. Based on this, it is possible to hypothesize that plasma-nitrided Ti implants may positively impact osseointegration. Objective The aim of this study was to evaluate the in vivo bone response to Ti surfaces modified by plasma-nitriding treatments. Material and Methods Surface treatments consisted of 20% N2 and 80% H2, 450°C and 1.5 mbar during 1 h for planar and 3 h for hollow cathode. Untreated surface was used as control. Ten implants of each surface were placed into rabbit tibiae and 6 weeks post-implantation they were harvested for histological and histomorphometric analyses. Results Bone formation was observed in contact with all implants without statistically significant differences among the evaluated surfaces in terms of bone-to-implant contact, bone area between threads, and bone area within the mirror area. Conclusion Our results indicate that plasma nitriding treatments generate Ti implants that induce similar bone response to the untreated ones. Thus, as these treatments improve the physico-chemical properties of Ti without affecting its biocompatibility, they could be combined with modifications that favor bone formation in order to develop new implant surfaces.

  14. ANN-based wear performance prediction for plasma nitrided Ti6Al4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kahraman, Fatih; Karadeniz, Sueleyman; Durmus, Izmir; Durmus, Huelya

    2012-07-01

    Surface modification of a Ti6Al4V titanium alloy was made by the plasma nitriding process. Plasma nitriding was performed in a constant gas mixture of 20% H{sub 2} -80% N{sub 2} at temperatures between 700 and 1000 C and process times between 2 and 15 h. Samples nitrided at different treatment times and temperatures were subjected to the dry sliding wear test using the pin-on-disc set up under 80N normal load with rotational speed of counter face disc of 0.8 m/s at room conditions. An artificial neural network (ANN) model of was developed for prediction of wear performance of the plasma nitrided Ti6Al4V alloy. The inputs of the ANN model were processing times and temperatures, diffusion layer thickness, Ti{sub 2}N thickness, TiN thickness and hardness. The output of the ANN model was wear loss. The model is based on the multilayer backpropagation neural technique. The ANN was trained with a comprehensive dataset collected from experimental conditions and results of authors. The model can be used for the prediction of wear properties of Ti6Al4V alloys nitrided at different parameters. The ANN model demonstrated the best statistical performance with the experimental results.

  15. Effect of plasma nitriding and titanium nitride coating on the corrosion resistance of titanium.

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    Wang, Xianli; Bai, Shizhu; Li, Fang; Li, Dongmei; Zhang, Jing; Tian, Min; Zhang, Qian; Tong, Yu; Zhang, Zichuan; Wang, Guowei; Guo, Tianwen; Ma, Chufan

    2016-09-01

    The passive film on the surface of titanium can be destroyed by immersion in a fluoridated acidic medium. Coating with titanium nitride (TiN) may improve the corrosion resistance of titanium. The purpose of this in vitro study was to investigate the effect of duplex treatment with plasma nitriding and TiN coating on the corrosion resistance of cast titanium. Cast titanium was treated with plasma nitriding and TiN coating. The corrosion resistance of the duplex-treated titanium in fluoride-containing artificial saliva was then investigated through electrochemical and immersion tests. The corroded surface was characterized by scanning electron microscopy (SEM) with energy-dispersive spectroscopy surface scan analysis. The data were analyzed using ANOVA (α=.05) RESULTS: Duplex treatment generated a dense and uniform TiN film with a thickness of 4.5 μm. Compared with untreated titanium, the duplex-treated titanium displayed higher corrosion potential (Ecorr) values (Pplasma nitriding and TiN coating significantly improved the corrosion resistance of cast titanium in a fluoride-containing environment. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  16. Cathodic Cage Plasma Nitriding of Ti6Al4V Alloy

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    Maciej OSSOWSKI

    2016-05-01

    Full Text Available Glow discharge nitriding is being used increasingly more often for modifying the properties of titanium and its alloys with the aim to increase their frictional wear resistance, fatigue strength, and, in the case of medical applications, to eliminate the metallosis effect. Unlike PVD methods, ion nitriding ensures the formation of diffusive layers with very good adhesion to the substrate, but which still have some disadvanteges such as the “edge effect” or “hollow cathode effect” which hinders treatment of complex workpieces. The paper compares nitrided layers produced on Ti6Al4V alloy using two different types of nitriding processes. The first process is conventional dc plasma nitriding (DCPN where the samples were placed at the cathode potential, while the second one is a new method of cathodic cage plasma nitriding (CCPN process, where the substrate is insulated from the cathode and anode. The experiments have shown that the treatment conducted in a cathodic cage can be alternative for conventional ion nitriding, especially when used for small parts with complicated shapes used in the space or medical industry. DOI: http://dx.doi.org/10.5755/j01.ms.22.1.7343

  17. Effect of plasma nitriding treatment on structural, tribological and electrochemical properties of commercially pure titanium.

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    Çelik, İlhan; Karakan, Mehmet

    2016-02-01

    In this study, plasma nitriding treatment was applied to commercially pure titanium (Grade 2). Structural properties, electrochemical and tribological behaviours of the nitrided pure titanium specimens were comparatively investigated. Microstructure and morphology of the plasma nitrided specimens were analysed by X-ray diffraction and scanning electron microscopy. Furthermore, corrosion tests were conducted in Ringer's solution, which represents a human body environment, to determine electrochemical properties. Then, tribological and frictional properties were investigated using pin-on-disc tribometer, and a micro-hardness tester was used to measure the hardness of the coatings. The results showed that plasma nitrided specimens exhibited higher surface hardness than the untreated specimens did. In addition, the plasma nitrided specimens at 700 °C presented significantly better performance than the other plasma nitrided specimens (at 500 °C and 600 °C) under dry wear conditions. Moreover, corrosion test results showed that corrosion behaviours of untreated and nitrided samples had similar characteristic. © IMechE 2015.

  18. Effect of Plasma Nitriding Parameters on the Wear Resistance of Alloy Inconel 718

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    Kovací, Halim; Ghahramanzadeh ASL, Hojjat; Albayrak, Çigdem; Alsaran, Akgün; Çelik, Ayhan

    2016-11-01

    The effect of the temperature and duration of plasma nitriding on the microstructure and friction and wear parameters of Inconel 718 nickel alloy is investigated. The process of plasma nitriding is conducted in a nitrogen-hydrogen gaseous mixture at a temperature of 400, 500 and 600°C for 1 and 4 h. The modulus of elasticity of the nitrided layer, the micro- and nanohardness, the surface roughness, the friction factor and the wear resistance of the alloy are determined prior to and after the nitriding. The optimum nitriding regime providing the best tribological characteristics is determined.

  19. Plasma Nitriding of CP Titanium Grade-2 and Ti-6Al-4V Grade-5

    Science.gov (United States)

    Deepak, J. R.; Bupesh Raja, V. K.; Senthil Kumar, J.; Thomas, Subin; Raju Vithaiyathil, Thomas

    2017-05-01

    Titanium metal is considered to be asset material due to its high tribological properties. Since these tribological properties like hardness, roughness, wear resistance etc. are influenced by the surface properties of the material, so obviously any changes in the surface of the material has direct impact on the tribological properties too. Nitriding is a heat-treating process that diffuses nitrogen into the surface of a metal to create a case hardened surface. The main objective is that to implement the plasma nitriding process to both CP Titanium grade-2 and Ti-6Al-4V grade-5 and to observe the improvements in the tribological properties with respect to the parent materials.

  20. Effect of SPD surface layer on plasma nitriding of Ti–6Al–4V alloy

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    Farokhzadeh, K.; Qian, J.; Edrisy, A., E-mail: edrisy@uwindsor.ca

    2014-01-01

    A severe plastic deformation (SPD) surface layer was introduced by shot peening to enhance the nitriding kinetics in low-temperature (600 °C) plasma nitriding of Ti–6Al–4V alloy. The effect of this pretreatment on the nitrided microstructures and phase compositions was investigated by analytical microscopy techniques e.g. scanning and transmission electron microscopy (SEM, TEM) and X-ray diffraction (XRD) analysis. Microstructural investigations revealed the formation of a compound layer consisting of a 0.6 µm thick nanocrystalline TiN layer followed by a 0.5 µm thick layer of Ti{sub 2}N with a larger grain size (0.1–0.5 µm). The development of TiN nanograins was attributed to accelerated nitriding kinetics due to the increased preferential nucleation sites in the SPD layer. Furthermore, the thickness of nitrogen diffusion zone (DZ) increased by 50% in the pretreated plasma nitrided alloy when compared with that of the untreated one. This is likely promoted by an increase in density of subsurface microstructural defects, such as twins and grain boundaries. The sliding behaviour and interfacial adhesion of the nitrided surfaces were evaluated by micro-scratch tests within a load range of 1–20 N. Compared with untreated-plasma-nitrided alloy, the pretreated nitrided surfaces exhibited a higher load bearing capacity and better interfacial bonding. They exhibited no chipping or spallation, even after multiple sliding passes at the highest applied load of 20 N in contrary to the untreated plasma nitrided surfaces.

  1. Minimizing Pseudomonas aeruginosa adhesion to titanium surfaces by a plasma nitriding process

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    Michelle de Medeiros Aires

    2016-12-01

    Full Text Available The research of the interaction between bacteria-surface has great importance for titanium biomedical applications once microorganisms offer risks because promoting implant loss. Therefore, study bacterial adhesion and colonization on titanium is interesting because are principal factors infections pathogeny on biomaterials. In this study, commercial grade II titanium was submitted to nitriding treatment to plasma at 2.2 mbar, using gas mixtures of 80% hydrogen (H2 and 20% nitrogen (N2 during 1 hour and 3 hour. The surfaces were physically and chemically characterized. In order to evaluate bacterial response, the surfaces were exposed to Pseudomonas aeruginosa. The titanium surface modified in nitriding plasma, although exposes a higher roughness as compared with untreated samples, exhibited lower bacterial growth. The nitrided sample for 3 hour exhibited the higher amount of TiN phase and the higher concentration of atomic nitrogen on surface and lower bacterial adhered count. These results were confirmed by scanning electron microscopy. Based on these results can be said to the thermochemical treatment of plasma nitriding on titanium samples results a significant reduction of adherence of Pseudomonas aeruginosa. It was found that the Ti surface nitrided offers significant reduction of bacterial adherence which prevent biofilm formation and offersing lower risk of infection and implant remotion.

  2. Structure and properties of nitrided surface layer produced on NiTi shape memory alloy by low temperature plasma nitriding

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    Czarnowska, Elżbieta [Children' s Memorial Health Institute, Pathology Department, Al. Dzieci Polskich 20, 04-730 Warsaw (Poland); Borowski, Tomasz [Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland); Sowińska, Agnieszka [Children' s Memorial Health Institute, Pathology Department, Al. Dzieci Polskich 20, 04-730 Warsaw (Poland); Lelątko, Józef [Silesia University, Faculty of Computer Science and Materials Science, 75 Pułku Piechoty 1A, 41-500 Chorzów (Poland); Oleksiak, Justyna; Kamiński, Janusz; Tarnowski, Michał [Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland); Wierzchoń, Tadeusz, E-mail: twierz@inmat.pw.edu.pl [Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland)

    2015-04-15

    Highlights: • Low temperature plasma nitriding process of NiTi shape memory alloy is presented. • The possibility of treatment details of sophisticated shape. • TiN surface layer has diffusive character. • TiN surface layer increases corrosion resistance of NiTi alloy. • Produced TiN layer modify the biological properties of NiTi alloy. - Abstract: NiTi shape memory alloys are used for bone and cardiological implants. However, on account of the metallosis effect, i.e. the release of the alloy elements into surrounding tissues, they are subjected to various surface treatment processes in order to improve their corrosion resistance and biocompatibility without influencing the required shape memory properties. In this paper, the microstructure, topography and morphology of TiN surface layer on NiTi alloy, and corrosion resistance, both before and after nitriding in low-temperature plasma at 290 °C, are presented. Examinations with the use of the potentiodynamic and electrochemical impedance spectroscopy methods were carried out and show an increase of corrosion resistance in Ringer's solution after glow-discharge nitriding. This surface titanium nitride layer also improved the adhesion of platelets and the proliferation of osteoblasts, which was investigated in in vitro experiments with human cells. Experimental data revealed that nitriding NiTi shape memory alloy under low-temperature plasma improves its properties for bone implant applications.

  3. Fatigue improvement in low temperature plasma nitrided Ti–6Al–4V alloy

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    Farokhzadeh, K.; Edrisy, A., E-mail: edrisy@uwindsor.ca

    2015-01-03

    In this study a low temperature (600 °C) treatment was utilized to improve the fatigue performance of plasma nitrided Ti–6Al–4V alloy by optimization of microstructure. In order to study the fatigue properties, rotation bending tests were conducted, the S–N curves were constructed, and the results were compared with those obtained by an elevated temperature treatment (900 °C) as well as conventional gas/plasma nitriding treatments reported in literature. The plasma nitrided alloy at 600 °C showed an endurance limit of 552 MPa which was higher than those achieved by conventional nitriding treatments performed at 750–1100 °C. In contrast, plasma nitriding at 900 °C resulted in the reduction of fatigue life by at least two orders of magnitude compared to the 600 °C treatment, accompanied by a 13% reduction of tensile strength and a 78% reduction of ductility. The deterioration of mechanical properties after the elevated temperature treatment was attributed to the formation of a thick compound layer (∼6 µm) on the surface followed by an α-Case (∼20 µm) and phase transformation in the bulk microstructure from fully equiaxed to bimodal with coarse grains (∼5 times higher average grain size value). The microstructure developed at 600 °C consisted of a thin compound layer (<2 µm) and a deep nitrogen diffusion zone (∼45 µm) while the bulk microstructure was maintained with only 40% grain growth. The micromechanisms of fatigue failures were identified by examination of the fracture surfaces under a scanning electron microscope (SEM). It was found that fatigue failure in the plasma nitrided alloy initiated from the surface in the low cycle region (N≤10{sup 5} cycles) and propagated in a ductile manner leading to the final rupture. No failures were observed in the high cycle region (N>10{sup 5} cycles) and the nitrided alloy endured cyclic loading until the tests were stopped at 10{sup 7} cycles. The thin morphology of the compound layer in this

  4. Laser melting of plasma nitrided Ti-6Al-4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Yilbas, B.S.; Sami, M.; Shuja, S.Z.; Aleem, A. [KFUPM, Dhahran (Saudi Arabia). Mechanical Engineering Dept.; Nickel, J.; Coban, A. [Energy Research Lab., Research Inst., KFUPM, Dhahran (Saudi Arabia)

    1997-11-30

    A laser surface modification technique can be used as a part of a dublex treatment process to improve the surface properties of Ti-6Al-4V alloy. The present study is conducted to investigate the surface properties of the Ti-6Al-4V alloy due to laser melting prior to a plasma nitriding process. Consequently, nitriding is carried out to obtain the depth of the nitride zone of 30 {mu}m. A CO{sub 2} laser with 1.6 kW output power was used to melt the nitride layers. The wear properties of the plasma nitrided and nitrided/melted surfaces were investigated using pin-on-disc equipment while the friction coefficient was determined using a ball-on-disc machine. The nitride depth profile was measured using a nuclear analyses reaction and elemental distribution in the melted zones was investigated using {mu}-PIXE. Scanning electron microscopy and optical microscopy were carried out to analyze the microstructures developed before and after the laser melting process. In addition, heating and cooling rates were predicted through the electron-kinetic theory approach. (orig.)

  5. Modeling of Nitrogen Penetration in Medical Grade CoCrMo Alloy during Plasma Nitriding

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    Arvaidas GALDIKAS

    2014-04-01

    Full Text Available For analysis of plasma nitriding process and nitrogen penetration into CoCrMo alloy the trapping-detrapping model is applied. This model is commonly used for analysis of stainless steel nitriding, however, in this work it is shown that the same nitrogen penetration mechanism takes place in CoCrMo alloys. From the fitting of experimental curves, taken from literature, it is found by the proposed model that diffusion coefficient depends on nitrogen concentration according to Einstein-Smoluchowski relation D µ 1/CN. The diffusion coefficients for 400oC temperature nitriding of in CoCrMo are calculated. The shape of nitrogen depth profile curves are analyzed showing influence of different parameters such as detrapping activation energy, chromium concentration, etc.DOI: http://dx.doi.org/10.5755/j01.ms.20.1.3458

  6. Modeling of Nitrogen Penetration in Medical Grade CoCrMo Alloy during Plasma Nitriding

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    Arvaidas GALDIKAS

    2014-04-01

    Full Text Available For analysis of plasma nitriding process and nitrogen penetration into CoCrMo alloy the trapping-detrapping model is applied. This model is commonly used for analysis of stainless steel nitriding, however, in this work it is shown that the same nitrogen penetration mechanism takes place in CoCrMo alloys. From the fitting of experimental curves, taken from literature, it is found by the proposed model that diffusion coefficient depends on nitrogen concentration according to Einstein-Smoluchowski relation D µ 1/CN. The diffusion coefficients for 400oC temperature nitriding of in CoCrMo are calculated. The shape of nitrogen depth profile curves are analyzed showing influence of different parameters such as detrapping activation energy, chromium concentration, etc.DOI: http://dx.doi.org/10.5755/j01.ms.20.1.3458

  7. 口腔用近β钛合金双层辉光离子渗氮改性后腐蚀性能的实验研究%Experimental study on the corrosion behavior of a type of oral near β-type titanium alloys modified with double glow plasma nitriding

    Institute of Scientific and Technical Information of China (English)

    温科; 李风兰

    2015-01-01

    Objective To study the electrochemical corrosion performance of a type of biomedical materials near beta titanium alloy(Ti-3Zr-2Sn-3Mo-25Nb, TLM) in artificial saliva before and after nitride changing, and to provide clinical basis for clinical application of titanium alloy TLM.Methods The double glow plasma alloying technology was used to nitride the surface of titanium alloy TLM.The surface properties of the modified layer were observed and tested by optical microscope, scanning electron microscope, glow discharge spectrum analyzer, X-ray diffraction and micro hardness tester.Then, electrochemical measurement system was used to test and compare titanium alloy TLM's electrochemical corrosion in artificial saliva before and after its surface change.Finally, the surface morphology of the original titanium alloy and the modified layer was compared by scanning electron microscope.Results By the technology of double glow plasma nitriding, the surface of the titanium alloy TLM had been successfully nitrided with a modified layer of 4-5 βm in thickness, uniform and compact.Its main compositions were Ti and Ti2N.The Microhardness of modified layer also had been improved from (236.8±5.4) to (871.8±5.2) HV.The self-corrosion potential in electrochemical corrosion tests had been increased from-0.559 V to-0.540 V,while the self-corrosion current density had been reduced from 2.091 × 10-7 A/cm2 to 7.188× 10-8 A/cm2.Besides, alternating-current impedance(AC Impedance) had also been increased.With the scanning electron microscope, it's obvious that the diameter of corrosion holes on modified layer were approximately 10 βm.As to the diameter and number of corrosion holes on modified layer, they had been decreased comparing with the original titanium alloy.Conclusions The type of near beta titanium alloy TLM can construct a nitriding modified layer on its surface.Meanwhile, the performance of its anti-corrosion in artificial saliva has been improved, comparing to the

  8. The effect of plasma-nitrided titanium surfaces on osteoblastic cell adhesion, proliferation, and differentiation.

    Science.gov (United States)

    Ferraz, Emanuela P; Sa, Juliana C; de Oliveira, Paulo T; Alves, Clodomiro; Beloti, Marcio M; Rosa, Adalberto L

    2014-04-01

    In this study, we evaluated the effect of new plasma-nitrided Ti surfaces on the progression of osteoblast cultures, including cell adhesion, proliferation and differentiation. Ti surfaces were treated using two plasma-nitriding protocols, hollow cathode for 3 h (HC 3 h) and 1 h (HC 1 h) and planar for 1 h. Untreated Ti surfaces were used as control. Cells derived from human alveolar and rat calvarial bones were cultured on Ti surfaces for periods of up to 14 days and the following parameters were evaluated: cell morphology, adhesion, spreading and proliferation, alkaline phosphatase (ALP) activity, extracellular matrix mineralization, and gene expression of key osteoblast markers. Plasma-nitriding treatments resulted in Ti surfaces with distinct physicochemical characteristics. The cell adhesion and ALP activity were higher on plasma-nitrided Ti surfaces compared with untreated one, whereas cell proliferation and extracellular matrix mineralization were not affected by the treatments. In addition, the plasma-nitrided Ti surfaces increased the ALP, reduced the osteocalcin and did not affect the Runx2 gene expression. We have shown that HC 3 h and planar Ti surfaces slightly favored the osteoblast differentiation process, and then these surfaces should be considered for further investigation using preclinical models. Copyright © 2013 Wiley Periodicals, Inc.

  9. Investigation of surface properties of high temperature nitrided titanium alloys

    Directory of Open Access Journals (Sweden)

    E. Koyuncu

    2009-12-01

    Full Text Available Purpose: The purpose of paper is to investigate surface properties of high temperature nitrided titanium alloys.Design/methodology/approach: In this study, surface modification of Ti6Al4V titanium alloy was made at various temperatures by plasma nitriding process. Plasma nitriding treatment was performed in 80% N2-20% H2 gas mixture, for treatment times of 2-15 h at the temperatures of 700-1000°C. Surface properties of plasma nitrided Ti6Al4V alloy were examined by metallographic inspection, X-Ray diffraction and Vickers hardness.Findings: Two layers were determined by optic inspection on the samples that were called the compound and diffusion layers. Compound layer contain TiN and Ti2N nitrides, XRD results support in this formations. Maximum hardness was obtained at 10h treatment time and 1000°C treatment temperature. Micro hardness tests showed that hardness properties of the nitrided samples depend on treatment time and temperature.Practical implications: Titanium and its alloys have very attractive properties for many industries. But using of titanium and its alloys is of very low in mechanical engineering applications because of poor tribological properties.Originality/value: The nitriding of titanium alloy surfaces using plasma processes has already reached the industrial application stage in the biomedical field.

  10. Cathodic Cage Plasma Nitriding of Ti6Al4V Alloy

    OpenAIRE

    Ossowski, Maciej (OPI); Borowski, Tomasz; Michal TARNOWSKI; Tadeusz WIERZCHON

    2016-01-01

    Glow discharge nitriding is being used increasingly more often for modifying the properties of titanium and its alloys with the aim to increase their frictional wear resistance, fatigue strength, and, in the case of medical applications, to eliminate the metallosis effect. Unlike PVD methods, ion nitriding ensures the formation of diffusive layers with very good adhesion to the substrate, but which still have some disadvanteges such as the “edge effect” or “hollow cathode effect” which hinder...

  11. The influence of active screen plasma nitriding parameters on corrosion behavior of a low-alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Ahangarani, Sh., E-mail: ahangarani@irost.i [Department of Advanced Materials and Renewable Energies, Iranian Research Organization for Science and Technology (IROST), P.O. Box 15815-3538, Tehran (Iran, Islamic Republic of); Sabour, A.R. [Department of Materials Engineering, Tarbiat Modarres University, Tehran (Iran, Islamic Republic of); Mahboubi, F. [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Shahrabi, T. [Department of Materials Engineering, Tarbiat Modarres University, Tehran (Iran, Islamic Republic of)

    2009-09-18

    This work presents a comparative study of low-alloy steel nitriding for different possible techniques. Active screen plasma nitriding (ASPN) is a successful surface modification method that has many advantages over the conventional DC plasma nitriding (CPN). The corrosion behavior of 30CrNiMo8 low-alloy steel has been examined using anodic polarization tests in 3.5% NaCl solution under varying conditions of ASPN and CPN processes. The process variables included active screen setup parameters, treatment temperature (550 and 580 deg. C), gas mixture (25/75 and 75/25 of N{sub 2}/H{sub 2}) and treatment time (5 and 10 h) in 500 Pa pressure. The structure and phases composition of the compound layer was studied by X-ray diffraction (XRD), microhardness tests, optical microscopy and scanning electron microscopy (SEM). It was observed that ASPN treated samples surface enhanced corrosion resistance while the temperature and/or hole size of screen setup increased.

  12. Evaluation of the Effect of Different Plasma-Nitriding Parameters on the Properties of Low-Alloy Steel

    Science.gov (United States)

    Zdravecká, Eva; Slota, Ján; Solfronk, Pavel; Kolnerová, Michaela

    2017-07-01

    This work is concerned with the surface treatment (ion nitriding) of different plasma-nitriding parameters on the characteristics of DIN 1.8519 low-alloy steel. The samples were nitrided from 500 to 570 °C for 5-40 h using a constant 25% N2-75% H2 gaseous mixture. Lower temperature (500-520 °C) favors the formation of compound layers of γ' and ɛ iron nitrides in the surface layers, whereas a monophase γ'-Fe4 N layer can be obtained at a higher temperature. The hardness of this layer can be obtained when nitriding is performed at a higher temperature, and the hardness decreases when the temperature increases to 570 °C. These results indicate that pulsed plasma nitriding is highly efficient at 550 °C and can form thick and hard nitrided layers with satisfactory mechanical properties. The results show the optimized nitriding process at 540 °C for 20 h. This process can be an interesting means of enhancing the surface hardness of tool steels to forge dies compared to stamped steels with zinc coating with a reduced coefficient of friction and improving the anti-sticking properties of the tool surface.

  13. Titanium Alloys

    Directory of Open Access Journals (Sweden)

    Mark T. Whittaker

    2015-08-01

    Full Text Available Although originally discovered in the 18th century [1], the titanium industry did not experience any significant advancement until the middle of the 20th century through the development of the gas turbine engine [2]. Since then, the aerospace sector has dominated worldwide titanium use with applications in both engines and airframe structures [3]. The highly desirable combination of properties, which include excellent corrosion resistance, favourable strength to weight ratios, and an impressive resistance to fatigue, has led to an extensive range of applications [4], with only high extraction and processing costs still restricting further implementation. [...

  14. Microstructure and Wear Behavior of Ti-6Al-4V Treated by Plasma Zr-alloying and Plasma Nitriding

    Institute of Scientific and Technical Information of China (English)

    CHEN Kai; LIU Xiaoping; LIU Xiaozhen; MENG Tianxu; GUO Qi; WANG Zhenxia; LIN Naimin

    2016-01-01

    A duplex treatment of plasma Zr-alloying and plasma nitriding was used to improve the tribological properties of Ti-6Al-4V. The microstructure of the Zr-N composite (alloyed) layer formed on Ti-6Al-4V and its hardness, friction and wear properties were investigated by using OM, SEM, GDOES, EDS, microhardness tester as well as ball-on-disk tribometer. The results of microstructural analysis show that the alloyed layer is compact and uniform and is mainly composed of ZrN, TiN0.3 and AlN. A very tiny adhesive and slight oxidation wear is the primary wear mechanism for the modiifed Ti-6Al-4V. The tribological property is improved signiifcantly after the duplex treatment. The good combination of antifriction and wear resistance for modiifed Ti-6Al-4V is mainly attributed to the higher surface hardness of metal nitrides formed on the surface and enhanced supporting of the Zr-diffusing layer.

  15. Surface hardening utilizing high-density plasma nitriding on stainless steel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lleonart-Davila, G; Gaudier, J; Rivera, R; Leal, D; Gonzalez-Lizardo, A; Leal-Quiros, E [Plasma Engineering Laboratory, Polytechnic University of Puerto Rico, San Juan, PR 00918 (Puerto Rico)

    2008-10-15

    By using a plasma nitriding procedure at the PUPR Mirror Cusp Plasma machine, surface hardness is increased in 302/304-type stainless steel samples by exposing them to high-ion-density plasma at high vacuum. This method successfully dopes the surface of the material with strengthening nitrogen ions, without the use of chemical procedures that sacrifice the resistance to corrosion of the given material. A 500 V negative bias is placed on the sample exposed to the nitrogen plasma, where high-energy ions are therefore attracted and immersed into the metallic matrix microns into the surface of the stainless steel. This potential maintains a constant surface temperature at approximately 800 deg. C. The plasma parameters including ion density and plasma temperature were diagnosed using single Langmuir probes. The stainless steel samples were then tested using scanning electron microscopy (SEM), and Vickers micro-hardness testing to determine the increment in the surface harness of the material. The SEM showed a significant presence of nitrogen imbedded in the grains of the stainless steel surface.

  16. Study of nanocrystallization in FINEMET alloy by active screen plasma nitriding

    Energy Technology Data Exchange (ETDEWEB)

    Shivaee, Hossein Asghari [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Hosseini, Hamid Reza Madaah, E-mail: madaah@sharif.ed [Department of Materials Science and Engineering, Sharif University of Technology, Azadi Ave., PO Box 11155-9466, Tehran, 1458889694 (Iran, Islamic Republic of); Lotfabad, Elmira Memarzadeh [Department of Materials Science and Engineering, Sharif University of Technology, Azadi Ave., PO Box 11155-9466, Tehran, 1458889694 (Iran, Islamic Republic of); Roostaie, Saied [Department of Materials Science and Engineering, Amir Kabir University of Technology, Tehran (Iran, Islamic Republic of)

    2010-02-18

    The nanocrystallization process of amorphous Fe{sub 73.5}Si{sub 13.5}B{sub 9}Nb{sub 3}Cu{sub 1} was investigated by active screen plasma nitriding (ASPN) treatment at temperatures ranging from 410 {sup o}C to 560 {sup o}C for 3 h in two gas mixtures of 75% N{sub 2}-25% H{sub 2} and 25% N{sub 2}-75% H{sub 2} at 5 mbar atmosphere. The amorphous ribbons were then annealed under vacuum at the same time and temperatures mentioned above. The structure of the samples was analyzed using various techniques such as X-ray diffraction (XRD), atomic force microscopy (AFM) and differential scanning calorimetry (DSC). Microhardness measurements, electrical resistivity and Vibrating Sample Magnetometer (VSM) were used to study mechanical, electrical and magnetic properties of the samples, respectively. It was observed that the ASPN treatment leads to finer grain size and higher crystalline volume fraction and modifies the structural features of Fe(Si) phase. The Fe(Si) lattice parameter for the nitrided samples decreased up to 520 {sup o}C, indicating that Si atoms form a solid solution in {alpha}-Fe and it was raised at 560 {sup o}C, due to Si ex-solution in the Fe(Si) phase and the formation of more nitrided phases. In ASPN treatment, the lowest magnitude of coercivity and the maximum saturated magnetization were obtained at 440 {sup o}C in 75% N{sub 2}-25% H{sub 2} and at 560 {sup o}C in 25% N{sub 2}-75% H{sub 2} gas mixtures, respectively. Our proposed method (ASPN treatment) increased the microhardness and electrical resistivity of the samples.

  17. Characterization of Sintered and Sintered/Plasma-Nitrided Fe-1.5% Mo Alloy by SEM, X-Ray Diffraction and Electrochemical Techniques

    Directory of Open Access Journals (Sweden)

    Alves Neto José de Pinho

    2002-01-01

    Full Text Available Electrochemical experiments together with SEM and X-Ray techniques were carried out in order to evaluate the corrosion resistance, to analyze the surface condition and to characterize the nitride layer of the sintered and sintered/plasma-nitrided Fe-1.5% Mo alloy in Mg(NO32 0.5mol.L-1 solution (pH 7.0. The sintered/plasma-nitrided samples presented a higher corrosion resistance, indicating that the surface treatment improved the electrochemical properties of the sintered material. In addition, the nitride layer formed at 500 °C showed better corrosion resistance that the layers formed at higher temperatures. This difference can be ascribed to the nitrogen content in the nitride layer, which at 500°C is higher due to the formation of a phase rich in nitrogen (epsilon phase while at higher temperatures a phase poor in nitrogen (gamma' phase is formed.

  18. Machining of titanium alloys

    CERN Document Server

    2014-01-01

    This book presents a collection of examples illustrating the resent research advances in the machining of titanium alloys. These materials have excellent strength and fracture toughness as well as low density and good corrosion resistance; however, machinability is still poor due to their low thermal conductivity and high chemical reactivity with cutting tool materials. This book presents solutions to enhance machinability in titanium-based alloys and serves as a useful reference to professionals and researchers in aerospace, automotive and biomedical fields.

  19. Microstructure and mechanical properties of multiphase layer formed during depositing Ti film followed by plasma nitriding on 2024 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, F.Y., E-mail: zfy19861010@163.com; Yan, M.F., E-mail: yanmufu@hit.edu.cn

    2014-05-01

    Highlights: • A novel duplex surface treatment on 2024 Al alloy was proposed. • A multiphase layer composed of TiN{sub 0.3}, Al{sub 3}Ti and Al{sub 18}Ti{sub 2}Mg{sub 3} was prepared on the surface of 2024 Al alloy. • The microstructures of TiN{sub 0.3}, Al{sub 3}Ti and Al{sub 18}Ti{sub 2}Mg{sub 3} were characterized by SEM and TEM. • The surface hardness of the multiphase layer reached to 590 HV{sub 0.01}, five times harder than 2024 Al alloy. • The wear resistance of 2024 Al alloy was improved significantly. - Abstract: In this study, a novel method was develop to fabricate an in situ multiphase layer on 2024 Al alloy to improve its surface mechanical properties. The method was divided into two steps, namely depositing pure Ti film on 2024 Al substrate by using magnetron sputtering, and plasma nitriding of Ti coated 2024 Al in a gas mixture comprising of 40% N{sub 2}–60% H{sub 2}. The microstructure and mechanical properties of the multiphase layer prepared at different nitriding time were investigated by using X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), microhardness tester and pin-on-disc tribometer. Results showed that multiphase layer with three sub-layers (i.e. the outmost TiN{sub 0.3} layer, the intermediate Al{sub 3}Ti layer and the inside Al{sub 18}Ti{sub 2}Mg{sub 3} layer) can be obtained. The thickness of the Al{sub 18}Ti{sub 2}Mg{sub 3} layer increased faster than TiN{sub 0.3} and Al{sub 3}Ti layer with increasing nitriding time. The hardness of the layer has reached about 593 HV, which is much higher than that of 2024 Al substrate. The wear rate of the coated samples decreased 53% for 4 h nitriding and 86% for 12 h nitriding, respectively, compared with that of the uncoated one. The analysis of worn surface indicated that the coated 2024 Al exhibited predominant abrasive wear, whereas the uncoated one showed severe adhesive wear.

  20. Effect of solute content on plasma nitriding behavior of Fe-Cr alloys; Fe-Cr gokin purazuma chikka kyodo ni oyobosu yoshitsu nodo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Weiyan; Okada, S. [Okayama Univ., Okayama (Japan). Graduate School; Takada, J. [Okayama Univ., Okayama (Japan). Faculty of Engineering; Kuwahara, H. [Research Inst. for Applied Science, Kyoto (Japan); Nishikawa, S.; Hama, T. [Kogi Ltd., Hyogo (Japan)

    1996-03-15

    It has been clarified by the present authors, based on the plasma nitriding of Fe-Cr alloys and Fe-Ti alloys carried out at the temperature under 550{degree}C hitherto, that an internal nitriding layer is formed due to the fine dispersion of the particles of Cr nitride and Ti nitride in {gamma}{prime} Fe4N layer on the specimen surface. In this study, the plasma nitriding of Fe-Cr alloys are carried out at 650{degree}C, and the effects of the solute (Cr) content on the structures, nitride and the thickness distribution are examined. The main results obtained therefrom are indicated hereafter. In accordance with the observation on the cross-sectional structure of the alloys, only the nitriding layer deduced as the dispersion and precipitation of the particles of Cr nitride from {alpha}-Fe of the mother phase is formed, while {gamma}{prime}-Fe4N layer, which is found at the temperature under 550{degree}C, is not formed. The nitride of Cr generated in the nitriding layer is CrN in all Fe-Cr alloys. The hardness in the nitriding layer is constant and increases with the increase of Cr content. 13 refs., 6 figs.

  1. Hardness evaluation, stoichiometry and grain size of titanium nitride films obtained with plasma nitriding on Ti-6Al-4V samples

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcellos, Marcos Antonio Zen; Lima, Saulo Cordeiro; Hinrichs, Ruth [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre (Brazil)

    2010-07-01

    Titanium nitride films were formed on the surface of Ti-6Al-4V discs by plasma nitriding (glow discharge) in different N{sub 2}:H{sub 2} atmospheres at several substrate temperatures. In this study the influence of the process parameters on dynamic micro-hardness were investigated. Grain sizes of the nitride films, determined with X Ray Diffraction, were related to the nitriding parameters. TiNx stoichiometry was determined with Nuclear Reaction Analysis and showed a correlation to substrate temperature during the nitriding process. Micro-hardness measurements were taken on the nitrided surfaces. Grain sizes increased for a particular gas composition of 60%N{sub 2}+40%H{sub 2} where hardness was lowest. (author)

  2. The effect of plasma nitriding and post oxidation on fretting wear behaviour of a high strength alloy steel

    Science.gov (United States)

    Prakash, N. Arun; Bennett, C. J.

    2017-05-01

    The fretting wear performance of the non-nitrided, nitrided and nitrided-post oxidized high strength alloy steel, W460 were investigated in the gross slip regime at ambient condition. Fretting wear tests were performed with an applied normal load of 250 and 650 N at a displacement amplitude of 100 μm using a cylinder-on-flat configuration. X-ray analysis (XRD) revealed the formation of the iron-nitrided Fe3N and Fe4N during plasma nitriding and iron oxide phases of hematite (Fe2O3) and magnetite (Fe3O4) during post-oxidation of the cylindrical steel samples. The steady state tangential force coefficient decreases when the nitrided and post-oxidized samples were fretted against the non-nitrided steel material when compared to the non-nitrided steel contact pair. The steady state tangential force coefficient decreased with an increase in applied normal load across all of the fretting conditions. The total dissipated energy and the total wear volume increased with an increase in applied normal load with total wear volume of the non-nitrided vs nitrided and non-nitrided vs nitrided post-oxidized sample pairs, showing a reduction in the wear volume of approximately 50% compared to the non-nitrided vs non-nitrided combination under the fretting conditions examined. The worn surface morphology of the fretted samples examined using a scanning electron microscope showed the presence of loose wear debris in the wear track, fragmented wear debris, delamination cracks, delamination with large discontinuities, plate-like wear debris, oxide patches and formation of large cavities.

  3. Titanium and titanium alloys fundamentals and applications

    CERN Document Server

    Peters, Manfred

    2003-01-01

    This handbook is an excellent reference for materials scientists and engineers needing to gain more knowledge about these engineering materials. Following introductory chapters on the fundamental materials properties of titanium, readers will find comprehensive descriptions of the development, processing and properties of modern titanium alloys. There then follows detailed discussion of the applications of titanium and its alloys in aerospace, medicine, energy and automotive technology.

  4. Plasma nitriding of steels

    CERN Document Server

    Aghajani, Hossein

    2017-01-01

    This book focuses on the effect of plasma nitriding on the properties of steels. Parameters of different grades of steels are considered, such as structural and constructional steels, stainless steels and tools steels. The reader will find within the text an introduction to nitriding treatment, the basis of plasma and its roll in nitriding. The authors also address the advantages and disadvantages of plasma nitriding in comparison with other nitriding methods. .

  5. High-temperature Titanium Alloys

    Directory of Open Access Journals (Sweden)

    A.K. Gogia

    2005-04-01

    Full Text Available The development of high-temperature titanium alloys has contributed significantly to the spectacular progress in thrust-to-weight ratio of the aero gas turbines. This paper presents anoverview on the development of high-temperature titanium alloys used in aero engines and potential futuristic materials based on titanium aluminides and composites. The role of alloychemistry, processing, and microstructure, in determining the mechanical properties of titanium alloys is discussed. While phase equilibria and microstructural stability consideration haverestricted the use of conventional titanium alloys up to about 600 "C, alloys based on TiPl (or,, E,AINb (0, TiAl (y, and titaniumltitanium aluminides-based composites offer a possibility ofquantum jump in the temperature capability of titanium alloys.

  6. Surface modification of titanium and titanium alloys by ion implantation.

    Science.gov (United States)

    Rautray, Tapash R; Narayanan, R; Kwon, Tae-Yub; Kim, Kyo-Han

    2010-05-01

    Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation.

  7. Analysis of plasma nitrided steels

    Science.gov (United States)

    Salik, J.; Ferrante, J.; Honecy, F.; Hoffman, R., Jr.

    1987-01-01

    The analysis of plasma nitrided steels can be divided to two main categories - structural and chemical. Structural analysis can provide information not only on the hardening mechanisms but also on the fundamental processes involved. Chemical analysis can be used to study the kinetics for the nitriding process and its mechanisms. In this paper preliminary results obtained by several techniques of both categories are presented and the applicability of those techniques to the analysis of plasma-nitrided steels is discussed.

  8. Nanodispersed boriding of titanium alloy

    Directory of Open Access Journals (Sweden)

    Kateryna O. Kostyk

    2015-12-01

    Full Text Available The problem of improving the operational reliability of machines is becoming increasingly important due to the increased mechanical, thermal and other loads on the details. There are many surface hardening methods for machines parts which breakdown begins with surface corruption. The most promising methods are chemo-thermal treatment. Aim: The aim of this work is to study the impact of boriding on the structure and properties of titanium alloy. Materials and Methods: The material of this study is VT3-1 titanium alloy. The boriding were conducted using nanodispersed powder blend based on boric substances. Results: It is established that boriding of paste compounds allows obtaining the surface hardness within 30...29 GPa and with declining to 27...26 GPa in layer to the transition zone (with total thickness up to 110 μm owing to changes of the layer phase composition where Ti2B, TiB, TiB2 titanium borides are formed. The increasing of chemical-thermal treatment time from 15 minutes to 2 hours leads to thickening of the borated layer (30...110 µm and transition zone (30...190 µm. Conclusions: Due to usage of nanodispersed boric powder, the boriding duration is decreasing in 2...3 times. This allows saving time and electric energy. The developed optimal mode of boriding the VT3-1 titanium alloy allows obtaining the required operational characteristics and to combine the saturation of the surface layer with atomic boron and hardening.

  9. Microstructural characterization of Ti-6Al-4V alloy subjected to the duplex SMAT/plasma nitriding.

    Science.gov (United States)

    Pi, Y; Faure, J; Agoda-Tandjawa, G; Andreazza, C; Potiron, S; Levesque, A; Demangel, C; Retraint, D; Benhayoune, H

    2013-09-01

    In this study, microstructural characterization of Ti-6Al-4V alloy, subjected to the duplex surface mechanical attrition treatment (SMAT)/nitriding treatment, leading to improve its mechanical properties, was carried out through novel and original samples preparation methods. Instead of acid etching which is limited for morphological characterization by scanning electron microscopy (SEM), an original ion polishing method was developed. Moreover, for structural characterization by transmission electron microscopy (TEM), an ion milling method based with the use of two ions guns was also carried out for cross-section preparation. To demonstrate the efficiency of the two developed methods, morphological investigations were done by traditional SEM and field emission gun SEM. This was followed by structural investigations through selected area electron diffraction (SAED) coupled with TEM and X-ray diffraction techniques. The results demonstrated that ionic polishing allowed to reveal a variation of the microstructure according to the surface treatment that could not be observed by acid etching preparation. TEM associated to SAED and X-ray diffraction provided information regarding the nanostructure compositional changes induced by the duplex SMAT/nitriding process. Copyright © 2013 Wiley Periodicals, Inc.

  10. Lightweight Protective Coatings For Titanium Alloys

    Science.gov (United States)

    Wiedemann, Karl E.; Taylor, Patrick J.; Clark, Ronald K.

    1992-01-01

    Lightweight coating developed to protect titanium and titanium aluminide alloys and titanium-matrix composite materials from attack by environment when used at high temperatures. Applied by sol-gel methods, and thickness less than 5 micrometers. Reaction-barrier and self-healing diffusion-barrier layers combine to protect titanium alloy against chemical attack by oxygen and nitrogen at high temperatures with very promising results. Can be extended to protection of other environmentally sensitive materials.

  11. Examination of Plasma Nitriding Microstructure with Addition of Rare Earths

    Institute of Scientific and Technical Information of China (English)

    张津

    2004-01-01

    Medium-carbon alloy steel was plasma nitrided with rare earths La,Ce and Nd into the nitriding chamber respectively.The nitriding layer microstructures with and without rare earths were compared using optical microscope,normal SEM and high resolution SEM,as well as TEM.It was found that the extent of the influence on plasma nitriding varies with different contents of rare earth.The effect of plasma nitriding is benefit from adding of Ce or Nd.The formation of hard and brittle phase Fe2-3N can be prevented and the butterfly-like structure can be improved by adding Ce or Nd.However,pure La may prevent the diffusion of nitrogen and the formation of iron nitride,and reduce the depth of diffusion layer.

  12. Titanium alloys Russian aircraft and aerospace applications

    CERN Document Server

    Moiseyev, Valentin N

    2005-01-01

    This text offers previously elusive information on state-of-the-art Russian metallurgic technology of titanium alloys. It details their physical, mechanical, and technological properties, as well as treatments and applications in various branches of modern industry, particularly aircraft and aerospace construction. Titanium Alloys: Russian Aircraft and Aerospace Applications addresses all facets of titanium alloys in aerospace and aviation technology, including specific applications, fundamentals, composition, and properties of commercial alloys. It is useful for all students and researchers interested in the investigation and applications of titanium.

  13. [Use of titanium alloys for medical instruments].

    Science.gov (United States)

    Feofilov, R N; Chirkov, V K; Levin, M V

    1977-01-01

    On the ground of an analysis into properties of titanium and its alloys the fields of their possible utilization for making various medical instruments are proposed. Because of their insufficient hardness and wear-resistance the titanium alloys cannot be recommended for making medical instruments with thin cutting edges. For the reasons of their insufficient strength, low wear-resistance and substandard modulus of elasticity, it is inexpedient to use titanium alloys in making many types of clamping medical instruments. Nor is it advisable to employ titanium alloys in handles of the instruments, for this may lead to a contact corrosion of their working parts. The use of titanium alloys is recommended for making bone-joining members, retracting medical instruments, of the spatula and speculum types, some kinds of non-magnetic pincers and ultrasonic medical instruments.

  14. Stress-corrosion cracking of titanium alloys.

    Science.gov (United States)

    Blackburn, M. J.; Feeney, J. A.; Beck, T. R.

    1973-01-01

    In the light of research material published up to May 1970, the current understanding of the experimental variables involved in the stress-corrosion cracking (SCC) behavior of titanium and its alloys is reviewed. Following a brief summary of the metallurgy and electrochemistry of titanium alloys, the mechanical, electrochemical, and metallurgical parameters influencing SCC behavior are explored with emphasis on crack growth kinetics. Macro- and microfeatures of fractures are examined, and it is shown that many transgranular SCC failures exhibit morphological and crystallographic features similar to mechanical cleavage failures. Current SCC models are reviewed with respect to their ability to explain the observed SCC behavior of titanium and its alloys. Possible methods for eliminating or minimizing stress corrosion hazards in titanium or titanium alloy components are described.

  15. Stress corrosion cracking of titanium alloys

    Science.gov (United States)

    Statler, G. R.; Spretnak, J. W.; Beck, F. H.; Fontana, M. G.

    1974-01-01

    The effect of hydrogen on the properties of metals, including titanium and its alloys, was investigated. The basic theories of stress corrosion of titanium alloys are reviewed along with the literature concerned with the effect of absorbed hydrogen on the mechanical properties of metals. Finally, the basic modes of metal fracture and their importance to this study is considered. The experimental work was designed to determine the effects of hydrogen concentration on the critical strain at which plastic instability along pure shear directions occurs. The materials used were titanium alloys Ti-8Al-lMo-lV and Ti-5Al-2.5Sn.

  16. Current assisted superplastic forming of titanium alloy

    Directory of Open Access Journals (Sweden)

    Wang Guofeng

    2015-01-01

    Full Text Available Current assisted superplastic forming combines electric heating technology and superplastic forming technology, and can overcome some shortcomings of traditional superplastic forming effectively, such as slow heating rate, large energy loss, low production efficiency, etc. Since formability of titanium alloy at room temperature is poor, current assisted superplastic forming is suitable for titanium alloy. This paper mainly introduces the application of current assisted superplastic forming in the field of titanium alloy, including forming technology of double-hemisphere structure and bellows.

  17. Effect of PostNitride Annealing on Wear and Corrosion Behavior of Titanium Alloy Ti-6Al-4V

    Science.gov (United States)

    Anandan, C.; Mohan, L.

    2016-10-01

    Titanium alloy, Ti-6Al-4V, was plasma nitrided using RF plasma with 100% N at 800 °C and annealed at 850 °C in vacuum. XRD and XPS studies show the formation of titanium nitrides after nitriding and redistribution of nitrogen after annealing. Potentiodynamic polarization and electrochemical impedance spectroscopy studies in Hank's solution show that nitriding decreases the corrosion resistance of the substrate and postnitride annealing improves the corrosion resistance of the nitrided samples. After nitriding, wear rate has decreased by an order of magnitude in reciprocating wear experiments and decreased further in annealed samples in comparison with that of substrate. Thus, postnitride annealing improves both corrosion and wear resistance of the nitrided sample. These improvements are attributed to redistribution of nitrogen and formation of a thin oxide layer on the sample due to annealing.

  18. Solid metal induced embrittlement of titanium alloys

    OpenAIRE

    Åkerfeldt, Pia

    2012-01-01

    Titanium alloys were for a time believed to be highly resistant to environmentally assisted cracking because of their ability to form a protective oxide film on the surface. Their resistance can still be considered to be high, but when cracking resistance was originally defined to ensure reliable functionality of fracture-critical components, certain conditions that promote cracking were discovered. One of the environmental assisted cracking processes relevant to titanium alloys is solid meta...

  19. Interfacial oxidations of pure titanium and titanium alloys with investments.

    Science.gov (United States)

    Ban, S; Watanabe, T; Mizutani, N; Fukui, H; Hasegawa, J; Nakamura, H

    2000-12-01

    External oxides of a commercially pure titanium (cpTi), Ti6Al4V alloy, and an experimental beta-type titanium alloy (Ti 53.4 wt%, Nb 29 wt%, Ta 13 wt%, and Zr 4.6 wt%) were characterized after heating to 600, 900, 1150, and 1400 degrees C in contact with three types of investments (alumina cement, magnesia cement, and phosphate-bonded) in air. XRD studies demonstrated that MgO, Li2TiO3 and/or Li2Ti3O7 were formed through reactions with the metal and the constituents in the magnesia cement-investment after heating to 900, 1150, and 1400 degrees C. Except for these conditions, TiO2 (rutile) was only formed on cpTi. For titanium alloys, the other components apart from Ti also formed simple and complex oxides such as Al2O3 and Al2TiO5 on Ti6Al4V, and Zr0.25Ti0.75Nb2O7 on the beta-type titanium alloy. However, no oxides containing V or Ta were formed. These results suggest that the constituents of titanium alloys reacted with the investment oxides and atmospheric oxygen to form external oxides due to the free energy of oxide formation and the concentration of each element on the metal surface.

  20. Initial cytotoxicity of novel titanium alloys.

    Science.gov (United States)

    Koike, M; Lockwood, P E; Wataha, J C; Okabe, T

    2007-11-01

    We assessed the biological response to several novel titanium alloys that have promising physical properties for biomedical applications. Four commercial titanium alloys [Super-TIX(R) 800, Super-TIX(R) 51AF, TIMETAL(R) 21SRx, and Ti-6Al-4V (ASTM grade 5)] and three experimental titanium alloys [Ti-13Cr-3Cu, Ti-1.5Si and Ti-1.5Si-5Cu] were tested. Specimens (n = 6; 5.0 x 5.0 x 3.0 mm(3)) were cast in a centrifugal casting machine using a MgO-based investment and polished to 600 grit, removing 250 mum from each surface. Commercially pure titanium (CP Ti: ASTM grade 2) and Teflon (polytetrafluoroethylene) were used as positive controls. The specimens were cleaned and disinfected, and then each cleaned specimen was placed in direct contact with Balb/c 3T3 fibroblasts for 72 h. The cytotoxicity [succinic dehydrogenase (SDH) activity] of the extracts was assessed using the MTT method. Cytotoxicity of the metals tested was not statistically different compared to the CP Ti and Teflon controls (p > 0.05). These novel titanium alloys pose cytotoxic risks no greater than many other commonly used alloys, including commercially pure titanium. The promising short-term biocompatibility of these Ti alloys is probably due to their excellent corrosion resistance under static conditions, even in biological environments.

  1. Double Glow Plasma Surface Alloyed Burn-resistant Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping-ze; XU Zhong; HE Zhi-yong; ZHANG Gao-hui

    2004-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, we have developed a new kind of burn-resistant titanium alloy-double glow plasma surface alloying burn-resistant titanium alloy. Alloying element Cr, Mo, Cu are induced into the Ti-6Al-4V and Ti-6.5Al-0.3Mo-l.5Zr-0.25Si substrates according to double glow discharge phenomenon, Ti-Cr ,Ti-Mo, Ti-Cu binary burn-resistant alloy layers are formed on the surface of Ti-6Al-4V and Ti-6.5Al-0.3Mo-l.5Zr-0.25Si alloys. The depth of the surface burn-resistant alloy layer can reach to above 200 microns and alloying element concentration can reach 90%.Burn-resistant property experiments reveal that if Cr concentration reach to 14%, Cu concentration reach to 12%, Mo concentration reach to 10% in the alloying layers, ignition and burn of titanium alloy can be effectively avoided.

  2. Double Glow Plasma Surface Alloyed Burn-resistant Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANGPing-ze; XUZhong; HEZhi-yong; ZHANGGao-hui

    2004-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, we have developed a new kind of burn-resistant titanium alloy-double glow plasma surface alloying burn-resistant titanium alloy. Alloying element Cr, Mo, Cu are induced into the Ti-6A1-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si substrates according to double glow discharge phenomenon, Ti-Cr ,Ti-Mo, Ti-Cu binary burn-resistant alloy layers are formed on the surface of Ti-6A1-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si alloys. The depth of the surface burn-resistant alloy layer can reach to above 200 microns and alloying element concentration can reach 90%. Burn-resistant property experiments reveal that if Cr concentration reach to 14%, Cu concentration reach to 12%, Mo concentration reach to 10% in the alloying layers, ignition and burn of titanium alloy can be effectively avoided.

  3. Oxidation resistant coating for titanium alloys and titanium alloy matrix composites

    Science.gov (United States)

    Brindley, William J. (Inventor); Smialek, James L. (Inventor); Rouge, Carl J. (Inventor)

    1992-01-01

    An oxidation resistant coating for titanium alloys and titanium alloy matrix composites comprises an MCrAlX material. M is a metal selected from nickel, cobalt, and iron. X is an active element selected from Y, Yb, Zr, and Hf.

  4. Biocorrosion study of titanium-nickel alloys.

    Science.gov (United States)

    Chern Lin, J H; Lo, S J; Ju, C P

    1996-02-01

    The present study provides results of the corrosion behaviour in Hank's physiological solution and some other properties of three Ti-Ni alloys with 18, 25 and 28.4 wt% Ni, respectively. Results indicate that alpha-titanium and Ti2Ni were the two major phases in all three Ti-Ni alloys. The relative amount of the Ti2Ni phase increased with additional Ni content. Hardness of the Ti-Ni alloys also increased with added nickel content, ranging from 310 to 390 VHN, similar to the hardness of enamel. Melting temperatures of the Ti-Ni alloys were all lower than that of pure titanium by least 600 degrees C. The three Ti-Ni alloys behaved almost identically when potentiodynamically polarized in Hank's solution at 37 degrees C. The critical anodic current densities of the alloys were nearly 30 microA/cm2 and the breakdown potentials were all above 1100 mV (SCE).

  5. ZIRCONIUM-TITANIUM-BERYLLIUM BRAZING ALLOY

    Science.gov (United States)

    Gilliland, R.G.; Patriarca, P.; Slaughter, G.M.; Williams, L.C.

    1962-06-12

    A new and improved ternary alloy is described which is of particular utility in braze-bonding parts made of a refractory metal selected from Group IV, V, and VI of the periodic table and alloys containing said metal as a predominating alloying ingredient. The brazing alloy contains, by weight, 40 to 50 per cent zirconium, 40 to 50 per cent titanium, and the balance beryllium in amounts ranging from 1 to 20 per cent, said alloy having a melting point in the range 950 to 1400 deg C. (AEC)

  6. Advances of Titanium Alloys and Its Biological Surface Modification

    Institute of Scientific and Technical Information of China (English)

    XU Ke-wei; HUANG Ping

    2004-01-01

    This paper reviews the past, present and future of surface modification of titanium alloy from the point of view of preparation of hard tissue replacement implants. The development of titanium alloy is also described.

  7. The Progress on Laser Surface Modification Techniques of Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    LIANG Cheng; PAN Lin; Al Ding-fei; TAO Xi-qi; XIA Chun-huai; SONG Yan

    2004-01-01

    Titanium alloy is widely used in aviation, national defence, automobile, medicine and other fields because of their advantages in lower density, corrosion resistance, and fatigue resistance etc. As titanium alloy is higher friction coefficients, weak wear resistance, bad high temperature oxidation resistance and lower biocompatibility, its applications are restricted. Using laser surface modification techniques can significantly improve the surface properties of titanium alloy. a review is given for progress on laser surface modification techniques of titanium alloy in this paper.

  8. Development and application of titanium alloy casting technology in China

    Institute of Scientific and Technical Information of China (English)

    NAN Hai; XIE Cheng-mu; ZHAO Jia-qi

    2005-01-01

    The development and research of titanium cast alloy and its casting technology, especially its application inaeronautical industry in China are presented. The technology of molding, melting and casting of titanium alloy, casting quality control are introduced. The existing problems and development trend in titanium alloy casting technology are also discussed.

  9. Biocorrosion study of titanium-cobalt alloys.

    Science.gov (United States)

    Chern Lin, J H; Lo, S J; Ju, C P

    1995-05-01

    The present work provides experimental results of corrosion behaviour in Hank's physiological solution and some other properties of in-house fabricated titanium-cobalt alloys with cobalt ranging from 25-30% in weight. X-ray diffraction (XRD) shows that, in water-quenched (WQ) alloys, beta-titanium is largely retained, whereas in furnace-cooled (FC) alloys, little beta-titanium is found. Hardness of the alloys increases with increasing cobalt content, ranging from 455 VHN for WQ Ti-25 wt% Co to 525 VHN for WQ Ti-30 wt% Co. Differential thermal analysis (DTA) indicates that melting temperatures of the alloys are lower than that of pure titanium by about 600 degrees C. Potentiodynamic polarization results show that all measured break-down potentials in Hank's solution at 37 degrees C are higher than 800 mV. The breakdown potential for the FC Ti-25 Wt% Co alloy is even as high as nearly 1200 mV.

  10. Current research situation of titanium alloys in China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Titanium and its alloys possess excellent comprehensive properties, and they are widely used in many fields. China pays great attentions to the research on new titanium alloys. This paper mainly reviews the research on new Ti alloys in China, for example, high strength and high toughness Ti alloys, burn resistant Tialloys, high temperature Ti alloys, low cost Ti alloys and so on.New basic theories on Ti alloys developed in China in recent years are also reviewed.

  11. Rapidly solidified titanium alloys by melt overflow

    Science.gov (United States)

    Gaspar, Thomas A.; Bruce, Thomas J., Jr.; Hackman, Lloyd E.; Brasmer, Susan E.; Dantzig, Jonathan A.; Baeslack, William A., III

    1989-01-01

    A pilot plant scale furnace was designed and constructed for casting titanium alloy strips. The furnace combines plasma arc skull melting techniques with melt overflow rapid solidification technology. A mathematical model of the melting and casting process was developed. The furnace cast strip of a suitable length and width for use with honeycomb structures. Titanium alloys Ti-6Al-4V and Ti-14Al-21 Nb were successfully cast into strips. The strips were evaluated by optical metallography, microhardness measurements, chemical analysis, and cold rolling.

  12. Effect of whitening toothpaste on titanium and titanium alloy surfaces.

    Science.gov (United States)

    Faria, Adriana Cláudia Lapria; Bordin, Angelo Rafael de Vito; Pedrazzi, Vinícius; Rodrigues, Renata Cristina Silveira; Ribeiro, Ricardo Faria

    2012-01-01

    Dental implants have increased the use of titanium and titanium alloys in prosthetic applications. Whitening toothpastes with peroxides are available for patients with high aesthetic requirements, but the effect of whitening toothpastes on titanium surfaces is not yet known, although titanium is prone to fluoride ion attack. Thus, the aim of the present study was to compare Ti-5Ta alloy to cp Ti after toothbrushing with whitening and conventional toothpastes. Ti-5Ta (%wt) alloy was melted in an arc melting furnace and compared with cp Ti. Disks and toothbrush heads were embedded in PVC rings to be mounted onto a toothbrushing test apparatus. A total of 260,000 cycles were carried out at 250 cycles/minute under a load of 5 N on samples immersed in toothpaste slurries. Surface roughness and Vickers microhardness were evaluated before and after toothbrushing. One sample of each material/toothpaste was analyzed by Scanning Electron Microscopy (SEM) and compared with a sample that had not been submitted to toothbrushing. Surface roughness increased significantly after toothbrushing, but no differences were noted after toothbrushing with different toothpastes. Toothbrushing did not significantly affect sample microhardness. The results suggest that toothpastes that contain and those that do not contain peroxides in their composition have different effects on cp Ti and Ti-5Ta surfaces. Although no significant difference was noted in the microhardness and roughness of the surfaces brushed with different toothpastes, both toothpastes increased roughness after toothbrushing.

  13. Cell response of anodized nanotubes on titanium and titanium alloys.

    Science.gov (United States)

    Minagar, Sepideh; Wang, James; Berndt, Christopher C; Ivanova, Elena P; Wen, Cuie

    2013-09-01

    Titanium and titanium alloy implants that have been demonstrated to be more biocompatible than other metallic implant materials, such as Co-Cr alloys and stainless steels, must also be accepted by bone cells, bonding with and growing on them to prevent loosening. Highly ordered nanoporous arrays of titanium dioxide that form on titanium surface by anodic oxidation are receiving increasing research interest due to their effectiveness in promoting osseointegration. The response of bone cells to implant materials depends on the topography, physicochemistry, mechanics, and electronics of the implant surface and this influences cell behavior, such as adhesion, proliferation, shape, migration, survival, and differentiation; for example the existing anions on the surface of a titanium implant make it negative and this affects the interaction with negative fibronectin (FN). Although optimal nanosize of reproducible titania nanotubes has not been reported due to different protocols used in studies, cell response was more sensitive to titania nanotubes with nanometer diameter and interspace. By annealing, amorphous TiO2 nanotubes change to a crystalline form and become more hydrophilic, resulting in an encouraging effect on cell behavior. The crystalline size and thickness of the bone-like apatite that forms on the titania nanotubes after implantation are also affected by the diameter and shape. This review describes how changes in nanotube morphologies, such as the tube diameter, the thickness of the nanotube layer, and the crystalline structure, influence the response of cells.

  14. On Silicides in High Temperature Titanium Alloys

    Directory of Open Access Journals (Sweden)

    C. Ramachandra

    1986-04-01

    Full Text Available High temperature titanium alloys like IMI 685 contain small amounts of silicon (~ 0.25 wt. per cent to improve creep resistance. Different types of silicides, namely Ti5Si3 (TiZr5Si3(S1 and (TiZr6 Si3 (S2, have been observed to precipitate in various silicon-bearing titanium alloys depending upon their composition and heat treatment. The precipitation of silicides, their orientation relationship with the matrix in different alloys, and the beneficial influence of thermo-mechanical treatment on the distribution of silicides have been pointed out. The effect of silicides on mechanical properties and fracture of the commercial alloy IMI 685 is also indicated.

  15. Study of the Active Screen Plasma Nitriding

    Institute of Scientific and Technical Information of China (English)

    Zhao Cheng; C. X. Li; H. Dong; T. Bell

    2004-01-01

    Active screen plasma nitriding (ASPN) is a novel nitriding process, which overcomes many of the practical problems associated with the conventional DC plasma nitriding (DCPN). Experimental results showed that the metallurgical characteristics and hardening effect of 722M24 steel nitrided by ASPN at both floating potential and anodic (zero) potential were similar to those nitrided by DCPN. XRD and high-resolution SEM analysis indicated that iron nitride particles with sizes in sub-micron scale were deposited on the specimen surface in AS plasma nitriding. These indicate that the neutral iron nitride particles, which are sputtered from the active screen and transferred through plasma to specimen surface, are considered to be the dominant nitrogen carder in ASPN. The OES results show that NH could not be a critical species in plasma nitriding.

  16. Analysis of plasma-nitrided steels

    Science.gov (United States)

    Salik, J.; Ferrante, J.; Honecy, F.; Hoffman, R., Jr.

    1986-01-01

    The analysis of plasma nitrided steels can be divided to two main categories - structural and chemical. Structural analysis can provide information not only on the hardening mechanisms but also on the fundamental processes involved. Chemical analysis can be used to study the kinetics for the nitriding process and its mechanisms. In this paper preliminary results obtained by several techniques of both categories are presented and the applicability of those techniques to the analysis of plasma-nitrided steels is discussed.

  17. [Study on biocompatibility of titanium alloys].

    Science.gov (United States)

    Kodama, T

    1989-06-01

    The biocompatibility of two different titanium alloys, Ti-6Al-4V ELI and Ti-5Al-2, 5Fe, and pure titanium were evaluated. The results were as follows: 1) Titanium alloys were implanted into the dorsal subcutaneous tissues of the Hartley guinea-pig for 12 weeks, immersed in calf serum or in Ringer's solution for 8 weeks. The surface changes of the titanium alloys were observed by SEM and the chemical composition was analyzed by XMA. No evident surface changes were found. 2) Three hundred mg, 200 mg and 100 mg of the powders of the tested materials were immersed in 2ml of Eagle's MEM, incubated for 1-7 days, 8-21 days and 22-70 days at 37 C degrees. The amount of metallic elements dissolved in the solutions was measured by ICP and AAS. The detected corrosion rates of V and Al contained in the solution, in which Ti-6Al-4V ELI 100 mg was immersed for 1-7 days, were 194.3 +/- 17.6 and 73.0 +/- 28, 1 pg/mg alloy/day, respectively. V was released more than Al. The amount of Ti was below the detectable limit. The solution Ti-5Al-2.5 Fe 100 mg immersed for 1-7 days contained 31.9 +/- 34.4 pg/mg alloy/day Fe and 25.7 +/- 6.3 pg/mg alloy/day Al. Only in the solution 300 mg immersed for 1-7 days was Ti detected at 1.4 pg/mg alloy/day. 3) By the bacterial mutation assay of Salmonella typhimurium TA 98, Salmonella typhimurium TA 100 and Escherichia coli WP2 uvrA, the solutions, in which the tested materials were immersed, were not found to be mutagenic. 4) By the UDS assay, the grain counts on autoradiography with the solutions, in which the tested materials were immersed, were not greater than the negative control. The results suggest an excellent corrosion resistance of the titanium alloys. Mutagenicity was negative by these mutation assays, indicating that the tested alloys and pure titanium are safe for humans and animals.

  18. Advanced Surface Engineering of Titanium Alloys

    Institute of Scientific and Technical Information of China (English)

    H. Dong

    2000-01-01

    Despite their outstanding combination of properties, titanium and its alloys are very susceptible to severe adhesive wear in rubbing with most engineering surfaces and can exhibit poorcorrosion resistance in some aggressive environments. Surface engineering research centred at the University of Birmingham has been focused on creating designer surfaces for titanium components via surface engineering.Great progress has been made recently through the development of such advanced surface engineering techniques as thermal oxidation, palladium-treated thermal oxidation, oxygen boost diffusion and duplex systems.Such advances thus provide scope for designing titanium components for a diversified range of engineering application, usually as direct replacements for steel components. By way of example, some of the successful steps towards titanium designer surfaces are demonstrated. To data, the potential of these advanced technologies has been realised first in auto-sport and off-shore industrials.

  19. Microstructure and Slip Character in Titanium Alloys

    Directory of Open Access Journals (Sweden)

    D. Banerjee

    1986-04-01

    Full Text Available Influence of microstructures in titanium alloys on the basic parameters of deformation behaviour such as slip character, slip length and slip intensity have been explored. Commercial titanium alloys contain the hexagonal close packed (alpha and body centred cubic (bita phases. Slip in these individual phases is shown to be dependent on the nature of alloying elements through their effect on phase stability as related to decomposition into ordered or w structures. When alpha and bita coexist, their relative crystallographic orientations, size, shape and volume fraction, control the nature of slip. For a given composition, structure may be manipulated through appropriate thermomechanical treatment to obtain the desired deformation behaviour and therefore fracture mode.

  20. Fatigue - corrosion of endoprosthesis titanium alloys.

    Science.gov (United States)

    Cornet, A; Muster, D; Jaeger, J H

    1979-01-01

    Commercial total hip prostheses often show certain metallurgical faults (porosities, coarse grains, growth dendrites, carbide networks). In order to investigate more accurately the role played by these different parameters in prostheses failure we performed a large number of systematic corrosion, fatigue and fatigue - corrosion tests on these materials and on commercial total hip prostheses. Ultimate strengthes seem to be reached for cast cobalt alloys, whereas titanium alloys, such as Ta 6 V, present very high fatigue limit under corrosion. Thus, rotative bending fatigue - corrosion tests in biological environment provide values about 50 DaN/mm2. This value, is nevertheless appreciably higher than those obtained with stellites and stainless steel. Titanium alloys, because of their mechanical performances, their weak Young's modulus (11000 DaN/mm2) and their relative lightness (4.5. g/cm3), which are associated with a good biocompatibility, seem very promising for permanent implants realisation.

  1. Preparation of titanium/aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jecker, G.

    1984-03-20

    Alloys comprising titanium and aluminum, or titanium, aluminum and at least one of the metals M, wherein M is vanadium, zirconium, chromium, niobium, tantalum and/or iron, are facilely prepared by reducing an alkali metal fluotitanate, or coreducing admixture of an alkali metal fluotitanate and at least one halide of a metal M, with aluminum, in the presence of an alkali metal oxide reactive flux, either Na/sub 2/O and/or K/sub 2/O; next solubilizing with water the fluorine compounds of reduction/coreduction which are in admixture of reduction/coreduction with dispersion of the aforesaid metals in metallic state; separating said dispersion of metals in metallic state from said admixture of reduction/coreduction; and then alloying by melting and cooling said separated dispersion of metals in metallic state.

  2. Dry face milling of titanium alloys

    Institute of Scientific and Technical Information of China (English)

    Ahmed Hassan; Zhenqiang Yao

    2004-01-01

    In machining titanium alloys, cutting tools generally wear out very rapidly because of the high cutting temperature resulted from the low thermal conductivity and density of the work material. In order to increase the tool life, it is necessary to suppress the cutting heat as much as possible by applying an abundant amount of coolant, but this will entail serious techno-environmental and biological problems. To study the performance and avoid these limitations, a PVD-coated insert was used to the dry face mill of (α +β) titanium alloys. As a result it was found that the inserts exhibit an excellent cutting performance at low cutting speeds and feed rates, and there is no significant difference in the dominant insert failure mode between the wet and dry cutting in discontinuous cutting.

  3. Bioactive borate glass coatings for titanium alloys.

    Science.gov (United States)

    Peddi, Laxmikanth; Brow, Richard K; Brown, Roger F

    2008-09-01

    Bioactive borate glass coatings have been developed for titanium and titanium alloys. Glasses from the Na(2)O-CaO-B(2)O(3) system, modified by additions of SiO(2), Al(2)O(3), and P(2)O(5), were characterized and compositions with thermal expansion matches to titanium were identified. Infrared and X-ray diffraction analyses indicate that a hydroxyapatite surface layer forms on the borate glasses after exposure to a simulated body fluid for 2 weeks at 37 degrees C; similar layers form on 45S5 Bioglass((R)) exposed to the same conditions. Assays with MC3T3-E1 pre-osteoblastic cells show the borate glasses exhibit in vitro biocompatibility similar to that of the 45S5 Bioglass((R)). An enameling technique was developed to form adherent borate glass coatings on Ti6Al4V alloy, with adhesive strengths of 36 +/- 2 MPa on polished substrates. The results show these new borate glasses to be promising candidates for forming bioactive coatings on titanium substrates.

  4. Corrosion wear fracture of new {beta} biomedical titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Niinomi, M.; Fukunaga, K.-I. [Toyohashi Univ. of Technol. (Japan). Dept. of Production Syst. Eng.; Kuroda, D.; Morinaga, M.; Kato, Y.; Yashiro, T.; Suzuki, A.

    1999-05-15

    Metallic materials such as stainless steel, Co-Cr alloy, pure titanium and titanium alloys have been used for surgical implant materials. The {alpha} + {beta} type titanium alloy such as Ti-6Al-4V ELI has been most widely used as an implant material for artificial hip joint and dental implant because of its high strength and excellent corrosion resistance. Toxicity of alloying elements in conventional biomedical titanium alloys like Al and V, and the high modulus of elasticity of these alloy as compared to that of bone have been, however, pointed out [1,2]. New {beta} type titanium alloys composed of non-toxic elements like Nb, Ta, Zr, Mo and Sn with lower moduli of elasticity, greater strength and greater corrosion resistance were, therefore, designed in this study. The friction wear properties of titanium alloys are, however, low as compared to those of other conventional metallic implant materials such as stainless steels and Co-Cr alloy. Tensile tests and friction wear tests in Ringer`s solution were conducted in order to investigate the mechanical properties of designed alloys. The friction wear characteristics of designed alloys and typical conventional biomedical titanium alloys were evaluated using a pin-on-disk type friction wear testing system and measuring the weight loss and width of groove of the specimen. (orig.) 8 refs.

  5. A sourcebook of titanium alloy superconductivity

    CERN Document Server

    Collings, E W

    1983-01-01

    In less than two decades the concept of supercon­ In every field of science there are one or two ductivity has been transformed from a laboratory individuals whose dedication, combined with an innate curiosity to usable large-scale applications. In the understanding, permits them to be able to grasp, late 1960's the concept of filamentary stabilization condense, and explain to the rest of us what that released the usefulness of zero resistance into the field is all about. For the field of titanium alloy marketplace, and the economic forces that drive tech­ superconductivity, such an individual is Ted Collings. nology soon focused on niobium-titanium alloys. They His background as a metallurgist has perhaps given him are ductile and thus fabricable into practical super­ a distinct advantage in understanding superconduc­ conducting wires that have the critical currents and tivity in titanium alloys because the optimization of fields necessary for large-scale devices. More than superconducting parameters in ...

  6. Characterization of plasma nitrided layers produced on sintered iron

    Directory of Open Access Journals (Sweden)

    Marcos Alves Fontes

    2014-07-01

    Full Text Available Plasma nitriding is a thermo-physical-chemical treatment process, which promotes surface hardening, caused by interstitial diffusion of atomic nitrogen into metallic alloys. In this work, this process was employed in the surface modification of a sintered ferrous alloy. Scanning electron microscopy (SEM, X-ray diffraction (XRD analyses, and wear and microhardness tests were performed on the samples submitted to ferrox treatment and plasma nitriding carried out under different conditions of time and temperature. The results showed that the nitride layer thickness is higher for all nitrided samples than for ferrox treated samples, and this layer thickness increases with nitriding time and temperature, and temperature is a more significant variable. The XRD analysis showed that the nitrided layer, for all samples, near the surface consists in a mixture of γ′-Fe4N and ɛ-Fe3N phases. Both wear resistance and microhardness increase with nitriding time and temperature, and temperature influences both the characteristics the most.

  7. Selection of crucible oxides in molten titanium and titanium aluminum alloys by thermo-chemistry calculations

    Directory of Open Access Journals (Sweden)

    Kostov A.

    2005-01-01

    Full Text Available Titanium and its alloys interstitially dissolve a large amount of impurities such as oxygen and nitrogen, which degrade the mechanical and physical properties of alloys. On the other hand crucible oxides based on CaO, ZrO2 Y2O3, etc., and their spinels (combination of two or more oxides can be used for melting titanium and its alloys. However, the thermodynamic behavior of calcium, zirconium, yttrium on the one side, and oxygen on the other side, in molten Ti and Ti-Al alloys have not been made clear and because of that, it is very interesting for research. Owing of literature data, as well as these crucibles are cheaper than standard crucibles for melting titanium and titanium alloys, in this paper will be presented the results of selection of thermo-chemistry analysis with the aim to determine the crucible oxide stability in contact with molten titanium and titanium-aluminum alloys.

  8. Nickel-titanium alloys: a systematic review

    Directory of Open Access Journals (Sweden)

    Marcelo do Amaral Ferreira

    2012-06-01

    Full Text Available OBJECTIVE: A systematic review on nickel-titanium wires was performed. The strategy was focused on Entrez-PubMed-OLDMEDLINE, Scopus and BioMed Central from 1963 to 2008. METHODS: Papers in English and French describing the behavior of these wires and laboratorial methods to identify crystalline transformation were considered. A total of 29 papers were selected. RESULTS: Nickel-titanium wires show exceptional features in terms of elasticity and shape memory effects. However, clinical applications request a deeper knowledge of these properties in order to allow the professional to use them in a rational manner. In addition, the necessary information regarding each alloy often does not correspond to the information given by the manufacturer. Many alloys called "superelastic" do not present this effect; they just behave as less stiff alloys, with a larger springback if compared to the stainless steel wires. CONCLUSIONS: Laboratory tests are the only means to observe the real behavior of these materials, including temperature transition range (TTR and applied tensions. However, it is also possible to determine in which TTR these alloys change the crystalline structure.

  9. Hydrogen content in titanium and a titanium-zirconium alloy after acid etching.

    Science.gov (United States)

    Frank, Matthias J; Walter, Martin S; Lyngstadaas, S Petter; Wintermantel, Erich; Haugen, Håvard J

    2013-04-01

    Dental implant alloys made from titanium and zirconium are known for their high mechanical strength, fracture toughness and corrosion resistance in comparison with commercially pure titanium. The aim of the study was to investigate possible differences in the surface chemistry and/or surface topography of titanium and titanium-zirconium surfaces after sand blasting and acid etching. The two surfaces were compared by X-ray photoelectron spectroscopy, secondary ion mass spectroscopy, scanning electron microscopy and profilometry. The 1.9 times greater surface hydrogen concentration of titanium zirconium compared to titanium was found to be the major difference between the two materials. Zirconium appeared to enhance hydride formation on titanium alloys when etched in acid. Surface topography revealed significant differences on the micro and nanoscale. Surface roughness was increased significantly (pzirconium alloy. High-resolution images showed nanostructures only present on titanium zirconium.

  10. Hydrogen behavior in titanium aluminide alloys

    Institute of Scientific and Technical Information of China (English)

    PAN Bao-wu; CHU Wu-yang

    2006-01-01

    This is a synthetical report about hydrogen behavior in titanium aluminide alloys in our group. There are two kinds of hydrogen solubility in titanium aluminides, one is the overall solubility at high temperature in the matrix without hydride and the other is the terminal solubility at low temperature in the matrix in equilibrium with the hydride. The former decreases but the later increases with increasing temperature. Hydrogen as a temporary β stabilizer clearly decreases the size of the α2 phase, and increases greatly the amount of β phase, and then increases evidently the mechanical properties of Ti3Al+Nb. The cathodic corrosion of TiAl during charging is due to hydride on the surface. The decrease of the strength, the strain to fracture and fracture toughness for hydrogenated samples is due to hydride. The enrichment of atomic hydrogen at the crack tip during charging under sustained load can enhance localized plastic deformation and cause hydrogen-induced delayed cracking.

  11. Titanium aluminide intermetallic alloys with improved wear resistance

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun; Lin, Hua-Tay; Blau, Peter J.; Sikka, Vinod K.

    2014-07-08

    The invention is directed to a method for producing a titanium aluminide intermetallic alloy composition having an improved wear resistance, the method comprising heating a titanium aluminide intermetallic alloy material in an oxygen-containing environment at a temperature and for a time sufficient to produce a top oxide layer and underlying oxygen-diffused layer, followed by removal of the top oxide layer such that the oxygen-diffused layer is exposed. The invention is also directed to the resulting oxygen-diffused titanium aluminide intermetallic alloy, as well as mechanical components or devices containing the improved alloy composition.

  12. Laser Welding of TC-1 Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    Hanbin DU; Lunji HU; Xiyuan HU; Jianhua LIU

    2003-01-01

    The technology of CO2 laser welding and joint properties of titanium alloy were investigated. The problem of moltenpool protection was resolved by designing a shielding trailer and a special clamp. Joints with silvery appearance wereobtained, which have no pore and crack. In addition, the welding speed could reach 3 m/min for the plate of 1.5 mmthickness being penetrated. The reason of the porosity formation in partial penetration joints is that the keyholescan be easily cut apart in the radial direction, which makes the gas enclosed in the molten pool. The surface oxideof specimens can not affect the porosity formation in welds directly.

  13. Laser-TIG Welding of Titanium Alloys

    Science.gov (United States)

    Turichin, G.; Tsibulsky, I.; Somonov, V.; Kuznetsov, M.; Akhmetov, A.

    2016-08-01

    The article presents the results of investigation the technological opportunity of laser-TIG welding of titanium alloys. The experimental stand for implementation of process with the capability to feed a filler wire was made. The research of the nature of transfer the filler wire into the welding pool has been demonstrated. The influence of distance between the electrode and the surface of the welded plates on the stability of the arc was shown. The relationship between welding velocity, the position of focal plane of the laser beam and the stability of penetration of plates was determined.

  14. Predictions of titanium alloy properties using thermodynamic modeling tools

    Science.gov (United States)

    Zhang, F.; Xie, F.-Y.; Chen, S.-L.; Chang, Y. A.; Furrer, D.; Venkatesh, V.

    2005-12-01

    Thermodynamic modeling tools have become essential in understanding the effect of alloy chemistry on the final microstructure of a material. Implementation of such tools to improve titanium processing via parameter optimization has resulted in significant cost savings through the elimination of shop/laboratory trials and tests. In this study, a thermodynamic modeling tool developed at CompuTherm, LLC, is being used to predict β transus, phase proportions, phase chemistries, partitioning coefficients, and phase boundaries of multicomponent titanium alloys. This modeling tool includes Pandat, software for multicomponent phase equilibrium calculations, and PanTitanium, a thermodynamic database for titanium alloys. Model predictions are compared with experimental results for one α-β alloy (Ti-64) and two near-β alloys (Ti-17 and Ti-10-2-3). The alloying elements, especially the interstitial elements O, N, H, and C, have been shown to have a significant effect on the β transus temperature, and are discussed in more detail herein.

  15. Electrochemical characterization of cast titanium alloys.

    Science.gov (United States)

    Cai, Zhuo; Shafer, Ty; Watanabe, Ikuya; Nunn, Martha E; Okabe, Toru

    2003-01-01

    A reaction layer forms on cast titanium alloy surfaces due to the reaction of the molten metal with the investment. This surface layer may affect the corrosion of the alloy in the oral environment. The objective of this study was to characterize the in vitro corrosion behavior of cast titanium alloys. ASTM Grade 2 CP titanium, Ti-6Al-4V, Ti-6Al-7Nb and Ti-13Nb-13Zr alloys were cast into a MgO-based investment. Experiments were performed on castings (N=4) with three surface conditions: (A) as-cast surface after sandblasting, (B) polished surface after removal of the reaction layer, and (C) sandblasted surface after removal of the reaction layer. Open-circuit potential (OCP) measurement, linear polarization, and potentiodynamic cathodic polarization were performed in aerated (air+10% CO(2)) modified Tani-Zucchi synthetic saliva at 37 degrees C. Potentiodynamic anodic polarization was subsequently conducted in the same medium deaerated with N(2)+10% CO(2) gas 2 h before and during the experiment. Polarization resistance (R(P)) and corrosion rate (I(CORR)) were calculated. Numerical results were subjected to nonparametric statistical analysis at alpha=0.05. The OCP stabilized for all the specimens after 6 x 10(4)s. Apparent differences in anodic polarization were observed among the different surfaces for all the metals. A passivation region followed by breakdown and repassivation were seen on specimens with surfaces A and C. An extensive passive region was observed on all the metals with surface B. The Kruskal-Wallis test showed no significant differences in OCP, R(p), I(CORR) or break down potential for each of the three surfaces among all the metals. The Mann-Whitney test showed significantly lower R(P) and higher I(CORR) values for surface C compared to the other surfaces. Results indicate that the surface condition has more effect on corrosion of these alloys than the surface reaction layer. Within the oxidation potential range of the oral cavity, all the metal

  16. Effect of whitening toothpaste on titanium and titanium alloy surfaces

    National Research Council Canada - National Science Library

    Faria, Adriana Cláudia Lapria; Bordin, Angelo Rafael de Vito; Pedrazzi, Vinícius; Rodrigues, Renata Cristina Silveira; Ribeiro, Ricardo Faria

    2012-01-01

    .... Whitening toothpastes with peroxides are available for patients with high aesthetic requirements, but the effect of whitening toothpastes on titanium surfaces is not yet known, although titanium...

  17. Surface modification by alkali and heat treatments in titanium alloys.

    Science.gov (United States)

    Lee, Baek-Hee; Do Kim, Young; Shin, Ji Hoon; Hwan Lee, Kyu

    2002-09-01

    Pure titanium and titanium alloys are normally used for orthopedic and dental prostheses. Nevertheless, their chemical, biological, and mechanical properties still can be improved by the development of new preparation technologies. This has been the limiting factor for these metals to show low affinity to living bone. The purpose of this study is to improve the bone-bonding ability between titanium alloys and living bone through a chemically activated process and a thermally activated one. Two kinds of titanium alloys, a newly designed Ti-In-Nb-Ta alloy and a commercially available Ti-6Al-4V ELI alloy, were used in this study. In this study, surface modification of the titanium alloys by alkali and heat treatments (AHT), alkali treated in 5.0M NaOH solution, and heat treated in vacuum furnace at 600 degrees C, is reported. After AHT, the effects of the AHT on the bone integration property were evaluated in vitro. Surface morphologies of AHT were observed by optical microscopy (OM) and scanning electron microscopy (SEM). Chemical compositional surface changes were investigated by X-ray diffractometry (XRD), energy dispersive spectroscopy (EDS), and auger electron spectroscopy (AES). Titanium alloys with surface modification by AHT showed improved bioactive behavior, and the Ti-In-Nb-Ta alloy had better bioactivity than the Ti-6Al-4V ELI alloy in vitro.

  18. Recent Advances in the Hot Working of Titanium Alloys

    Institute of Scientific and Technical Information of China (English)

    DANG Xiao-ling

    2012-01-01

    In this paper, recent advances in titanium alloy processing are reviewed. The casting, superplastic forming, friction stir welding and thermohydrogen processing of titanium alloys are developed. The great cost saving results from using casting comparing with the conventional machining for rings. The superplastic forming of titanium alloys is a feasible manufacturing technology for civil and military aircraft. The friction stir welding leds to the production of fully-formed, high quality friction stirwelds. In thermohydrogen processing, the high diffusivity of hydrogen in titanium is firstly used to add hydrogen to titanium alloys by controlled diffusion from a hydrogen environment , after thermohydrogen processing, to remove it by a controlled vacuum anneal so as to improve processing and mechanical properties.

  19. Titanium Alloys and Processing for High Speed Aircraft

    Science.gov (United States)

    Brewer, William D.; Bird, R. Keith; Wallace, Terryl A.

    1996-01-01

    Commercially available titanium alloys as well as emerging titanium alloys with limited or no production experience are being considered for a variety of applications to high speed commercial aircraft structures. A number of government and industry programs are underway to improve the performance of promising alloys by chemistry and/or processing modifications and to identify appropriate alloys and processes for specific aircraft structural applications. This paper discusses some of the results on the effects of heat treatment, service temperatures from - 54 C to +177 C, and selected processing on the mechanical properties of several candidate beta and alpha-beta titanium alloys. Included are beta alloys Timetal 21S, LCB, Beta C, Beta CEZ, and Ti-10-2-3 and alpha-beta alloys Ti-62222, Ti-6242S, Timetal 550, Ti-62S, SP-700, and Corona-X. The emphasis is on properties of rolled sheet product form and on the superplastic properties and processing of the materials.

  20. Sheath Characteristic in ECR Plasma Nitriding

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The sheath plasma characteristics changing with the negative bias applied to the substrate during electron cyclotron resonance plasma nitriding are studied. The sheath characteristics obtained by a Langmuir single probe and an ion energy analyzer show that when the negative bias applied to the substrate is increasing, the most probable energy of ions in the sheath and the full width of half maximum of ions energy distribution increase, the thickness of the sheath also increases, whereas the saturation current of ion decreases. It has been found from the optical emission spectrum that there are strong lines of N2 and N2+. Based on our experiment results the mechanism of plasma nitriding is discussed.

  1. Residual stress state in titanium alloy remelted using GTAW method

    Directory of Open Access Journals (Sweden)

    A. Dudek

    2009-04-01

    Full Text Available Test materials comprised two-phase titanium alloy Ti6Al4V (Grade5. The surface of the tested alloy was remelted by means of TIG welding method using variable current-voltage parameters. The investigations aimed to determine surface geometry and residual stresses in the remelted surface layer in the investigated alloy.

  2. Cathodic Cage Plasma Nitriding: An Innovative Technique

    OpenAIRE

    Sousa,R.R.M.; de Araújo, F. O.; J. A. P. da Costa; Brandim,A.S.; R. A. de Brito; C. Alves

    2012-01-01

    Cylindrical samples of AISI 1020, AISI 316, and AISI 420 steels, with different heights, were simultaneously treated by a new technique of ionic nitriding, entitled cathodic cage plasma nitriding (CCPN), in order to evaluate the efficiency of this technique to produce nitrided layers with better properties compared with those obtained using conventional ionic nitriding technique. This method is able to eliminate the edge effect in the samples, promoting a better uniformity of temperature, and...

  3. Implants for surgery -- Metallic materials -- Part 3: Wrought titanium 6-aluminium 4-vanadium alloy

    CERN Document Server

    International Organization for Standardization. Geneva

    1996-01-01

    Specifies the characteristics of, and corresponding test methods for, the wrought titanium alloy known as titanium 6-aluminium 4-vanadium alloy (Ti 6-Al 4-V alloy) for use in the manufacture of surgical implants.

  4. Subcritical crack growth in two titanium alloys.

    Science.gov (United States)

    Williams, D. N.

    1973-01-01

    Measurement of subcritical crack growth during static loading of precracked titanium alloys in salt water using samples too thin for plane strain loading to predominate was examined as a method for determining the critical stress intensity for crack propagation in salt water. Significant internal crack growth followed by arrest was found at quite low stress intensities, but crack growth rates were relatively low. Assuming these techniques provided a reliable measurement of the critical stress intensity, the value for annealed Ti-4Al-1.5Mo-0.5V alloy was apparently about 35 ksi-in. to the 1/2 power, while that for annealed Ti-4Al-3Mo-1V was below 45 ksi-in. to the 1/2 power. Crack growth was also observed in tests conducted in both alloys in an air environment. At 65 ksi-in. to the 1/2 power, the extent of crack growth was greater in air than in salt water. Ti-4Al-3Mo-1V showed arrested crack growth in air at a stress intensity of 45 ksi-in. to the 1/2 power.

  5. Friction and wear of titanium alloys and copper alloys sliding against titanium 6-percent-aluminum - 4-percent-vanadium alloy in air at 430 C

    Science.gov (United States)

    Wisander, D. W.

    1976-01-01

    Experiments were conducted to determine the friction and wear characteristics of aluminum bronzes and copper-tin, titanium-tin, and copper-silver alloys sliding against a titanium-6% aluminum-4% vanadium alloy (Ti-6Al-4V). Hemispherically tipped riders of aluminum bronze and the titanium and copper alloys were run against Ti-6Al-4V disks in air at 430 C. The sliding velocity was 13 cm/sec, and the load was 250 g. Results revealed that high tin content titanium and copper alloys underwent significantly less wear and galling than commonly used aluminum bronzes. Also friction force was less erratic than with the aluminum bronzes.

  6. [Comparison of the biological tolerance of titanium and titanium alloys in human gingiva cell cultures].

    Science.gov (United States)

    Hehner, B; Heidemann, D

    1989-01-01

    Mirror-finished solid specimens of pure titanium and the titanium alloys Ti-6Al-4V as well as Ti-5Al-2.5Fe showed no effects on the growth behavior and cell morphology of human gingival epithelial cell and fibroblast cultures. The growth of the cells contacting all three materials was uninhibited. SEM revealed growth of fibroblasts on the surfaces of the specimens, too. No differences could be found between the biocompatibility of titanium alloys and that of pure titanium. The formation of a stable surface oxide layer providing resistance to corrosion may be decisive.

  7. Effect of active screen plasma nitriding pretreatment on wear behavior of TiN coating deposited by PACVD technique

    Energy Technology Data Exchange (ETDEWEB)

    Raoufi, M., E-mail: raoufi@iust.ac.ir [School of Metallurgical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Mirdamadi, Sh. [School of Metallurgical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Mahboubi, F. [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Ahangarani, Sh. [Advanced Materials and Renewable Energies Dep., Iranian Research Organization for Science and Technology (Iran, Islamic Republic of); Mahdipoor, M.S. [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Elmkhah, H. [Department of Metallurgical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2012-08-01

    Titanium based alloys are used extensively for improving wear properties of different parts due to their high hardness contents. Titanium nitride (TiN) is among these coatings which can be deposited on surface using various techniques such as CVD, PVD and PACVD. Their weak interface with substrate is one major drawback which can increase the total wear in spite of favorite wear behavior of TiN. Disc shaped samples from AISI H13 (DIN 1.2344) steel were prepared in this study. Single TiN coating was deposited on some of them while others have experienced a TiN deposition by active screen plasma nitriding (ASPN). Hardness at the surface and depth of samples was measured through Vickers micro hardness test which revealed 1810 Hv hardness as the maximum values for a dual-layered ASPN-TiN. Pin-on-disc wear test was done in order to study the wear mechanism. In this regard, the wear behavior of samples was investigated against pins from 100Cr6 (Din 1.3505) bearing steel and tungsten carbide-cobalt (WC-Co) steel. It was evidenced that the dual-layer ASPN-TiN coating has shown the least weight loss with the best wearing behavior because of its high hardness values, stable interface and acceptable resistance against peeling during wearing period.

  8. A Novel Surface Treatment for Titanium Alloys

    Science.gov (United States)

    Lowther, S. E.; Park, C.; SaintClair, T. L.

    2004-01-01

    High-speed commercial aircraft require a surface treatment for titanium (Ti) alloy that is both environmentally safe and durable under the conditions of supersonic flight. A number of pretreatment procedures for Ti alloy requiring multi-stages have been developed to produce a stable surface. Among the stages are, degreasing, mechanical abrasion, chemical etching, and electrochemical anodizing. These treatments exhibit significant variations in their long-term stability, and the benefits of each step in these processes still remain unclear. In addition, chromium compounds are often used in many chemical treatments and these materials are detrimental to the environment. Recently, a chromium-free surface treatment for Ti alloy has been reported, though not designed for high temperature applications. In the present study, a simple surface treatment process developed at NASA/LaRC is reported, offering a high performance surface for a variety of applications. This novel surface treatment for Ti alloy is conventionally achieved by forming oxides on the surface with a two-step chemical process without mechanical abrasion. This acid-followed-by-base treatment was designed to be cost effective and relatively safe to use in a commercial application. In addition, it is chromium-free, and has been successfully used with a sol-gel coating to afford a strong adhesive bond after exposure to hot-wet environments. Phenylethynyl containing adhesives were used to evaluate this surface treatment with sol-gel solutions made of novel imide silanes developed at NASA/LaRC. Oxide layers developed by this process were controlled by immersion time and temperature and solution concentration. The morphology and chemical composition of the oxide layers were investigated using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES). Bond strengths made with this new treatment were evaluated using single lap shear tests.

  9. Polyimide weld bonding for titanium alloy joints

    Science.gov (United States)

    Vaughan, R. W.; Kurland, R. M.

    1974-01-01

    Two weld bonding processes were developed for joining titanium alloy; one process utilizes a weld-through technique and the other a capillary-flow technique. The adhesive used for the weld-through process is similar to the P4/A5F system. A new polyimide laminating resin, BFBI/BMPM, was used in the capillary-flow process. Static property information was generated for weld-bonded joints over the temperature range of 219 K (-65 F) to 561 K (+550 F) and fatigue strength information was generated at room temperature. Significant improvement in fatigue strength was demonstrated for weld-bonded joints over spot-welded joints. A demonstration was made of the applicability of the weld-through weld-bonding process for fabricating stringer stiffened skin panels.

  10. Bacterial adherence to anodized titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Peremarch, C Perez-Jorge; Tanoira, R Perez; Arenas, M A; Matykina, E; Conde, A; De Damborenea, J J; Gomez Barrena, E; Esteban, J, E-mail: cperemarch@fjd.es

    2010-11-01

    The aim of this study was to evaluate Staphylococcus sp adhesion to modified surfaces of anodized titanium alloy (Ti-6Al-4V). Surface modification involved generation of fluoride-containing titanium oxide nanotube films. Specimens of Ti-6Al-4V alloy 6-4 ELI-grade 23- meets the requirements of ASTM F136 2002A (AMS 2631B class A1) were anodized in a mixture of sulphuric/hydrofluoric acid at 20 V for 5 and 60 min to form a 100 nm-thick porous film of 20 nm pore diameter and 230 nm-thick nanotube films of 100 nm in diameter. The amount of fluorine in the oxide films was of 6% and of 4%, respectively. Collection strains and six clinical strains each of Staphylococcus aureus and Staphylococcus epidermidis were studied. The adherence study was performed using a previously published protocol by Kinnari et al. The experiments were performed in triplicates. As a result, lower adherence was detected for collection strains in modified materials than in unmodified controls. Differences between clinical strains were detected for both species (p<0.0001, Kruskal-Wallis test), although global data showed similar results to that of collection strains (p<0.0001, Kruskal-Wallis test). Adherence of bacteria to modified surfaces was decreased for both species. The results also reflect a difference in the adherence between S. aureus and S. epidermidis to the modified material. As a conclusion, not only we were able to confirm the decrease of adherence in the modified surface, but also the need to test multiple clinical strains to obtain more realistic microbiological results due to intraspecies differences.

  11. Sintering of titanium alloy by powder metallurgy

    Energy Technology Data Exchange (ETDEWEB)

    Cosme, C.R.M. [Universidade de Brasilia (UnB), DF (Brazil); Henriques, V.A.R.; Cairo, C.A.A.; Taddei, E.B. [Centro Tecnico Aeroespacial (CTA), Sao Jose dos Campos, SP (Brazil)

    2009-07-01

    Full text: Titanium alloys are suitable for biomaterial applications, considering its biocompatibility and low elastic modulus compared to steel. Bone resorption in this case can be reduced by load sharing between the implant and natural bone.Starting powders were obtained by hydride method, carried out under positive hydrogen pressure at 500 deg C for titanium and 800 deg C for Nb, Zr and Ta powders. After reaching the nominal temperature, the material was held for 3h, with subsequent cooling to room temperature and milling of the friable hydride. Samples were produce by mixing of initial metallic powders followed by and cold isostatic pressing. Subsequent densification by sintering was performed at temperature range between 900 and 1700 deg C. Characterization was carried out with scanning electron microscopy, X-ray diffractometry and microhardness measurements. Microstructural examinations revealed higher amount of &⧣946;-phase for higher sintering temperature and dissolution of Ta and NB particles. In vitro tests revealed low cytotoxicity of sintered samples. (author)

  12. The use of titanium alloys for details of downhole hammers

    Science.gov (United States)

    Popelyukh, A. I.; Repin, A. A.; Alekseev, S. E.; Martyushev, N. V.; Drozdov, Yu Yu

    2016-04-01

    The influence of cementation technology of titanium alloy Ti-Al-Mn on its wear resistance is studied. It is established that after lubrication a friction pair with mineral oil the wear resistance of the cemented titanium alloy is comparable to wear resistance of the tempered steel 12HN3A, and in water medium surpasses it by 1.5 times. Decrease in the tendency to seizure with steel is the main reason for increase of wear resistance of titanium alloy. Industrial tests of the ASH43 hammer have shown that the use of titanium alloys for the manufacture of hammer strikers allows to increase impact capacity by 1.5 times and to increase drilling rate by 30 % compared to hammers with steel strikers.

  13. Solid State Joining of Dissimilar Titanium Alloys

    Science.gov (United States)

    Morton, Todd W.

    Solid state joining of titanium via friction stir welding and diffusion bonding have emerged as enablers of efficient monolithic structural designs by the eliminations fasteners for the aerospace industry. As design complexity and service demands increase, the need for joints of dissimilar alloys has emerged. Complex thermomechanical conditions in friction stir weld joints and high temperature deformation behavior differences between alloys used in dissimilar joints gives rise to a highly variable flow pattern within a stir zone. Experiments performed welding Ti-6Al-4V to beta21S show that mechanical intermixing of the two alloys is the primary mechanism for the generation of the localized chemistry and microstructure, the magnitude of which can be directly related to pin rotation and travel speed weld parameters. Mechanical mixing of the two alloys is heavily influenced by strain rate softening phenomena, and can be used to manipulate weld nugget structure by switching which alloy is subjected to the advancing side of the pin. Turbulent mixing of a weld nugget and a significant reduction in defects and weld forces are observed when the beta21S is put on the advancing side of the weld where higher strain rates are present. Chemical diffusion driven by the heat of weld parameters is characterized using energy dispersive x-ray spectroscopy (EDS) and is shown to be a secondary process responsible for generating short-range chemical gradients that lead to a gradient of alpha particle structures. Diffusion calculations are inconsistent with an assumption of steady-state diffusion and show that material interfaces in the weld nugget evolve through the break-down of turbulent interface features generated by material flows. A high degree of recrystallization is seen throughout the welds, with unique, hybrid chemistry grains that are generated at material interfaces in the weld nugget that help to unify the crystal structure of dissimilar alloys. The degree of

  14. Enhanced ultrasonically assisted turning of a β-titanium alloy.

    Science.gov (United States)

    Maurotto, Agostino; Muhammad, Riaz; Roy, Anish; Silberschmidt, Vadim V

    2013-09-01

    Although titanium alloys have outstanding mechanical properties such as high hot hardness, a good strength-to-weight ratio and high corrosion resistance; their low thermal conductivity, high chemical affinity to tool materials severely impair their machinability. Ultrasonically assisted machining (UAM) is an advanced machining technique, which has been shown to improve machinability of a β-titanium alloy, namely, Ti-15-3-3-3, when compared to conventional turning processes.

  15. Biocompatibility of beta-stabilizing elements of titanium alloys.

    Science.gov (United States)

    Eisenbarth, E; Velten, D; Müller, M; Thull, R; Breme, J

    2004-11-01

    In comparison to the presently used alpha + beta titanium alloys for biomedical applications, beta-titanium alloys have many advantageous mechanical properties, such as an improved wear resistance, a high elasticity and an excellent cold and hot formability. This will promote their future increased application as materials for orthopaedic joint replacements. Not all elements with beta-stabilizing properties in titanium alloys are suitable for biomaterial applications-corrosion and wear processes cause a release of these alloying elements to the surrounding tissue. In this investigation, the biocompability of alloying elements for beta- and near beta-titanium alloys was tested in order to estimate their suitability for biomaterial components. Titanium (grade 2) and the implant steel X2CrNiMo18153 (AISI 316 L) were tested as reference materials. The investigation included the corrosion properties of the elements, proliferation, mitochondrial activity, cell morphology and the size of MC3T3-E1 cells and GM7373 cells after 7 days incubation in direct contact with polished slices of the metals. The statistical significance was considered by Weir-test and Lord-test (alpha = 0.05). The biocompatibility range of the investigated metals is (decreasing biocompatibility): niobium-tantalum, titanium, zirconium-aluminium-316 L-molybdenum.

  16. Artefacts in multimodal imaging of titanium, zirconium and binary titanium-zirconium alloy dental implants: an in vitro study.

    Science.gov (United States)

    Smeets, Ralf; Schöllchen, Maximilian; Gauer, Tobias; Aarabi, Ghazal; Assaf, Alexandre T; Rendenbach, Carsten; Beck-Broichsitter, Benedicta; Semmusch, Jan; Sedlacik, Jan; Heiland, Max; Fiehler, Jens; Siemonsen, Susanne

    2017-02-01

    To analyze and evaluate imaging artefacts induced by zirconium, titanium and titanium-zirconium alloy dental implants. Zirconium, titanium and titanium-zirconium alloy implants were embedded in gelatin and MRI, CT and CBCT were performed. Standard protocols were used for each modality. For MRI, line-distance profiles were plotted to quantify the accuracy of size determination. For CT and CBCT, six shells surrounding the implant were defined every 0.5 cm from the implant surface and histogram parameters were determined for each shell. While titanium and titanium-zirconium alloy induced extensive signal voids in MRI owing to strong susceptibility, zirconium implants were clearly definable with only minor distortion artefacts. For titanium and titanium-zirconium alloy, the MR signal was attenuated up to 14.1 mm from the implant. In CT, titanium and titanium-zirconium alloy resulted in less streak artefacts in comparison with zirconium. In CBCT, titanium-zirconium alloy induced more severe artefacts than zirconium and titanium. MRI allows for an excellent image contrast and limited artefacts in patients with zirconium implants. CT and CBCT examinations are less affected by artefacts from titanium and titanium-zirconium alloy implants compared with MRI. The knowledge about differences of artefacts through different implant materials and image modalities might help support clinical decisions for the choice of implant material or imaging device in the clinical setting.

  17. Effect of titanium addition on fracture toughness behavior of ZL108 alloy

    Institute of Scientific and Technical Information of China (English)

    WENG Yong-gang; LI Zi-jing; LIU Zhi-yong; LIU Wen-cai; WANG Ming-xing; SONG Tian-fu

    2006-01-01

    Two different titanium alloying methods were applied to ZL108 alloy for preparing specimens containing titanium. The specimens were tested on the MTS 810 material test system for studying their behavior of the plane strain fracture toughness KIC. The experimental data were analyzed by the statistical significance tests. The results show that the fracture toughness of the ZL108 alloy containing titanium is superior to that of common ZL108 alloy containing no titanium, but there is no significant difference for different titanium alloying methods. Therefore titanium addition is an effective method for improving the fracture toughness of the alloy ZL108.

  18. Superplastic Forming and Diffusion Bonding of Titanium Alloys

    Directory of Open Access Journals (Sweden)

    A. K. Ghosh

    1986-04-01

    Full Text Available New and advanced fabrication methods for titanium components are emerging today to replace age-old fabrication processes and reduce component cost. Superplastic forming and diffusion bonding are two such advanced fabrication technologies which when applied individually or in combination can provide significant cost and weight benefits and a rather broad manufacturing technology base. This paper briefly reviews the state of understanding of the science and technology of super plastic forming of titanium alloys, and their diffusion bonding capability. Emphasis has been placed on the metallurgy of superplastic flow in two phase titanium alloys, the microstructural and external factors which influence this behaviour.

  19. Recent research and development in titanium alloys for biomedical applications and healthcare goods

    Directory of Open Access Journals (Sweden)

    Mitsuo Niinomi

    2003-01-01

    Full Text Available Nb, Ta and Zr are the favorable non-toxic alloying elements for titanium alloys for biomedical applications. Low rigidity titanium alloys composed of non-toxic elements are getting much attention. The advantage of low rigidity titanium alloy for the healing of bone fracture and the remodeling of bone is successfully proved by fracture model made in tibia of rabbit. Ni-free super elastic and shape memory titanium alloys for biomedical applications are energetically developed. Titanium alloys for not only implants, but also dental products like crowns, dentures, etc. are also getting much attention in dentistry. Development of investment materials suitable for titanium alloys with high melting point is desired in dental precision castings. Bioactive surface modifications of titanium alloys for biomedical applications are very important for achieving further developed biocompatibility. Low cost titanium alloys for healthcare goods, like general wheel chairs, etc. has been recently proposed.

  20. Bond strength of binary titanium alloys to porcelain.

    Science.gov (United States)

    Yoda, M; Konno, T; Takada, Y; Iijima, K; Griggs, J; Okuno, O; Kimura, K; Okabe, T

    2001-06-01

    The purpose of this study was to investigate the bond strength between porcelain and experimental cast titanium alloys. Eleven binary titanium alloys were examined: Ti-Cr (15, 20, 25 wt%), Ti-Pd (15, 20, 25 wt%), Ti-Ag (10, 15, 20 wt%), and Ti-Cu (5, 10 wt%). As controls, the bond strengths for commercially pure titanium (KS-50, Kobelco, Japan) and a high noble gold alloy (KIK, Ishifuku, Japan) were also examined. Castings were made using a centrifugal casting unit (Ticast Super R, Selec Co., Japan). Commercial porcelain for titanium (TITAN, Noritake, Japan) was applied to cast specimens. The bond strengths were evaluated using a three-point bend test according to ISO 9693. Since the elastic modulus value is needed to evaluate the bond strength, the modulus was measured for each alloy using a three-point bend test. Results were analyzed using one-way ANOVA/S-N-K test (alpha = 0.05). Although the elastic moduli of the Ti-Pd alloys were significantly lower than those of other alloys (p = 0.0001), there was a significant difference in bond strength only between the Ti-25Pd and Ti-15Ag alloys (p = 0.009). The strengths determined for all the experimental alloys ranged from 29.4 to 37.2MPa, which are above the minimum value required by the ISO specification (25 MPa).

  1. Electrochemical and surface characterization of a nickel-titanium alloy

    NARCIS (Netherlands)

    Wever, Dirk; Veldhuizen, AG; de Vries, J; Busscher, HJ; Uges, DRA; van Horn, James

    1998-01-01

    For clinical implantation purposes of shape memory metals the nearly equiatomic nickel-titanium (NiTi) alloy is generally used. In this study, the corrosion properties and surface characteristics of this alloy were investigated and compared with two reference controls, AISI 316 LVM stainless steel a

  2. Electrochemical and surface characterization of a nickel-titanium alloy

    NARCIS (Netherlands)

    Wever, Dirk; Veldhuizen, AG; de Vries, J; Busscher, HJ; Uges, DRA; van Horn, James

    1998-01-01

    For clinical implantation purposes of shape memory metals the nearly equiatomic nickel-titanium (NiTi) alloy is generally used. In this study, the corrosion properties and surface characteristics of this alloy were investigated and compared with two reference controls, AISI 316 LVM stainless steel a

  3. Modeling corrosion behavior of gas tungsten arc welded titanium alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The pitting corrosion characteristics of pulse TIG welded Ti-6Al-4V titanium alloy in marine environment were explained.Besides the rapid advance of titanium metallurgy, this is also due to the successful solution of problems associated with the development of titanium alloy welding. The preferred welding process of titanium alloy is frequently gas tungsten arc(GTA) welding due to its comparatively easier applicability and better economy. In the case of single pass GTA welding of thinner section of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current process. The benefit of the process is utilized to obtain better quality titanium weldments. Four factors, five levels, central composite, rotatable design matrix are used to optimize the required number of experiments. The mathematical models have been developed by response surface method(RSM). The results reveal that the titanium alloy can form a protective scale in marine environment and is resistant to pitting corrosion. Experimental results are provided to illustrate the proposed approach.

  4. [Experimental research on porcelain fused to the surface of pure titanium and titanium alloys].

    Science.gov (United States)

    Wang, D; Ai, S; Xu, J

    1995-07-01

    Titanium material has been widely used in prosthodontics since the end of 1980s. However, the research on porcelain fused to the surfaces of titanium material was quite few. This article introduced the technological process of low-fusing dental porcelain--Ceratin fused to pure titanium and titanium alloys. The values of the bond strength of Ceratin and titanium substrates were obtained by shearing test with INSTRON Model-1185. The average value of the shearing strength between TA2 and Ceratin was 31. 01MPa. The corresponding value between TC4 and Ceratin was 33.73MPa. The interface between Ceratin and titanium substrate was observed with scanning electron microscope (SEM). The results of this research proposed that it is hopeful that Ceratin is used as special procelain with titanium material.

  5. Trace Carbon in Biomedical Beta-Titanium Alloys: Recent Progress

    Science.gov (United States)

    Zhao, D.; Ebel, T.; Yan, M.; Qian, M.

    2015-08-01

    Owing to their relatively low Young's modulus, high strength, good resistance to corrosion, and excellent biocompatibility, β-titanium (Ti) alloys have shown great potential for biomedical applications. In β-Ti alloys, carbon can exist in the form of titanium carbide (TiC x ) as well as interstitial atoms. The Ti-C binary phase diagram predicts a carbon solubility value of 0.08 wt.% in β-Ti, which has been used as the carbon limit for a variety of β-Ti alloys. However, noticeable grain boundary TiC x particles have been observed in β-Ti alloys containing impurity levels of carbon well below the predicted 0.08 wt.%. This review focuses its attention on trace carbon (≤0.08 wt.%) in biomedical β-Ti alloys containing niobium (Nb) and molybdenum (Mo), and it discusses the nature and precipitation mechanism of the TiC x particles in these alloys.

  6. Casting behavior of titanium alloys in a centrifugal casting machine.

    Science.gov (United States)

    Watanabe, K; Miyakawa, O; Takada, Y; Okuno, O; Okabe, T

    2003-05-01

    Since dental casting requires replication of complex shapes with great accuracy, this study examined how well some commercial titanium alloys and experimental titanium-copper alloys filled a mold cavity. The metals examined were three types of commercial dental titanium [commercially pure titanium (hereinafter noted as CP-Ti), Ti-6Al-4V (T64) and Ti-6Al-7Nb (T67)], and experimental titanium-copper alloys [3%, 5% and 10% Cu (mass %)]. The volume percentage filling the cavity was evaluated in castings prepared in a very thin perforated sheet pattern and cast in a centrifugal casting machine. The flow behavior of the molten metal was also examined using a so-called "tracer element technique." The amounts of CP-Ti and all the Ti-Cu alloys filling the cavity were similar; less T64 and T67 filled the cavity. However, the Ti-Cu alloys failed to reach the end of the cavities due to a lower fluidity compared to the other metals. A mold prepared with specially designed perforated sheets was effective at differentiating the flow behavior of the metals tested. The present technique also revealed that the more viscous Ti-Cu alloys with a wide freezing range failed to sequentially flow to the end of the cavity.

  7. Preparation and properties of biomedical porous titanium alloys by gelcasting.

    Science.gov (United States)

    Yang, Donghua; Shao, Huiping; Guo, Zhimeng; Lin, Tao; Fan, Lianpeng

    2011-08-01

    Porous titanium alloys have been prepared by gelcasting in this study. The elastic solid green body was first polymerized and then vacuum sintered to porous titanium alloys with low contamination by controlling sintering conditions. The microstructure and the total porosity of the vacuum sintered porous Ti-Co and Ti-Mo alloys were analyzed by using scanning electron microscopy and x-ray diffraction. Moreover, compression and bending tests were conducted to investigate their mechanical properties. The results show that open and closed three-dimensional pore morphologies and total porosity ranging from 38.34% to 58.32% can be achieved. In contrast to porous Ti by gelcasting, the compression and bending strengths of porous titanium alloys were significantly increased by adding Mo and Co with Young's modulus ranging between 7-25 GPa, which is close to that of human cortical bone, therefore being suited for potential application in load-bearing implants.

  8. New Nomenclatures for Heat Treatments of Additively Manufactured Titanium Alloys

    Science.gov (United States)

    Baker, Andrew H.; Collins, Peter C.; Williams, James C.

    2017-07-01

    The heat-treatment designations and microstructure nomenclatures for many structural metallic alloys were established for traditional metals processing, such as casting, hot rolling or forging. These terms do not necessarily apply for additively manufactured (i.e., three-dimensionally printed or "3D printed") metallic structures. The heat-treatment terminology for titanium alloys generally implies the heat-treatment temperatures and their sequence relative to a thermomechanical processing step (e.g., forging, rolling). These designations include: β-processing, α + β-processing, β-annealing, duplex annealing and mill annealing. Owing to the absence of a thermomechanical processing step, these traditional designations can pose a problem when titanium alloys are first produced via additive manufacturing, and then heat-treated. This communication proposes new nomenclatures for heat treatments of additively manufactured titanium alloys, and uses the distinct microstructural features to provide a correlation between traditional nomenclature and the proposed nomenclature.

  9. Thin-film diffusion brazing of titanium alloys

    Science.gov (United States)

    Mikus, E. B.

    1972-01-01

    A thin film diffusion brazing technique for joining titanium alloys by use of a Cu intermediate is described. The method has been characterized in terms of static and dynamic mechanical properties on Ti-6Al-4V alloy. These include tensile, fracture toughness, stress corrosion, shear, corrosion fatigue, mechanical fatigue and acoustic fatigue. Most of the properties of titanium joints formed by thin film diffusion brazing are equal or exceed base metal properties. The advantages of thin film diffusion brazing over solid state diffusion bonding and brazing with conventional braze alloys are discussed. The producibility advantages of this process over others provide the potential for producing high efficiency joints in structural components of titanium alloys for the minimum cost.

  10. Processing of carbon containing gamma titanium aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    Paul, J.D.H.; Froebel, U.; Oehring, M.; Appel, F. [Inst. for Materials Research, GKSS Research Centre, Geesthacht (Germany)

    2003-07-01

    Gamma-based titanium aluminide alloys have received much attention over the last decade with the intention of being used in turbine applications. In the as-cast state these alloys are relatively brittle when compared with conventional materials. In order to meet property requirements, optimisation of both alloy composition and microstructure are necessary. Alloys based on Ti-45Al-(5-10)Nb (at.%) with carbon additions seems capable of meeting many of the properties necessary for application. This paper addresses the reasons behind the choice of this alloy composition and discusses a relevant processing route. (orig.)

  11. Galvanic corrosion behavior of titanium implants coupled to dental alloys.

    Science.gov (United States)

    Cortada, M; Giner, L; Costa, S; Gil, F J; Rodríguez, D; Planell, J A

    2000-05-01

    The corrosion of five materials for implant suprastructures (cast-titanium, machined-titanium, gold alloy, silver-palladium alloy and chromium-nickel alloy), was investigated in vitro, the materials being galvanically coupled to a titanium implant. Various electrochemical parameters E(CORR), i(CORR) Evans diagrams, polarization resistance and Tafel slopes) were analyzed. The microstructure of the different dental materials was observed before and after corrosion processes by optical and electron microscopy. Besides, the metallic ions released in the saliva environment were quantified during the corrosion process by means of inductively coupled plasma-mass spectrometry technique (ICP-MS). The cast and machined titanium had the most passive current density at a given potential and chromium-nickel alloy had the most active critical current density values. The high gold content alloys have excellent resistance corrosion, although this decreases when the gold content is lower in the alloy. The palladium alloy had a low critical current density due to the presence of gallium in this composition but a selective dissolution of copper-rich phases was observed through energy dispersive X-ray analysis.

  12. Tribocorrosion studies of metallic biomaterials: The effect of plasma nitriding and DLC surface modifications.

    Science.gov (United States)

    Zhao, Guo-Hua; Aune, Ragnhild E; Espallargas, Nuria

    2016-10-01

    The medical grade pure titanium, stainless steel and CoCrMo alloy have been utilized as biomaterials for load-bearing orthopedic prosthesis. The conventional surgery metals suffer from a combined effect of wear and corrosion once they are implanted, which may significantly accelerate the material degradation process. In this work, the tribocorrosion performance of the metallic biomaterials with different surface modifications was studied in the simulated body fluid for the purpose of investigating the effect of the surface treatments on the tribocorrosion performance and eventually finding the most suitable implantation materials. The metals were subjected to surface modifications by plasma nitriding in different treatment temperatures or physical vapor deposition (PVD) to produce diamond-like carbon (DLC) coating, respectively. The dry wear and tribocorrosion properties of the samples were evaluated by using a reciprocating ball-on-disc tribometer equipped with an electrochemical cell. Prior to the tribocorrosion tests, their electrochemical behavior was measured by the potentiodynamic polarization in phosphate buffer saline (PBS) solution at room temperature. Both stainless steel and CoCrMo after low temperature nitriding kept their passive nature by forming an expanded austenite phase. The DLC coated samples presented the low anodic corrosion current due to the chemical inertness of the carbon layer. During the tribocorrosion tests at open circuit potential, the untreated and low temperature nitrided samples exhibited significant potential drop towards the cathodic direction, which was a result of the worn out of the passive film. Galvanic coupling was established between the depassivated (worn) area and the still passive (unworn) area, making the materials suffered from wear-accelerated corrosion. The DLC coating performed as a solid lubricant in both dry wear and tribocorrosion tests, and the resulting wear after the tests was almost negligible. Copyright

  13. Microstructure and tensile properties of low cost titanium alloys at different cooling rate

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Titanium and titanium alloys have several advantages, but the cost of titanium alloys is very expensive compared with the traditional metal materials. This article introduces two new low-cost titanium alloys Ti-2.1Cr-1.3Fe (TCF alloy) and Ti-3Al-2.1Cr-1.3Fe (TACF alloy). In this study, we used Cr-Fe master alloy as one of the raw materials to develop the two new alloys. We introduce the microstructure and tensile properties of the two new alloys from β solution treated with different cooling methods. Optica...

  14. Properties of titanium-alloyed DLC layers for medical applications.

    Science.gov (United States)

    Joska, Ludek; Fojt, Jaroslav; Cvrcek, Ladislav; Brezina, Vitezslav

    2014-01-01

    DLC-type layers offer a good potential for application in medicine, due to their excellent tribological properties, chemical resistance, and bio-inert character. The presented study has verified the possibility of alloying DLC layers with titanium, with coatings containing three levels of titanium concentration prepared. Titanium was present on the surface mainly in the form of oxides. Its increasing concentration led to increased presence of titanium carbide as well. The behavior of the studied systems was stable during exposure in a physiological saline solution. Electrochemical impedance spectra practically did not change with time. Alloying, however, changed the electrochemical behavior of coated systems in a significant way: from inert surface mediating only exchange reactions of the environment in the case of unalloyed DLC layers to a response corresponding rather to a passive surface in the case of alloyed specimens. The effect of DLC layers alloying with titanium was tested by the interaction with a simulated body fluid, during which precipitation of a compound containing calcium and phosphorus--basic components of the bone apatite--occurred on all doped specimens, in contrast to pure DLC. The results of the specimens' surface colonization with cells test proved the positive effect of titanium in the case of specimens with a medium and highest content of this element.

  15. Temporarily alloying titanium to facilitate friction stir welding

    Energy Technology Data Exchange (ETDEWEB)

    Hovanski, Yuri [Washington State Univ., Pullman, WA (United States)

    2009-05-01

    While historically hydrogen has been considered an impurity in titanium, when used as a temporary alloying agent it promotes beneficial changes to material properties that increase the hot-workability of the metal. This technique known as thermohydrogen processing was used to temporarily alloy hydrogen with commercially pure titanium sheet as a means of facilitating the friction stir welding process. Specific alloying parameters were developed to increase the overall hydrogen content of the titanium sheet ranging from commercially pure to 30 atomic percent. Each sheet was evaluated to determine the effect of the hydrogen content on process loads and tool deformation during the plunge phase of the friction stir welding process. Two materials, H-13 tool steel and pure tungsten, were used to fabricate friction stir welding tools that were plunged into each of the thermohydrogen processed titanium sheets. Tool wear was characterized and variations in machine loads were quantified for each tool material and weld metal combination. Thermohydrogen processing was shown to beneficially lower plunge forces and stabilize machine torques at specific hydrogen concentrations. The resulting effects of hydrogen addition to titanium metal undergoing the friction stir welding process are compared with modifications in titanium properties documented in modern literature. Such comparative analysis is used to explain the variance in resulting process loads as a function of the initial hydrogen concentration of the titanium.

  16. Temporarily alloying titanium to facilitate friction stir welding

    Energy Technology Data Exchange (ETDEWEB)

    Hovanski, Yuri [Washington State Univ., Pullman, WA (United States)

    2009-05-01

    While historically hydrogen has been considered an impurity in titanium, when used as a temporary alloying agent it promotes beneficial changes to material properties that increase the hot-workability of the metal. This technique known as thermohydrogen processing was used to temporarily alloy hydrogen with commercially pure titanium sheet as a means of facilitating the friction stir welding process. Specific alloying parameters were developed to increase the overall hydrogen content of the titanium sheet ranging from commercially pure to 30 atomic percent. Each sheet was evaluated to determine the effect of the hydrogen content on process loads and tool deformation during the plunge phase of the friction stir welding process. Two materials, H-13 tool steel and pure tungsten, were used to fabricate friction stir welding tools that were plunged into each of the thermohydrogen processed titanium sheets. Tool wear was characterized and variations in machine loads were quantified for each tool material and weld metal combination. Thermohydrogen processing was shown to beneficially lower plunge forces and stabilize machine torques at specific hydrogen concentrations. The resulting effects of hydrogen addition to titanium metal undergoing the friction stir welding process are compared with modifications in titanium properties documented in modern literature. Such comparative analysis is used to explain the variance in resulting process loads as a function of the initial hydrogen concentration of the titanium.

  17. Production of new titanium alloy for orthopedic implants

    Energy Technology Data Exchange (ETDEWEB)

    Taddei, E.B. [Instituto Tecnologico de Aeronautica (ITA), Centro Tecnico Aeroespacial, Sao Jose dos Campos-SP, 12228-904 (Brazil)]. E-mail: elisa@ita.br; Henriques, V.A.R. [AMR-DiviSao de Materiais-Instituto de Aeronautica e Espaco (IAE), Centro Tecnico Aeroespacial, Sao Jose dos Campos-SP, 12228-904 (Brazil); Silva, C.R.M. [AMR-DiviSao de Materiais-Instituto de Aeronautica e Espaco (IAE), Centro Tecnico Aeroespacial, Sao Jose dos Campos-SP, 12228-904 (Brazil); Cairo, C.A.A. [AMR-DiviSao de Materiais-Instituto de Aeronautica e Espaco (IAE), Centro Tecnico Aeroespacial, Sao Jose dos Campos-SP, 12228-904 (Brazil)

    2004-11-01

    The beta titanium alloys is one of the most promising groups of the titanium alloys. This fact is due to the good formability, mechanical properties and potential applications; moreover, these alloys present the highest level of mechanical, fatigue and corrosion resistance. The beta titanium alloys present the lowest elastic modulus, an interesting property for orthopedic implants. A {beta} alloy recently developed for this application is Ti-35Nb-7Zr-5Ta. In this work, the alloy was produced by powder metallurgy, unique available alternative for obtaining parts with porous structure (until 50% of porosity), that is one important characteristic for the osteointegration. The Ti-35Nb-7Zr-5Ta samples were manufactured by blended elemental method from a sequence of uniaxial and cold isostatic pressing with subsequent densification by sintering among 900 at 1700 deg. C, in vacuum. The objective of this work is the analysis of alloy microstructural evolution from the elemental powders dissolution under the increase of the sintering temperature. The alloy was characterized by scanning electron microscopy, X-ray diffraction and Vickers microhardness measurements. Density was measured by Archimedes method. The results show that a {beta}-homogeneous microstructure is obtained in the whole sample with the increase of sintering temperature. With the beginning of the {beta}-stabilizers (Nb and Ta) dissolution, at low sintering temperatures, there is the formation of an intermediary Widmanstaetten ({alpha}+{beta}) phase.

  18. Method for the production of strongly adhesive films on titanium and titanium alloys with a metallization process

    Science.gov (United States)

    Hahn, H. J.

    1986-01-01

    A process for the spray-application of a strongly adhesive, thick antifriction layer on titanium and titanium alloys is proposed. The titanium/titanium alloy component to be coated is first subjected to cleaning in a pickling bath with reducing additives and sand-blasting, then coated with an intermediate layer of nickel, after which the final layer is applied. The formation of TiNi at the interface ensures strong bonding of the antifriction layer.

  19. Study of corrosion between a titanium implant and dental alloys.

    Science.gov (United States)

    Reclaru, L; Meyer, J M

    1994-06-01

    The infiltration of saliva into the multi-metallic structures on titanium implants brings different types of alloys into temporary or permanent contact. In this way a galvanic cell is established as a result of their potential difference. The galvanic cell phenomenon is compounded by another type of corrosion resulting from the geometry of the assembly: localized crevice corrosion. Fifteen galvanic couples (Ti/gold-based alloys, Ti/palladium-based alloy and Ti/non-precious alloys) were studied. Various electrochemical parameters (Ecorr, Ecommon, Ecouple corr, Ecrevice, icorr, icouple corr and Tafel slopes) were analysed. The galvanic currents measured are of the same order of magnitude (except Ti/stainless steel). They remain low. Application of the mixed-potential theory shows that titanium in coupling with the alloys studied will be under either cathodic or anodic control. According to the results obtained, an alloy that is potentially usable for superstructures in a galvanic coupling with titanium must fulfil a certain number of parameters: in a coupling, titanium must have a weak anodic polarization; the current generated by the galvanic cell must also be weak; the crevice potential must be markedly higher than the common potential.

  20. Lunar-derived titanium alloys for hydrogen storage

    Science.gov (United States)

    Love, S.; Hertzberg, A.; Woodcock, G.

    1992-01-01

    Hydrogen gas, which plays an important role in many projected lunar power systems and industrial processes, can be stored in metallic titanium and in certain titanium alloys as an interstitial hydride compound. Storing and retrieving hydrogen with titanium-iron alloy requires substantially less energy investment than storage by liquefaction. Metal hydride storage systems can be designed to operate at a wide range of temperatures and pressures. A few such systems have been developed for terrestrial applications. A drawback of metal hydride storage for lunar applications is the system's large mass per mole of hydrogen stored, which rules out transporting it from earth. The transportation problem can be solved by using native lunar materials, which are rich in titanium and iron.

  1. Cathodic Cage Plasma Nitriding: An Innovative Technique

    Directory of Open Access Journals (Sweden)

    R. R. M. de Sousa

    2012-01-01

    Full Text Available Cylindrical samples of AISI 1020, AISI 316, and AISI 420 steels, with different heights, were simultaneously treated by a new technique of ionic nitriding, entitled cathodic cage plasma nitriding (CCPN, in order to evaluate the efficiency of this technique to produce nitrided layers with better properties compared with those obtained using conventional ionic nitriding technique. This method is able to eliminate the edge effect in the samples, promoting a better uniformity of temperature, and consequently, a smaller variation of the thickness/height relation can be obtained. The compound layers were characterized by X-ray diffraction, optical microscopy, and microhardness test profile. The results were compared with the properties of samples obtained with the conventional nitriding, for the three steel types. It was verified that samples treated by CCPN process presented, at the same temperature, a better uniformity in the thickness and absence of the edge effect.

  2. An Oxygen-Permeation Treatment for Hardening Titanium Alloys

    Institute of Scientific and Technical Information of China (English)

    MA Hong-yan; WANG Mao-cai; WEI Zheng; XIN Gong-chun

    2004-01-01

    In this paper, the characterization of oxygen permeation (OP) in titanium alloy TC11 at high temperature and the influence of oxygen solution layer on performances of substrate were characterized with the help of apparatus, such as TGA,SEM/EDAX, XRD, EPMA, Micro-hardness Tester, Two-body Abrasion Tester, Amsler Wear Test Machine, Potentiostat/Galvanostat Model 273 system. The results showed that there was a little shift in X-ray diffraction peaks of α and β phase during the OPT process as a result of oxygen solution. The OP treatment can significantly increase the surface hardness of titanium alloys and, accordingly, the abrasive wear resistance was improved. Titanium alloys with oxygen solution layer exhibited improved corrosion resistance both in 3.5 % NaCl and in 5 % HCl solution. Oxidation resistance of TC11 with oxygen solution layer at high temperature was also enhanced. The solution and hardening mechanisms were discussed based on the experimental results.

  3. Potential of rapid heat treatment of titanium alloys and steels

    Energy Technology Data Exchange (ETDEWEB)

    Ivasishin, O.M.; Teliovich, R.V. [Institute of Metal Physics, Kiev (Ukraine)

    1999-05-15

    Rapid heat treatment (RHT) of titanium alloys and steels, which includes rapid heating into the single-phase field, {beta} and {gamma} of titanium alloys and steels, respectively, is reviewed. Heating rate is an important parameter that affects the mechanism and kinetics of phase and/or structural transformation. Refinement of grain structure, formation of micro-chemical inhomogeneity and substructure in the high temperature phase following RHT are addressed. Thermo-kinetic effects during rapid heating of material with an initial metastable (quenched or deformed) microstructure are discussed. The response of titanium alloys and steels to RHT is compared. The improvement in mechanical properties of both material system following RHT is also presented. (orig.) 48 refs.

  4. High strength beta titanium alloys: New design approach

    Energy Technology Data Exchange (ETDEWEB)

    Okulov, I.V., E-mail: okulovilya@yandex.ru [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); TU Dresden, Institut für Werkstoffwissenschaft, D-01062 Dresden (Germany); Wendrock, H. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Volegov, A.S. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg (Russian Federation); Attar, H. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); School of Engineering, Edith Cowan University, 270 Joondalup Drive, Joondalup, Perth, WA 6027 (Australia); Kühn, U. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Skrotzki, W. [TU Dresden, Institut für Strukturphysik, D-01062 Dresden (Germany); Eckert, J. [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); TU Dresden, Institut für Werkstoffwissenschaft, D-01062 Dresden (Germany)

    2015-03-25

    A novel approach for development of high strength and ductile beta titanium alloys was proposed and successfully applied. The microstructure of the designed alloys is fully composed of a bcc β-Ti phase exhibiting dendritic morphology. The new Ti{sub 68.8}Nb{sub 13.6}Cr{sub 5.1}Co{sub 6}Al{sub 6.5} (at%) alloy (BETA{sup tough} alloy) exhibits a maximum tensile strength of 1290±50 MPa along with 21±3% of fracture strain. The specific energy absorption value upon mechanical deformation of the BETA{sup tough} alloy exceeds that of Ti-based metallic glass composites and commercial high strength Ti-based alloys. The deformation behavior of the new alloys was correlated with their microstructure by means of in-situ studies of the microstructure evolution upon tensile loading in a scanning electron microscope.

  5. Hydrogen embrittlement and galvanic corrosion of titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Soh, Jeong Ryong; Jeong, Y. H.; Choi, B. K.; Baek, J. H.; Hwang, D. Y.; Choi, B. S.; Lee, D. J

    2000-06-01

    The material properties including the fracture behavior of titanium alloys used as a steam generator tube in SMART can be degraded de to the hydrogen embrittlement and the galvanic corrosion occurring as a result of other materials in contact with titanium alloys in a conducting corrosive environment. In this report the general concepts and trends of hydrogen embrittlement are qualitatively described to adequately understand and expect the fracture behavior from hydrogen within the bulk of materials and under hydrogen containing environments because hydrogen embrittlement may be very complicated process. And the characteristics of galvanic corrosion closely related to hydrogen embrittlement is qualitatively based on wimple electrochemical theory.

  6. Mechanical biocompatibilities of titanium alloys for biomedical applications.

    Science.gov (United States)

    Niinomi, Mitsuo

    2008-01-01

    Young's modulus as well as tensile strength, ductility, fatigue life, fretting fatigue life, wear properties, functionalities, etc., should be adjusted to levels that are suitable for structural biomaterials used in implants that replace hard tissue. These factors may be collectively referred to as mechanical biocompatibilities. In this paper, the following are described with regard to biomedical applications of titanium alloys: the Young's modulus, wear properties, notch fatigue strength, fatigue behaviour on relation to ageing treatment, improvement of fatigue strength, fatigue crack propagation resistance and ductility by the deformation-induced martensitic transformation of the unstable beta phase, and multifunctional deformation behaviours of titanium alloys.

  7. Rough surfaces of titanium and titanium alloys for implants and prostheses

    Energy Technology Data Exchange (ETDEWEB)

    Conforto, E. [Swiss Federal Institute of Technology (EPFL), CH-1015, Lausanne (Switzerland)]. E-mail: egle.conforto@epfl.ch; Aronsson, B.-O. [GAP Biomedical, University of Geneva, CH-1211 Geneva 4 (Switzerland); Salito, A. [Sulzer-Metco AG, CH-5610 Wohlen (Switzerland); Crestou, C. [CEMES/CNRS, 29 rue Jeanne Marvig, F-31055 Toulouse Cedex 4 (France); Caillard, D. [CEMES/CNRS, 29 rue Jeanne Marvig, F-31055 Toulouse Cedex 4 (France)

    2004-11-01

    Titanium and titanium alloys for dental implants and hip prostheses were surface-treated and/or covered by metallic or ceramic rough layers after being submitted to sand blasting. The goal of these treatments is to improve the surface roughness and consequently the osteointegration, the fixation, and the stability of the implant. The microstructure of titanium and titanium alloys submitted to these treatments has been studied and correlated to their mechanical behavior. As-treated/covered and mechanically tested surfaces were characterized by scanning electron microscopy (SEM). Structural analyses performed by transmission electron microscopy (TEM), mainly in cross-section, reveal the degree of adherence and cohesion between the surface layer and the substrate (implant). We observed that, although the same convenient surface roughness was obtained with the two types of process, many characteristics as structural properties and mechanical behavior are very different.

  8. Tissue response to implanted ceramic-coated titanium alloys in rats.

    Science.gov (United States)

    Satomi, K; Akagawa, Y; Nikai, H; Tsuru, H

    1988-07-01

    In order to assess the tissue compatibility of the hybrid materials for the dental implant (hydroxyapatite, titanium oxide and titanium nitride coated titanium alloys), tissue response to these materials implanted in the rat subcutaneous tissue was histologically examined. Initial inflammatory response was less evident in titanium oxide coated and non-coated titanium alloys. All materials were encapsulated by thin fibrous connective tissues. The membrane thickness of hydroxyapatite coated titanium alloy was significantly higher than that of titanium nitride coated one. These results suggest that all materials possess favourable tissue compatibility and may encourage clinical use as the dental implant.

  9. Design of new titanium alloys for orthopaedic applications.

    Science.gov (United States)

    Guillemot, F; Prima, F; Bareille, R; Gordin, D; Gloriant, T; Porté-Durrieu, M C; Ansel, D; Baquey, Ch

    2004-01-01

    Parallel to the biofunctionalisation of existing materials, innovation in biomaterials engineering has led to the specific design of titanium alloys for medical applications. Studies of the biological behaviour of metallic elements have shown that the composition and structure of the material should be carefully tailored to minimise adverse body reactions and to enhance implant longevity, respectively. Consequently, interest has focused on a new family of titanium alloys: Ti-6Mo-3Fe-5Ta, Ti-4Mo-2Fe-5Ta and Ti-6Mo-3Fe-5Zr-5Hf alloys. The non-toxicity of the specially designed titanium alloys compared with osteoblastic cells has been ascertained using MTT and RN tests. In addition, phase transformations upon thermal processing have been investigated, with comparison with a well-defined beta titanium alloy. Optimum thermal processing windows (above 550 degrees C) have been designed to generate a stable and nanostructured alpha phase from the isothermal omega phase that precipitates in a low temperature range (150-350 degrees C). The generation of such nanostructured microstructures should provide a promising opportunity to investigate tissue-biomaterial interactions at the scale of biomolecules such as proteins.

  10. Environmental protection to 922K (1200 F) for titanium alloys

    Science.gov (United States)

    Groves, M. T.

    1973-01-01

    Evaluations are presented of potential coating systems for protection of titanium alloys from hot-salt stress-corrosion up to temperatures of 755 K (900 F) and from oxidation embrittlement up to temperature of 922 K (1200 F). Diffusion type coatings containing Si, Al, Cr, Ni or Fe as single coating elements or in various combinations were evaluated for oxidation protection, hot-salt stress-corrosion (HSSC) resistance, effects on tensile properties, fatigue properties, erosion resistance and ballistic impact resistance on an alpha and beta phase titanium alloy (Ti-6Al-2Sn-4Zr-2Mo). All of the coatings investigated demonstrated excellent oxidation protectiveness, but none of the coatings provided protection from hot-salt stress-corrosion. Experimental results indicated that both the aluminide and silicide types of coatings actually decreased the HSSC resistance of the substrate alloy. The types of coatings which have typically been used for oxidation protection of refractory metals and nickel base superalloys are not suitable for titanium alloys because they increase the susceptibility to hot-salt stress-corrosion, and that entirely new coating concepts must be developed for titanium alloy protection in advanced turbine engines.

  11. Effect of hydrogen on mechanical properties of -titanium alloys

    Indian Academy of Sciences (India)

    H-J Christ; A Senemmar; M Decker; K Prüßner

    2003-06-01

    Conflicting opinions exist in the literature on the manner in which hydrogen influences the mechanical properties of -titanium alloys. This can be attributed to the -stabilizing effect of hydrogen in these materials leading to major changes in the microstructure as a result of hydrogen charging. The resulting (extrinsic) effect of hydrogen on the mechanical properties can possibly cover up the direct (intrinsic) influences. On the basis of experimentally determined thermodynamic and kinetic data regarding the interaction of hydrogen with -titanium alloys, hydrogen concentrations of up to 8 at.% were established in three commercial alloys by means of hydrogen charging from the gas phase. In order to separate intrinsic and extrinsic effects the charging was carried out during one step of the two-step heat treatment typical of metastable -titanium alloys, while the other step was performed in vacuum. The results on the single-phase condition represent the intrinsic hydrogen effect. Monotonic and cyclic strength increase at the expense of ductility with increasing hydrogen concentration. The brittle to ductile transition temperature shifts to higher values and the fatigue crack propagation threshold value decreases. The microstructure of the metastable, usually two-phase -titanium alloys is strongly affected by hydrogen, although the extent of this effect depends not only on the hydrogen concentration but also on the temperature of charging. This microstructural influence (extrinsic effect) changes the mechanical properties in the opposite direction as compared to the intrinsic hydrogen effect.

  12. Thermodynamics of Titanium-Aluminum-Oxygen Alloys Studied

    Science.gov (United States)

    Copland, Evan H.; Jacobson, Nathan S.

    2001-01-01

    Titanium-aluminum alloys are promising intermediate-temperature alloys for possible compressor applications in gas-turbine engines. These materials are based on the a2-Ti3Al + g-TiAl phases. The major issue with these materials is high oxygen solubility in a2-Ti3Al, and oxidation of unsaturated alloys generally leads to mixed non-protective TiO2+Al2O3 scales. From phase diagram studies, oxygen saturated a2-Ti3Al(O) is in equilibrium with Al2O3; however, oxygen dissolution has a detrimental effect on mechanical properties and cannot be accepted. To better understand the effect of oxygen dissolution, we examined the thermodynamics of titanium-aluminum-oxygen alloys.

  13. Diffusion kinetics of nitrogen in tantalum during plasma-nitriding

    Institute of Scientific and Technical Information of China (English)

    张德元; 林勤; 曾卫军; 李放; 许兰萍; 付青峰

    2001-01-01

    The activation energies of nitrogen in tantalum on plasma nitriding conditions were calculated according to the experimental data of hardness of plasma-nitriding of tantalum vs time and temperature. The activation energy calculated is 148.873±0.390  kJ/mol. The depth increasing of nitriding layer with time follows square root relation. The nitriding process of tantalum is controlled by diffusion of nitrogen atoms in tantalum solid solution.

  14. Modifying ability of titanium-based pelleted master alloys

    Science.gov (United States)

    Bazhin, V. Yu.; Savchenkov, S. A.; Kosov, Ya. I.

    2017-05-01

    The problem of enhancing the quality of pressed titanium master alloys is discussed to increase the rate and degree of dissolution of their components and to ensure the formation of a fine-grained structure in aluminum alloys. A technology of producing a pelleted titanium master alloy for effective correction of the chemical composition of an aluminum alloy in casting is developed and tested. Incoming inspection of the component composition and the flux distribution in the volume of pressed pellets of various manufacturers is performed. The rate of dissolution of pressed powder master alloys in the aluminum melt is studied, and their modifying ability is estimated after studying the microstructures of cast blanks. Molasses is used as a binder in a pelleted master alloy. As a result, we achieved a uniform flux distribution over the pellet volume and the formation of uniform pores after annealing as compared pelleted master alloys of other manufacturers. The fabricated alloying briquettes have higher strength characteristics and their dissolution rate in the aluminum melt is higher than those of analogs by 15-20%.

  15. Marginal and internal adaptation of commercially pure titanium and titanium-aluminum-vanadium alloy cast restorations.

    Science.gov (United States)

    Al Wazzan, Khalid A; Al-Nazzawi, Ahmad A

    2007-01-01

    The purpose of this in vitro study was to investigate the marginal accuracy and internal fit of complete cast crowns and three-unit fixed partial dentures (FPDs) cast with commercially pure titanium (CPTi) and Titanium-Aluminum-Vanadium alloy (Ti-6Al-4V). CPTi and Ti-6Al-4V alloy were used to cast twelve single crowns and twelve three-unit FPDs. A traveling microscope was used to measure marginal gap and discrepancies in internal fit. Two and one-way analysis of variance (ANOVA) analyses were used to determine the effects of the marginal and internal fit discrepancies. The Ti-6Al-4V alloy demonstrated a significantly smaller marginal gap than CPTi (Pcast by CPTi or Ti-6Al-4V alloy were within the range of what is clinically acceptable for longevity of restorations.

  16. Phase evolution and alloying mechanism of titanium aluminide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Luo, J.S.; Li, K.; Li, X.B. [Research Center of Laser Fusion, Science and Technology on Plasma Physics Laboratory, China Academy of Engineering Physics, Mianyang 621900 (China); Shu, Y.J. [Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900 (China); Tang, Y.J., E-mail: tangyongjian2000@sina.com [Research Center of Laser Fusion, Science and Technology on Plasma Physics Laboratory, China Academy of Engineering Physics, Mianyang 621900 (China)

    2014-12-05

    Highlights: • An evolution of phase composition of TiAl alloy nanoparticles was investigated. • An alloying mechanism was analyzed according to the variation of phase composition. • The alloying reaction was possible to perform between the small clusters of Ti and Al. • The alloying product is determined by the temperature of Ti and Al small clusters. • The alloying mechanism can be explained based on Gibbs free energy of alloying reaction. - Abstract: The evolution of phase composition of titanium aluminide nanoparticles synthesized by the flow-levitation method was systematically investigated by adjustment of the evaporating temperature of the mixed metallic droplet and the X-ray diffraction spectrum. Their alloying mechanism was analyzed according to the variation of phase composition. ε(h, l)-TiAl{sub 3,} γ-TiAl and α{sub 2}-Ti{sub 3}Al phases are gradually formed in TiAl alloy nanoparticles with the increasing of evaporating temperature of the mixed droplet. The alloying reaction is possible to perform between the small clusters of Ti and Al during the cooling process with high cooling rate. And the alloying mechanism can be explained based on the Gibbs free energy of alloying reaction of Ti and Al small clusters.

  17. [Evaluating occupational health risk in titanium alloys production workers].

    Science.gov (United States)

    Bazarova, E L

    2007-01-01

    The authors present data on evaluation of personified and non-personified occupational risk of health disorders in titanium alloys production workers, concerning hygienic, medical and biologic, social and psychologic criteria. One-digit assessment of the work conditions is suggested.

  18. Mechanical properties of titanium alloys with strengthened surface layers

    Directory of Open Access Journals (Sweden)

    I.M. Pohreliuk

    2011-12-01

    Full Text Available Influence of oxinitriding and boriding on the mechanical properties (ultimate strength to destruction at uniaxial tension, plasticity, tendency to delayed destruction, fatigue resistance at bending with rotation, fatigue life at lowcycle pure bending of titanium alloys is studied.

  19. Chemical milling solution reveals stress corrosion cracks in titanium alloy

    Science.gov (United States)

    Braski, D. N.

    1967-01-01

    Solution of hydrogen flouride, hydrogen peroxide, and water reveals hot salt stress corrosion cracks in various titanium alloys. After the surface is rinsed in water, dried, and swabbed with the solution, it can be observed by the naked eye or at low magnification.

  20. Development of Low Density Titanium Alloys for Structural Applications

    Science.gov (United States)

    Froes, F. H.; Suryanarayana, C.; Powell, C.; Ward-Close, C. Malcolm; Wilkes, D. M. J.

    1996-01-01

    In this report the results of a program designed to reduce the density of titanium by adding magnesium are presented. Because these two elements are immiscible under conventional ingot metallurgy techniques, two specialized powder metallurgy methods namely, mechanical alloying (MA) and physical vapor deposition (PVD) were implemented. The mechanical alloying experiments were done both at the University of Idaho and at the Defense Research Agency in UK. Since titanium is reactive with interstitial elements, a secondary goal of this research was to correlate solubility extensions with interstitial contamination content, especially oxygen and nitrogen. MA was carried out in SPEX 8000 shaker mils and different milling containers were utilized to control the level of contamination. Results showed that solubilities of Mg in Ti were obtained up to 28 at.% (16.4 wt. %) Mg in Ti for Ti-39.6 at. % (25 wt. %) Mg alloys, which greatly exceed those obtained under equilibrium conditions. This reflects a density reduction of approximately 26 %. Contamination of oxygen and nitrogen seemed to increase the solubility of magnesium in titanium in some cases; however, we were not able to make a clear correlation between contamination levels with solubilities. Work at the DRA has emphasized optimization of present PVD equipment, specifically composition and temperature control. Preliminary PVD data has shown Ti-Mg deposits have successfully been made up to 2 mm thick and that solubility extensions were achieved. The potential for density reduction of titanium by alloying with magnesium has been demonstrated; however, this work has only scratched the surface of the development of such low density alloys. Much research is needed before such alloys could be implemented into industry. Further funding is required in order to optimize the MA/PVD processes including contamination control, determination of optimal alloy compositions, microstructure development, and mechanical property

  1. Titanium-zirconium-phosphonate hybrid film on 6061 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Shuanghong WANG; Lei WANG; Changsheng LIU

    2011-01-01

    Three titanium-zirconium-phosphonate hybrid films were formed on AA6061 aluminum alloy by immersing in fluorotitanic acid and fluorozirconic acid based solution containing different phosphonic acids for protective coatings of aluminium alloy. The corrosion resistance of three hybrid films as the substitute for chromate film were evaluated and compared. The neutral salt spray test was explored,the immersion test was conducted and electrochemical test was also executed. The hybrid films exhibited well-pleasing corrosion resistance and adhesion to epoxy resin paints. It was found out that the hybrid films could efficiently be a substitute for chromate based primer over aluminium alloy.

  2. Alloying element's substitution in titanium alloy with improved oxidation resistance and enhanced magnetic properties

    Science.gov (United States)

    Yu, Ang-Yang; Wei, Hua; Hu, Qing-Miao; Yang, Rui

    2017-01-01

    First-principles method is used to characterize segregation and magnetic properties of alloyed Ti/TiO2interface. We calculate the segregation energy of the doped Ti/TiO2 interface to investigate alloying atom's distribution. The oxidation resistance of Ti/TiO2 interface is enhanced by elements Fe and Ni but reduced by element Co. Magnetism could be produced by alloying elements such as Co, Fe and Ni in the bulk of titanium and the surface of Ti at Ti/TiO2 interface. The presence of these alloying elements could transform the non-magnetic titanium alloys into magnetic systems. We have also calculated the temperature dependence of magnetic permeability for the doped and pure Ti/TiO2 interfaces. Alloying effects on the Curie temperature of the Ti/TiO2 interface have been elaborated.

  3. Sulfur segregation in titanium and selected titanium alloys

    Science.gov (United States)

    Outlaw, R. A.; Lee, W. S.; Hoekje, S. J.; Sankaran, S. N.

    1994-10-01

    The segregation of S in electrotransport-purified polycrystalline α-Ti and in several polycrystalline Ti alloys has been studied by Auger electron spectroscopy and ion scattering spectroscopy in the temperature range extending from 20 to 1000°C. The chemisorbed oxygen and carbon on Ti were observed to disappear at T ≈ 400°C after which the S signal increased to levels approaching 0.5 monolayer. At lower temperatures the presence of the surface oxygen and carbon appeared to inhibit the segregation, presumably because there were no available surfaces sites for the S emerging from the bulk. The activation energy for the S segregation in pure polycrystalline Ti was determined to be 16.7 kcal/mol, which, when compared to S segregation from single-crystal Ti, is quite small and suggest grain boundary or defect diffusion segregation kinetics. In the Ti-aluminide alloys, the presence of Al appeared to enhance the retention of surface oxygen which, in turn, substantially reduced the S segregation. The γ alloy, with its high Al content, exhibited the greatest retention of surface oxygen and the smallest quantity of S segregation ( T ≈ 1000°C). On the other hand, the β-21S alloy exhibited a greater segregation rate for the S than did α-Ti.

  4. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, S., E-mail: hamann@inp-greifswald.de; Röpcke, J. [INP-Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Börner, K.; Burlacov, I.; Spies, H.-J. [TU Bergakademie Freiberg, Institute of Materials Engineering, Gustav-Zeuner-Str. 5, 09599 Freiberg (Germany); Strämke, M.; Strämke, S. [ELTRO GmbH, Arnold-Sommerfeld-Ring 3, 52499 Baesweiler (Germany)

    2015-12-15

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH{sub 4}, C{sub 2}H{sub 2}, HCN, and NH{sub 3}). With the help of OES, the rotational temperature of the screen plasma could be determined.

  5. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

    Science.gov (United States)

    Hamann, S.; Börner, K.; Burlacov, I.; Spies, H.-J.; Strämke, M.; Strämke, S.; Röpcke, J.

    2015-12-01

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH4, C2H2, HCN, and NH3). With the help of OES, the rotational temperature of the screen plasma could be determined.

  6. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen.

    Science.gov (United States)

    Hamann, S; Börner, K; Burlacov, I; Spies, H-J; Strämke, M; Strämke, S; Röpcke, J

    2015-12-01

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH4, C2H2, HCN, and NH3). With the help of OES, the rotational temperature of the screen plasma could be determined.

  7. Wire electrochemical machining with axial electrolyte flushing for titanium alloy

    Institute of Scientific and Technical Information of China (English)

    Qu Ningsong; Fang Xiaolong; Li Wei; Zeng Yongbin; Zhu Di

    2013-01-01

    Titanium and its alloys have found very wide application in aerospace due to their excellent characteristics although their processing is still a challenge.Electrochemical machining is an important issue in the fabrication of titanium and titanium alloys.Wire electrochemical machining (WECM) is mainly used for workpiece cutting under the condition of different thickness plates.It has a great advantage over wire electro-discharge machining,which is the absence of heat-affected zone around the cutting area.Moreover,the wire electrode in WECM could be used repetitively because it is not worn out.Thus,much attention has been paid to WECM.The effective way of removing electrolysis products is of importance to WECM.In this paper,the axial electrolyte flushing is presented to WECM for removing electrolysis products and renewing electrolyte.The Taguchi experiment is conducted to optimize the machining parameters,such as wire feedrate,machining voltage,electrolyte concentration,etc.Experimental results show that WECM with axial electrolyte flushing is a promising issue in the fabrication of titanium alloy (TC1).The feasibility of multi-wire electrochemical machining is also demonstrated to improve the machining productivity of WECM.

  8. Corrosion resistance improvement of titanium base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Popa, Mihai V.; Vasilescu, Ecaterina; Drob, Paula; Vasilescu, Cora; Drob, Silviu I., E-mail: ec_vasilescu@yahoo.co [Institute of Physical Chemistry ' Ilie Murgulescu' , Bucharest (Romania); Mareci, Daniel [Technical University ' Gh. Asachi' , Iasi (Romania); Rosca, Julia C. Mirza [Las Palmas de Gran Canaria University, Tafira (Spain). Mechanical Engineering Dept.

    2010-07-01

    The corrosion resistance of the new Ti-6Al-4V-1Zr alloy in comparison with ternary Ti-6Al-4V alloy in Ringer-Brown solution and artificial Carter-Brugirard saliva of different pH values was studied. In Ringer-Brown solution, the new alloy presented an improvement of all electrochemical parameters due to the alloying with Zr; also, impedance spectra revealed better protective properties of its passive layer. In Carter-Brugirard artificial saliva, an increase of the passive film thickness was proved. Fluoride ions had a slight negative influence on the corrosion and ion release rates, without to affect the very good stability of the new Ti-6Al-4V-1Zr alloy. (author)

  9. Corrosion resistance improvement of titanium base alloys

    Directory of Open Access Journals (Sweden)

    Mihai V. Popa

    2010-01-01

    Full Text Available The corrosion resistance of the new Ti-6Al-4V-1Zr alloy in comparison with ternary Ti-6Al-4V alloy in Ringer-Brown solution and artificial Carter-Brugirard saliva of different pH values was studied. In Ringer-Brown solution, the new alloy presented an improvement of all electrochemical parameters due to the alloying with Zr; also, impedance spectra revealed better protective properties of its passive layer. In Carter-Brugirard artificial saliva, an increase of the passive film thickness was proved. Fluoride ions had a slight negative influence on the corrosion and ion release rates, without to affect the very good stability of the new Ti-6Al-4V-1Zr alloy.

  10. Micro-Structures of Hard Coatings Deposited on Titanium Alloys by Laser Alloying Technique

    Science.gov (United States)

    Li, Wei; Yu, Huijun; Chen, Chuanzhong; Wang, Diangang; Weng, Fei

    2013-01-01

    This work is based on micro-structural performance of the Ti-B4C-C laser alloying coatings on Ti-6Al-4V titanium alloy. The test results indicated that laser alloying of the Ti-B4C-C pre-placed powders on the Ti-6Al-4V alloy substrate can form the ceramics reinforced hard alloying coatings, which increased the micro-hardness and wear resistance of substrate. The test result also indicated that the TiB phase was produced in alloying coating, which corresponded to its (101) crystal plane. In addition, yttria has a refining effect on micro-structures of the laser alloying coating, and its refinement mechanism was analyzed. This research provided essential experimental and theoretical basis to promote the applications of the laser alloying technique in manufacturing and repairing of the aerospace parts.

  11. Improved adherence of sputtered titanium carbide coatings on nickel- and titanium-base alloys

    Science.gov (United States)

    Wheeler, D. R.; Brainard, W. A.

    1979-01-01

    Rene 41 and Ti-6Al-4V alloys were radio frequency sputter coated with titanium carbide by several techniques in order to determine the most effective. Coatings were evaluated in pin-on-disk tests. Surface analysis by X-ray photoelectron spectroscopy was used to relate adherence to interfacial chemistry. For Rene 41, good coating adherence was obtained when a small amount of acetylene was added to the sputtering plasma. The acetylene carburized the alloy surface and resulted in better bonding to the TiC coating. For Ti-6Al-4V, the best adherence and wear protection was obtained when a pure titanium interlayer was used between the coating and the alloy. The interlayer is thought to prevent the formation of a brittle, fracture-prone, aluminum oxide layer.

  12. The effect of Mo on the characteristics of a plasma nitrided layer of sintered iron

    Energy Technology Data Exchange (ETDEWEB)

    Bendo, T., E-mail: tatiana.bendo@labmat.ufsc.br [UFSC – LabMat - Laboratório de Materiais, Bloco B – Eng. Mecânica, 88040900, Florianópolis, SC (Brazil); Maliska, A.M., E-mail: a.maliska@ufsc.br [UFSC – LabMat - Laboratório de Materiais, Bloco B – Eng. Mecânica, 88040900, Florianópolis, SC (Brazil); Acuña, J.J.S., E-mail: Javier.acuna@ufabc.edu.br [UFABC – Universidade Federal do ABC, Centro de Ciências Nat. e Humanas, R. Sta. Adélia 166, 09210170, Santo André, SP (Brazil); Binder, C., E-mail: Cristiano.binder@labmat.ufsc.br [UFSC – LabMat - Laboratório de Materiais, Bloco B – Eng. Mecânica, 88040900, Florianópolis, SC (Brazil); Hammes, G., E-mail: gisele.hammes@labmat.ufsc.br [UFSC – LabMat - Laboratório de Materiais, Bloco B – Eng. Mecânica, 88040900, Florianópolis, SC (Brazil); Consoni, D.R., E-mail: deise.r.c@labmat.ufsc.br [UFSC – LabMat - Laboratório de Materiais, Bloco B – Eng. Mecânica, 88040900, Florianópolis, SC (Brazil); Klein, A.N., E-mail: a.n.klein@labmat.ufsc.br [UFSC – LabMat - Laboratório de Materiais, Bloco B – Eng. Mecânica, 88040900, Florianópolis, SC (Brazil)

    2016-02-15

    Graphical abstract: - Highlights: • Microstructure of the white layer formed on nitrided Fe-Mo. • Plasma nitriding. • Nitriding of the Fe-Mo alloys. • Morphology of the hererogeneous Fe-Mo-N nitrides. • Morphology and constitution of the compound layer formed on Fe-Mo alloy. - Abstract: Samples of PM (powder metallurgy) plain iron were superficially enriched with Mo during a sintering process using a DC discharge. The Mo atoms from the cathode produced an enriched layer of approximately 15–20 μm thick, and it was enriched with up to 2.0 at.% Mo. Subsequently, the samples were plasma nitrided in a gas mixture (N{sub 2}/H{sub 2}) at different temperatures and nitrogen concentrations. The effect of the molybdenum on the plasma nitrided layer of sintered iron was investigated. Abnormal nitride morphologies that developed in the surface layer were observed. The presence of Mo that was substitutionally dissolved in ferrite influences the nucleation and growth of the iron-nitride compound layer. The microstructure and (local) composition changes of the layers were investigated using scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) and glow discharge optical emission spectroscopy (GDOES) analyses. To evaluate the mechanical properties, Vickers microhardness tests were conducted along the sample cross-sections. According to the nitriding conditions, submicroscopic fcc Mo{sub 2}N-type nitrides that are coherent with the α-Fe matrix develop, as confirmed by the TEM analysis and by the broadening of the diffraction lines in the X-ray diffractogram. Molybdenum nitrides, γ-Mo{sub 2}N, with an fcc structure and sphere-like shapes were observed on the sample surface where the Mo concentrations were higher.

  13. Plasma surface alloying of titanium alloy for enhancing burn-resistant property

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping-ze; XU Zhong; ZHANG Gao-hui; HE Zhi-yong; YAO Zheng-jun

    2006-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, burn-resistant alloying layers were made on the surface of Ti-6Al-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si titanium alloys by using double glow plasma surface alloying technology (DG Technology). Two typical burn-resistant layers Ti-Cr and Ti-Mo were made by DG plasma chromizing and DG plasma molybdenizing, respectively. Burn-resistant properties were tested by layer ignition method using 2 kW laser machine. Ignition experiments result reveals that the ignition temperature of alloyed layer with Mo and Cr concentration above 10% is about 200℃ higher than ignition temperature of Ti-6Al-4V substrate.

  14. Producing titanium-niobium alloy by high energy beam

    Energy Technology Data Exchange (ETDEWEB)

    Sharkeev, Yu. P., E-mail: sharkeev@ispms.tsc.ru [Institute of Strength Physics and Materials Science, SB RAS, 2/4 Akademicheski Prosp., Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, 30 Lenin Av., Tomsk, 634050 (Russian Federation); Golkovski, M. G., E-mail: golkoski@mail.ru [Budker Institute of Nuclear Physics, 11 Akademika Lavrentiev Prosp., Novosibirsk, 630090 (Russian Federation); Glukhov, I. A., E-mail: gia@ispms.tsc.ru; Eroshenko, A. Yu., E-mail: eroshenko@ispms.tsc.ru; Fortuna, S. V., E-mail: s-fortuna@mail.ru [Institute of Strength Physics and Materials Science, SB RAS, 2/4 Akademicheski Prosp., Tomsk, 634055 (Russian Federation); Bataev, V. A., E-mail: bataev@vadm.ustu.ru [Novosibirsk State Technical University, 20 K. Marx Prosp., Novosibirsk, 630073 (Russian Federation)

    2016-01-15

    The research is involved in producing a Ti-Nb alloy surface layer on titanium substrate by high energy beam method, as well as in examining their structures and mechanical properties. Applying electron-beam cladding it was possible to produce a Ti-Nb alloy surface layer of several millimeters, where the niobium concentration was up to 40% at. and the structure itself could be related to martensite quenching structure. At the same time, a significant microhardness increase of 3200-3400 MPa was observed, which, in its turn, is connected with the formation of martensite structure. Cladding material of Ti-Nb composition could be the source in producing alloys of homogeneous microhardness and desired concentration of alloying niobium element.

  15. Plasma-nitriding of tantalum at relatively low temperature

    Institute of Scientific and Technical Information of China (English)

    ZHANG Deyuan; LIN Qin; ZHAO Haomin; FEI Qinyong; GENG Man

    2004-01-01

    The combined quadratic orthogonal regression method of experiment design was employed to explore the effects of process parameters of plasma nitriding of tantalum such as total pressure, temperature and original hydrogen molar fraction on the hardness, roughness and structure of nitriding surfaces. The regression equations of hardness, roughness and structure were given according to the results of regression and statistic analysis. And the diffusion activation energy of nitrogen in tantalum on plasma nitriding conditions was calculated according to the experimental data of hardness of plasma-nitriding of tantalum vs time and temperature. The diffusion activation energy calculated belongs to (155.49 + 10.51)kJ/mol (783-983 K).

  16. Microcrack formation in high-deformed titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Gridnev, V.N.; Ivasishin, O.M.; Svechnikov, V.L. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)

    1984-10-01

    ..cap alpha..-phase interlayers on the ..cap alpha../..beta.. boundary with orientation different from a matrix alloys can act as cause of titanium alloys hardening with simultaneous decrease of their ductility. Electron microexamination of the structure of ..cap alpha..-phase located both on interfaces and in ..cap alpha..-grain volume provides evidence that deformation twinning on different planes and slip in a matrix ..cap alpha..-phase are the mechanism of the ..cap alpha..-phase formation. Examples of ..cap alpha..-phase participation with orientation different from the matrix one are presented in the process of microcracks formation.

  17. Environmental protection of titanium alloys at high temperatures

    Science.gov (United States)

    Wright, I. G.; Wood, R. A.; Seltzer, M. S.

    1974-01-01

    Various concepts were evaluated for protecting titanium alloys from oxygen contamination at 922 K (1200 F) and from hot-salt stress-corrosion at 755 K (900 F). It is indicated that oxygen-contamination resistance can be provided by a number of systems, but for hot-salt stress-corrosion resistance, factors such as coating integrity become very important. Titanium aluminides resist oxygen ingress at 922 K through the formation of alumina (on TiAl3) or modified TiO2 (on Ti3Al, TiAl) scales. TiAl has some resistance to attack by hot salt, but has limited ductility. Ductile Ti-Ni and Ti-Nb-Cr-Al alloys provide limited resistance to oxygen ingress, but are not greatly susceptible to hot-salt stress-corrosion cracking.

  18. Superplastic forming gas pressure of titanium alloy bellows

    Institute of Scientific and Technical Information of China (English)

    王刚; 张凯锋; 陈军; 阮雪榆

    2004-01-01

    The complex superplastic forming (SPF) technology applying gas pressure and compressive axial load is an advanced forming method for titanium alloy bellows, whose forming process consists of the three main forming phases namely bulging, clamping and calibrating phase. The influence of forming gas pressure in various phases on the forming process was analyzed and the models of forming gas pressure for bellows were derived according to the thin shell theory and the plasticity deformation theory. Using the model values, taking a two-convolution DN250 Ti6Al-4V titanium alloy bellows as an example, a series of superplastic forming tests were performed to evaluate the influence of the variation of forming gas pressure on the forming process. According to the experimental results these models were corrected to make the forming gas pressures prediction more accurate.

  19. Isothermal Aging Precipitate of TB17 Titanium Alloy

    Directory of Open Access Journals (Sweden)

    WANG Zhe

    2016-10-01

    Full Text Available Transmission Electron Microscope (TEM, X-Ray Diffraction(XRD and Optical Microscope(OMwere employed to investigate the aging precipitation behavior of a new type of ultra-high strength TB17 titanium alloy. The results show that during heat solution treated in the β phase field followed by aging the secondary α phase is nucleated, precipitated and grew on the β phase matrix,and the precipitated phase is lamellar structure which has burgers relation with the matrix. The secondary α phase content is increased rapidly and finally reach a steady-state as aging time increased and the final product of aging consists of α phase and β phase. there is a good linearity relationship between the content of secondary α phase and the hardness of age hardening. The TB17 titanium alloy isothermal phase transformation kinetics can be described by JMAK equation.

  20. Low-Temperature Forming of Beta Titanium Alloys

    Science.gov (United States)

    Kaneko, R. S.; Woods, C. A.

    1983-01-01

    Low cost methods for titanium structural fabrication using advanced cold-formable beta alloys were investigated for application in a Mach 2.7 supersonic cruise vehicle. This work focuses on improving processing and structural efficiencies as compared with standard hot formed and riveted construction of alpha-beta alloy sheet structure. Mechanical property data and manufacturing parameters were developed for cold forming, brazing, welding, and processing Ti-15V-3Cr-3Sn-3Al sheet, and Ti-3Al-8V-6Cr-4Zr on a more limited basis. Cost and structural benefits were assessed through the fabrication and evaluation of large structural panels. The feasibility of increasing structural efficiency of beta titanium structure by selective reinforcement with metal matrix composite was also explored.

  1. Tool Failure Analysis in High Speed Milling of Titanium Alloys

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiuxu; MEYER Kevin; HE Rui; YU Cindy; NI Jun

    2006-01-01

    In high speed milling of titanium alloys the high rate of tool failure is the main reason for its high manufacturing cost. In this study, fractured tools which were used in a titanium alloys 5-axis milling process have been observed both in the macro scale using a PG-1000 light microscope and in the micro scale using a Scanning Electron Microscope (SEM) respectively. These observations indicate that most of these tool fractures are the result of tool chipping. Further analysis of each chipping event has shown that beachmarks emanate from points on the cutting edge. This visual evidence indicates that the cutting edge is failing in fatigue due to cyclical mechanical and/or thermal stresses. Initial analyses explaining some of the outlying conditions for this phenomenon are discussed. Future analysis regarding determining the underlying causes of the fatigue phenomenon is then outlined.

  2. Mechanical properties and corrosion resistance of some titanium alloys in marine environment

    Directory of Open Access Journals (Sweden)

    Dupuis Jennifer

    2013-11-01

    Full Text Available Titanium alloys are used in several fields such as aerospace industry or biomedical. They are increasingly used in marine applications, a highly corrosive environment. We chose titanium alloys for their good properties such as high mechanical strength, low density and excellent corrosion resistance. This study is focused on titanium alloys potentially interesting to be used in marine transports, and mainly for the boats fittings such as a winch for example.

  3. Corrosion of Titanium Alloys in High Temperature Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Pang, J. J.; Blackwood, D. J. [National University of Singapore, Singapore (Singapore)

    2015-08-15

    Materials of choice for offshore structures and the marine industry have been increasingly favoring materials that offer high strength-to-weight ratios. One of the most promising families of light-weight materials is titanium alloys, but these do have two potential Achilles' heels: (i) the passive film may not form or may be unstable in low oxygen environments, leading to rapid corrosion; and (ii) titanium is a strong hydride former, making it vulnerable to hydrogen embrittlement (cracking) at high temperatures in low oxygen environments. Unfortunately, such environments exist at deep sea well-heads; temperatures can exceed 120 °C, and oxygen levels can drop below 1 ppm. The present study demonstrates the results of investigations into the corrosion behavior of a range of titanium alloys, including newly developed alloys containing rare earth additions for refined microstructure and added strength, in artificial seawater over the temperature range of 25 °C to 200 °C. Tests include potentiodynamic polarization, crevice corrosion, and U-bend stress corrosion cracking.

  4. Isothermal and Near Isothermal Processing of Titanium Alloys

    Directory of Open Access Journals (Sweden)

    T. Raghu

    2011-01-01

    Full Text Available Isothermal and near isothermal forging are specialized metal processing techniques which are used for producing critical aeroengine components out of advanced materials such as titanium alloys. The process can be used to produce net / near net shape components leading to optimum utilization of materials. As titanium alloys are highly sensitive to temperature and strain rate, these processes help to deform them under slow and controlled strain rates.  Further, these processes can be combined with other conventional and non conventional metal forming processes to refine the microstructure. For example, multiaxial isothermal forging coupled with pack rolling can be used to produce thin sheets out of titanium alloys with submicron grain size. The refined structure exhibits superplastic characteristics at low temperatures and high strain rates. This lower temperature superplastic characteristic can be exploited to establish technologies for producing various components. The paper throws light on the capabilities of isothermal forging process and its variants.Defence Science Journal, 2011, 61(1, pp.72-80, DOI:http://dx.doi.org/10.14429/dsj.61.321

  5. Experimental study of multiple scattering in anisotropic titanium alloys

    Science.gov (United States)

    Baelde, Aurelien; Laurent, Jérôme; Coulette, Richard; Khalifa, Warida Ben; Duclos, Daniel; Jenson, Frédéric; Fink, Mathias; Prada, Claire

    2017-02-01

    Ultrasonic testing of jet engine titanium alloys is of high importance for the aircraft manufacturing industry. The quality of ultrasonic non-destructive testing is severely impacted by the titanium complex microstructure. These alloys have been extensively studied and single scattering models are now well known and implemented in ultrasonic propagation simulators. In addition, titanium billets and forged parts have been known to exhibit a highly anisotropic microstructure. We studied ultrasonic wave scattering in Ti17 forged disk, through statistical analysis of the backscattered noise generated by the microstructure. More specifically, we focused on the quantification of multiple scattering relative to single scattering in the backscattered wave. To that end, we used the full matrix capture acquisition with a linear transducer array. Two phenomena were used to quantify the proportion of single scattering with respect to multiple scattering. The first is the coherent backscattering effect, used as a binary indicator of multiple scattering. The second is a repurposed version of the multiple scattering filter, recently developed on random rod forest and applied on Inconel alloys. With these methods, significant level of multiple scattering was consistently measured in Ti17 forged disks, showing that ultrasonic testing could be enhanced by filtering the multiple scattering contribution.

  6. Formation of titanium carbide layer by laser alloying with a light-transmitting resin

    Science.gov (United States)

    Yamaguchi, Takuto; Hagino, Hideki

    2017-01-01

    The weight reduction of mechanical components is becoming increasingly important, especially in the transportation industry, as fuel efficiency continues to improve. Titanium and titanium alloys are recognized for their outstanding potential as lightweight materials with high specific strength. Yet they also have poor tribological properties that preclude their use for sliding parts. Improved tribological properties of titanium would expand the application of titanium into different fields. Laser alloying is an effective process for improving surface properties such as wear resistance. The process has numerous advantages over conventional surface modification techniques. Many researchers have reported the usefulness of laser alloying as a technique to improve the wear resistance of titanium. The process has an important flaw, however, as defects such as cracks or voids tend to appear in the laser-alloyed zone. Our group performed a novel laser-alloying process using a light-transmitting resin as a source for the carbon element. We laser alloyed a surface layer of pure titanium pre-coated with polymethyl methacrylate (PMMA) and investigated the microstructure and wear properties. A laser-alloyed zone was formed by a reaction between the molten titanium and thermal decomposition products of PMMA at the interface between the substrate and PMMA. The cracks could be eliminated from the laser-alloyed zone by optimizing the laser alloying conditions. The surface of the laser-alloyed zone was covered with a titanium carbide layer and exhibited a superior sliding property and wear resistance against WC-Co.

  7. Research and Development on Titanium Alloys

    Science.gov (United States)

    1949-08-31

    0.010 0.09 131 Middle 0.05 0.009 0.11 137 0.04 0.008 0.18 131 Bottom 0.04 0.013 0.12 137 0.06 0.007 0.19 131 EVALUATION OF EXPERIENTAL TITANIUM-BASE...018 together with the vacuum- fusion method. The procedure consisted of diluting a known amount of 018 (1) Private communication from Dr. G. Derge...Carnegie Institute of Technology, arranged through the eourtesy of D. Walter A. Findlay, Remington Arms, Co., Inc. (2) Private communication from Mr. E. J

  8. Laser cladding of titanium alloy coating on titanium aluminide alloy substrate

    Institute of Scientific and Technical Information of China (English)

    徐子文; 黄正; 阮中健

    2003-01-01

    A new diffusion bonding technique combined with laser cladding process was developed to join TiAl alloy to itself and Ti-alloys. In order to enhance the weldability of TiAl alloys, Ti-alloy coatings were fabricated by laser cladding on the TiAl alloy. Ti powder and shaped Ti-alloy were respectively used as laser cladding materials. The materials characterization was carried out by OM, SEM, EDS and XRD analysis. The results show that the laser cladding process with shaped Ti-alloy remedy the problems present in the conventional process with powder, such as impurities, cracks and pores. The diffusion bonding of TiAl alloy with Ti-alloy coating to itself and Ti-alloy was carried out with a Gleeble 1500 thermal simulator. The sound bonds of TiAl/TiAl, TiAl/Ti were obtained at a lower temperature and with shorter time.

  9. Modification of the titanium alloy surface in electroexplosive alloying with boron carbide and subsequent electron-beam treatment

    Science.gov (United States)

    Gromov, Victor E.; Budovskikh, Evgeniy A.; Ivanov, Yurii F.; Bashchenko, Lyudmila P.; Wang, Xinli; Kobzareva, Tatyana Yu.; Semin, Alexander P.

    2015-10-01

    The modification of the VT6 titanium alloy surface in electroexplosion alloying with plasma being formed in titanium foil with a weighed powder of boron carbide with subsequent irradiation by a pulsed electron beam has been carried out. An electroexplosive alloying zone of a thickness up to 50 μm with a gradient structure is found to form. The subsequent electron-beam treatment of the alloying zone results in smoothing of the alloying surface and is accompanied by the formation of the multilayer structure with alternating layers of various alloying degree at a depth of 30 μm.

  10. Modification of the titanium alloy surface in electroexplosive alloying with boron carbide and subsequent electron-beam treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gromov, Victor E., E-mail: gromov@physics.sibsiu.ru; Budovskikh, Evgeniy A., E-mail: budovskikh-ea@physics.sibsiu.ru; Bashchenko, Lyudmila P., E-mail: gromov@physics.sibsiu.ru; Kobzareva, Tatyana Yu., E-mail: gromov@physics.sibsiu.ru; Semin, Alexander P., E-mail: gromov@physics.sibsiu.ru [Siberian State Industrial University, Novokuznetsk, 654007 (Russian Federation); Ivanov, Yurii F., E-mail: yufi55@mail.ru [Institute of High Current Electronics SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Wang, Xinli, E-mail: wangxl520@hotmail.com [Northeastern University, Liaoning, Shenyang 110819 China (China)

    2015-10-27

    The modification of the VT6 titanium alloy surface in electroexplosion alloying with plasma being formed in titanium foil with a weighed powder of boron carbide with subsequent irradiation by a pulsed electron beam has been carried out. An electroexplosive alloying zone of a thickness up to 50 μm with a gradient structure is found to form. The subsequent electron-beam treatment of the alloying zone results in smoothing of the alloying surface and is accompanied by the formation of the multilayer structure with alternating layers of various alloying degree at a depth of 30 μm.

  11. Wettability Modification for Biosurface of Titanium Alloy by Means of Sequential Carburization

    Institute of Scientific and Technical Information of China (English)

    Yong Luo; Shirong Ge; Zhong-min Jin

    2009-01-01

    Microporous titanium carbide coating was successfully synthesized on medical grade titanium alloy by using sequential carburization. Changes in the surface morphology of titanium alloy occasioned by sequential carburization were characterized and the wettability characteristics were quantified. Furthermore, the dispersion forces were calculated and discussed. The results indicate that sequential carburization is an effective way to modify the wettability of titanium alloy. After the carburization the surface dispersion force of titanium alloy increased from 76.5 × 10-3 J·m-2 to 105.5 × 10-3 J·m-2, with an enhancement of 37.9 %. Meanwhile the contact angle of titanium alloy decreased from 83° to 71.5°, indicating a significant improvement of wettability, which is much closer to the optimal water contact angle for cell adhesion of 70°.

  12. Wear resistance of experimental titanium alloys for dental applications.

    Science.gov (United States)

    Faria, Adriana Cláudia Lapria; Rodrigues, Renata Cristina Silveira; Claro, Ana Paula Rosifini Alves; da Gloria Chiarello de Mattos, Maria; Ribeiro, Ricardo Faria

    2011-11-01

    The present study evaluated microstructure, microhardness and wear resistance of experimental titanium alloys containing zirconium and tantalum. Alloys were melted in arc melting furnace according to the following compositions: Ti-5Zr, Ti-5Ta and Ti-5Ta-5Zr (%wt). Hemispheres and disks were obtained from wax patterns that were invested and cast by plasma. Microstructures were evaluated using optical microscopy and X-ray diffraction (XRD) analysis and also Vickers microhardness was measured. Hemispherical samples and disks were used for 2-body wear tests, performed by repeated grinding of the samples. Wear resistance was assessed as height loss after 40,000 cycles. The data were compared using ANOVA and post-hoc Tukey test. Ti-5Zr presented a Widmanstätten structure and the identified phases were α and α' while Ti-5Ta and Ti-5Ta-5Zr presented α, β, α' and α" phases, but the former presented a lamellar structure, and the other, acicular. The microhardness of Ti-5Zr was significantly greater than other materials and cp Ti presented wear resistance significantly lower than experimental alloys. It was concluded that wear resistance was improved when adding Ta and Zr to titanium and Zr increased microhardness of Ti-5Zr alloy.

  13. Diffusion bonding of Al7075 alloy to titanium aluminum vanadate alloy

    Science.gov (United States)

    Alhazaa, Abdulaziz Nasser

    The aluminum alloy (Al7075) and titanium alloy (Ti-6Al-4V) are used in a variety of applications in the aerospace industry. However, the high cost of Ti-6Al-4V alloy has been a major factor which has limited its use and therefore, the ability to join Al7075 alloy to Ti-6Al-4V alloy can provide a product that is less costly, but retains the high strength and light weight properties necessary for the transport industry. However, the large difference in the physical properties between these two alloys prevents the use of conventional joining techniques such as fusion welding to join these dissimilar alloys. Therefore, the diffusion bonding technique was used to join Al7075 alloy to Ti-6Al-4V alloy with the objective of minimizing microstructural changes of the two alloys during the bonding process. In this thesis, solid state and liquid phase bonding processes were undertaken. Solid state bonding was employed without interlayers and was successful at 510°C and 7 MPa. The bond interface showed an absence of the oxides due to the dissolution of oxygen into the titanium solution. Bonds made using copper interlayers at a temperature sufficient enough to form eutectic liquid formation between copper and aluminum were produced. The intermetallics theta(Al2Cu), S(Al2CuMg) and T(Al2Mg3Zn3) were identified at the aluminum interface while Cu3Ti2 intermetallic was identified at the titanium interface. Bonds made using tin based alloys interlayers and copper coatings were successful and gave the highest shear strength. The eutectic formation on the Al7075 alloy was responsible for joint formation at the aluminum interface while the formation of Sn3Ti5 intermetallic was responsible for the joint formation at titanium interface. The corrosion rate of the bonds decreased with increasing bonding time for joints made using the tin based interlayer in 3% NaCl solution. However, the presence of copper within the joint increased the corrosion rate of the bonds and this was attributed to

  14. Development of Titanium Alloy Casting Technology

    Science.gov (United States)

    1976-08-01

    Tensile Property Evaluacions 34 3.1.4.4 Microstructural Evaluation 35 3.1.5 Task IiT - investigations 37 3.1.5.1 Alloy Selections 38 3.1.5.2 Tensile...ganic sintering aids (CaO, SiO 2 , etc.) for integrating the lower reactivity ceramics (Y203, ThO2, HREMO, etc.) into the mold fabrication process

  15. /SiC Composite to Titanium Alloy

    Science.gov (United States)

    Hernandez, X.; Jiménez, C.; Mergia, K.; Yialouris, P.; Messoloras, S.; Liedtke, V.; Wilhelmi, C.; Barcena, J.

    2014-08-01

    In view of aerospace applications, an innovative structure for joining a Ti alloy to carbon fiber reinforced silicon carbide has been developed. This is based on the perforation of the CMC material, and this procedure results in six-fold increase of the shear strength of the joint compared to the unprocessed CMC. The joint is manufactured using the active brazing technique and TiCuAg as filler metal. Sound joints without defects are produced and excellent wetting of both the composite ceramic and the metal is observed. The mechanical shear tests show that failure occurs always within the ceramic material and not at the joint. At the CMC/filler, Ti from the filler metal interacts with the SiC matrix to form carbides and silicides. In the middle of the filler region depletion of Ti and formation of Ag and Cu rich regions are observed. At the filler/Ti alloy interface, a layered structure of the filler and Ti alloy metallic elements is formed. For the perforation to have a significant effect on the improvement of the shear strength of the joint appropriate geometry is required.

  16. Alloy Design and Thermomechanical Processing of a Beta Titanium Alloy for a Heavy Vehicle Application

    Energy Technology Data Exchange (ETDEWEB)

    Blue, C.A.; Peter, W.H.

    2010-07-02

    With the strength of steel, but at half the weight, titanium has the potential to offer significant benefits in the weight reduction of heavy vehicle components while possibly improving performance. However, the cost of conventional titanium fabrication is a major barrier in implementation. New reduction technologies are now available that have the potential to create a paradigm shift in the way the United States uses titanium, and the economics associated with fabrication of titanium components. This CRADA project evaluated the potential to develop a heavy vehicle component from titanium powders. The project included alloy design, development of manufacturing practices, and modeling the economics associated with the new component. New Beta alloys were designed for this project to provide the required mechanical specifications while utilizing the benefits of the new fabrication approach. Manufacturing procedures were developed specific to the heavy vehicle component. Ageing and thermal treatment optimization was performed to provide the desired microstructures. The CRADA partner established fabrication practices and targeted capital investment required for fabricating the component out of titanium. Though initial results were promising, the full project was not executed due to termination of the effort by the CRADA partner and economic trends observed in the heavy vehicle market.

  17. Hydrogen trapping in aged {beta}-titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Pound, B.G. [SRI International, Menlo Park, CA (United States). Materials Research Center

    1997-05-01

    Hydrogen trapping in three {beta}-titanium alloys (unaged and aged Ti-15V-3Cr-3Al-3Sn and Beta-21S, and partially aged Beta-C) was investigated using a potentiostatic pulse technique. The apparent trapping constant ({kappa}{sub a}) and hydrogen entry flux were determined for each alloy in 1 mol l{sup {minus}1} acetic acid/1 mol l{sup {minus}1} sodium acetate. The results were compared with those for other {beta}-Ti alloys (Ti-10V-2Fe-3Al, Ti-13V-11Cr-3Al and fully aged Beta-C) studied previously. Aging caused a negligible change in {kappa}{sub a} for Ti-15-3, whereas a marked increase was observed for Beta-21S and the other {beta}-Ti alloys. Among the aged alloys, Ti-13-11-3 had the highest value of {kappa}{sub a} and Ti-15-3 had the lowest value. The intrinsic susceptibilities of Beta-C and Beta-21S to hydrogen embrittlement (HE), as represented by the trapping constants, were comparable and significantly higher than that of Ti-15-3. The susceptibilities were consistent with the relative resistances to HE observed for these alloys.

  18. [The effect of plasma nitriding on tungsten burs].

    Science.gov (United States)

    Cicciu, D; Russo, S; Grasso, C

    1989-01-01

    The authors have experimented the nitriding's effects on some cilindrical burs carbide utilized in dentistry after disamination on the applications methodics on plasma nitriding in neurosurgery, orthopedic surgery and in odontotherapy. This reacherys point out that nitriding plasma a durings increase and cutis greater capacity establish.

  19. Shear bond strength between titanium alloys and composite resin: sandblasting versus fluoride-gel treatment.

    Science.gov (United States)

    Lim, Bum-Soon; Heo, Seok-Mo; Lee, Yong-Keun; Kim, Cheol-We

    2003-01-15

    The aim of this study was to investigate the effect of fluoride gel treatment on the bond strength between titanium alloys and composite resin, and the effect of NaF solution on the bond strength of titanium alloys. Five titanium alloys and one Co-Cr-Mo alloy were tested. Surface of the alloys were treated with three different methods; SiC polishing paper (No. 2000), sandblasting (50-microm Al2O3), and commercially available acidulated phosphate fluoride gel (F-=1.23%, pH 3.0). After treatment, surfaces of alloy were analyzed by SEM/EDXA. A cylindrical gelatin capsule was filled with a light-curable composite resin. The composite resin capsule was placed on the alloy surface after the application of bonding agent, and the composite resin was light cured for 30 s in four different directions. Shear bond strength was measured with the use of an Instron. Fluoride gel did not affect the surface properties of Co-Cr-Mo alloy and Ni-Ti alloy, but other titanium alloys were strongly affected. Alloys treated with the fluoride gel showed similar bond strengths to the alloys treated with sandblasting. Shear bond strength did not show a significant difference (ptitanium alloys. To enhance the bond strength of composite resin to titanium alloys, fluoride-gel treatment may be used as an alternative technique to the sandblasting treatment.

  20. Application of sintered titanium alloys to metal denture bases: a study of titanium powder sheets for complete denture base.

    Science.gov (United States)

    Doi, H; Harrori, M; Hasegawa, K; Yoshinari, M; Kawada, E; Oda, Y

    2001-02-01

    The purpose of this study was the fabrication of titanium powder sheets to enable the application of sintered titanium alloys as metal denture bases. The effects of titanium particle shape and size, binder content, and plasticizer content on the surface smoothness, tensile strength and elongation of titanium powder sheets was investigated. To select a suitable ratio of powdered metal contents for application as a metal denture base, the effects of aluminum content in Ti sheets and various other powder metal contents in Ti-Al sheets on the density, sintering shrinkage, and bending strength were evaluated. Based on the results of the above experiments, we developed a mixed powder sheet composed of 83Ti-7Al-10Cr with TA45 titanium powder (atomized, -45 microm), and 8 mass% binder content. This titanium alloy sheet had good formability and ductility. Its sintered titanium alloy had a density of 3.2 g/cm3, sintering shrinkage of 3.8%, and bending strength of 403 MPa. The titanium alloy sheet is clinically acceptable for fabricating denture bases.

  1. Cytotoxicity of alloying elements and experimental titanium alloys by WST-1 and agar overlay tests.

    Science.gov (United States)

    Song, Yo-Han; Kim, Min-Kang; Park, Eun-Jin; Song, Ho-Jun; Anusavice, Kenneth J; Park, Yeong-Joon

    2014-09-01

    This study was performed to evaluate the biocompatibility of nine types of pure metals using 36 experimental prosthetic titanium-based alloys containing 5, 10, 15, and 20wt% of each substituted metal. The cell viabilities for pure metals on Ti alloys that contain these elements were compared with that of commercially pure (CP) Ti using the WST-1 test and agar overlay test. The ranking of pure metal cytotoxicity from most potent to least potent was: Co>Cu>In>Ag>Cr>Sn>Au>Pd>Pt>CP Ti. The cell viability ratios for pure Co, Cu, In, and Ag were 13.9±4.6%, 21.7±10.4%, 24.1±5.7%, and 24.8±6.0%, respectively, which were significantly lower than that for the control group (p<0.05). Pure Pd and Pt demonstrated good biocompatibility with cell viabilities of 93.8±9.6% and 97.2±7.1%, respectively. The Ti-5Pd alloy exhibited the highest cell viability (128.4±21.4%), which was greater than that of CP Ti. By alloying pure Co or Cu with Ti, the cell viabilities for the Ti-xCo and Ti-xCu alloys increased significantly up to 10wt% of the alloying element followed by a gradual decrease with a further increase in the concentration of the alloying element. Based on the agar overlay test, pure Ag, Co, Cr, Cu, and In were ranked as 'moderately cytotoxic', whereas all Ti alloys were ranked as 'noncytotoxic'. The cytotoxicity of pure Ag, Co, Cr, Cu, and In suggests a need for attention in alloy design. The cytotoxicity of alloying elements became more biocompatible when they were alloyed with titanium. However, the cytotoxicity of titanium alloys was observed when the concentration of the alloying element exceeded its respective allowable limit. The results obtained in this study can serve as a guide for the development of new Ti-based alloy systems. Copyright © 2014 Academy of Dental Materials. All rights reserved.

  2. Heat-Resistance of the Powder Cobalt Alloys Reinforced by Niobium or Titanium Carbide

    Directory of Open Access Journals (Sweden)

    Cherepova, T.S.

    2016-01-01

    Full Text Available The characteristics of heat-resistance of powder cobalt alloys at 1100 °C were investigated. These alloys were developed for the protection of workers banding shelves GTE blades from wear. The alloys were prepared by hot pressing powders of cobalt, chromium, aluminum, iron and niobium or titanium carbides. The values of heat resistance alloys containing carbides between 30 and 70% (vol. depend on the type made of carbide alloys: alloys with titanium carbide superior in heat-resistant alloy of niobium carbide. The most significant factor affecting on the heat-resistant alloys, is porosity: with its increase the parameters decline regardless of the type and content of carbide. The optimum composition of powder heat resisting alloys of titanium carbide with a melting point above 1300 °C were determined for use in the aircraft engine.

  3. Mechanical behaviour of pressed and sintered titanium alloys obtained from master alloy addition powders.

    Science.gov (United States)

    Bolzoni, L; Esteban, P G; Ruiz-Navas, E M; Gordo, E

    2012-11-01

    The fabrication of the workhorse Ti-6Al-4V alloy and of the Ti-3Al-2.5V alloy was studied considering the master alloy addition variant of the blending elemental approach conventionally used for titanium powder metallurgy. The powders were characterised by means thermal analysis and X-ray diffraction and shaped by means of uniaxial pressing. The microstructural evolution with the sintering temperature (900-1400 °C) was evaluated by SEM and EDS was used to study the composition. XRD patterns as well as the density by Archimedes method were also obtained. The results indicate that master alloy addition is a suitable way to fabricate well developed titanium alloy but also to produce alloy with the desired composition, not available commercially. Density of 4.3 g/cm³ can be obtained where a temperature higher than 1200 °C is needed for the complete diffusion of the alloying elements. Flexural properties comparable to those specified for wrought Ti-6Al-4V medical devices are, generally, obtained.

  4. Hydrothermal treatment of titanium alloys for the enhancement of osteoconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Zuldesmi, Mansjur, E-mail: mzuldesmi@yahoo.com [Department of Materials Science & Engineering, Graduate School of Engineering, Nagoya University, Nagoya (Japan); Department of Mechanical Engineering, Manad State University (UNIMA) (Indonesia); Waki, Atsushi [Department of Materials Science & Engineering, Graduate School of Engineering, Nagoya University, Nagoya (Japan); Kuroda, Kensuke; Okido, Masazumi [EcoTopia Science Institute, Nagoya University, Nagoya (Japan)

    2015-04-01

    The surface wettability of implants is a crucial factor in their osteoconductivity because it influences the adsorption of cell-attached proteins onto the surface. In this study, a single-step hydrothermal surface treatment using distilled water at a temperature of 180 °C for 3 h was applied to titanium (Ti) and its alloys (Ti–6Al–4V, Ti–6Al–7Nb, Ti–29Nb–13Ta–4.6Zr, Ti–13Cr–1Fe–3Al; mass%) and compared with as-polished Ti implants and with implants produced by anodizing Ti in 0.1 M of H{sub 3}PO{sub 4} with applied voltages from 0 V to 150 V at a scanning rate of 0.1 V s{sup −1}. The surface-treated samples were stored in a five time phosphate buffered saline (× 5 PBS(−)) solution to prevent increasing the water contact angle (WCA) with time. The surface characteristics were evaluated using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Auger electron spectroscopy, surface roughness, and contact angle measurement using a 2 μL droplet of distilled water. The relationship between WCA and osteoconductivity at various surface modifications was examined using in vivo tests. The results showed that a superhydrophilic surface with a WCA ≤ 10° and a high osteoconductivity (R{sub B–I}) of up to 50% in the cortical bone part, about four times higher than the as-polished Ti and Ti alloys, were provided by the combination of the hydrothermal surface treatment and storage in × 5 of PBS(−). - Highlights: • Hydrothermal treatment in distilled water was applied to titanium alloys. • Surface characteristics and osteoconductivity by in vivo test were evaluated. • Water contact angles of titanium alloys were decreased by hydrothermal treatment. • Osteoconductivity of titanium alloys improved notably by hydrothermal treatment after stored in × 5 of PBS (−)

  5. Fracture characteristics of structural aerospace alloys containing deep surface flaws. [aluminum-titanium alloys

    Science.gov (United States)

    Masters, J. N.; Bixler, W. D.; Finger, R. W.

    1973-01-01

    Conditions controlling the growth and fracture of deep surface flaws in aerospace alloys were investigated. Static fracture tests were performed on 7075-T651 and 2219-T87 aluminum, and 6Ai-4V STA titanium . Cyclic flaw growth tests were performed on the two latter alloys, and sustain load tests were performed on the titanium alloy. Both the cyclic and the sustain load tests were performed with and without a prior proof overload cycle to investigate possible growth retardation effects. Variables included in all test series were thickness, flaw depth-to-thickness ratio, and flaw shape. Results were analyzed and compared with previously developed data to determine the limits of applicability of available modified linear elastic fracture solutions.

  6. Formation of Ti-N graded bioceramic layer by DC hollow-cathode plasma nitriding

    Institute of Scientific and Technical Information of China (English)

    ZHENG Chuan-lin

    2004-01-01

    Ti-N graded ceramic layer was formed on titanium by using DC hollow-cathode plasma nitriding technique. The structure of Ti-N layer was analyzed using X-ray diffractometry(XRD) with Cu Kα radiation, and the microhardness( HV0.1) was measured from the surface to inner along the cross section of Ti-N layer. The results indicate that the Ti-N graded layer is composed of ε-Ti2 N, δ-TiN and α-Ti(N) phases. Mechanism discussion shows that hollow-cathode discharge can intensify gas ionization, increase current density and enhance the nitriding potential, which directly increases the thickness of the diffusion coatings compared with traditional nitriding methods.

  7. Interstitial control in titanium alloys produced by powder metallurgy

    Energy Technology Data Exchange (ETDEWEB)

    Henriques, V.A.R.; Petroni, S.L.G.; Cairo, C.A.A. [Instituto de Aeronautica e Espaco (AMR/CTA/IAE), Sao Jose dos Campos, SP (Brazil). Centro Tecnico Aeroespacial. Divisao de Materiais; Paula, M.S.M.; Galvani, E.T., E-mail: vinicius@iae.cta.br, E-mail: slpetroni@iae.cta.br, E-mail: Matheus@gmx.com, E-mail: ccairo@iae.cta.br, E-mail: eduardotgalvani@yahoo.com.br [Instituto Tecnologico de Aeronautica (ITA/CTA), Sao Jose dos Campos, SP (Brazil). Centro Tecnico Aeroespacial

    2009-07-01

    The titanium alloys are used for applications that demand high performance, including surgical implants and aerospace applications. Powder metallurgy is an advantageous alternative for titanium parts production with complex geometries at a relative low cost. Despite that, it is verified that the introduction of interstitial elements (oxygen, nitrogen and carbon) wile processing these alloys, though can increase hardness and mechanical resistance, which is frequently related to the reduction of ductility and fragility increase. The objective of this work is to investigate the influence of the interstitial elements in commercially pure Ti and Ti-{sup 13}Nb-{sup 13}Zr alloy produced by powder metallurgy (P/M). Samples were produced by the mixing of hydride metallic powders followed by uniaxial and cold isostatic pressing with subsequent densification by sintering at 1400 °C, in vacuum. Sintered samples were characterized for phase composition, microstructure and microhardness by X-ray diffraction, scanning electron microscopy and Vickers indentation, respectively. The interstitial content was analysed by Leco equipment. It was shown that the samples were sintered to high densities with a Widmanstatten microstructure. The oxygen and nitrogen contents are above the ELI (Extra Low Interstitial) and the critical issues were identified in the original blended elemental route. (author)

  8. Crack path in aeronautical titanium alloy under ultrasonic torsion loading

    Directory of Open Access Journals (Sweden)

    A. Nikitin

    2016-01-01

    Full Text Available This paper discusses features of fatigue crack initiation and growth in aeronautical VT3-1 titanium alloy under pure torsion loading in gigacycle regime. Two materials: extruded and forged VT3-1 titanium alloys were studied. Torsion fatigue tests were performed up to fatigue life of 109 cycles. The results of the torsion tests were compared with previously obtained results under fully reversed axial loading on the same alloys. It has been shown that independently on production process as surface as well subsurface crack initiation may appear under ultrasonic torsion loading despite the maximum stress amplitude located at the specimen surface. In the case of surface crack initiation, a scenario of crack initiation and growth is similar to HCF regime except an additional possibility for internal crack branching. In the case of subsurface crack, the initiation site is located below the specimen surface (about 200 μm and is not clearly related to any material flaw. Internal crack initiation is produced by shear stress in maximum shear plane and early crack growth is in Mode II. Crack branching is limited in the case of internal crack initiation compared to surface one. A typical ‘fish-eye’ crack can be observed at the torsion fracture surface, but mechanism of crack initiation seems not to be the same than under axial fatigue loading.

  9. Welding of titanium and nickel alloy by combination of explosive welding and spark plasma sintering technologies

    Energy Technology Data Exchange (ETDEWEB)

    Malyutina, Yu. N., E-mail: iuliiamaliutina@gmail.com; Bataev, A. A., E-mail: bataev@adm.nstu.ru; Shevtsova, L. I., E-mail: edeliya2010@mail.ru [Novosibirsk State Technical University, Novosibirsk, 630073 (Russian Federation); Mali, V. I., E-mail: vmali@mail.ru; Anisimov, A. G., E-mail: anis@hydro.nsc.ru [Lavrentyev Institute of Hydrodynamics SB RAS, Novosibirsk, 630090 (Russian Federation)

    2015-10-27

    A possibility of titanium and nickel-based alloys composite materials formation using combination of explosive welding and spark plasma sintering technologies was demonstrated in the current research. An employment of interlayer consisting of copper and tantalum thin plates makes possible to eliminate a contact between metallurgical incompatible titanium and nickel that are susceptible to intermetallic compounds formation during their interaction. By the following spark plasma sintering process the bonding has been received between titanium and titanium alloy VT20 through the thin powder layer of pure titanium that is distinguished by low defectiveness and fine dispersive structure.

  10. Welding of titanium and nickel alloy by combination of explosive welding and spark plasma sintering technologies

    Science.gov (United States)

    Malyutina, Yu. N.; Bataev, A. A.; Mali, V. I.; Anisimov, A. G.; Shevtsova, L. I.

    2015-10-01

    A possibility of titanium and nickel-based alloys composite materials formation using combination of explosive welding and spark plasma sintering technologies was demonstrated in the current research. An employment of interlayer consisting of copper and tantalum thin plates makes possible to eliminate a contact between metallurgical incompatible titanium and nickel that are susceptible to intermetallic compounds formation during their interaction. By the following spark plasma sintering process the bonding has been received between titanium and titanium alloy VT20 through the thin powder layer of pure titanium that is distinguished by low defectiveness and fine dispersive structure.

  11. HIGH THROUGHPUT DRILLING OF TITANIUM ALLOYS

    Institute of Scientific and Technical Information of China (English)

    LI Rui; SHIH Albert Jau-Min

    2007-01-01

    The experiments of high throughput drilling of Ti-6Al-4V at 183 m/min cutting speed and 156 mm3/s material removal rate using a 4 mm diameter WC-Co spiral point drill are conducted. At this material removal rate, it took only 0.57 s to drill a hole in a 6.35 mm thick Ti plate. Supplying the cutting fluid via through-the-drill holes and the balance of cutting speed and feed have proven to be critical for drill life. An inverse heat transfer model is developed to predict the heat flux and the drill temperature distribution in drilling. A three-dimensional finite element modeling of drilling is conducted to predict the thrust force and torque. Experimental result demonstrates that, using proper machining process parameters, tool geometry, and fine-grained WC-Co tool material, the high throughput machining of Ti alloy is technically feasible.

  12. In vitro biocompatibility evaluation of surface-modified titanium alloys.

    Science.gov (United States)

    Treves, Cristina; Martinesi, Maria; Stio, Maria; Gutiérrez, Alejandro; Jiménez, José Antonio; López, María Francisca

    2010-03-15

    The present work is aimed to evaluate the effects of a surface modification process on the biocompatibility of three vanadium-free titanium alloys with biomedical applications interest. Chemical composition of alloys investigated, in weight %, were Ti-7Nb-6Al, Ti-13Nb-13Zr, and Ti-15Zr-4Nb. An easy and economic method intended to improve the biocompatibiblity of these materials consists in a simple thermal treatment at high temperature, 750 degrees C, in air for different times. The significance of modification of the surface properties to the biological response was studied putting in contact both untreated and thermally treated alloys with human cells in culture, Human Umbilical Vein Endothelial Cells (HUVEC) and Human Peripheral Blood Mononuclear Cells (PBMC). The TNF-alpha release data indicate that thermal treatment improves the biological response of the alloys. The notable enhancement of the surface roughness upon oxidation could be related with the observed reduction of the TNF-alpha levels for treated alloys. A different behavior of the two cell lines may be observed, when adhesion molecules (ICAM-1 and VCAM-1 in HUVEC, ICAM-1, and LFA-1 in PBMC) were determined, PBMC being more sensitive than HUVEC to the contact with the samples. The data also distinguish surface composition and corrosion resistance as significant parameters for the biological response.

  13. Biomedical titanium alloys with Young’s moduli close to that of cortical bone

    Science.gov (United States)

    Niinomi, Mitsuo; Liu, Yi; Nakai, Masaki; Liu, Huihong; Li, Hua

    2016-01-01

    Biomedical titanium alloys with Young’s moduli close to that of cortical bone, i.e., low Young’s modulus titanium alloys, are receiving extensive attentions because of their potential in preventing stress shielding, which usually leads to bone resorption and poor bone remodeling, when implants made of their alloys are used. They are generally β-type titanium alloys composed of non-toxic and allergy-free elements such as Ti–29Nb–13Ta–4.6Zr referred to as TNTZ, which is highly expected to be used as a biomaterial for implants replacing failed hard tissue. Furthermore, to satisfy the demands from both patients and surgeons, i.e., a low Young’s modulus of the whole implant and a high Young’s modulus of the deformed part of implant, titanium alloys with changeable Young’s modulus, which are also β-type titanium alloys, for instance Ti–12Cr, have been developed. In this review article, by focusing on TNTZ and Ti–12Cr, the biological and mechanical properties of the titanium alloys with low Young’s modulus and changeable Young’s modulus are described. In addition, the titanium alloys with shape memory and superelastic properties were briefly addressed. Surface modifications for tailoring the biological and anti-wear/corrosion performances of the alloys have also been briefly introduced. PMID:27252887

  14. Biomedical titanium alloys with Young's moduli close to that of cortical bone.

    Science.gov (United States)

    Niinomi, Mitsuo; Liu, Yi; Nakai, Masaki; Liu, Huihong; Li, Hua

    2016-09-01

    Biomedical titanium alloys with Young's moduli close to that of cortical bone, i.e., low Young's modulus titanium alloys, are receiving extensive attentions because of their potential in preventing stress shielding, which usually leads to bone resorption and poor bone remodeling, when implants made of their alloys are used. They are generally β-type titanium alloys composed of non-toxic and allergy-free elements such as Ti-29Nb-13Ta-4.6Zr referred to as TNTZ, which is highly expected to be used as a biomaterial for implants replacing failed hard tissue. Furthermore, to satisfy the demands from both patients and surgeons, i.e., a low Young's modulus of the whole implant and a high Young's modulus of the deformed part of implant, titanium alloys with changeable Young's modulus, which are also β-type titanium alloys, for instance Ti-12Cr, have been developed. In this review article, by focusing on TNTZ and Ti-12Cr, the biological and mechanical properties of the titanium alloys with low Young's modulus and changeable Young's modulus are described. In addition, the titanium alloys with shape memory and superelastic properties were briefly addressed. Surface modifications for tailoring the biological and anti-wear/corrosion performances of the alloys have also been briefly introduced.

  15. Surface characterization of alloy Ti-6Al-7Nb treated plasma; Caracterizacao superficial de ligas de Ti-6Al-7Nb tratadas a plasma

    Energy Technology Data Exchange (ETDEWEB)

    Moura, J.K.L.; Macedo, H.R.A.; Brito, E.M.; Brandim, A.S., E-mail: jessika.kaline@hotmail.com [Instituto Federal do Piaui (PPGEM/IFPI), Teresina, PI (Brazil)

    2014-07-01

    Plasma surface modifications are subject of numerous studies to improve the quality of a given material. Titanium and its alloys are widely used in biomedical applications and plasma treatment technique is increasingly used to improve the surface properties thereof. The research have a objective in the comparative analysis of the change in microstructure of Ti-6Al-7Nb alloys after treatment of plasma nitriding. The technical are: nitriding with cathode cage (NGC) and planar discharge. The characterization was obtained by MEV (Scanning Electronic Microscope) and hardness. The results was compared about the better surface modification that meets future prospects of the biocompatibility of the alloy.(author)

  16. Microstructure and corrosion behavior of binary titanium alloys with beta-stabilizing elements.

    Science.gov (United States)

    Takada, Y; Nakajima, H; Okuno, O; Okabe, T

    2001-03-01

    Binary titanium alloys with the beta-stabilizing elements of Co, Cr, Cu, Fe, Mn and Pd (up to 30%) and Ag (up to 45%) were examined through metallographic observation and X-ray diffractometry to determine whether beta phases that are advantageous for dental use could be retained. Corrosion behavior was also investigated electrochemically and discussed thermodynamically. Some cast alloys with Co, Cr, Fe, Mn, and Pd retained the beta phase, whereas those with Ag and Cu had no beta phase. In some alloys, an intermetallic compound formed, based on information from the phase diagram. The corrosion resistance deteriorated in the TiAg alloys because Ti2Ag and/or TiAg intermetallic compounds preferentially dissolved in 0.9% NaCl solution. On the other hand, the remaining titanium alloys became easily passive and revealed good corrosion resistance similar to pure titanium since their matrices seemed to thermodynamically form titanium oxides as did pure titanium.

  17. Review about laser nitriding of titanium alloys; Revision sobre nitruraciones laser de aleaciones de titanio

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Artieda, M.G.; Fernandez-Carrasquilla, J.

    2010-07-01

    A common technique used to improve the wear response of titanium alloys is to nitride the surface, using chemical or physical vapour deposition, ion implantation or surface remelting in a nitrogen atmosphere. In this revision nitriding systems with laser technology are studied, used in titanium alloys surface treatments.For high temperature, high strength applications, titanium based alloys are an attractive light-weight alternative to steel, due to their high strength to weight ratio and corrosion resistance. In applications that require good wear resistance, titanium alloys pose a problem due to their poor tribological characteristics.Titanium alloys used with a suitable nitriding treatment could allow the replacement of steel in different applications, obtaining weight savings in fabricated components. (Author). 68 refs.

  18. Selective laser melting of titanium alloy: investigation of mechanical properties and microstructure

    Science.gov (United States)

    Agapovichev, A. V.; Kokareva, V. V.; Smelov, V. G.; Sotov, A. V.

    2016-11-01

    This article presents the mechanical properties and microstructure of titanium alloy after selective laser melting (SLM). Titanium alloys are ideal material for selective laser melting (SLM), because they are expensive and difficult to machinery using traditional technologies. The application of SLM in the biomedical area has been slow due to the stringent performance criteria and concerns related to personification and part quality. In this article we focused on the manufacture by SLM and determination of microstructure and mechanical properties of titanium alloy (Ti Grade 2 Powder) using tensile tests and X-ray diffraction. The results reveal that the alloy exhibits a pronounced the homogeneous microstructure and high mechanical strength.

  19. Development of Oxidation Protection Coatings for Gamma Titanium Aluminide Alloys

    Science.gov (United States)

    Wallace, T. A.; Bird, R. K.; Sankaran, S. N.

    2003-01-01

    Metallic material systems play a key role in meeting the stringent weight and durability requirements for reusable launch vehicle (RLV) airframe hot structures. Gamma titanium aluminides (gamma-TiAl) have been identified as high-payoff materials for high-temperature applications. The low density and good elevated temperature mechanical properties of gamma-TiAl alloys make them attractive candidates for durable lightweight hot structure and thermal protection systems at temperatures as high as 871 C. However, oxidation significantly degrades gamma-TiAl alloys under the high-temperature service conditions associated with the RLV operating environment. This paper discusses ongoing efforts at NASA Langley Research Center to develop durable ultrathin coatings for protecting gamma-TiAl alloys from high-temperature oxidation environments. In addition to offering oxidation protection, these multifunctional coatings are being engineered to provide thermal control features to help minimize heat input into the hot structures. This paper describes the coating development effort and discusses the effects of long-term high-temperature exposures on the microstructure of coated and uncoated gamma-TiAl alloys. The alloy of primary consideration was the Plansee alloy gamma-Met, but limited studies of the newer alloy gamma-Met-PX were also included. The oxidation behavior of the uncoated materials was evaluated over the temperature range of 704 C to 871 C. Sol-gel-based coatings were applied to the gamma-TiAl samples by dipping and spraying, and the performance evaluated at 871 C. Results showed that the coatings improve the oxidation resistance, but that further development is necessary.

  20. Diffusion bonding of titanium alloy to tin-bronze

    Institute of Scientific and Technical Information of China (English)

    李卓然; 冯吉才; 刘会杰

    2002-01-01

    The vacuum diffusion bonding of titanium alloy to tin-bronze has been studied and the feasibility and appropriate processing parameters have been investigated. The maximum tensile strength of the joints is bonded joint has been observed by SEM, X-ray and EPMA, and the main factors affecting diffusion bonding have been analyzed. The intermetallic compounds Ti2Cu and TiCu were formed near the interface. The width and quantity of the intermetallic compound increases with the increase of the bonding time. The formation of the intermetallic compounds results in embrittlement of the joint and the poor joint properties.

  1. Finishing Titanium Alloy Cutting Zone Analysis Via Multifunction Measuring System

    Science.gov (United States)

    Andrej, Czán; Michal, Šajgalík; Drbúl, Mário; Holubják, Jozef; Mrázik, Jozef; Babík, Ondrej; Zaušková, Lucia; Piešová, Marianna

    2015-12-01

    With the development of automotive, aerospace and biomedical industry, there is higher demand for exotic alloys, often based on titanium or nickel, though they are hard to machine. Therefore, it is essential to thoroughly understand their behavior during machining. Processes in the cutting zone of said materials are due to the complexity and dynamics defined by specific models. These include some deviations, thus it is essential to improve machining observation methodology, so exhibited errors and deviations are minimal or none. Based on the observations, multifunction measuring system has been designed, which allows simultaneous observation of characteristics such as e.g. cutting forces, deformations and thermal spread without uninterrupting machining process.

  2. Effect of Carburization on the Mechanical Properties of Biomedical Grade Titanium Alloys

    Institute of Scientific and Technical Information of China (English)

    Yong Luo; Haibo Jiang; Gang Cheng; Hongtao Liu

    2011-01-01

    Titanium cermets were successfully synthesized on the surface of biomedical grade titanium alloys by using sequential carburization method. The mechanical properties such as hardness, fracture toughness and plasticity were measured to estimate the potential application of titanium cermets. The results show that after carburization the surface hardness of titanium cermets was 778 HV, with a significant improvement of 128% compared with that of titanium alloys. In addition, the fracture toughness of titanium cermets was 21.5×106 Pa·m1/2, much higher than that of other ceramics. Furthermore, the analysis of the loading-unloading curve in the nanoindentation test also indicates that the plasticity of titanium cermet reached 32.1%, a relatively high value which illustrates the combination of the metal and ceramics properties. The results suggest that sequential carburization should be an efficient way to produce titanium cermets with hard surface, high toughness and plasticity.

  3. Tribological coating of titanium alloys by laser processing

    Science.gov (United States)

    Pang, Wang

    Titanium-based alloys have been used for aerospace materials for many years. Recently, these alloys are now being increasingly considered for automotive, industrial and consumer applications. Their excellent creep resistance, corrosion resistance and relative higher specific strength ratio are attractive for many applications. However, the main obstacle for the wide adoption of Ti alloys in various industries is their poor tribological properties. In slide wear, Ti deforms and adhesive wear readily occurs. Their poor tribological properties are mainly due to low hardness and absolute values of tensile and shear strength. Different surface modification techniques have been studied in order to improve the tribological characteristics of Ti alloys, i.e. PVD, nitrding, carburizing, boriding, plating etc. Coatings produced by these techniques have their own limitations such as thermal distortion and grain growth. A different approach is to introduce hard particles in the Ti alloy matrix to form a MMC coating, which has tailor-made hardness and wear resistance properties. Laser cladding or laser alloying techniques facilitate the fabrication of surface MMC on Ti alloys without thermal distortion to the substrate. In this project, the fabrication of hard and wear resistant layers of metal matrix composite on titanium alloys substrate by laser surface alloying was investigated. Powder mixtures of Mo and WC were used to form the MMC layer. By optimizing the processing parameters and pre-placed powder mixture compositions, surface MMC of different properties have been successfully fabricated on CP-Ti and Ti6A14V respectively. The structure and characteristics of the MMC surface were investigated by metallography, SEM, XRD, and E-DAX. It was found that the hardness of the laser alloyed Mo/WC MMC surface was 300% higher than that of the CP-Ti substrate Excellent metallurgical bonding with the MMC layer of the substrate has been achieved. The relative kinetic frictional tests

  4. Discoloration and dissolution of titanium and titanium alloys with immersion in peroxide- or fluoride-containing solutions.

    Science.gov (United States)

    Noguchi, Tatsumi; Takemoto, Shinji; Hattori, Masayuki; Yoshinari, Masao; Kawada, Eiji; Oda, Yutaka

    2008-01-01

    This study compared differences in discoloration and dissolution in several titanium alloys with immersion in peroxide- or fluoride-containing solution. Commercially pure titanium (CP-Ti) and six titanium-based alloys were used: Ti-0.15Pd, Ti-6Al-4V, Ti-7Nb-6Al, Ti-55Ni, Ti-10Cu, and Ti-20Cr. Two test solutions were prepared for immersion of polished titanium and titanium alloys: one consisting of 0.2% NaF + 0.9% NaCl (pH 3.8 with lactic acid) and the other of 0.1 mol/l H2O2 + 0.9% NaCl (pH 5.5). Following immersion, color changes were determined with a color meter and released elements were measured using ICP-OES. Discoloration and dissolution rates differed between the two solutions. In the hydrogen peroxide-containing solution, color difference was higher in Ti-55Ni and Ti-6Al-4V than in any of the other alloys, and that Ti-55Ni showed the highest degree of dissolution. In the acidulated fluoride-containing solution, CP-Ti, Ti-0.15Pd, Ti-6Al-4V, Ti-7Nb-6Al, and Ti-10Cu alloys showed remarkable discoloration and dissolution with immersion. On the contrary, Ti-20Cr alloy showed very little discoloration and dissolution in either solution.

  5. Thermographic studies on IMI-834 titanium alloy during tensile loading

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Jalaj [Defence Metallurgical Research Laboratory, Hyderabad 500058 (India)], E-mail: k_jalaj@yahoo.com; Baby, Sony; Kumar, Vikas [Defence Metallurgical Research Laboratory, Hyderabad 500058 (India)

    2008-11-25

    To study the material deformation kinetics under monotonic loading conditions, infrared radiation thermography (IRT) has been used in the present investigation. Studies were performed on IMI-834 titanium alloy, which is used in the compressor module of an aeroengine. The compressor has variable states of stress triaxialities at different locations. The effect of stress triaxiality on material deformation was investigated with the use of smooth and axisymmetrically notched round tensile specimens of the alloy. Instantaneous surface temperatures were measured on specimens during tensile deformation through IRT technique. The notched specimen exhibited localized and higher rate of temperature evolution during loading. Using surface temperature evolution curves, thermoelastic and inelastic regions were identified for smooth and notched specimens. With the help of Lord Kelvin's equation, stresses were predicted for thermoelastic region. A good correlation was found between the predicted and experimental stresses for this region.

  6. Reactive Spark Plasma Sintering (SPS) of Nitride Reinforced Titanium Alloy Composites (Postprint)

    Science.gov (United States)

    2014-08-15

    ies on in situ alloying and reactions during the SPS process. A recent study on SPS processing of hafnium carbide (HfC) starting from a blend of...AFRL-RX-WP-JA-2014-0177 REACTIVE SPARK PLASMA SINTERING (SPS) OF NITRIDE REINFORCED TITANIUM ALLOY COMPOSITES (POSTPRINT) Jaimie S...SINTERING (SPS) OF NITRIDE REINFORCED TITANIUM ALLOY COMPOSITES (POSTPRINT) 5a. CONTRACT NUMBER In-House 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

  7. Advances in the Development of Processing - Microstructure Relations for Titanium Alloys (Postprint)

    Science.gov (United States)

    2016-05-06

    microstructure and composition on the superplastic flow behavior of α/β titanium alloys. Particular attention is given to models describing the refinement...titanium alloys, challenges in the rolling of foil of and gamma-TiAl alloys, and the effect of microstructure and composition on the superlastic flow...materials to billets, slabs , sheet etc. via upsetting, drawing/cogging, and rolling to produce semi-finished products such as billets, plate, and

  8. Electron Beam Freeform Fabrication of Titanium Alloy Gradient Structures

    Science.gov (United States)

    Brice, Craig A.; Newman, John A.; Bird, Richard Keith; Shenoy, Ravi N.; Baughman, James M.; Gupta, Vipul K.

    2014-01-01

    Historically, the structural optimization of aerospace components has been done through geometric methods. A monolithic material is chosen based on the best compromise between the competing design limiting criteria. Then the structure is geometrically optimized to give the best overall performance using the single material chosen. Functionally graded materials offer the potential to further improve structural efficiency by allowing the material composition and/or microstructural features to spatially vary within a single structure. Thus, local properties could be tailored to the local design limiting criteria. Additive manufacturing techniques enable the fabrication of such graded materials and structures. This paper presents the results of a graded material study using two titanium alloys processed using electron beam freeform fabrication, an additive manufacturing process. The results show that the two alloys uniformly mix at various ratios and the resultant static tensile properties of the mixed alloys behave according to rule-of-mixtures. Additionally, the crack growth behavior across an abrupt change from one alloy to the other shows no discontinuity and the crack smoothly transitions from one crack growth regime into another.

  9. Design of Metastable Tin Titanium Nitride Semiconductor Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bikowski, Andre [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States; Siol, Sebastian [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States; Gu, Jing [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States; Holder, Aaron [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States; Mangum, John S. [Colorado School of Mines, 1500; Gorman, Brian [Colorado School of Mines, 1500; Tumas, William [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States; Lany, Stephan [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States; Zakutayev, Andriy [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States

    2017-07-21

    We report on design of optoelectronic properties in previously unreported metastable tin titanium nitride alloys with spinel crystal structure. Theoretical calculations predict that Ti alloying in metastable Sn3N4 compound should improve hole effective mass by up to 1 order of magnitude, while other optical bandgaps remains in the 1-2 eV range up to x ~ 0.35 Ti composition. Experimental synthesis of these metastable alloys is predicted to be challenging due to high required nitrogen chemical potential (uN = +1.0 eV) but proven to be possible using combinatorial cosputtering from metal targets in the presence of nitrogen plasma. Characterization experiments confirm that thin films of such (Sn1-xTix)3N4 alloys can be synthesized up to x = 0.45 composition, with suitable optical band gaps (1.5-2.0 eV), moderate electron densities (1017 to 1018 cm-3), and improved photogenerated hole transport (by 5x). Overall, this study shows that it is possible to design the metastable nitride materials with properties suitable for potential use in solar energy conversion applications.

  10. Titanium alloyed with rhenium by selective laser melting

    Energy Technology Data Exchange (ETDEWEB)

    Chlebus, Edward; Kuźnicka, Bogumiła, E-mail: bogumila.kuznicka@pwr.edu.pl; Dziedzic, Robert; Kurzynowski, Tomasz

    2015-01-03

    The paper presents results of processing Ti–Re alloys by consolidating mixtures of powders of both metals with the use of selective laser melting (SLM). Ti-based alloys containing 0.5, 1.0 and 1.5 at% Re were obtained in this way. Optimum process parameters were determined by accepting the criterion of minimum porosity of manufactured parts and maximum effectiveness of dissolving Re particles in molten Ti. Density of the SLM-processed parts reached over 99.9% and 90–85% of Re powder (by volume) was dissolved. The effects of Re content on the microstructure and mechanical properties of SLM-processed parts in as-built condition were investigated. Light microscopy and X-ray diffraction examinations revealed that rhenium changed the microstructure of CP-Ti lath-type α′ martensite to acicular-shaped by lowering the temperature of martensitic transformation. A very intensive effect of strengthening titanium by the addition of small amounts of Re was found, due to α′-lattice distortion and grain refinement. Alloying with 1.5 at% Re made it possible to obtain mechanical properties similar to those of the SLM-processed Ti6Al4V alloy in as-built condition.

  11. Surface Corrosion Resistance in Turning of Titanium Alloy

    Directory of Open Access Journals (Sweden)

    Rui Zhang

    2015-01-01

    Full Text Available This work addresses the issues associated with implant surface modification. We propose a method to form the oxide film on implant surfaces by dry turning to generate heat and injecting oxygen-rich gas at the turning-tool flank. The morphology, roughness, composition, and thickness of the oxide films in an oxygen-rich atmosphere were characterized using scanning electron microscopy, optical profiling, and Auger electron spectroscopy. Electrochemical methods were used to study the corrosion resistance of the modified surfaces. The corrosion resistance trends, analyzed relative to the oxide film thickness, indicate that the oxide film thickness is the major factor affecting the corrosion resistance of titanium alloys in a simulated body fluid (SBF. Turning in an oxygen-rich atmosphere can form a thick oxide film on the implant surface. The thickness of surface oxide films processed at an oxygen concentration of 80% was improved to 4.6 times that of films processed at an oxygen concentration of 21%; the free corrosion potential shifted positively by 0.357 V, which significantly improved the corrosion resistance of titanium alloys in the SBF. Therefore, the proposed method may (partially replace the subsequent surface oxidation. This method is significant for biomedical development because it shortens the process flow, improves the efficiency, and lowers the cost.

  12. Effect of nitrocarburizing on shape of titanium alloy parts

    Energy Technology Data Exchange (ETDEWEB)

    Clark, E.A.

    1993-09-27

    Components are being developed for plutonium casting in support of Lawrence Livermore National Laboratory. A vendor used a proprietary process to grow a nitrocarburized surface layer on a titanium alloy shot sleeve to be used in a prototype die casting machine. The shot sleeve was significantly out-of-round upon return from the vendor and could not be used. Purpose of this study was to determine whether the shape change could have been caused by this surface treatment. Visual observation of disk and ring samples exposed first to surface treatment alone temperature and then the actual nitrocarburizing environment revealed no gross warping in either case. Dimension measurements of each sample before and after both the thermal treatment and the nitrocarburizing revealed no significant changes. Visual examination of the shot sleeve revealed a surface flaw likely made during handling after machining at SRS and before the part was nitrocarburized. The out-of-roundness of the shot sleeve could be related to the damage observed on the surface, but the possibility of warping during the nitrocarburizing cannot be excluded. Nitrocarburization should remain a candidate method to protect titanium alloys from molten metals.

  13. Multiaxial fatigue strength of severely notched titanium grade 5 alloy

    Directory of Open Access Journals (Sweden)

    F. Berto

    2015-07-01

    Full Text Available The multiaxial fatigue strength of severely notched titanium grade 5 alloy (Ti-6Al-4V is investigated. Experimental tests under combined tension and torsion loading, both in-phase and out-of-phase, have been carried out on axisymmetric V-notched specimens considering different nominal load ratios (R = -1, 0. All specimens are characterized by a notch tip radius less than 0.1 mm, a notch depth of 6 mm and a notch opening angle equal to 90 degrees. The experimental data from multiaxial tests are compared with those from pure tension and pure torsion tests on un-notched and notched specimens, carried out at load ratio ranging from R = -3 to R = 0.5. In total, more than 160 new fatigue data are examined, first in terms of nominal stress amplitudes referred to the net area and then in terms of the local strain energy density averaged over a control volume surrounding the V-notch tip. The dependence of the control radius on the loading mode is analysed showing a very different notch sensitivity for tension and torsion. For the titanium alloy Ti-6Al-4V, the control volume is found to be strongly dependent on the loading mode

  14. Recent advances in the design of titanium alloys for orthopedic applications.

    Science.gov (United States)

    Guillemot, Fabien

    2005-11-01

    To increase an orthopedic implant's lifetime, research trends have included the development of new titanium alloys made of nontoxic elements with suitable mechanical properties (low Young's modulus - high fatigue strength), good workability and corrosion resistance. In accordance with the background on titanium and metallic biomaterials, recent interesting developments in titanium-based biomaterials are reported in this review, with a special emphasis on the design of new metastable beta-titanium alloys for orthopedic applications. In addition, as the concept of titanium alloys can now be regarded as relatively old, having emerged at the beginning of the 1980s, the author suggests some future directions that would permit the emergence of a new generation of titanium implants.

  15. Effects of titanium-dental restorative alloy galvanic couples on cultured cells.

    Science.gov (United States)

    Bumgardner, J D; Johansson, B I

    1998-01-01

    The potential exists for titanium and amalgams to become galvanically coupled in the oral cavity. While low galvanic corrosion rates have been measured in vivo for titanium-amalgam or mercury-free alloy couples, concerns exist over released corrosion products and adverse tissue responses. It was hypothesized in this study that coupling titanium to amalgams or gallium alloys increased the release of metallic corrosion products and decreased cellular activity and function. The effects of titanium coupled and uncoupled to a conventional amalgam, palladium-enriched spherical high copper amalgam, a dispersed type high copper amalgam, and a mercury-free gallium alloy were evaluated in 24-h cell culture tests. Viability, proliferation, and collagen synthesis were evaluated by the uptake of neutral red, 3H-thymidine, and immunoassay of procollagen, respectively, and compared to cells not exposed to any test material. The gallium alloy-titanium couple resulted in significant decreases in cellular viability, proliferation, and collagen synthesis as compared to the other coupled and uncoupled samples. Few differences in the cellular responses of the other coupled and uncoupled samples were observed. Atomic absorption analyses indicated increased release of metal ions from the amalgam and gallium alloy samples coupled to titanium as compared to their uncoupled condition, although the differences were not always significant. Galvanic corrosion of amalgam-titanium couples in the long term may become significant, and further research is needed. Coupling the gallium alloy to titanium may result in increased galvanic corrosion and cytotoxic responses.

  16. Nanotribological response of a plasma nitrided bio-steel.

    Science.gov (United States)

    Samanta, Aniruddha; Chakraborty, Himel; Bhattacharya, Manjima; Ghosh, Jiten; Sreemany, Monjoy; Bysakh, Sandip; Rane, Ramkrishna; Joseph, Alphonsa; Jhala, Ghanshyam; Mukherjee, Subroto; Das, Mitun; Mukhopadhyay, Anoop K

    2017-01-01

    AISI 316L is a well known biocompatible, austenitic stainless steel (SS). It is thus a bio-steel. Considering its importance as a bio-prosthesis material here we report the plasma nitriding of AISI 316L (SS) followed by its microstructural and nanotribological characterization. Plasma nitriding of the SS samples was carried out in a plasma reactor with a hot wall vacuum chamber. For ease of comparison these plasma nitrided samples were termed as SSPN. The experimental results confirmed the formations of an embedded nitrided metal layer zone (ENMLZ) and an interface zone (IZ) between the ENMLZ and the unnitrided bulk metallic layer zone (BMLZ) in the SSPN sample. These ENMLZ and IZ in the SSPN sample were richer in iron nitride (FeN) chromium nitride (CrN) along with the austenite phase. The results from nanoindentation, microscratch, nanoscratch and sliding wear studies confirmed that the static contact deformation resistance, the microwear, nanowear and sliding wear resistance of the SSPN samples were much better than those of the SS samples. These results were explained in terms of structure-property correlations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Hydrogen content in titanium and a titanium–zirconium alloy after acid etching

    Energy Technology Data Exchange (ETDEWEB)

    Frank, Matthias J.; Walter, Martin S. [Department of Biomaterials, Institute for Clinical Dentistry, University of Oslo, P.O. Box 1109, Blindern, NO-0317 Oslo (Norway); Institute of Medical and Polymer Engineering, Chair of Medical Engineering, Technische Universität München, Boltzmannstrasse 15, 85748 Garching (Germany); Lyngstadaas, S. Petter [Department of Biomaterials, Institute for Clinical Dentistry, University of Oslo, P.O. Box 1109, Blindern, NO-0317 Oslo (Norway); Wintermantel, Erich [Institute of Medical and Polymer Engineering, Chair of Medical Engineering, Technische Universität München, Boltzmannstrasse 15, 85748 Garching (Germany); Haugen, Håvard J., E-mail: h.j.haugen@odont.uio.no [Department of Biomaterials, Institute for Clinical Dentistry, University of Oslo, P.O. Box 1109, Blindern, NO-0317 Oslo (Norway)

    2013-04-01

    Dental implant alloys made from titanium and zirconium are known for their high mechanical strength, fracture toughness and corrosion resistance in comparison with commercially pure titanium. The aim of the study was to investigate possible differences in the surface chemistry and/or surface topography of titanium and titanium–zirconium surfaces after sand blasting and acid etching. The two surfaces were compared by X-ray photoelectron spectroscopy, secondary ion mass spectroscopy, scanning electron microscopy and profilometry. The 1.9 times greater surface hydrogen concentration of titanium zirconium compared to titanium was found to be the major difference between the two materials. Zirconium appeared to enhance hydride formation on titanium alloys when etched in acid. Surface topography revealed significant differences on the micro and nanoscale. Surface roughness was increased significantly (p < 0.01) on the titanium–zirconium alloy. High-resolution images showed nanostructures only present on titanium zirconium. - Highlights: ► TiZr alloy showed increased hydrogen levels over Ti. ► The alloying element Zr appeared to catalyze hydrogen absorption in Ti. ► Surface roughness was significantly increased for the TiZr alloy over Ti. ► TiZr alloy revealed nanostructures not observed for Ti.

  18. Titanium alloys in total joint replacement--a materials science perspective.

    Science.gov (United States)

    Long, M; Rack, H J

    1998-09-01

    Increased use of titanium alloys as biomaterials is occurring due to their lower modulus, superior biocompatibility and enhanced corrosion resistance when compared to more conventional stainless steels and cobalt-based alloys. These attractive properties were a driving force for the early introduction of alpha (cpTi) and alpha + beta (Ti-6A1-4V) alloys as well as for the more recent development of new Ti-alloy compositions and orthopaedic metastable beta titanium alloys. The later possess enhanced biocompatibility, reduced elastic modulus, and superior strain-controlled and notch fatigue resistance. However, the poor shear strength and wear resistance of titanium alloys have nevertheless limited their biomedical use. Although the wear resistance of beta-Ti alloys has shown some improvement when compared to alpha + beta alloys, the ultimate utility of orthopaedic titanium alloys as wear components will require a more complete fundamental understanding of the wear mechanisms involved. This review examines current information on the physical and mechanical characteristics of titanium alloys used in artifical joint replacement prostheses, with a special focus on those issues associated with the long-term prosthetic requirements, e.g., fatigue and wear.

  19. Research and Application of New Type of High Performance Titanium Alloy

    Directory of Open Access Journals (Sweden)

    ZHU Zhishou

    2016-06-01

    Full Text Available With the continuous extension of the application quantity and range for titanium alloy in the fields of national aviation, space, weaponry, marine and chemical industry, etc., even more critical requirements to the comprehensive mechanical properties, low cost and process technological properties of titanium alloy have been raised. Through the alloying based on the microstructure parameters design, and the comprehensive strengthening and toughening technologies of fine grain strengthening, phase transformation and process control of high toughening, the new type of high performance titanium alloy which has good comprehensive properties of high strength and toughness, anti-fatigue, failure resistance and anti-impact has been researched and manufactured. The new titanium alloy has extended the application quantity and application level in the high end field, realized the industrial upgrading and reforming, and met the application requirements of next generation equipment.

  20. Phase transformations in titanium alloys hardened by rapid heating

    Energy Technology Data Exchange (ETDEWEB)

    Gridnev, V.N.; Ivasishin, O.M.; Oshkaderov, S.P.; Smirnov, A.M. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)

    Features of phase transformations in titanium alloys, which subjected to hardening by rapid heating, are studied. The model for mathematical description of ..cap alpha..+..beta.. ..-->.. ..beta..- transformation under the conditions of continuous heating with different rate, is proposed. The increase of the polymorphic transformation temperature with the heating rate, is predicted and confirmed experimentally. Under certain conditions this fact can result in a two-stage process, of ..cap alpha..+..beta.. ..-->.. ..beta..-transformation, which begins according to difussion mechanism, and completes according to the non-diffusion one. It is shown, that ..cap alpha..+..beta.. ..-->.. ..beta..-transformation under non-equilibrium conditions is followed by appearing of concentration non-uniformity in reacting phases, that essentially affects the grain and intragranular structure of hardened alloys, and their phase composition. Variants of phase composition of the alloys of different classes quenched after rapid heating in the ..beta..-field, are analyzed. Possible aspects of the effect of increased heating rates on the ageing process are considered.

  1. Influence of Duplex Treatment on Structural and Tribological Properties of Commercially Pure Titanium

    Science.gov (United States)

    Çelik, Ilhan

    2017-01-01

    Titanium and its alloys are widely used in many fields, including aerospace and the chemical and biomedical industries. This is due to their mechanical properties, excellent corrosion resistance, and biocompatibility although they do have poor wear resistance. In this study, a duplex layer was successfully formed on the commercially pure titanium surface by duplex treatments (plasma nitriding and physical vapor deposition (PVD)). In the initial treatment, plasma nitriding was performed on the pure titanium samples and in the second treatment, the nitrided samples were coated with CrN by PVD. The friction and wear properties of the duplex-treated samples were investigated for tribological applications. Surface morphology and microstructure of the duplex-treated samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, the tribological properties were investigated using pin-on-disc tribometer. A compound layer composed of ɛ-Ti2N and δ-TiN phases and a diffusion layer formed under the compound layer were obtained on the surface of pure titanium after the nitriding treatments. CrN coated on the nitrided surface provided an increase in the surface hardness and in the wear resistance.

  2. Tribocorrosion behavior of beta titanium biomedical alloys in phosphate buffer saline solution.

    Science.gov (United States)

    Pina, V Guiñón; Dalmau, A; Devesa, F; Amigó, V; Muñoz, A Igual

    2015-06-01

    The tribo-electrochemical behavior of different β titanium alloys for biomedical applications sintered by powder metallurgy has been investigated. Different mechanical, electrochemical and optical techniques were used to study the influence of the chemical composition, Sn content, and the electrochemical conditions on the tribocorrosion behavior of those alloys Ti30NbxSn alloys (where "x" is the weight percentage of Sn content, 2% and 4%). Sn content increases the active and passive dissolution rate of the titanium alloys, thus increasing the mechanically activated corrosion under tribocorrosion conditions. It also increases the mechanical wear of the alloy. Prevailing electrochemical conditions between -1 and 2V influences the wear accelerated corrosion by increasing it with the applied potential and slightly increases the mechanical wear of Ti30Nb4Sn. Wear accelerated corrosion can be predicted by existing models as a function of electrochemical and mechanical parameters of the titanium alloys.

  3. Nickel-Titanium Alloys: Corrosion "Proof" Alloys for Space Bearing, Components and Mechanism Applications

    Science.gov (United States)

    DellaCorte, Christopher

    2010-01-01

    An intermetallic nickel-titanium alloy, 60NiTi (60 wt% Ni, 40 wt% Ti), is shown to be a promising candidate tribological material for space mechanisms. 60NiTi offers a broad combination of physical properties that make it unique among bearing materials. 60NiTi is hard, electrically conductive, highly corrosion resistant, readily machined prior to final heat treatment, and is non-magnetic. Despite its high Ti content, 60NiTi is non-galling even under dry sliding. No other bearing alloy, metallic or ceramic, encompasses all of these attributes. Since 60NiTi contains such a high proportion of Ti and possesses many metallic properties, it was expected to exhibit poor tribological performance typical of Ti alloys, namely galling type behavior and rapid lubricant degradation. In this poster-paper, the oil-lubricated behavior of 60NiTi is presented.

  4. Numerical assessment of bone remodeling around conventionally and early loaded titanium and titanium-zirconium alloy dental implants.

    Science.gov (United States)

    Akça, Kıvanç; Eser, Atılım; Çavuşoğlu, Yeliz; Sağırkaya, Elçin; Çehreli, Murat Cavit

    2015-05-01

    The aim of this study was to investigate conventionally and early loaded titanium and titanium-zirconium alloy implants by three-dimensional finite element stress analysis. Three-dimensional model of a dental implant was created and a thread area was established as a region of interest in trabecular bone to study a localized part of the global model with a refined mesh. The peri-implant tissues around conventionally loaded (model 1) and early loaded (model 2) implants were implemented and were used to explore principal stresses, displacement values, and equivalent strains in the peri-implant region of titanium and titanium-zirconium implants under static load of 300 N with or without 30° inclination applied on top of the abutment surface. Under axial loading, principal stresses in both models were comparable for both implants and models. Under oblique loading, principal stresses around titanium-zirconium implants were slightly higher in both models. Comparable stress magnitudes were observed in both models. The displacement values and equivalent strain amplitudes around both implants and models were similar. Peri-implant bone around titanium and titanium-zirconium implants experiences similar stress magnitudes coupled with intraosseous implant displacement values under conventional loading and early loading simulations. Titanium-zirconium implants have biomechanical outcome comparable to conventional titanium implants under conventional loading and early loading.

  5. In vitro biocompatibility of titanium-nickel alloy with titanium oxide film by H2O2 oxidation

    Institute of Scientific and Technical Information of China (English)

    HU Tao; CHU Cheng-lin; YIN Li-hong; PU Yao-pu; DONG Yin-sheng; GUO Chao; SHENG Xiao-bo; CHUNG Jonathan-CY; CHU Paul-K

    2007-01-01

    Titanium oxide film with a graded interface to NiTi matrix was synthesized in situ on NiTi shape memory alloy(SMA) by oxidation in H2O2 solution. In vitro studies including contact angle measurement, hemolysis, MTT cytotoxicity and cell morphology tests were employed to investigate the biocompatibility of the H2O2-oxidized NiTi SMAs with this titanium oxide film. The results reveal that wettability, blood compatibility and fibroblasts compatibility of NiTi SMA are improved by the coating of titanium oxide film through H2O2 oxidation treatment.

  6. Deoxidation Limits of Titanium Alloys during Pressure Electro Slag Remelting

    Science.gov (United States)

    Bartosinski, M.; Hassan-Pour, S.; Friedrich, B.; Ratiev, S.; Ryabtsev, A.

    2016-07-01

    This paper focuses on deoxidation of titanium alloys produced by aluminothermic reduction (ATR) and subsequent homogenizing and alloying by vacuum induction melting (VIM). The main goal of the performed research work is to outline the deoxidation limit during pressure electro slag remelting (PESR) of the described material. To obtain electrodes for deoxidation, a Ti-24Al-16V masteralloy was produced by ATR and afterwards melted in a 0.5 litre calcium- zirconate (lab scale) or 14 litres high purity calcia (pilot scale) crucibles with continuous addition of Ti-sponge after reaching liquid state in order to obtain a final Ti-6Al-4V alloy. During melting, in both cases evaporation of calcium was noticed. The cast ingots were analysed for oxygen using inert gas fusion method, matrix and alloying elements were analysed by XRF. Results show oxygen levels between 0.5 and 0.95 wt.-% for the ingots which were melted in calcium-zirconate crucibles and approx. 1 - 1.2 wt.-% for the material produced by utilization of calcia crucibles. The subsequent deoxidation was carried out in lab and pilot scale electroslag remelting furnaces using a commercially pure calcium fluoride slag and metallic calcium as deoxidation agent. It could be shown, that deoxidation of the highly contaminated material is possible applying this method to a certain limit. Pilot scale trials showed a reduction of oxygen contents by 1500 - 3500 ppm. Oxygen levels in lab scale trials showed weaker deoxidation effects. In order to describe the achieved deoxidation effects in a quantitative way, the analyzed oxygen contents of the obtained ingots are compared with calculated data resulting from a mathematical kinetic model. The modelled datasets are in good agreement with experimental oxygen values.

  7. Titanium-Zirconium-Nickel Alloy Inside Marshall's Electrostatic Levitator (ESL)

    Science.gov (United States)

    2003-01-01

    This Photo, which appeared on the July cover of `Physics Today', is of the Electrostatic Levitator (ESL) at NASA's Marshall Space Flight Center (MSFC). The ESL uses static electricity to suspend an object (about 3-4 mm in diameter) inside a vacuum chamber allowing scientists to record a wide range of physical properties without the sample contracting the container or any instruments, conditions that would alter the readings. Once inside the chamber, a laser heats the sample until it melts. The laser is then turned off and the sample cools, changing from a liquid drop to a solid sphere. In this particular shot, the ESL contains a solid metal sample of titanium-zirconium-nickel alloy. Since 1977, the ESL has been used at MSFC to study the characteristics of new metals, ceramics, and glass compounds. Materials created as a result of these tests include new optical materials, special metallic glasses, and spacecraft components.

  8. Electrochemical process for the manufacturing of titanium alloy matrix composites

    Directory of Open Access Journals (Sweden)

    V. Soare

    2009-07-01

    Full Text Available The paper presents a new method for precursors’ synthesis of titanium alloys matrix composites through an electrochemical process in molten calcium chloride. The cathode of the cell was made from metallic oxides powders and reinforcement ceramic particles, which were pressed and sintered into disk form and the anode from graphite. The process occurred at 850 °C, in two stages, at 2,7 / 3,2 V: the ionization of the oxygen in oxides and the reduction with calcium formed by electrolysis of calcium oxide fed in the electrolyte. The obtained composite precursors, in a form of metallic sponge, were consolidated by pressing and sintering. Chemical and structural analyses on composites samples were performed.

  9. Process on cold crucible electromagnetic casting for titanium alloy

    Directory of Open Access Journals (Sweden)

    CHEN Rui-run

    2007-08-01

    Full Text Available The parameters and factors that influence the surface quality and macrostructure of titanium alloy with reactive properties under liquid state were studied experimentally using a cold crucible electromagnetic casting method. The variations in the process parameters have great impact on the surface quality and macrostructure of cast billets. Billets with crack free and smooth surfaces as well as directional solidified primary structures were obtained after the selection of optimized process parameters. The formation mechanisms of defects such as cracks and non-directional structural morphology were interpreted briefly. Finally, the casting of billets with good outer qualities and inner column grains has been attained successfully, which in turn gives a solid foundation for further development of the technology.

  10. Process on cold crucible electromagnetic casting for titanium alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The parameters and factors that influence the surface quality and macrostructure of titanium alloy with reactive properties under liquid state were studied experimentally using a cold crucible electromagnetic casting method. The variations in the process parameters have great impact on the surface quality and macrostructure of cast billets. Billets with crack free and smooth surfaces as well as directional solidified primary structures were obtained after the selection of optimized process parameters. The formation mechanisms of defects such as cracks and non-directional structural morphology were interpreted briefly. Finally, the casting of billets with good outer qualities and inner column grains has been attained successfully, which in turn gives a solid foundation for further development of the technology.

  11. Standard Method for Analyzing Gases in Titanium and Titanium Alloys. Standard Method for the Chemical Analysis of Titanium Alloys.

    Science.gov (United States)

    1982-10-28

    acid solution, a cupferron reaaent and copper reagent are used to precipate the titanium, tin, vana- dium, iron and zirconium, and trichloromethane is...alcolohol solution Trichloromethane : Sodium fluroide : solid 4 Sodium acetate buffer solution (PH5-6) : 2M. 60 grams of anhydrous sodium acetate are...milliliters). Add 20 milliliters of a 10% test solution of copper-iron, 5 milliliters of 20% copper test solution, 30 milliliters of trichloromethane , shake

  12. Infection free titanium alloys by stabile thiol based nanocoating.

    Science.gov (United States)

    Cökeliler, Dilek; Göktaş, Hilal; Tosun, Pinar Deniz; Mutlu, Selma

    2010-04-01

    As biomedical materials, titanium and titanium alloys (Ti-6Al-4V) are superior to many materials in terms of mechanical properties and biocompatibility. However, they are still not sufficient for prolonged clinical use because the biocompatibility of these materials must be improved. In this study, the prevention of the attachment of test microorganism on the Ti alloy surfaces by thiol (-SH) and hydroxyl (-OH) functional group containing monomer in plasma based electron beam generator was reported in order to prepare anti-fouling surfaces. The precursor, 11-mercaptoundecanoic acid is used as plasma source to create nano-film with 30-60 nm approximately. The surface chemistry and topology of uncoated and coated samples are characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Atomic Force Microscopy (AFM). Static contact angle measurements are performed to state the change of surface hydrophilicity. All coated samples are tested in-vitro environment with Staphylococcus epidermidis that is chosen as the test bacteria strain in view of its significance for the pathogenesis of medical-device-related infections. This test is repeated after certain period of times and samples are waited in dynamic fluid media in order to investigate the stability of nano-coating. Plasma polymerized 11-mercaptoundecanoic acid film (PP MUA) with 42 +/- 4 nm is found alternative, stabile and simple method to create bacterial anti-fouling surfaces. The static contact angle of the coated surface is 34 +/- 80 whereas the uncoated surface is 57 +/- 50. For the coated surface, the presence of C-OH and C==O groups in infrared spectra defining the PP MUA is achieved by the plasma polymerization. The attachment of the model microorganism on the biomaterial surface prepared by PP MUA is reduced 85.3% if compared to unmodified control surface.

  13. Chemical vapor deposition coatings for oxidation protection of titanium alloys

    Science.gov (United States)

    Cunnington, G. R.; Robinson, J. C.; Clark, R. K.

    1991-01-01

    Results of an experimental investigation of the oxidation protection afforded to Ti-14Al-21Nb and Ti-14Al-23Nb-2V titanium aluminides and Ti-17Mo-3Al-3Nb titanium alloy by aluminum-boron-silicon and boron-silicon coatings are presented. These coatings are applied by a combination of physical vapor deposition (PVD) and chemical vapor deposition (CVD) processes. The former is for the application of aluminum, and the latter is for codeposition of boron and silicon. Coating thickness is in the range of 2 to 7 microns, and coating weights are 0.6 to 2.0 mg/sq cm. Oxidation testing was performed in air at temperatures to 1255 K in both static and hypersonic flow environments. The degree of oxidation protection provided by the coatings is determined from weight change measurements made during the testing and post test compositional analyses. Temperature-dependent total normal emittance data are also presented for four coating/substrate combinations. Both types of coatings provided excellent oxidation protection for the exposure conditions of this investigation. Total normal emittances were greater than 0.80 in all cases.

  14. Electrochemical Impedance Analysis of β-TITANIUM Alloys as Implants in Ringers Lactate Solution

    Science.gov (United States)

    Bhola, Rahul; Bhola, Shaily M.; Mishra, Brajendra; Olson, David L.

    2010-02-01

    Commercially pure titanium and two β-titanium alloys, TNZT and TMZF, have been characterized using various electrochemical techniques for their corrosion behavior in Ringers lactate solution. The variation of corrosion potential and solution pH with time has been discussed. Electrochemical Impedance Spectroscopy has been used to fit the results into a circuit model. The stability of the oxides formed on the surface of these alloys has been correlated with impedance phase angles. Cyclic Potentiodynamic Polarization has been used to compute the corrosion parameters for the alloys. TMZF is found to be a better β-alloy as compared to TNZT.

  15. Modeling of Microstructure Evolution During the Thermomechanical Processing of Titanium Alloys (Preprint)

    National Research Council Canada - National Science Library

    Semiatin, S. L; Furrer, D. U

    2008-01-01

    ... (or combination of properties) can be obtained through microstructural modification. Microstructure evolution and control in titanium alloys is heavily dependent on the allotropic transformation from a hexagonal-close-packed crystal structure...

  16. Effect of temperature on vacuum hot bulge forming of BT20 titanium alloy cylindrical workpiece

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Temperature is one of the key parameters for BT20 titanium alloy cylindrical workpiece manufactured by vacuum hot bulge forming. A two-dimensional nonlinear thermo-mechanical coupled FE model was established. Numerical simulation of vacuum hot bulge forming process of titanium alloy cylindrical workpiece was carried out using FE analysis software MSC Marc. The effects of temperature on vacuum hot bulge forming of BT20 titanium alloy cylindrical workpiece were analyzed by numerical simulation.The simulated results show that the Y-direction displacement and the equivalent plastic strain of the workpiece increase with increasing bulge temperature. The residual stress decreases with increasing bulge temperature. The optimal temperature range of BT20 titanium alloy during vacuum hot bulge forming is 750-850 ℃. The corresponding experiments were carried out. The simulated results agreed well with the experimental results.

  17. [MEDICAL AND PREVENTIVE MEASURES FOR REDUCING CHEMICAL OCCUPATIONAL RISKS IN THE PRODUCTION OF TITANIUM ALLOYS].

    Science.gov (United States)

    Bazarova, E L; Osherov, I S; Roslyĭ, O F; Tartakovskaia, L Ia

    2015-01-01

    An innovative approach in the prevention and rehabilitation of workers employed in the production of titanium alloys envisages the implementation of targeted multi-stage rehabilitation measures in groups with high occupational risk.

  18. Surface integrity after pickling and anodization of Ti-6Al-4V titanium alloy

    Science.gov (United States)

    Vermesse, Eric; Mabru, Catherine; Arurault, Laurent

    2013-11-01

    The surface integrity of Ti-6Al-4V titanium alloy was studied at different stages of surface treatments, especially pickling and compact anodization, through surface characteristics potentially worsening fatigue resistance.

  19. The two steps thermal decomposition of titanium hydride and two steps foaming of Al alloy

    Institute of Scientific and Technical Information of China (English)

    SHANG Jintang; HE Deping

    2005-01-01

    Two steps foaming (TSF) technique was proposed to prepare shaped Al alloy foam. Based on the thermal decomposition kinetics equation of titanium hydride, the relationship between two steps thermal decomposition kinetics of titanium hydride and two steps foaming Al alloy melt was studied. Two steps thermal decomposition curve of titanium hydride under increasing and constant temperature was calculated respectively. The hydrogen mass needed in the second foaming step was also calculated. Results showed that the hydrogen mass of the second thermal decomposition of titanium hydride is enough for the second foaming step in the condition of as-received Al melt foaming. Experimental and theoretical results indicate that two steps foaming technique can be used to prepare Al alloy foam with high porosity, shaped components and sandwich with Al alloy foam core.

  20. Development of a database system for operational use in the selection of titanium alloys

    Science.gov (United States)

    Han, Yuan-Fei; Zeng, Wei-Dong; Sun, Yu; Zhao, Yong-Qing

    2011-08-01

    The selection of titanium alloys has become a complex decision-making task due to the growing number of creation and utilization for titanium alloys, with each having its own characteristics, advantages, and limitations. In choosing the most appropriate titanium alloys, it is very essential to offer a reasonable and intelligent service for technical engineers. One possible solution of this problem is to develop a database system (DS) to help retrieve rational proposals from different databases and information sources and analyze them to provide useful and explicit information. For this purpose, a design strategy of the fuzzy set theory is proposed, and a distributed database system is developed. Through ranking of the candidate titanium alloys, the most suitable material is determined. It is found that the selection results are in good agreement with the practical situation.

  1. Enhancement of surface integrity of titanium alloy with copper by means of laser metal deposition process

    CSIR Research Space (South Africa)

    Erinosho, MF

    2016-04-01

    Full Text Available The laser metal deposition process possesses the combination of metallic powder and laser beam respectively. However, these combinations create an adhesive bonding that permanently solidifies the laser-enhanced-deposited powders. Titanium alloys (Ti...

  2. Galvanic corrosion and cytotoxic effects of amalgam and gallium alloys coupled to titanium.

    Science.gov (United States)

    Bumgardner, J D; Johansson, B I

    1996-06-01

    The aim of this study was to examine and compare the galvanic corrosion of a conventional, a dispersed high-copper, and a palladium-enriched spherical high-copper amalgam and a gallium alloy coupled to titanium in saline and cell culture solutions, and to evaluate the effects of the couples on cultured cells. The potentials and charge transfers between amalgams and titanium were measured by electrochemical corrosion methods. Cytotoxicity of the couples, as indicated by the uptake of neutral red vital stain, was determined in 24-h direct contact human gingival fibroblast cell cultures. Results of this study indicated that before connecting the high-copper amalgams to titanium, the amalgams exhibited more positive potentials which resulted in initial negative charge transfers, i.e. corrosion of titanium. However, this initial corrosion appeared to cause titanium to passivate, and a shift in galvanic currents to positive charge transfers, i.e. corrosion of the amalgam samples. Lower galvanic currents were measured for the amalgam-titanium couples as compared to the gallium alloy-titanium couple. Coupling the conventional or the palladium-enriched high-copper amalgams to titanium did not significantly affect the uptake of neutral red as compared to cells not exposed to any test alloy. However, significant cytotoxic effects were observed when the dispersed-type high-copper amalgam and the gallium alloy were coupled to titanium. Even though the corrosion currents measured for these couples were less than gold alloys coupled to amalgam, these results suggest there is the potential for released galvanic corrosion products to become cytotoxic. These data warrant further investigations into the effects of coupling amalgam and gallium alloys to titanium in the oral environment.

  3. Improvement of the fatigue life of titanium alloys for biomedical devices through microstructural control.

    Science.gov (United States)

    Niinomi, Mitsuo; Akahori, Toshikazu

    2010-07-01

    A limited number of reports exist regarding the systematic investigation or comparison of the fatigue strength of titanium alloys for medical devices, including plain, fretting and notch fatigue, for improvement through various treatments and processes, with respect to related microstructures. This article focuses on the changes and improvements in fatigue strength of newly developed beta-type and practically used alpha + beta-titanium alloys for medical devices through heat treatments, thermomechanical treatments and surface modifications.

  4. Analysis of plastic properties of titanium alloys under severe deformation conditions in machining

    Directory of Open Access Journals (Sweden)

    Alexander I. Khaimovich

    2014-10-01

    Full Text Available The present paper presents a method of analysis of titanium alloys plastic properties under severe deformation conditions during milling with registration of the cutting force components Fx, Fy, Fz in real time using a special stand. The obtained constitutive relations in the form the Johnson-Cook law for stresses and dependence for a friction coefficient describing the titanium alloy VT9 plastic properties under simulate operating conditions.

  5. Technological aspects regarding machining the titanium alloys by means of incremental forming

    Directory of Open Access Journals (Sweden)

    Bologa Octavian

    2017-01-01

    Full Text Available Titanium alloys are materials with reduced formability, due to their low plasticity. However, today there are high demands regarding their use in the automotive industry and in bio-medical industry, for prosthetic devices. This paper presents some technological aspects regarding the machinability of titanium alloys by means of incremental forming. The research presented in this paper aimed to demonstrate that the parts made from these materials could be machined at room temperature, in certain technological conditions.

  6. Effects of titanium additions to austenitic ternary alloys on microstructural evolution and void swelling

    Energy Technology Data Exchange (ETDEWEB)

    Okita, T; Wolfer, W G; Garner, F A; Sekimura, N

    2003-12-01

    Ternary austenitic model alloys were modified with 0.25 wt.% titanium and irradiated in FFTF reactor at dose rates ranging over more than two orders in magnitude. While lowering of dose rate strongly increases swelling by shortening the incubation dose, the steady state swelling rate is not affected by dose rate. Although titanium addition strongly alters the void microstructure, swelling at {approx} 420 C does not change with titanium additions, but the sensitivity to dose rate is preserved.

  7. Effect of silver addition on the properties of nickel-titanium alloys for dental application.

    Science.gov (United States)

    Oh, Keun-Taek; Joo, Uk-Hyon; Park, Gee-Ho; Hwang, Chung-Ju; Kim, Kyoung-Nam

    2006-02-01

    Equiatomic and near-equiatomic nickel-titanium alloys exhibit a shape-memory effect and superelasticity. However, the properties of such alloys are extremely sensitive to the precise nickel-titanium ratio and the addition of alloying elements. High corrosion resistance is necessary for biomedical applications, especially orthodontic. The purpose of this study was to investigate the effect of silver addition to nickel-titanium alloys for dental and medical application. Arc melting, homogenization, hot rolling, and solution heat treatment were performed to prepare the nickel-titanium-silver (NiTi-Ag) specimens. The properties of the ternary NiTi-Ag alloys such as phase-transformation temperature, microstructure, microhardness, corrosion resistance, and cytotoxicity were investigated. The NiTi-Ag alloys showed low silver recovery rate for the cast alloy, due to silver's low evaporation temperature, and low silver solubility in nickel-titanium. Silver addition to nickel-titanium increased the transition temperature range to 100 degrees C and stabilized the martensitic phase (monoclinic structure) at room temperature, because the martensitic transformation starting temperature (Ms) was above room temperature. Martensitic and austenitic phases existed in X-ray diffraction patterns of solution-annealed NiTi-Ag alloys. The silver addition was considered to improve the corrosion resistance and form a stable passive film. Significantly, the mechanical properties of the silver-added alloys were dependent upon the amount of alloying addition. There was no toxicity in the NiTi-Ag alloys, as the response index showed none or mild levels.

  8. Effect of composition of titanium in silver-copper-titanium braze alloy on dissimilar laser brazing of binder-less cubic boron nitride and tungsten carbide

    Science.gov (United States)

    Sechi, Yoshihisa; Nagatsuka, Kimiaki; Nakata, Kazuhiro

    2014-08-01

    Laser brazing with Ti as an active element in silver-copper alloy braze metal has been carried out for binder-less cubic boron nitride and tungsten carbide, using silver-copper- titanium braze alloys with titanium content that varied between 0.28 mass% and 1.68 mass%. Observations of the interface using electron probe microanalysis and scanning acoustic microscopy show that efficient interface adhesion between binder-less cubic boron nitride and the silver-copper-titanium braze alloy was achieved for the braze with a titanium content of 0. 28 mass%.

  9. EXPERIMENTAL INVESTIGATION ON ELECTRICAL DISCHARGE MACHINING OF TITANIUM ALLOY USING COPPER, BRASS AND ALUMINUM ELECTRODES

    Directory of Open Access Journals (Sweden)

    S. DHANABALAN

    2015-01-01

    Full Text Available In the present study, an evaluation has been done on Material Removal Rate (MRR, Surface Roughness (SR and Electrode Wear Rate (EWR during Electrical Discharge Machining (EDM of titanium alloy using copper, brass and aluminum electrodes. Analyzing previous work in this field, it is found that electrode wear and material removal rate increases with an increase current. It is also found that the electrode wear ratio increases with an increase in current. The higher wear ratio is found during machining of titanium alloy using a brass electrode. An attempt has been made to correlate the thermal conductivity and melting point of electrode with the MRR and electrode wear. The MRR is found to be high while machining titanium alloy using brass electrode. During machining of titanium alloy using copper electrodes, a comparatively smaller quantity of heat is absorbed by the work material due to low thermal conductivity. Due to the above reason, the MRR becomes very low. Duringmachining of titanium alloy using aluminium electrodes, the material removal rate and electrode wear rate are only average value while machining of titanium alloy using brass and copper electrodes.

  10. Titanium Alloy Strong Back for IXO Mirror Segments

    Science.gov (United States)

    Byron, Glenn P.; Kai-Wang, Chan

    2011-01-01

    A titanium-alloy mirror-holding fixture called a strong back allows the temporary and permanent bonding of a 50 degree D263 glass x-ray mirror (IXO here stands for International X-ray Observatory). The strong back is used to hold and position a mirror segment so that mounting tabs may be bonded to the mirror with ultra-low distortion of the optical surface. Ti-15%Mo alloy was the material of choice for the strong back and tabs because the coefficient of thermal expansion closely matches that of the D263 glass and the material is relatively easy to machine. This invention has the ability to transfer bonded mounting points from a temporary location on the strong back to a permanent location on the strong back with minimal distortion. Secondly, it converts a single mirror segment into a rigid body with an acceptable amount of distortion of the mirror, and then maneuvers that rigid body into optical alignment such that the mirror segment can be bonded into a housing simulator or mirror module. Key problems are that the mirrors are 0.4-mm thick and have a very low coefficient of thermal expansion (CTE). Because the mirrors are so thin, they are very flexible and are easily distorted. When permanently bonding the mirror, the goal is to achieve a less than 1-micron distortion. Temperature deviations in the lab, which have been measured to be around 1 C, have caused significant distortions in the mirror segment.

  11. Magnetron-sputtered coatings for titanium aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska, E.; Mitoraj, M.; Mania, R. [AGH-UST, Cracow (Poland). Faculty of Materials Science and Ceramics; Zimowski, S.; Kot, M. [AGH-UST, Cracow (Poland). Faculty of Mechanical Engineering and Robotics

    2010-07-01

    Third-generation titanium aluminide alloys fulfil major requirements as lightweight materials for structural applications at moderate temperatures and loads. They are known for attractive combination of physical, chemical and mechanical properties, e.g. low density, good oxidation resistance and strength. Still a lot of work is being done to develop protection systems enabling their use at temperatures exceeding current limit of about 600-650 C. The protection systems under investigation include thick thermal barriers similar to the state-of-the-art coatings for superalloys but also thin layers functioning as diffusion barriers for gases to prevent embrittlement. The paper presents investigations on surface modification of a ({alpha}+{gamma}{sub 2}) Ti-46-8Nb alloy by means of magnetron sputtering of two-component targets: Cr-0.5Si, Cr-5Si, CrSi{sub 2} and Ti-10Si. Targets were obtained from elemental powders by hot pressing. The properties of thus produced surface layers were evaluated on the basis of nanoindentation and scratch tests in the as-received condition and after exposure to air at elevated temperature. Surfaces and cross-sections of the oxidized specimens were examined by SEM, EDS and XRD/GID. (orig.)

  12. Glow Discharge Plasma Nitriding of AISI 304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    A.QAYYUM; M.A.NAVEED; S.ZEB; G.MURTAZA; M.ZAKAULLAH

    2007-01-01

    Glow discharge plasma nitriding of AISI 304 austenitic stainless steel has been carried out for different processing time under optimum discharge conditions established by spectroscopic analysis.The treated samples were analysed by X-ray diffraction(XRD)to explore the changes induced in the crystallographic structure.The XRD pattern confirmed the formation of an expanded austenite phase(γN)owing to incorporation of nitrogen as an interstitial solid solution in the iron lattice.A Vickers microhardness tester was used to evaluate the surface hardness as a function of indentation depth(μm).The results showed clear evidence of surface changes with substantial increase in surface hardness.

  13. Titanium nitride deposition in titanium implant alloys produced by powder metallurgy

    Energy Technology Data Exchange (ETDEWEB)

    Henriques, V.A.R.; Cairo, C.A.A.; Faria, J., E-mail: vinicius@iae.cta.br, E-mail: ccairo@iae.cta.br, E-mail: juliacfaria@gmail.com [Instituto de Aeronautica e Espaco (AMR/CTA/IAE), Sao Jose dos Campos, SP (Brazil). Centro Tecnico Aeroespacial. Divisao de Materiais; Lemos, T.G., E-mail: tgorla@hotmail.com [Universidade de Sao Paulo (DEMAR/EEL/USP), Lorena, SP (Brazil). Escola de Engenharia; Galvani, E.T., E-mail: eduardotgalvani@yahoo.com.br [Instituto Tecnologico de Aeronautica (CTA/ITA), Sao Jose dos Campos, SP (Brazil). Centro Tecnico Aeroespacial

    2009-07-01

    Titanium nitride (TiN) is an extremely hard material, often used as a coating on titanium alloy, steel, carbide, and aluminum components to improve wear resistance. Electron Beam Physical Vapor Deposition (EB-PVD) is a form of deposition in which a target anode is bombarded with an electron beam given off by a charged tungsten filament under high vacuum, producing a thin film in a substrate. In this work are presented results of TiN deposition in targets and substrates of Ti (C.P.) and Ti-{sup 13}Nb-{sup 13}Zr obtained by powder metallurgy. Samples were produced by mixing of hydride metallic powders followed by uniaxial and cold isostatic pressing with subsequent densification by sintering between 900°C up to 1400 °C, in vacuum. The deposition was carried out under nitrogen atmosphere. Sintered samples were characterized for phase composition, microstructure and microhardness by X-ray diffraction, scanning electron microscopy and Vickers indentation, respectively. It was shown that the samples were sintered to high densities and presented homogeneous microstructure, with ideal characteristics for an adequate deposition and adherence. The film layer presented a continuous structure with 15μm. (author)

  14. Electro-Explosive Doping of VT6 Titanium Alloy Surface by Boron Carbide

    Science.gov (United States)

    Kobzareva, T. Yu; Gromov, V. E.; Ivanov, Yu F.; Budovskkh, E. A.; Konovalov, S. V.

    2016-09-01

    The studies carried out in this work target detection of changes in the surface layer of titanium alloy VT6 after electro-explosive alloying (EEA) by boron carbide. EEA of VT6 titanium alloy surface is the plasma alloying formed during the electric explosion of foil with the sample powder of boron carbide. Carbon fibers with weight 140 mg were used as an explosive conductor. Sample powder of boron carbide B4C was placed in the area of explosion on the carbon fibers. It was revealed that EEA of the surface layers of titanium alloy samples VT6 leads to the modification of the layer, thickness of which changes from 10 pm to 50 pm. Heterogeneous distribution of alloying elements was found in the treatment zone by the methods of X-ray microanalysis. A significant difference in their concentration in the identified layers leads to difference in their structural and tribological behaviour. It was revealed that after electro-explosive alloying the microhardness of titanium alloy VT6 significantly increases. Electro-explosive alloying leads to the formation of a structure of submicro- and nano-scale level. It allows strength and tribological properties of the treated surface to be increased.

  15. Research on depositing Ni45 alloy on titanium alloy surface by electrospark deposition

    OpenAIRE

    Su Guiqiao; You Tao; Zhang Chunhui

    2008-01-01

    Taking Ni45 bar as electrode, a strengthened layer of thickness up to 50 μm was built up on BT20 titanium alloy matrix by means of electrospark deposition. Results of phase analysis by using of X-ray diffraction confirmed that the deposition layer was composed mostly of three phases, NiTi, NiTi2 and Ti. The surface microhardness of the deposition layer was up to 910 HV0.05, about 2.7 times as high as that of the matrix. The hardness at the cross-section of the entire deposition layer showed a...

  16. Crestal remodelling and osseointegration at surface-modified commercially pure titanium and titanium alloy implants in a canine model.

    Science.gov (United States)

    Lee, Jaebum; Hurson, Steve; Tadros, Hatem; Schüpbach, Peter; Susin, Cristiano; Wikesjö, Ulf M E

    2012-08-01

    Ti-6Al-7Nb alloys exhibit enhanced mechanical properties and corrosion resistance and may represent an improvement to present commercially pure (CP) titanium oral implant technology. To evaluate crestal remodelling and osseointegration at CP titanium compared with Ti-6Al-7Nb alloy oral implants using a canine model. Two threaded anodized CP titanium and two Ti-6Al-7Nb alloy anodized oral implants (ø4.5 × 6.1 mm) were placed into each jaw quadrant in the edentulated posterior mandible in six adult male Hound Labrador mongrel dogs. Abutments were placed onto the implants, and the mucogingival flaps were adapted and sutured for transmucosal wound healing. Block biopsies were collected for histometric analysis following an 8-week healing interval. Healing was uneventful. Bone density outside and within the root of the threads averaged (± SE) 49.0 ± 4.5% and 38.7 ± 5.1% for CP titanium implants and 43.2 ± 3.6% and 34.2 ± 4.8% for Ti-6Al-7Nb alloy implants. Mean osseointegration reached 68.0 ± 4.4% and 62.8 ± 2.5% for CP titanium and Ti-6Al-7Nb alloy implants, respectively. Although crestal resorption at lingual sites averaged 0.2 ± 0.1 mm for both technologies, crestal resorption at buccal sites averaged 0.9 ± 0.2 and 1.0 ± 0.6 mm for CP titanium and Ti-6Al-7Nb alloy implants, respectively. There were no statistically significant differences between implant technologies for any parameter assessed. Notably, advanced/advancing buccal crestal resorption exposing the implant threads was observed in 50% of the implants (four of six animals) regardless of implant technology; osteoclastic resorption still observed at 8 weeks following implant placement. Within the limitations of study, anodized Ti-6Al-7Nb alloy implants may represent a feasible alternative to benchmark anodized CP titanium implants. Remodelling of the buccal crestal plate resulting in advanced bone loss appears a major impediment to oral implant osseointegration and possibly, in extension, implant

  17. Double Glow Plasma Surface Alloying Antibacterial Silver Coating on Pure Titanium

    Science.gov (United States)

    Lin, Naiming; Guo, Junwen; Hang, Ruiqiang; Zou, Jiaojuan; Tang, Bin

    2014-12-01

    In order to endow the commercial pure titanium dental implant material with antibacterial property and aimed at avoiding the invalidation that is caused by bacterial adhesion on the surface, a silver coating was fabricated via double glow plasma surface alloying. The antibacterial property of the silver coating was assessed via in vitro estimation. The results showed that a continuous and compact coating was formed. The silver coating had absolute superiority in antibacterial property to raw commercial pure titanium. Double glow plasma surface alloying with silver on commercial pure titanium dental implant material could be considered as a potentially effective method for preventing bacterial adhesion.

  18. Validity of "sputtering and re-condensation" model in active screen cage plasma nitriding process

    Science.gov (United States)

    Saeed, A.; Khan, A. W.; Jan, F.; Abrar, M.; Khalid, M.; Zakaullah, M.

    2013-05-01

    The validity of "sputtering and re-condensation" model in active screen plasma nitriding for nitrogen mass transfer mechanism is investigated. The dominant species including NH, Fe-I, N2+, N-I and N2 along with Hα and Hβ lines are observed in the optical emission spectroscopy (OES) analysis. Active screen cage and dc plasma nitriding of AISI 316 stainless steel as function of treatment time is also investigated. The structure and phases composition of the nitrided layer is studied by X-ray diffraction (XRD). Surface morphology is studied by scanning electron microscopy (SEM) and hardness profile is obtained by Vicker's microhardness tester. Increasing trend in microhardness is observed in both cases but the increase in active screen plasma nitriding is about 3 times greater than that achieved by dc plasma nitriding. On the basis of metallurgical and OES observations the use of "sputtering and re-condensation" model in active screen plasma nitriding is tested.

  19. Multiscale Characterization of Nickel Titanium Shape Memory Alloys

    Science.gov (United States)

    Gall, Keith

    Shape memory alloys were characterized by a variety of methods to investigate the relationship between microstructural phase transformation, macroscale deformation due to mechanical loading, material geometry, and initial material state. The major portion of the work is application of digital image correlation at several length scales to SMAs under mechanical loading. In addition, the connection between electrical resistance, stress, and strain was studied in NiTi wires. Finally, a new processing method was investigated to develop porous NiTi samples, which can be examined under DIC in future work. The phase transformation temperatures of a Nickel-Titanium based shape memory alloy (SMA) were initially evaluated under stress-free conditions by the differential scanning calorimetric (DSC) technique. Results show that the phase transformation temperature is significantly higher for transition from de-twinned martensite to austenite than from twinned martensite or R phase to austenite. To further examine transformation temperatures as a function of initial state a tensile test apparatus with in-situ electrical resistance (ER) measurements was used to evaluate the transformation properties of SMAs at a variety of stress levels and initial compositions. The results show that stress has a significant influence on the transformation of detwinned martensite, but a small influence on R phase and twinned martensite transformations. Electrical resistance changes linearly with strain during the transformations from both kinds of martensite to austenite. The linearity between ER and strain during the transformation from de-twinned martensite to austenite is not affected by the stress, facilitating application to control algorithms. A revised phase diagram is drawn to express these results. To better understand the nature of the local and global strain fields that accompany phase transformation in shape memory alloys (SMAs), here we use high resolution imaging together with image

  20. A study on the porosity of CO2 laser welding of titanium alloy

    Institute of Scientific and Technical Information of China (English)

    Chen Li; Hu Lunji; Gong Shuili

    2006-01-01

    The CO2 laser welding of BT20 titanium alloy and Ti-23Al-17Nb titanium aluminide was conducted to investigate into the porosity in titanium alloy weld. The results show that there are two sorts of porosities observed in welds of titanium alloy laser welding based on the microscopic characteristics of the porosities. One is the metallurgical porosity with round and smooth inner wall, which results from the surface contamination. The other is the processing porosity with irregular and rough inner wall that displays the trace of the pool flowing, which results from the ruffle on the keyhole wall gathering together locally and closing down the gas in the keyhole into bubbles because of the keyhole fluctuating. The CO2 laser welding could break down easily the surface oxide film and produce little metallurgical porosity, but produces easily processing porosity when partial penetration or unstable-full penetration laser welding is conducted, which always occurs in the center of weld.

  1. Electrochemical Deoxidation of Titanium and Its Alloy Using Molten Magnesium Chloride

    Science.gov (United States)

    Taninouchi, Yu-ki; Hamanaka, Yuki; Okabe, Toru H.

    2016-08-01

    Oxygen was directly removed from pure titanium and a Ti-6Al-4V alloy by electrolysis in molten MgCl2 at 1173 K (900 °C), where the metal being refined was the cathode and a graphite rod was used as the anode. By applying a voltage of approximately 3 V between the electrodes, commercially pure titanium, containing 1200 mass ppm oxygen, and the Ti-6Al-4V alloy, containing 1400 mass ppm oxygen, were deoxidized to 500 mass ppm or less. Under certain conditions, extra-low-oxygen titanium (as low as 80 mass ppm oxygen) was obtained using this electrochemical technique. The results obtained in this study indicate that the electrochemical deoxidation of titanium in molten MgCl2 is feasible and applicable not only to the refinement of primary metals, but also for upgrading machined titanium products and recycling metal scraps.

  2. Electrochemical Deoxidation of Titanium and Its Alloy Using Molten Magnesium Chloride

    Science.gov (United States)

    Taninouchi, Yu-ki; Hamanaka, Yuki; Okabe, Toru H.

    2016-12-01

    Oxygen was directly removed from pure titanium and a Ti-6Al-4V alloy by electrolysis in molten MgCl2 at 1173 K (900 °C), where the metal being refined was the cathode and a graphite rod was used as the anode. By applying a voltage of approximately 3 V between the electrodes, commercially pure titanium, containing 1200 mass ppm oxygen, and the Ti-6Al-4V alloy, containing 1400 mass ppm oxygen, were deoxidized to 500 mass ppm or less. Under certain conditions, extra-low-oxygen titanium (as low as 80 mass ppm oxygen) was obtained using this electrochemical technique. The results obtained in this study indicate that the electrochemical deoxidation of titanium in molten MgCl2 is feasible and applicable not only to the refinement of primary metals, but also for upgrading machined titanium products and recycling metal scraps.

  3. The effect of microstructure on the fracture toughness of titanium alloys

    Science.gov (United States)

    Vanstone, R. H.; Low, J. R., Jr.; Shannon, J. L., Jr.

    1974-01-01

    The microstructure of the alpha titanium alloy Ti-5Al-2.5Sn and the metastable beta titanium alloy Beta 3 was examined. The material was from normal and extra low interstitial grade plates which were either air-cooled or furnace-cooled from an annealing treatment. Beta 3 was studied in alpha-aged and omega-aged plates which were heat treated to similar strength levels. Tensile and plane strain fracture toughness tests were conducted at room temperature on the alpha-aged material. The microstructure and fracture mechanisms of alloys were studied using optical metallography, electron microscopy, microprobe analyses, and texture pole figures. Future experiments are described.

  4. Ion Nitriding of Titanium Alloys with a Hollow Cathode Effect Application

    Directory of Open Access Journals (Sweden)

    V.V. Budilov

    2015-09-01

    Full Text Available The method of ion nitriding the titanium VT6 alloy in glow discharge with the hollow cathode effect (HCE was investigated. Probe measurements of glow discharge plasma under HCE conditions and without it were performed; ion densities near the cathode surface were measured. The effect of HCE on microstructure, microhardness and wear resistance of VT6 alloy was determined. The technology of ion nitriding titanium alloys, based on phase modification of the surface layer in glow discharge with HCE, was developed.

  5. The influence of cooling techniques on cutting forces and surface roughness during cryogenic machining of titanium alloys

    Science.gov (United States)

    Wstawska, Iwona; Ślimak, Krzysztof

    2016-12-01

    Titanium alloys are one of the materials extensively used in the aerospace industry due to its excellent properties of high specific strength and corrosion resistance. On the other hand, they also present problems wherein titanium alloys are extremely difficult materials to machine. In addition, the cost associated with titanium machining is also high due to lower cutting velocities and shorter tool life. The main objective of this work is a comparison of different cooling techniques during cryogenic machining of titanium alloys. The analysis revealed that applied cooling technique has a significant influence on cutting force and surface roughness (Ra parameter) values. Furthermore, in all cases observed a positive influence of cryogenic machining on selected aspects after turning and milling of titanium alloys. This work can be also the starting point to the further research, related to the analysis of cutting forces and surface roughness during cryogenic machining of titanium alloys.

  6. Internal state variable models for micro- structure in high temperature deformation of titanium alloys

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    There exists an interaction between microstructural evolution and deformation behavior in high temperature deformation of titanium alloys. And the microstruc- ture of titanium alloys is very sensitive to the process parameters of plastic de- formation process. In this paper, on the basis of plastic deformation mechanism of metals and alloys, a microstructural model including dislocation density rate equa- tion and grain growth rate equation is established with the dislocation density rate being an internal state variable. Applying the model to the high temperature de- formation process of Ti60 titanium alloy, the average relative errors of grain sizes between the experiments and the predictions are 9.47% for sampled data, and 13.01% for non-sampled data.

  7. Internal state variable models for micro-structure in high temperature deformation of titanium alloys

    Institute of Scientific and Technical Information of China (English)

    LUO Jiao; LI MiaoQuan; LI XiaoLi

    2008-01-01

    There exists an interaction between microstructural evolution and deformation behavior in high temperature deformation of titanium alloys. And the microstruc-ture of titanium alloys is very sensitive to the process parameters of plastic de-formation process. In this paper, on the basis of plastic deformation mechanism of metals and alloys, a microstructural model including dislocation density rate equa-tion and grain growth rate equation is established with the dislocation density rate being an internal state variable. Applying the model to the high temperature de-formation process of Ti60 titanium alloy, the average relative errors of grain sizes between the experiments and the predictions are 9.47% for sampled data, and 13.01% for non-sampled data.

  8. A low-cost hierarchical nanostructured beta-titanium alloy with high strength.

    Science.gov (United States)

    Devaraj, Arun; Joshi, Vineet V; Srivastava, Ankit; Manandhar, Sandeep; Moxson, Vladimir; Duz, Volodymyr A; Lavender, Curt

    2016-04-01

    Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission. Working towards this goal we achieved high strength in a low cost β-titanium alloy, Ti-1Al-8V-5Fe (Ti185), by hierarchical nanostructure consisting of homogenous distribution of micron-scale and nanoscale α-phase precipitates within the β-phase matrix. The sequence of phase transformation leading to this hierarchical nanostructure is explored using electron microscopy and atom probe tomography. Our results suggest that the high number density of nanoscale α-phase precipitates in the β-phase matrix is due to ω assisted nucleation of α resulting in high tensile strength, greater than any current commercial titanium alloy. Thus hierarchical nanostructured Ti185 serves as an excellent candidate for replacing costlier titanium alloys and other structural alloys for cost-effective lightweighting applications.

  9. Peculiarities of high-temperature. beta. -phase formation during rapid heating of titanium-molybdenum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gridnev, V.N.; Zhuravlev, A.F.; Zhuravlev, B.F.; Ivasishin, O.M.; Oshkaderov, S.P. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)

    1983-11-01

    In the framework of the diffusion mechanism of ..cap alpha..+..beta.. ..-->.. ..beta.. transformation the model for calculating interface location determining the degree of transformation and concentration of the formed ..beta..-phase during continuous heating under different rates in titanium alloys with ..beta..-isomorphous alloying elements is suggested. On the example of Ti-10% Mo alloy the comparison of calculation and experimental results of determining parameters of ..cap alpha..+..beta.. ..-->.. ..beta.. transformation is performed.

  10. Hydrothermal treatment of titanium alloys for the enhancement of osteoconductivity.

    Science.gov (United States)

    Zuldesmi, Mansjur; Waki, Atsushi; Kuroda, Kensuke; Okido, Masazumi

    2015-04-01

    The surface wettability of implants is a crucial factor in their osteoconductivity because it influences the adsorption of cell-attached proteins onto the surface. In this study, a single-step hydrothermal surface treatment using distilled water at a temperature of 180°C for 3h was applied to titanium (Ti) and its alloys (Ti-6Al-4V, Ti-6Al-7Nb, Ti-29Nb-13Ta-4.6Zr, Ti-13Cr-1Fe-3Al; mass%) and compared with as-polished Ti implants and with implants produced by anodizing Ti in 0.1M of H3PO4 with applied voltages from 0V to 150V at a scanning rate of 0.1Vs(-1). The surface-treated samples were stored in a five time phosphate buffered saline (×5 PBS(-)) solution to prevent increasing the water contact angle (WCA) with time. The surface characteristics were evaluated using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Auger electron spectroscopy, surface roughness, and contact angle measurement using a 2μL droplet of distilled water. The relationship between WCA and osteoconductivity at various surface modifications was examined using in vivo tests. The results showed that a superhydrophilic surface with a WCA≤10° and a high osteoconductivity (RB-I) of up to 50% in the cortical bone part, about four times higher than the as-polished Ti and Ti alloys, were provided by the combination of the hydrothermal surface treatment and storage in ×5 of PBS(-).

  11. Nanostructured Nickel-Cobalt-Titanium Alloy Grown on Titanium Substrate as Efficient Electrocatalyst for Alkaline Water Electrolysis.

    Science.gov (United States)

    Ganesan, Pandian; Sivanantham, Arumugam; Shanmugam, Sangaraju

    2017-04-12

    One of the important challenges in alkaline water electrolysis is to utilize a bifunctional catalyst for both hydrogen evolution (HER) and oxygen evolution (OER) reactions to increase the efficiency of water splitting devices for the long durable operations. Herein, nickel-cobalt-titanium (NCT) alloy is directly grown on a high corrosion resistance titanium foil by a simple, single, and rapid electrochemical deposition at room temperature. The electrocatalytic activity of NCT alloy electrodes is evaluated for both HER and OER in aqueous electrolyte. Our NCT electrocatalyst exhibits low overpotentials around 125 and 331 mV for HER and OER, respectively, in 1 M KOH. In addition to this outstanding activity, the bifunctional catalyst also exhibits excellent OER and HER electrode stability up to 150 h of continuous operation with a minimal loss in activity. Further, the NCT alloy directly grown on titanium foil is used to directly construct membrane electrode assembly (MEA) for alkaline electrolyte membrane (AEM) water electrolyzer, which make the practical applicability. This single-step electrodeposition reveals NCT on titanium foil with high activity and excellent electrode stability suitable for replacing alternative commercial viable catalyst for the alkaline water splitting.

  12. Spark plasma sintering synthesis of porous nanocrystalline titanium alloys for biomedical applications.

    Science.gov (United States)

    Nicula, R; Lüthen, F; Stir, M; Nebe, B; Burkel, E

    2007-11-01

    The reason for the extended use of titanium and its alloys as implant biomaterials stems from their lower elastic modulus, their superior biocompatibility and improved corrosion resistance compared to the more conventional stainless steel and cobalt-based alloys [Niinomi, M., Hattori, T., Niwa, S., 2004. Material characteristics and biocompatibility of low rigidity titanium alloys for biomedical applications. In: Jaszemski, M.J., Trantolo, D.J., Lewandrowski, K.U., Hasirci, V., Altobelli, D.E., Wise, D.L. (Eds.), Biomaterials in Orthopedics. Marcel Dekker Inc., New York, pp. 41-62]. Nanostructured titanium-based biomaterials with tailored porosity are important for cell-adhesion, viability, differentiation and growth. Newer technologies like foaming or low-density core processing were recently used for the surface modification of titanium alloy implant bodies to stimulate bone in-growth and improve osseointegration and cell-adhesion, which in turn play a key role in the acceptance of the implants. We here report preliminary results concerning the synthesis of mesoporous titanium alloy bodies by spark plasma sintering. Nanocrystalline cp Ti, Ti-6Al-4V, Ti-Al-V-Cr and Ti-Mn-V-Cr-Al alloy powders were prepared by high-energy wet-milling and sintered to either full-density (cp Ti, Ti-Al-V) or uniform porous (Ti-Al-V-Cr, Ti-Mn-V-Cr-Al) bulk specimens by field-assisted spark plasma sintering (FAST/SPS). Cellular interactions with the porous titanium alloy surfaces were tested with osteoblast-like human MG-63 cells. Cell morphology was investigated by scanning electron microscopy (SEM). The SEM analysis results were correlated with the alloy chemistry and the topographic features of the surface, namely porosity and roughness.

  13. Automated microstructural analysis of titanium alloys using digital image processing

    Science.gov (United States)

    Campbell, A.; Murray, P.; Yakushina, E.; Marshall, S.; Ion, W.

    2017-02-01

    Titanium is a material that exhibits many desirable properties including a very high strength to weight ratio and corrosive resistance. However, the specific properties of any components depend upon the microstructure of the material, which varies by the manufacturing process. This means it is often necessary to analyse the microstructure when designing new processes or performing quality assurance on manufactured parts. For Ti6Al4V, grain size analysis is typically performed manually by expert material scientists as the complicated microstructure of the material means that, to the authors knowledge, no existing software reliably identifies the grain boundaries. This manual process is time consuming and offers low repeatability due to human error and subjectivity. In this paper, we propose a new, automated method to segment microstructural images of a Ti6Al4V alloy into its constituent grains and produce measurements. The results of applying this technique are evaluated by comparing the measurements obtained by different analysis methods. By using measurements from a complete manual segmentation as a benchmark we explore the reliability of the current manual estimations of grain size and contrast this with improvements offered by our approach.

  14. Crystallographic features of {alpha}``-martensite in titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ivasishin, O.M. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Metallov Fiziki; Kosenko, N.S. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Metallov Fiziki; Shevchenko, S.V. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Metallov Fiziki

    1995-12-01

    Equilibrium volume fractions of twins ({alpha}{sub 0}) and habit plane orientation (anti n{sub 0}) of the orthorhombic {alpha}``-martensite in titanium alloys with {beta}-stabilizing elements were determined by minimization of the elastic strain energy. Calculations were made in the basis of one of the twinned domains. It was shown that these parameters are varying considerably depending on the solute element content. For Ti-Ta and Ti-Mo systems habit plane rotated from {l_brace}434{r_brace}{sub {beta}} to {l_brace}433{r_brace}{sub {beta}} pole and {alpha}{sub 0} grew with Ta (Mo) content increase. For Ti-20at%Ta {alpha}{sub 0} reached the value of 1, i.e. martensite plate became monodomain. For Ti-Mo system monodomain state was not achieved. For Ti-Nb system converse concentrational dependence of martensite parameters was obtained: {alpha}{sub 0} decreased with Nb content increase, and n showed a rotation from {l_brace}434{r_brace}{sub {beta}} pole in a direction opposite to that for Ti-Ta and Ti-Mo systems. (orig.).

  15. Titanium alloy as a potential low radioactivation vacuum material

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Junichiro, E-mail: kamiya.junichiro@jaea.go.jp; Hikichi, Yusuke; Kinsho, Michikazu; Ogiwara, Norio [Japan Atomic Energy Agency, J-PARC Center, 2-4 Shirane Shirakata, Tokai, Naka, Ibaraki 319-1195 (Japan); Fukuda, Mitsuhiro; Hamatani, Noriaki; Hatanaka, Kichiji; Kamakura, Keita; Takahisa, Keiji [Research Center for Nuclear Physics, Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2015-05-15

    For the vacuum systems of high-intensity beam accelerators, low radioactivation materials with good vacuum characteristics and high mechanical strength are required. The titanium alloy Ti-6Al-4V was investigated as a potential low activation vacuum material with high mechanical strength for the fabrication of vacuum components, particularly the flanges of beam pipes, in the J-PARC 3 GeV synchrotron. The dose rate of Ti-6Al-4V when irradiated by a 400 MeV proton was observed to decrease more rapidly than that of stainless steel. Furthermore, the generated radioactive isotopes were nuclides with relatively short half-lives. The outgassing rate per unit area of Ti-6Al-4V was approximately 10{sup −8 }Pa m{sup 3}/s m{sup 2} after pumping for 100 h, which is the same as the typical value for stainless steel. Additionally, the hydrogen concentration in bulk Ti-6Al-4V was reduced to approximately 1 ppm by vacuum firing at 700 °C for 9 h; the mechanical strength was not reduced by this process. These results indicate that Ti-6Al-4V is a good candidate for use as a low activation vacuum material with high mechanical strength.

  16. Material morphological characteristics in laser ablation of alpha case from titanium alloy

    Science.gov (United States)

    Yue, Liyang; Wang, Zengbo; Li, Lin

    2012-08-01

    Alpha case (an oxygen enriched alloy layer) is commonly formed in forged titanium alloys during the manufacturing process and it reduces the service life of the materials. This layer is normally removed mechanically or chemically. This paper reports the feasibility and characteristics of using a short pulsed laser to remove oxygen-enriched alpha case layer from a titanium alloy (Ti6Al4V) substrate. The material removal rate, i.e., ablation rate, and ablation threshold of the alpha case titanium were experimentally determined, and compared with those for the removal of bulk Ti6Al4V. Surface morphologies of laser processed alpha case titanium layer, especially that of cracks at different ablated depths, were carefully examined, and also compared with those for Ti6Al4V. It has been shown that in the alpha case layer, laser ablation has always resulted in crack formation while for laser ablation of alpha case free Ti6Al4V layers, cracking was not present. In addition, the surface is rougher within the alpha case layer and becomes smoother (Ra - 110 nm) once the substrate Ti-alloy is reached. The work has demonstrated that laser is a feasible processing tool for removing alpha case titanium, and could also be used for the rapid detection of the presence of alpha case titanium on Ti6Al4V surfaces in aerospace applications.

  17. Plasma nitriding of AISI 52100 ball bearing steel and effect of heat treatment on nitrided layer

    Indian Academy of Sciences (India)

    Ravindra Kumar; J Alphonsa; Ram Prakash; K S Boob; J Ghanshyam; P A Rayjada; P M Raole; S Mukherjee

    2011-02-01

    In this paper an effort has been made to plasma nitride the ball bearing steel AISI 52100. The difficulty with this specific steel is that its tempering temperature (∼170–200°C) is much lower than the standard processing temperature (∼460–580°C) needed for the plasma nitriding treatment. To understand the mechanism, effect of heat treatment on the nitrided layer steel is investigated. Experiments are performed on three different types of ball bearing races i.e. annealed, quenched and quench-tempered samples. Different gas compositions and process temperatures are maintained while nitriding these samples. In the quenched and quench-tempered samples, the surface hardness has decreased after plasma nitriding process. Plasma nitriding of annealed sample with argon and nitrogen gas mixture gives higher hardness in comparison to the hydrogen–nitrogen gas mixture. It is reported that the later heat treatment of the plasma nitrided annealed sample has shown improvement in the hardness of this steel. X-ray diffraction analysis shows that the dominant phases in the plasma nitrided annealed sample are (Fe2−3N) and (Fe4N), whereas in the plasma nitrided annealed sample with later heat treatment only -Fe peak occurs.

  18. Enhancement of wear and corrosion resistance of beta titanium alloy by laser gas alloying with nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Chi-Wai, E-mail: c.w.chan@qub.ac.uk [School of Mechanical and Aerospace Engineering, Queen' s University Belfast, BT9 5AH (United Kingdom); Lee, Seunghwan [Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Smith, Graham [Department of Natural Sciences, University of Chester, Thornton Science Park, Chester CH2 4NU (United Kingdom); Sarri, Gianluca [School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Ng, Chi-Ho [School of Mechanical and Aerospace Engineering, Queen' s University Belfast, BT9 5AH (United Kingdom); Laser Engineering and Manufacturing Research Centre, Faculty of Science and Engineering, University of Chester, Parkgate Road, Chester CH1 4BJ (United Kingdom); Sharba, Ahmed [School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Man, Hau-Chung [Department of Industrial and Systems Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, Hong Kong (China)

    2016-03-30

    Graphical abstract: - Highlights: • Laser technology is a fast, clean and flexible method for surface hardening of TNZT. • Laser can form a protective hard layer on TNZT surface without altering surface roughness. • The laser-formed layer is metallurgically bonded to the substrate. • Laser-treated TNZT is highly resistant to corrosion and wear in Hank's solution. - Abstract: The relatively high elastic modulus coupled with the presence of toxic vanadium (V) in Ti6Al4V alloy has long been a concern in orthopaedic applications. To solve the problem, a variety of non-toxic and low modulus beta-titanium (beta-Ti) alloys have been developed. Among the beta-Ti alloy family, the quaternary Ti–Nb–Zr–Ta (TNZT) alloys have received the highest attention as a promising replacement for Ti6Al4V due to their lower elastic modulus and outstanding long term stability against corrosion in biological environments. However, the inferior wear resistance of TNZT is still a problem that must be resolved before commercialising in the orthopaedic market. In this work, a newly developed laser surface treatment technique was employed to improve the surface properties of Ti–35.3Nb–7.3Zr–5.7Ta alloy. The surface structure and composition of the laser-treated TNZT surface were examined by grazing incidence X-ray diffraction (GI-XRD) and X-ray photoelectron spectroscopy (XPS). The wear and corrosion resistance were evaluated by pin-on-plate sliding test and anodic polarisation test in Hanks’ solution. The experimental results were compared with the untreated (or base) TNZT material. The research findings showed that the laser surface treatment technique reported in this work can effectively improve the wear and corrosion resistance of TNZT.

  19. Structural characterization of plasma nitrided interstitial-free steel at different temperatures by SEM, XRD and Rietveld method

    Directory of Open Access Journals (Sweden)

    Ana Paula de Andrade Manfridini

    2017-01-01

    Full Text Available Plasma nitriding processes are widely used to improve surface properties of several steels and alloys. In this work, the formation of nitrides in the surface of plasma nitrided IF steels as a function of the temperature was investigated. Three cold-rolled IF steel plates were nitrided for 4 h after shot peening at three different temperatures: 450 °C, 475 °C, and 500 °C. The resultant nitrided layers were then characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD, Rietveld method, and hardness measurements. Through SEM images, it was possible to visualize two main sublayers: a compound layer and a diffusion zone. Through XRD, two phases were identified in the compound layer, which were ɛ-Fe2–3N and γ′-Fe4N. The diffusion zone presented a ferritic matrix with fine precipitates, possibly α″-Fe16N2. By Rietveld, the calculated quantity of γ′-Fe4N was 68 wt.% for the sample treated at 475 °C and 58 wt.% for the one treated at 500 °C. These values were consistent with the hardness measurements. Thus, it is suggested that higher nitriding temperatures facilitate the decreasing of γ′-Fe4N and, consequently, the increasing of ɛ-Fe2–3N in the compound layer.

  20. Variable viscosity on unsteady dissipative Carreau fluid over a truncated cone filled with titanium alloy nanoparticles

    Science.gov (United States)

    Raju, C. S. K.; Sekhar, K. R.; Ibrahim, S. M.; Lorenzini, G.; Viswanatha Reddy, G.; Lorenzini, E.

    2017-01-01

    In this study, we proposed a theoretical investigation on the temperature-dependent viscosity effect on magnetohydrodynamic dissipative nanofluid over a truncated cone with heat source/sink. The involving set of nonlinear partial differential equations is transforming to set of nonlinear ordinary differential equations by using self-similarity solutions. The transformed governing equations are solved numerically using Runge-Kutta-based Newton's technique. The effects of various dimensionless parameters on the skin friction coefficient and the local Nusselt number profiles are discussed and presented with the support of graphs. We also obtained the validation of the current solutions with existing solution under some special cases. The water-based titanium alloy has a lesser friction factor coefficient as compared with kerosene-based titanium alloy, whereas the rate of heat transfer is higher in water-based titanium alloy compared with kerosene-based titanium alloy. From this we can highlight that depending on the industrial needs cooling/heating chooses the water- or kerosene-based titanium alloys.

  1. Variable viscosity on unsteady dissipative Carreau fluid over a truncated cone filled with titanium alloy nanoparticles

    Science.gov (United States)

    Raju, C. S. K.; Sekhar, K. R.; Ibrahim, S. M.; Lorenzini, G.; Viswanatha Reddy, G.; Lorenzini, E.

    2017-05-01

    In this study, we proposed a theoretical investigation on the temperature-dependent viscosity effect on magnetohydrodynamic dissipative nanofluid over a truncated cone with heat source/sink. The involving set of nonlinear partial differential equations is transforming to set of nonlinear ordinary differential equations by using self-similarity solutions. The transformed governing equations are solved numerically using Runge-Kutta-based Newton's technique. The effects of various dimensionless parameters on the skin friction coefficient and the local Nusselt number profiles are discussed and presented with the support of graphs. We also obtained the validation of the current solutions with existing solution under some special cases. The water-based titanium alloy has a lesser friction factor coefficient as compared with kerosene-based titanium alloy, whereas the rate of heat transfer is higher in water-based titanium alloy compared with kerosene-based titanium alloy. From this we can highlight that depending on the industrial needs cooling/heating chooses the water- or kerosene-based titanium alloys.

  2. The surface nanostructures of titanium alloy regulate the proliferation of endothelial cells

    Directory of Open Access Journals (Sweden)

    Min Lai

    2014-02-01

    Full Text Available To investigate the effect of surface nanostructures on the behaviors of human umbilical vein endothelial cells (HUVECs, surface nanostructured titanium alloy (Ti-3Zr2Sn-3Mo-25Nb, TLM was fabricated by surface mechanical attrition treatment (SMAT technique. Field emission scanning electron microscopy (FE-SEM, atomic force microscopy (AFM, transmission electron microscopy (TEM and X-ray diffraction (XRD were employed to characterize the surface nanostructures of the TLM, respectively. The results demonstrated that nano-crystalline structures with several tens of nanometers were formed on the surface of TLM substrates. The HUVECs grown onto the surface nanostructured TLM spread well and expressed more vinculin around the edges of cells. More importantly, HUVECs grown onto the surface nanostructured TLM displayed significantly higher (p < 0.01 or p < 0.05 cell adhesion and viabilities than those of native titanium alloy. HUVECs cultured on the surface nanostructured titanium alloy displayed significantly higher (p < 0.01 or p < 0.05 productions of nitric oxide (NO and prostacyclin (PGI2 than those of native titanium alloy, respectively. This study provides an alternative for the development of titanium alloy based vascular stents.

  3. Research and Development of Some Advanced High Temperature Titanium Alloys for Aero-engine

    Directory of Open Access Journals (Sweden)

    CAI Jian-ming

    2016-08-01

    Full Text Available Some advanced high temperature titanium alloys are usually selected to be manufactured into blade, disc, case, blisk and bling under high temperature environment in compressor and turbine system of a new generation high thrust-mass ratio aero-engine. The latest research progress of 600℃ high temperature titanium alloy, fireproof titanium alloy, TiAl alloy, continuous SiC fiber reinforced titanium matrix composite and their application technology in recent years in China were reviewed in this paper. The key technologies need to be broken through in design, processing and application of new material and component are put forward, including industrial ingot composition of high purified and homogeneous control technology, preparation technology of the large size bar and special forgings, machining technology of blisk and bling parts, material property evaluation and application design technique. The future with the continuous application of advanced high temperature titanium alloys, will be a strong impetus to the development of China's aero-engine technology.

  4. Effects of sodium tartrate anodizing on fatigue life of TA15 titanium alloy

    Directory of Open Access Journals (Sweden)

    Fu Chunjuan

    2015-08-01

    Full Text Available Anodizing is always used as an effective surface modification method to improve the corrosion resistance and wear resistance of titanium alloy. The sodium tartrate anodizing is a new kind of environmental anodizing method. In this work, the effects of sodium tartrate anodizing on mechanical property were studied. The oxide film was performed on the TA15 titanium alloy using sodium tartrate as the film former. The effects of this anodizing and the traditional acid anodizing on the fatigue life of TA15 alloy were compared. The results show that the sodium tartrate anodizing just caused a slight increase of hydrogen content in the alloy, and had a slight effect on the fatigue life. While, the traditional acid anodizing caused a significant increase of hydrogen content in the substrate and reduced the fatigue life of the alloy significantly.

  5. Knowledge-based artificial neural network model to predict the properties of alpha+ beta titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Banu, P. S. Noori; Rani, S. Devaki [Dept. of Metallurgical Engineering, Jawaharlal Nehru Technological University, HyderabadI (India)

    2016-08-15

    In view of emerging applications of alpha+beta titanium alloys in aerospace and defense, we have aimed to develop a Back propagation neural network (BPNN) model capable of predicting the properties of these alloys as functions of alloy composition and/or thermomechanical processing parameters. The optimized BPNN model architecture was based on the sigmoid transfer function and has one hidden layer with ten nodes. The BPNN model showed excellent predictability of five properties: Tensile strength (r: 0.96), yield strength (r: 0.93), beta transus (r: 0.96), specific heat capacity (r: 1.00) and density (r: 0.99). The developed BPNN model was in agreement with the experimental data in demonstrating the individual effects of alloying elements in modulating the above properties. This model can serve as the platform for the design and development of new alpha+beta titanium alloys in order to attain desired strength, density and specific heat capacity.

  6. Stabilizing the body centered cubic crystal in titanium alloys by a nano-scale concentration modulation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H. L.; Shah, S. A. A.; Hao, Y. L.; Prima, F.; Li, T.; Cairney, J. M.; Wang, Y. D.; Wang, Y.; Obbard, E. G.; Li, S. J.; Yang, R.

    2017-04-01

    It is well-known that the body centered cubic (bcc) crystal in titanium alloys reaches its stability limit as the electron-to-atom (e/a) ratio of the alloy drops down to ~4.24. This critical value, however, is much higher than that of a multifunctional bcc type alloy (e/a = 4.15). Here we demonstrate that a nano-scale concentration modulation created by spinodal decomposition is what stabilizes the bcc crystal of the alloy. Aided by such a nano-scale concentration heterogeneity, unexpected properties from its chemically homogeneous counterpart are obtained. This provides a new strategy to design functional titanium alloys by tuning the spinodal decomposition.

  7. CRYSTAL DEFECTS IN PLASMA NITRIDED LAYER CATALYZED BY RARE EARTH

    Institute of Scientific and Technical Information of China (English)

    F.S. Chen; Y.X. Liu; D.K. Liang; L.M. Xiao

    2002-01-01

    The microstructure of plasma nitrided layer catalyzed by rare-earth elements has beenstudied with TEM. The results show that the grains of γ'-Fe4N phase are refinedby rare-earth elements and the plane defects in boundary are increased by rare-earthelements. The addition of rare-earth element increases the bombardment effect andthe number of crystal defects such as vacancies, dislocation loops, twins and stackingfaults in γ'-Fe4N phase and can produce the high-density dislocations in the ferrite ofdiffusion layer at a distance 0. 08mm from the surface. The production of a numberof crystal defects is one of important reasons why rare-earth element accelerates thediffusion of nitrogen atoms during plasma-nitridiug.

  8. The Study of Plasma Nitriding of AISI304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    WANG Liang; JI Shi-jun; GAO Yu-zhou; SUN Jun-cai

    2004-01-01

    This paper presents results on the plasma nitriding of AISI 304 stainless steel at different temperatures in NH 3 gas. The working pressure was 100~200 Pa and the discharge voltage was 700~800V. The phase of nitrided layer formed on the surface was confirmed by X-ray diffraction. The hardness of the samples was measured by using a Vickers microhardness tester with the load of 50g. After nitriding at about 400 ℃ for two hours a nitrided layer consisting of single γN phase with thickness of 5μm was obtained. Microhardness measurements showed significant increase in the hardness from 240 HV (for untreated samples) up to 950 HV (for nitrided samples at temperature of 420℃). The phase composition, the thickness, the microstructure and the surface topography of the nitrided layer as well as its properties depend essentially on the process parameters.

  9. Imprecise knowledge based design and development of titanium alloys for prosthetic applications.

    Science.gov (United States)

    Datta, S; Mahfouf, M; Zhang, Q; Chattopadhyay, P P; Sultana, N

    2016-01-01

    Imprecise knowledge on the composition-processing-microstructure-property correlation of titanium alloys combined with experimental data are used for developing rule based models for predicting the strength and elastic modulus of titanium alloys. The developed models are used for designing alloys suitable for orthopedic and dental applications. Reduced Space Searching Algorithm is employed for the multi-objective optimization to find composition, processing and microstructure of titanium alloys suitable for orthopedic applications. The conflicting requirements attributes of the alloys for this particular purpose are high strength with low elastic modulus, along with adequate biocompatibility and low costs. The 'Pareto' solutions developed through multi-objective optimization show that the preferred compositions for the fulfilling the above objectives lead to β or near β-alloys. The concept of decision making employed on the solutions leads to some compositions, which should provide better combination of the required attributes. The experimental development of some of the alloys has been carried out as guided by the model-based design methodology presented in this research. Primary characterizations of the alloys show encouraging results in terms of the mechanical properties.

  10. Corrosion behaviour of polished and sandblasted titanium alloys in PBS solution.

    Science.gov (United States)

    Burnat, Barbara; Walkowiak-Przybyło, Magdalena; Błaszczyk, Tadeusz; Klimek, Leszek

    2013-01-01

    In this work, we performed comparative studies of the effect of surface preparation of Ti6Al4V and Ti6Al7Nb biomedical alloys and the influence of endothelial cells on their corrosion behaviour in PBS (Phosphate Buffered Saline). Two different methods of surface modification were applied - polishing and sandblasting. The polished Ti6Al7Nb alloy was found to have the best resistance against general corrosion in PBS. It was characterized by the lowest corrosion rate, the widest passive range and the lowest reactivity. Both alloys prepared by sandblasting exhibited worse corrosion properties in comparison to the polished ones. This can be associated with a greater development of their surface and the presence of Al2O3 grains which caused an increase of corrosion potential but might also influence the weakening of the passive layer. Results of potentiodynamic anodic polarization indicated that more resistant to pitting corrosion was Ti6Al7Nb alloy regardless of the method of surface preparation. In those cases, anodic polarization caused only an increase of passive layer, while in the case of sandblasted Ti6Al4V alloy it caused a pitting corrosion. The results obtained allowed us to conclude that the niobium-titanium alloys had higher corrosion resistance than titanium alloys with vanadium. Moreover, it was stated that endothelial cells improved the corrosion resistance of all the titanium alloys examined.

  11. Wear behavior of tetragonal zirconia polycrystal versus titanium and titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kanbara, Tsunemichi; Yajima, Yasutomo [Department of Oral Implantology, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba 261-8502 (Japan); Yoshinari, Masao, E-mail: yosinari@tdc.ac.jp [Division of Oral Implant Research, Oral Health Science Center, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba 261-8502 (Japan)

    2011-04-15

    The aim of this study was to clarify the influence of tetragonal zirconia polycrystal (TZP) on the two-body wear behavior of titanium (Ti). Two-body wear tests were performed using TZP, two grades of cp-Ti or Ti alloy in distilled water, and the cross-sectional area of worn surfaces was measured to evaluate the wear behavior. In addition, the surface hardness and coefficient of friction were determined and an electron probe microanalysis performed to investigate the underlying mechanism of wear. The hardness of TZP was much greater than that of Ti. The coefficient of friction between Ti and Ti showed a higher value than the Ti/TZP combination. Ti was more susceptible to wear by both TZP and Ti than TZP, indicating that the mechanism of wear between TZP and Ti was abrasive wear, whereas that between Ti and Ti was adhesive wear. No remarkable difference in the amount of wear in Ti was observed between TZP and Ti as the opposite material, despite the hardness value of Ti being much smaller than that of TZP. (communication)

  12. Modeling Hydrogen-Induced Cracking of Titanium Alloys in Nuclear Waste Repository Environments

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua; K. Mon; P. Pasupathi; G. Gordon

    2004-09-08

    This paper reviews the current understanding of hydrogen-induced cracking (HIC) of Ti Grade 7 and other relevant titanium alloys within the context of the current waste package design for the repository environmental conditions anticipated within the Yucca Mountain repository. The review concentrates on corrosion processes possible in the aqueous environments expected within this site. A brief background discussion of the relevant properties of titanium alloys, the hydrogen absorption process, and the properties of passive film on titanium alloys is presented as the basis for the subsequent discussion of model developments. The key corrosion processes that could occur are addressed individually. Subsequently, the expected corrosion performance of these alloys under the specific environmental conditions anticipated at Yucca Mountain is considered. It can be concluded that, based on the conservative modeling approaches adopted, hydrogen-induced cracking of titanium alloys will not occur under nuclear waste repository conditions since there will not be sufficient hydrogen in the alloy after 10,000 years of emplacement.

  13. 76 FR 72929 - Decision To Evaluate a Petition To Designate a Class of Employees From Titanium Alloys...

    Science.gov (United States)

    2011-11-28

    ... evaluation, is as follows: Facility: Titanium Alloys Manufacturing. Location: Niagara Falls, New York. Job... HUMAN SERVICES Decision To Evaluate a Petition To Designate a Class of Employees From Titanium Alloys...: HHS gives notice as required by 42 CFR 83.12(e) of a decision to evaluate a petition to designate a...

  14. Optimum surface roughness prediction for titanium alloy by adopting response surface methodology

    Science.gov (United States)

    Yang, Aimin; Han, Yang; Pan, Yuhang; Xing, Hongwei; Li, Jinze

    Titanium alloy has been widely applied in industrial engineering products due to its advantages of great corrosion resistance and high specific strength. This paper investigated the processing parameters for finish turning of titanium alloy TC11. Firstly, a three-factor central composite design of experiment, considering the cutting speed, feed rate and depth of cut, are conducted in titanium alloy TC11 and the corresponding surface roughness are obtained. Then a mathematic model is constructed by the response surface methodology to fit the relationship between the process parameters and the surface roughness. The prediction accuracy was verified by the one-way ANOVA. Finally, the contour line of the surface roughness under different combination of process parameters are obtained and used for the optimum surface roughness prediction. Verification experimental results demonstrated that material removal rate (MRR) at the obtained optimum can be significantly improved without sacrificing the surface roughness.

  15. COMPARISON OF STATISTICALLY CONTROLLED MACHINING SOLUTIONS OF TITANIUM ALLOYS USING USM

    Directory of Open Access Journals (Sweden)

    R. Singh

    2010-06-01

    Full Text Available The purpose of the present investigation is to compare the statistically controlled machining solution of titanium alloys using ultrasonic machining (USM. In this study, the previously developed Taguchi model for USM of titanium and its alloys has been investigated and compared. Relationships between the material removal rate, tool wear rate, surface roughness and other controllable machining parameters (power rating, tool type, slurry concentration, slurry type, slurry temperature and slurry size have been deduced. The results of this study suggest that at the best settings of controllable machining parameters for titanium alloys (based upon the Taguchi design, the machining solution with USM is statistically controlled, which is not observed for other settings of input parameters on USM.

  16. Microstructure control techniques in primary hot working of titanium alloy bars:A review

    Institute of Scientific and Technical Information of China (English)

    Guo Lianggang; Fan Xiaoguang; Yu Gaofeng; Yang He

    2016-01-01

    How to control the microstructure of titanium alloy bars is important to fabricating high-performance aerial forgings. This paper gives a thorough survey of the manufacturing meth-ods and microstructure control techniques for titanium alloy bars. It summarizes the effects of pro-cessing parameters on the mechanisms and laws of microstructure evolution during b working and (a+b) working, including the kinetics and grains size of dynamic recrystallization (DRX) during b deformation and the kinetics and grains size of spheroidization during (a+b) deformation. The trends in microstructure control techniques are presented for fabricating titanium alloy bars with high efficiency, low cost, and high quality by means of b/(a+b) working, and the puzzles and chal-lenges in the future are also pointed out.

  17. Structure and properties of sintered titanium alloyed with aluminium, molybdenum and oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Anokhin, V.M.; Petrunko, A.N. [State Research and Design Titanium Institute, Zaporozhye (Ukraine); Ivasishin, O.M. [Institute for Metal Physics, National Academy of Sciences of Ukraine, 36 Vernadsky St, 142 Kiev (Ukraine)

    1998-03-15

    Titanium alloys of Ti-Al-Mo-O system were manufactured by blended elemental powder method using Ti, Al, Mo and TiO{sub 2} powders as starting materials. It was found that cold compaction pressure of 800 MPa followed by sintering at 1150-1200 C, for 4 h provided sufficient densification of titanium materials. Complete dissolution of alloying elements in the titanium matrix resulted in a good combination of mechanical properties. Examples of alloys chosen for possible application were Ti-(1.5-2.0)%Mo-0.7%TiO{sub 2} and Ti-2%Al-2%Mo. The latter has already been tried for manufacturing parts in automotive industry. (orig.) 3 refs.

  18. Experimental Investigation of Machining Parameters in Drilling Operation Using Conventional and CNC Machines on Titanium Alloy

    Directory of Open Access Journals (Sweden)

    B.Suresh kumar

    2014-05-01

    Full Text Available Titanium alloy is one of the newer materials in manufacturing industries due to its high strength to weight ratio and corrosion resistance properties. Making a hole on this component is very difficult task due to its poor machinability. Hence, the machining parameter investigation on titanium alloy material is very important for predicting the drilling performance characteristics. In addition, the modern manufacturing industries are used the conventional drilling machine and CNC drilling machines for making a hole. In the sense, the main aim of this work is to investigate the machining parameters on vibration, thrust force, torque, machining time, burr dimension, tool wear and surface roughness occurrences when drilling titanium alloy with conventional and CNC machines. The effects of spindle speed and feed rate on these responses were reported.

  19. Standard Test Method for Stress-Corrosion of Titanium Alloys by Aircraft Engine Cleaning Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This test method establishes a test procedure for determining the propensity of aircraft turbine engine cleaning and maintenance materials for causing stress corrosion cracking of titanium alloy parts. 1.2 The evaluation is conducted on representative titanium alloys by determining the effect of contact with cleaning and maintenance materials on tendency of prestressed titanium alloys to crack when subsequently heated to elevated temperatures. 1.3 Test conditions are based upon manufacturer's maximum recommended operating solution concentration. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see and .

  20. Electrochemical behavior of near-beta titanium biomedical alloys in phosphate buffer saline solution.

    Science.gov (United States)

    Dalmau, A; Guiñón Pina, V; Devesa, F; Amigó, V; Igual Muñoz, A

    2015-03-01

    The electrochemical behavior of three different near-β titanium alloys (composed by Ti, Nb and Sn) obtained by powder metallurgy for biomedical applications has been investigated. Different electrochemical and microscopy techniques were used to study the influence of the chemical composition (Sn content) and the applied potential on the microstructure and the corrosion mechanisms of those titanium alloys. The addition of Sn below 4wt.% to the titanium powder improves the microstructural homogeneity and generates an alloy with high corrosion resistance with low elastic modulus, being more suitable as a biomaterial. When the Sn content is above 4%, the corrosion resistance considerably decreases by increasing the passive dissolution rate; this effect is enhanced with the applied potential.

  1. AN EVALUATION OF HYDROGEN INDUCED CRACKING SUSCEPTIBILITY OF TITANIUM ALLOYS IN US HIGH-LEVEL NUCLEAR WASTE REPOSITORY ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    G. De; K. Mon; G. Gordon; D. Shoesmith; F. Hua

    2006-02-21

    This paper evaluates hydrogen-induced cracking (HIC) susceptibility of titanium alloys in environments anticipated in the Yucca Mountain nuclear waste repository with particular emphasis on the. effect of the oxide passive film on the hydrogen absorption process of titanium alloys being evaluated. The titanium alloys considered in this review include Ti 2, 5 , 7, 9, 11, 12, 16, 17, 18, 24 and 29. In general, the concentration of hydrogen in a titanium alloy can increase due to absorption of atomic hydrogen produced from passive general corrosion of that alloy or galvanic coupling of it to a less noble metal. It is concluded that under the exposure conditions anticipated in the Yucca Mountain repository, the HIC of titanium drip shield will not occur because there will not be sufficient hydrogen in the metal even after 10,000 years of emplacement. Due to the conservatisms adopted in the current evaluation, this assessment is considered very conservative.

  2. Effect of combined deformation on the structure and properties of copper and titanium alloys

    Science.gov (United States)

    Stolyarov, V. V.; Pashinskaya, E. G.; Beigel'Zimer, Ya. E.

    2010-10-01

    The effect of a combination scheme of severe plastic deformation and subsequent cold rolling or electroplastic rolling on the deformability, microstructural evolution, and mechanical properties of copper, titanium of various purities, and a titanium alloy of an equiatomic composition is studied. The combined deformation method is shown to create a number of new nanostructured and ultrafine-grained states with a high strength and ductility.

  3. Two-Phase (TiAl+TiCrAl) Coating Alloys for Titanium Aluminides

    Science.gov (United States)

    Brady, Michael P. (Inventor); Smialek, James L. (Inventor); Brindley, William J. (Inventor)

    1998-01-01

    A coating for protecting titanium aluminide alloys, including the TiAl gamma + Ti3Al (alpha(sub 2)) class, from oxidative attack and interstitial embrittlement at temperatures up to at least 1000 C. is disclosed. This protective coating consists essentially of titanium, aluminum. and chromium in the following approximate atomic ratio: Ti(41.5-34.5)Al(49-53)Cr(9.5-12.5)

  4. Research on depositing Ni45 alloy on titanium alloy surface by electrospark deposition

    Institute of Scientific and Technical Information of China (English)

    You Tao; Zhang Chunhui; Su Guiqiao; Yan Ping

    2008-01-01

    Taking Ni45 bar as electrode, a strengthened layer of thickness up to 50 pm was built up on BT20 titanium alloy matrix by means of electrospark deposition. Results of phase analysis by using of X-ray diffraction confirmed that the deposition layer was composed mostly of three phases, NiTi, NiTi2layer was up to 910 HV0.05, about 2.7 times as high as that of the matrix. The hardness at the cross-section of the entire deposition layer showed a gradient distribution. The effects of capacitance and deposition time on thickness of deposition layer were also studied, and results showed that with relatively low capacity and short deposition time the deposition layer without cracks can be obtained.

  5. Research on depositing Ni45 alloy on titanium alloy surface by electrospark deposition

    Directory of Open Access Journals (Sweden)

    Su Guiqiao

    2008-11-01

    Full Text Available Taking Ni45 bar as electrode, a strengthened layer of thickness up to 50 μm was built up on BT20 titanium alloy matrix by means of electrospark deposition. Results of phase analysis by using of X-ray diffraction confirmed that the deposition layer was composed mostly of three phases, NiTi, NiTi2 and Ti. The surface microhardness of the deposition layer was up to 910 HV0.05, about 2.7 times as high as that of the matrix. The hardness at the cross-section of the entire deposition layer showed a gradient distribution. The effects of capacitance and deposition time on thickness of deposition layer were also studied, and results showed that with relatively low capacity and short deposition time the deposition layer without cracks can be obtained.

  6. Structure of. cap alpha. -phase in two-phase titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gridnev, V.N.; Ivasishin, O.M.; Svechnikov, V.L. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)

    1982-08-01

    The structure of ..cap alpha..-phase in ..beta..-annealed titanium alloys VT 6 and VT 23 and its changes on heating up to ..cap alpha..+..beta.. ..-->.. ..beta.. transformation temperatures with accelerated cooling is studied. An assumption is made that the observed peculiarities of the residual ..cap alpha..-phase structure in alloys after such treatment are the consequence of the relaxation of interphase stresses resulting from a partial polymorphic transformation while the relaxation mechanism is determined by the alloying degree and initial alloy morphology.

  7. Ablation experiment and threshold calculation of titanium alloy irradiated by ultra-fast pulse laser

    Directory of Open Access Journals (Sweden)

    Buxiang Zheng

    2014-02-01

    Full Text Available The interaction between an ultra-fast pulse laser and a material's surface has become a research hotspot in recent years. Micromachining of titanium alloy with an ultra-fast pulse laser is a very important research direction, and it has very important theoretical significance and application value in investigating the ablation threshold of titanium alloy irradiated by ultra-fast pulse lasers. Irradiated by a picosecond pulse laser with wavelengths of 1064 nm and 532 nm, the surface morphology and feature sizes, including ablation crater width (i.e. diameter, ablation depth, ablation area, ablation volume, single pulse ablation rate, and so forth, of the titanium alloy were studied, and their ablation distributions were obtained. The experimental results show that titanium alloy irradiated by a picosecond pulse infrared laser with a 1064 nm wavelength has better ablation morphology than that of the green picosecond pulse laser with a 532 nm wavelength. The feature sizes are approximately linearly dependent on the laser pulse energy density at low energy density and the monotonic increase in laser pulse energy density. With the increase in energy density, the ablation feature sizes are increased. The rate of increase in the feature sizes slows down gradually once the energy density reaches a certain value, and gradually saturated trends occur at a relatively high energy density. Based on the linear relation between the laser pulse energy density and the crater area of the titanium alloy surface, and the Gaussian distribution of the laser intensity on the cross section, the ablation threshold of titanium alloy irradiated by an ultra-fast pulse laser was calculated to be about 0.109 J/cm2.

  8. Cost-effective blended elemental powder metallurgy of titanium alloys for transportation application

    Energy Technology Data Exchange (ETDEWEB)

    Ivasishin, O.M.; Demidik, A.N.; Savvakin, D.G. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Fiziki Metallov; Anokhin, V.M. [State Research and Design Titanium Inst., Zaporozhie (Ukraine)

    2000-07-01

    Transportation industry is one of the perspective areas of application for lightweight advanced materials, including titanium alloys. However, despite the excellent mechanical properties and corrosion resistance of titanium alloys, automobile and other transportation industries cannot afford titanium unless its cost is significantly reduced. Near-net-shape processings, amongst which are powder metallurgy (PM) techniques, look the most appealing ways of cost reduction. Economic potentiality of titanium PM processes depends on the availability of low-cost powder and particular consolidation technology used. In this paper the blended elemental technology by a simple press-and-sinter method has been investigated using various titanium powders, in order to find if this technology can be applied to production of parts from titanium alloys for transportation industry. Main part of work was done on Ti-6Al-4V (wt.%) composition although some other compositions were tried. Chemical and dimensional characteristics of initial powders, cold-compaction pressure, temperature and time of sintering were main variables of the study. It was shown that at proper choice of elemental constituents and consolidation parameters high density of the final product (98% of theoretical) could be obtained. For this case, microstructural investigations showed a phase and structural homogeneity of the synthesized material. This can give rise to the mechanical properties to be comparable with those of cast and wrought material. (orig.)

  9. Tribological Characteristic of Titanium Alloy Surface Layers Produced by Diode Laser Gas Nitriding

    Directory of Open Access Journals (Sweden)

    Lisiecki A.

    2016-06-01

    Full Text Available In order to improve the tribological properties of titanium alloy Ti6Al4V composite surface layers Ti/TiN were produced during laser surface gas nitriding by means of a novel high power direct diode laser with unique characteristics of the laser beam and a rectangular beam spot. Microstructure, surface topography and microhardness distribution across the surface layers were analyzed. Ball-on-disk tests were performed to evaluate and compare the wear and friction characteristics of surface layers nitrided at different process parameters, base metal of titanium alloy Ti6Al4V and also the commercially pure titanium. Results showed that under dry sliding condition the commercially pure titanium samples have the highest coefficient of friction about 0.45, compared to 0.36 of titanium alloy Ti6Al4V and 0.1-0.13 in a case of the laser gas nitrided surface layers. The volume loss of Ti6Al4V samples under such conditions is twice lower than in a case of pure titanium. On the other hand the composite surface layer characterized by the highest wear resistance showed almost 21 times lower volume loss during the ball-on-disk test, compared to Ti6Al4V samples.

  10. High-precision Thickness Setting Models for Titanium Alloy Plate Cold Rolling without Tension

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaochen; YANG Quan; HE Fei; SUN Youzhao; XIAO Huifang

    2015-01-01

    Due to its highly favorable physical and chemical properties, titanium and titanium alloy are widely used in a variety of industries. Because of the low output of a single batch, plate cold rolling without tension is the most common rolling production method for titanium alloy. This method is lack of on-line thickness closed-loop control, with carefully thickness setting models for precision. A set of high-precision thickness setting models are proposed to suit the production method. Because of frequent variations in rolling specification, a model structural for the combination of analytical models and statistical models is adopted to replace the traditional self-learning method. The deformation resistance and friction factor, the primary factors which affect model precision, are considered as the objectives of statistical modeling. Firstly, the coefficient fitting of deformation resistance analytical model based on over-determined equations set is adopted. Additionally, a support vector machine(SVM) is applied to the modeling of the deformation resistance and friction factor. The setting models are applied to a 1450 plate-coiling mill for titanium alloy plate rolling, and then thickness precision is found consistently to be within 3%, exceeding the precision of traditional setting models with a self-learning method based on a large number of stable rolling data. Excellent application performance is obtained. The proposed research provides a set of high-precision thickness setting models which are well adapted to the characteristics of titanium alloy plate cold rolling without tension.

  11. High-precision thickness setting models for titanium alloy plate cold rolling without tension

    Science.gov (United States)

    Wang, Xiaochen; Yang, Quan; He, Fei; Sun, Youzhao; Xiao, Huifang

    2015-03-01

    Due to its highly favorable physical and chemical properties, titanium and titanium alloy are widely used in a variety of industries. Because of the low output of a single batch, plate cold rolling without tension is the most common rolling production method for titanium alloy. This method is lack of on-line thickness closed-loop control, with carefully thickness setting models for precision. A set of high-precision thickness setting models are proposed to suit the production method. Because of frequent variations in rolling specification, a model structural for the combination of analytical models and statistical models is adopted to replace the traditional self-learning method. The deformation resistance and friction factor, the primary factors which affect model precision, are considered as the objectives of statistical modeling. Firstly, the coefficient fitting of deformation resistance analytical model based on over-determined equations set is adopted. Additionally, a support vector machine(SVM) is applied to the modeling of the deformation resistance and friction factor. The setting models are applied to a 1450 plate-coiling mill for titanium alloy plate rolling, and then thickness precision is found consistently to be within 3%, exceeding the precision of traditional setting models with a self-learning method based on a large number of stable rolling data. Excellent application performance is obtained. The proposed research provides a set of high-precision thickness setting models which are well adapted to the characteristics of titanium alloy plate cold rolling without tension.

  12. Fatigue modification of TA15 titanium alloy weldments by an ultrasonic impact treatment

    DEFF Research Database (Denmark)

    Gao, Yukui; Zhong, Zheng; Zhang, Xiaodan;

    2014-01-01

    The welded components of TA15 titanium alloy were ultrasonically impact treated. The fatigue lives were investigated under the same test conditions. The fatigue strength was determined by stair-step method and the residual stresses were analyzed by an X-ray diffraction stress tester. The results...... show that the fatigue properties of TA15 titanium alloy welded components are sensitive to the surface treatment and ultrasonic impacting can prolong the fatigue lives. The effect of fatigue strength improvement mainly depends on compressive residual stresses and grain refinement....

  13. Optimization of Cutting Parameters for Face Milling Titanium Alloy Using MQL

    Institute of Scientific and Technical Information of China (English)

    AHMED Hassan; YAO Zhen-qiang

    2005-01-01

    When using MQL as a cooling technique, many parameters have to be adjusted. The Taguchi method was used in this study to investigate the cutting characteristics of face milling of titanium alloys using PVD-coated inserts. To find the optimal volume removed and surface roughness, an orthogonal array, the signal-to-noise (S/N) ratio and the analysis of variance (ANOVA) were employed. The optimum cutting parameters was obtained. Throughout this study, it was found that the feed rate is the most influencing cutting parameter in the face milling of titanium alloys.

  14. Titanium Alloy Surface Modification by a Spatio-Temporal Atmospheric Pressure DBD Afterglow

    Institute of Scientific and Technical Information of China (English)

    E.PANOUSIS; F.CLEMENT; J.F.LOISEAU; N.SPYROU; B.HELD1; J.LARRIEU; F.GUERTON

    2007-01-01

    The experimental work reported here is devoted to the study of the modifications inflicted on the surface of titanium alloy specimens by an atmospheric pressure dielectric barrier discharge(DBD) reactor in both spatial and temporal afterglow conditions.A commercially available (AcXys Technologies) modified reactor system was used for the surface treatment of the TiA6V4 titanium alloy that is widely used in the aeronautical industry.Wettability surface characterisation and XPS analyses are performed to give a macroscopic and microscopic insight to the surface modifications.Best operating conditions,at constant input energy,were obtained for a duty cycle equal to 10%.

  15. Plasma Niobium Surface Alloying of Pure Titanium and its Oxidation at 900 ℃

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-bo; ZHONG Xu; HE Zhi-yong; WANG Zhen-xia; ZHANG Ping-ze

    2007-01-01

    A niobium-modified layer on pure titanium surface was obtained by means of double glow plasma surface alloying technique. The modified layer was uniform, continuous, compact and well adhered to the substrate. The niobium composition in the modified layer decreased gradually from the surface to the substrate. The oxidation behavior of the niobium-modified layer was investigated and compared with the untreated surface at 900 ℃ for 100 h. Characterization of the layers was performed using X-ray diffraction and scanning electron microscope, respectively. The test results show that the oxidation behavior of pure titanium was improved by niobium alloying process. Niobium has a positive influence on the oxidation resistance.

  16. The technology of precision casting of titanium alloys by centrifugal process

    Directory of Open Access Journals (Sweden)

    A. Karwiński

    2011-07-01

    Full Text Available The article describes the development of a procedure for the preparation of foundry ceramic moulds and making first test castings. The presented studies included:development of technological parameters of the ceramic mould preparation process using water-based zirconium binders and zirconia ceramic materials, where moulds are next used for the centrifugal casting of titanium alloys melted in vacuum furnaces, designing of pouring process using simulation software, making test castings,testing and control of the casting properties. The technological process described in this paper enables making castings in titanium alloys weighing up to about 500 g and used in the majority of technical applications.

  17. Multi-objective Optimization in the Milling of Titanium Alloys Using the MQL Technique

    Institute of Scientific and Technical Information of China (English)

    Ahmed Hassan; YAO Zhen-qiang

    2004-01-01

    The process for face milling of (α+β) titanium alloy while using minimum quantity librication (MQL) as the cooling technique was optimized by using of the Taguchi method to improve characteristics.The cutting speed, feed rate, and depth of cut were optimized with consideration of multiple performance characteristics including tool life, volume removed and surface roughness. The experimental results show that the multiple performance characteristics can be simultaneously improved through this approach, and the feed rate is the most influential cutting parameter in the face milling of titanium alloys.

  18. NUMERICAL SIMULATION OF CONTROLLING IN TITANIUM ALLOY SHEETS WELDING RESIDUAL STRESS BY TRAILING PEENING

    Institute of Scientific and Technical Information of China (English)

    X.S. Liu; H. Y. Fang; W.L. Xu; Z.B. Dong; D.Y. Yu

    2004-01-01

    It is a promising and new technology to apply welding with trailing peening to control welding stress and distortion of titanium alloy. Numerical simulation of conventional welding and welding with trailing peening of the titanium alloy sheet is carried out,using nonlinear finite element theory and the engineering analysis software MARC.The result shows that welding with trailing peening technology reduces longitudinal residual stress in welding joint effectively, and it is more effective to reduce residual stress to peen the weld than to peen the weld toe. It is a effective result that other technology and method used in welding can never achieved.

  19. An overview of the corrosion aspect of dental implants (titanium and its alloys

    Directory of Open Access Journals (Sweden)

    Chaturvedi T

    2009-01-01

    Full Text Available Titanium and its alloys are used in dentistry for implants because of its unique combination of chemical, physical, and biological properties. They are used in dentistry in cast and wrought form. The long term presence of corrosion reaction products and ongoing corrosion lead to fractures of the alloy-abutment interface, abutment, or implant body. The combination of stress, corrosion, and bacteria contribute to implant failure. This article highlights a review of the various aspects of corrosion and biocompatibility of dental titanium implants as well as suprastructures. This knowledge will also be helpful in exploring possible research strategies for probing the biological properties of materials.

  20. Low void content autoclave molded titanium alloy and polyimide graphite composite structures.

    Science.gov (United States)

    Vaughan, R. W.; Jones, R. J.; Creedon, J. F.

    1972-01-01

    This paper discusses a resin developed for use in autoclave molding of polyimide graphite composite stiffened, titanium alloy structures. Both primary and secondary bonded structures were evaluated that were produced by autoclave processing. Details of composite processing, adhesive formulary, and bonding processes are provided in this paper, together with mechanical property data for structures. These data include -65 F, room temperature, and 600 F shear strengths; strength retention after aging; and stress rupture properties at 600 F under various stress levels for up to 1000 hours duration. Typically, shear strengths in excess of 16 ksi at room temperature with over 60% strength retention at 600 F were obtained with titanium alloy substrates.

  1. Thermal decomposition kinetics of titanium hydride and Al alloy melt foaming process

    Institute of Scientific and Technical Information of China (English)

    YANG; Donghui; HE; Deping; YANG; Shangrun

    2004-01-01

    A temperature programmed decomposition (TPD) apparatus with metal tube structure, in which Ar is used as the carrier gas, is established and the TPD spectrum of titanium hydride is acquired. Using consulting table method (CTM), spectrum superposition method (SSM) and differential spectrum technique, TPD spectrum of titanium hydride is separated and a set of thermal decomposition kinetics equations are acquired. According to these equations, the relationship between decomposition quantity and time for titanium hydride at the temperature of 940 K is obtained and the result well coincides with the Al alloy melt foaming process.

  2. A new antibacterial titanium-copper sintered alloy: preparation and antibacterial property.

    Science.gov (United States)

    Zhang, Erlin; Li, Fangbing; Wang, Hongying; Liu, Jie; Wang, Chunmin; Li, Muqin; Yang, Ke

    2013-10-01

    Copper element was added in pure titanium by a powder metallurgy to produce a new antibacterial titanium-copper alloy (Ti-Cu alloy). This paper reported the very early stage results, emphasizing on the preparation, mechanical property and antibacterial activity. The phase constitution was analyzed by XRD and the microstructure was observed under SEM equipped with EDS. The hardness, the compressive strength and the corrosion resistance of Ti-Cu alloy were tested in comparison with cp-Ti. The antibacterial property of the Ti-Cu alloy was assessed by two methods: agar diffusion assay and plate-count method, in which Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were used. XRD and SEM results showed that Ti2Cu phase and Cu-rich phase were synthesized in the Ti-Cu sintered alloy, which significantly increases the hardness and the compressive strength compared with cp-Ti and slightly improves the corrosion resistance. No antibacterial activity was detected by the agar diffusion assay on the Ti-Cu alloy, but the plate-count results indicated that the Ti-Cu alloy exhibited strong antibacterial property against both bacteria even after three polishing treatments, which demonstrates strongly that the whole alloy is of antibacterial activity. The antibacterial mechanism was thought to be in associated with the Cu ion released from the Ti-Cu alloy. © 2013.

  3. The Development of Titanium Alloys for Application in the Space Shuttle Main Engine

    Science.gov (United States)

    Halchak, John A.; Jerman, Gregory A.; Zimmerman, Frank R.

    2010-01-01

    The high-strength-to-weight ratio of titanium alloys, particularly at cryogenic temperatures, make them attractive for application in rocket engines - offering the potential of superior performance while minimizing component weight. This was particularly attractive for rotating components, such as pump impellers, where titanium alloys presented the potential to achieve a major advance in rotational tip speed, with a reduction in stages and resultant saving in pump weight and complexity. The investigation into titanium alloys for application in cryogenic turbopumps began in the early 1960's. However, it was found that the reactivity of titanium limited applications and produced unique processing challenges. Specialized chemical compositions and processing techniques had to be developed. A substantial amount of material properties testing and trials in experimental turbopumps occurred, ultimately leading to application in the Space Shuttle Main Engine. One particular alloy stood out for use at liquid hydrogen temperatures, Ti-5Al-2.5Sn ELI. This alloy was employed for several critical components. This presentation deals with the development effort, the challenges that were encountered and operational experiences with Ti-5Al-2.5Sn ELI in the SSME.

  4. Intermetallic Nickel-Titanium Alloys for Oil-Lubricated Bearing Applications

    Science.gov (United States)

    DellaCorte, C.; Pepper, S. V.; Noebe, R.; Hull, D. R.; Glennon, G.

    2009-01-01

    An intermetallic nickel-titanium alloy, NITINOL 60 (60NiTi), containing 60 wt% nickel and 40 wt% titanium, is shown to be a promising candidate material for oil-lubricated rolling and sliding contact applications such as bearings and gears. NiTi alloys are well known and normally exploited for their shape memory behavior. When properly processed, however, NITINOL 60 exhibits excellent dimensional stability and useful structural properties. Processed via high temperature, high-pressure powder metallurgy techniques or other means, NITINOL 60 offers a broad combination of physical properties that make it unique among bearing materials. NITINOL 60 is hard, electrically conductive, highly corrosion resistant, less dense than steel, readily machined prior to final heat treatment, nongalling and nonmagnetic. No other bearing alloy, metallic or ceramic encompasses all of these attributes. Further, NITINOL 60 has shown remarkable tribological performance when compared to other aerospace bearing alloys under oil-lubricated conditions. Spiral orbit tribometer (SOT) tests were conducted in vacuum using NITINOL 60 balls loaded between rotating 440C stainless steel disks, lubricated with synthetic hydrocarbon oil. Under conditions considered representative of precision bearings, the performance (life and friction) equaled or exceeded that observed with silicon nitride or titanium carbide coated 440C bearing balls. Based upon this preliminary data, it appears that NITINOL 60, despite its high titanium content, is a promising candidate alloy for advanced mechanical systems requiring superior and intrinsic corrosion resistance, electrical conductivity and nonmagnetic behavior under lubricated contacting conditions.

  5. Plasma Nitriding of Austenitic Stainless Steel with Severe Surface Deformation Layer

    Institute of Scientific and Technical Information of China (English)

    JI Shi-jun; GAO Yu-zhou; WANG Liang; SUN Jun-cai; HEI Zu-kun

    2004-01-01

    The dc glow discharge plasma nitriding of austenite stainless steel with severe surface deformation layer is used to produce much thicker surface modified layer. This kind of layers has useful properties such as a high surface hardness of about 1500 Hv 0.1 and high resistance to frictional wear. This paper presents the structures and properties of low temperature plasma nitrided austenitic stainless steel with severe surface deformation layer.

  6. Study of stress ratio effect on titanium alloy fatigue under high-frequency loading

    Energy Technology Data Exchange (ETDEWEB)

    Voznyj, T.S.; Gurvich, Yu.V.; Kirillov, V.I.; Troyan, I.A. (AN Ukrainskoj SSR, Kiev. Inst. Problem Prochnosti)

    1983-02-01

    Endurance of two titanium alloys, OT4 type ..cap alpha..-alloy and VT6 martensite class, (..cap alpha..+..beta..)-alloy was studied under symmetric and asymmetric tension-compression at 10 kHz frequency and room temperature using a magnetostriction resonance device. The tests were carried out in the air without water cooling usual in high-frequency tests, since a very low hysteresis dissipation of energy was observed under cyclic loading near the fatigue limit of these titanium alloys. Fatigue curves are obtained on the basis of 10/sup 9/ cycles. The ratio is found for the endurance limit based on 10/sup 7/ and 10/sup 8/ cycles to the ultimate strength under symmetric loading. An equation is given which satisfactorily describes limiting amplitude diagrams, and its coefficients are analyzed.

  7. A study of the method of making dental prosthetic appliances by sintered titanium alloys: effect of copper powder content on properties of sintered titanium alloy.

    Science.gov (United States)

    Oda, Y; Nakanishi, K; Sumii, T

    1990-02-01

    The effects of added copper powder to the properties of the sintered titanium alloys were investigated by measuring the compressive strength and densities of the green and sintered compacts, the thermal expansion curves and dimensional changes in the sintered compacts, and the accuracy of the crown-type restorations. The compressive strengths of green compacts ranged from 55 to 75 MPa. The expansion of green compacts increased with increased copper content. The sintered density was lower than the green density. The compressive yield strength of sintered compacts ranged from 260 MPa to 410 MPa. The sintered compacts expanded from 0.35% to 1.03% and the expansion increased with increased copper content. The dimensional accuracy of crown-type restorations showed the same dimensional change tendencies as did the sintered compacts. These results showed that the fit and the strength of sintered titanium alloy restorations could be improved.

  8. Manufacturing techniques for titanium aluminide based alloys and metal matrix composites

    Science.gov (United States)

    Kothari, Kunal B.

    Dual phase titanium aluminides composed vastly of gamma phase (TiAl) with moderate amount of alpha2 phase (Ti3Al) have been considered for several high temperature aerospace and automobile applications. High specific strength coupled with good high temperature performance in the areas of creep and oxidation resistance makes titanium aluminides "materials of choice" for next generation propulsion systems. Titanium alumnides are primarily being considered as potential replacements for Ni-based superalloys in gas turbine engine components with aim of developing more efficient and leaner engines exhibiting high thrust-to-weight ratio. Thermo-mechanical treatments have shown to enhance the mechanical performance of titanium aluminides. Additionally, small additions of interstitial elements have shown further and significant improvement in the mechanical performance of titanium alumnide alloys. However, titanium aluminides lack considerably in room temperature ductility and as a result manufacturing processes of these aluminides have greatly suffered. Traditional ingot metallurgy and investment casting based methods to produce titanium aluminide parts in addition to being expensive, have also been unsuccessful in producing titanium aluminides with the desired mechanical properties. Hence, the manufacturing costs associated with these methods have completely outweighed the benefits offered by titanium aluminides. Over the last two decades, several powder metallurgy based manufacturing techniques have been studied to produce titanium aluminide parts. These techniques have been successful in producing titanium aluminide parts with a homogeneous and refined microstructure. These powder metallurgy techniques also hold the potential of significant cost reduction depending on the wide market acceptance of titanium aluminides. In the present study, a powder metallurgy based rapid consolidation technique has been used to produce near-net shape parts of titanium aluminides. Micron

  9. IMPROVEMENT OF MECHANICAL PROPERTIES OF MARTENSITIC STAINLESS STEEL BY PLASMA NITRIDING AT LOW TEMPERATURE

    Institute of Scientific and Technical Information of China (English)

    Y.T. Xi; D.X. Liu; D. Han; Z.F. Han

    2008-01-01

    A series of experiments were carried out to study the influence of low temperature plasma nitriding on the mechanical properties of AISI 420 martensitic stainless steel. Plasma nitriding ezperiments were carried out for 15 h at 350℃ by means of DC-pulsed plasma in 25%N2+ 75%H2 atmosphere. The microstructure, phase composition, and residual stresses profiles of the nitrided layers were determined by optical microscopy and X-ray diffraction. The microhardness profiles of the nitridied surfaces were also studied. The fatigue life, sliding wear, and erosion wear loss of the untreated specimens and plasma nitriding specimens were determined on the basks of a rotating bending fatigue tester, a ball-on-disc wear tester, and a solid particle erosion tester. The results show that the 350℃ nitrided surface is dominated by ε-Fe3N and αN, which is supersaturated nitrogen solid solution. They have high hardness and chemical stabilities. So the low temperature plasma nitriding not only increases the surface hardness values but also improves the wear and erosion resistance. In addition, the fatigue limit of AISI 420 steel can also be improved by plasma nitriding at 350℃ because plasma nitriding produces residual compressive stress inside the modified layer.

  10. Mechanical properties and biocompatibility of plasma-nitrided laser-cut 316L cardiovascular stents.

    Science.gov (United States)

    Arslan, Erdem; Iğdil, Mustafa C; Yazici, Hilal; Tamerler, Candan; Bermek, Hakan; Trabzon, Levent

    2008-05-01

    The effect of surface modification of laser-cut 316L cardiovascular stents by low-T plasma nitriding was evaluated in terms of mechanical properties and biocompatibility of the stents. The plasma nitriding was performed at 400, 450 or 500 degrees C using various ratios of nitrogen-hydrogen gas mixtures. The flexibility and radial strength were measured in crimped and expanded state of the stents, respectively. The mechanical properties could be adjusted and improved by plasma nitriding conducted at temperatures lower than 450 degrees C and/or nitrogen content less than 10% in the treatment gas. An osteoblast cell culture model system was utilized to investigate the effect of plasma nitriding of the stents on the biological response towards the stents, using biological criteria such as cell viability, alkaline phosphatase and nitric oxide production. In terms of cell viability and alkaline phosphatase production, the plasma nitriding procedure did not appear to negatively affect the biocompatibility of the 316L steel stents. However, in terms of nitric oxide production that was slightly increased in the presence of the plasma-nitrided stents, an indirect improvement in the biocompatibility could possibly be expected.

  11. Homogenization of. beta. -solid solution during fast heating of two-phase titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gridnev, V.N.; Zhuravlev, A.F.; Zhuravlev, B.F.; Ivasishin, O.M.; Markovskij, P.E. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)

    1985-01-01

    Using model alloy Ti-10%Mo as an example the homogenization of high-temperature ..beta..-phase during fast heating has been studied by calculational and experimental methods. The effect of heating rate and the initial structure disoersion on the homogenization is shown. A method is suggested for evaluation of the concentration state of ..beta..-solid solution depleted parts of commercial two-phase titanium alloys. The method has been used to study the homogenization process.

  12. Adhesion wear mechanisms under dry friction of titanium alloys in vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Lebedeva, I.L.; Presnyakova, G.N. (Physico-Technical Inst. for Low Temperature Physics and Engineering, Ukrainian Academy of Sciences, Kharkov (Ukrainian SSR))

    1991-08-15

    Physicochemical processes taking place in the surface layers of titanium alloys were studied. For vacuum conditions, a range of external parameters was proved to exist where the alloys have high wear resistance and a low coefficient of friction. The transition from seizure, with tearing of the material at a large depth, to fatigue wear is related to surface hardening due to {alpha} {r reversible} {beta} transitions under friction. Thermodynamic parameters were calculated and the criteria of protective secondary structure formation defined. (orig.).

  13. Detonation nanodiamonds biofunctionalization and immobilization to titanium alloy surfaces as first steps towards medical application.

    Science.gov (United States)

    Gonçalves, Juliana P L; Shaikh, Afnan Q; Reitzig, Manuela; Kovalenko, Daria A; Michael, Jan; Beutner, René; Cuniberti, Gianaurelio; Scharnweber, Dieter; Opitz, Jörg

    2014-01-01

    Due to their outstanding properties nanodiamonds are a promising nanoscale material in various applications such as microelectronics, polishing, optical monitoring, medicine and biotechnology. Beyond the typical diamond characteristics like extreme hardness or high thermal conductivity, they have additional benefits as intrinsic fluorescence due to lattice defects without photobleaching, obtained during the high pressure high temperature process. Further the carbon surface and its various functional groups in consequence of the synthesis, facilitate additional chemical and biological modification. In this work we present our recent results on chemical modification of the nanodiamond surface with phosphate groups and their electrochemically assisted immobilization on titanium-based materials to increase adhesion at biomaterial surfaces. The starting material is detonation nanodiamond, which exhibits a heterogeneous surface due to the functional groups resulting from the nitrogen-rich explosives and the subsequent purification steps after detonation synthesis. Nanodiamond surfaces are chemically homogenized before proceeding with further functionalization. Suspensions of resulting surface-modified nanodiamonds are applied to the titanium alloy surfaces and the nanodiamonds subsequently fixed by electrochemical immobilization. Titanium and its alloys have been widely used in bone and dental implants for being a metal that is biocompatible with body tissues and able to bind with adjacent bone during healing. In order to improve titanium material properties towards biomedical applications the authors aim to increase adhesion to bone material by incorporating nanodiamonds into the implant surface, namely the anodically grown titanium dioxide layer. Differently functionalized nanodiamonds are characterized by infrared spectroscopy and the modified titanium alloys surfaces by scanning and transmission electron microscopy. The process described shows an adsorption and

  14. Detonation nanodiamonds biofunctionalization and immobilization to titanium alloy surfaces as first steps towards medical application

    Directory of Open Access Journals (Sweden)

    Juliana P. L. Gonçalves

    2014-11-01

    Full Text Available Due to their outstanding properties nanodiamonds are a promising nanoscale material in various applications such as microelectronics, polishing, optical monitoring, medicine and biotechnology. Beyond the typical diamond characteristics like extreme hardness or high thermal conductivity, they have additional benefits as intrinsic fluorescence due to lattice defects without photobleaching, obtained during the high pressure high temperature process. Further the carbon surface and its various functional groups in consequence of the synthesis, facilitate additional chemical and biological modification. In this work we present our recent results on chemical modification of the nanodiamond surface with phosphate groups and their electrochemically assisted immobilization on titanium-based materials to increase adhesion at biomaterial surfaces. The starting material is detonation nanodiamond, which exhibits a heterogeneous surface due to the functional groups resulting from the nitrogen-rich explosives and the subsequent purification steps after detonation synthesis. Nanodiamond surfaces are chemically homogenized before proceeding with further functionalization. Suspensions of resulting surface-modified nanodiamonds are applied to the titanium alloy surfaces and the nanodiamonds subsequently fixed by electrochemical immobilization. Titanium and its alloys have been widely used in bone and dental implants for being a metal that is biocompatible with body tissues and able to bind with adjacent bone during healing. In order to improve titanium material properties towards biomedical applications the authors aim to increase adhesion to bone material by incorporating nanodiamonds into the implant surface, namely the anodically grown titanium dioxide layer. Differently functionalized nanodiamonds are characterized by infrared spectroscopy and the modified titanium alloys surfaces by scanning and transmission electron microscopy. The process described shows an

  15. Potentiality of the “Gum Metal” titanium-based alloy for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Gordin, D.M. [Institut des Sciences Chimiques de Rennes (UMR CNRS 6226), INSA Rennes, 20 Avenue des Buttes de Coësmes, F-35043 Rennes Cedex (France); Ion, R. [University of Bucharest, Department of Biochemistry and Molecular Biology, 91-95 Spl. Independentei, 050095 Bucharest (Romania); Vasilescu, C.; Drob, S.I. [Institute of Physical Chemistry “Ilie Murgulescu” of Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Cimpean, A. [University of Bucharest, Department of Biochemistry and Molecular Biology, 91-95 Spl. Independentei, 050095 Bucharest (Romania); Gloriant, T., E-mail: Thierry.Gloriant@insa-rennes.fr [Institut des Sciences Chimiques de Rennes (UMR CNRS 6226), INSA Rennes, 20 Avenue des Buttes de Coësmes, F-35043 Rennes Cedex (France)

    2014-11-01

    In this study, the “Gum Metal” titanium-based alloy (Ti–23Nb–0.7Ta–2Zr–1.2O) was synthesized by melting and then characterized in order to evaluate its potential for biomedical applications. Thus, the mechanical properties, the corrosion resistance in simulated body fluid and the in vitro cell response were investigated. It was shown that this alloy presents a very high strength, a low Young's modulus and a high recoverable strain by comparison with the titanium alloys currently used in medicine. On the other hand, all electrochemical and corrosion parameters exhibited more favorable values showing a nobler behavior and negligible toxicity in comparison with the commercially pure Ti taken as reference. Furthermore, the biocompatibility tests showed that this alloy induced an excellent response of MC3T3-E1 pre-osteoblasts in terms of attachment, spreading, viability, proliferation and differentiation. Consequently, the “Gum Metal” titanium-based alloy processes useful characteristics for the manufacturing of highly biocompatible medical devices. - Highlights: • The Gum Metal alloy composition was synthesized by melting in this study. • Appropriate mechanical properties for biomedical applications were obtained. • High corrosion resistance in simulated body fluids was observed. • Excellent in-vitro cell response was evidenced.

  16. Titanium-35niobium alloy as a potential material for biomedical implants: In vitro study.

    Science.gov (United States)

    de Andrade, Dennia Perez; de Vasconcellos, Luana Marotta Reis; Carvalho, Isabel Chaves Silva; Forte, Lilibeth Ferraz de Brito Penna; de Souza Santos, Evelyn Luzia; Prado, Renata Falchete do; Santos, Dalcy Roberto Dos; Cairo, Carlos Alberto Alves; Carvalho, Yasmin Rodarte

    2015-11-01

    Research on new titanium alloys and different surface topographies aims to improve osseointegration. The objective of this study is to analyze the behavior of osteogenic cells cultivated on porous and dense samples of titanium-niobium alloys, and to compare them with the behavior of such type of cells on commercial pure titanium. Samples prepared using powder metallurgy were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and metallographic and profilometer analyses. Osteogenic cells from newborn rat calvaria were plated over different groups: dense or porous samples composed of Ti or Ti-35niobium (Nb). Cell adhesion, cell proliferation, MTT assay, cell morphology, protein total content, alkaline phosphatase activity, and mineralization nodules were assessed. Results from XRD and EDS analysis confirmed the presence of Ti and Nb in the test alloy. Metallographic analysis revealed interconnected pores, with pore size ranging from 138 to 150μm. The profilometer analysis detected the greatest rugosity within the dense alloy samples. In vitro tests revealed similar biocompatibility between Ti-35Nb and Ti; furthermore, it was possible to verify that the association of porous surface topography and the Ti-35Nb alloy positively influenced mineralized matrix formation. We propose that the Ti-35Nb alloy with porous topography constitutes a biocompatible material with great potential for use in biomedical implants. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Strain localization during tensile Hopkinson bar testing of commercially pure titanium and Ti6Al4V titanium alloy

    Directory of Open Access Journals (Sweden)

    Moćko Wojciech

    2015-01-01

    Full Text Available The goal of the analysis was to determine the strain localization for various specimen shapes (type A and type B according to PN-EN ISO 26203-1 standard and different loading conditions, i.e. quasi- static and dynamic. Commercially pure titanium (Grade 2 and titanium alloy Ti6Al4V (Grade 5 were selected for the tests. Tensile loadings were applied out using servo-hydraulic testing machine and tensile Hopkinson bar with pre-tension. The results were recorded using ARAMIS system cameras and fast camera Phantom V1210, respectively at quasi-static and dynamic loading conditions. Further, specimens outline was determined on the basis of video data using TEMA MOTION software. The strain distribution on the specimen surface was estimated using digital image correlation method. The larger radius present in the specimen of type B in comparison to specimen of type A, results in slight increase of the elongation for commercially pure titanium at both quasi-static and dynamic loading conditions. However this effect disappears for Ti6Al4V alloy. The increase of the elongation corresponds to the stronger necking effect. Material softening due to increase of temperature induced by plastic work was observed at dynamic loading conditions. Moreover lower elongation at fracture point was found at high strain rates for both materials.

  18. Degradation mode survey candidate titanium-base alloys for Yucca Mountain project waste package materials. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Gdowski, G.E.

    1997-12-01

    The Yucca Mountain Site Characterization Project (YMP) is evaluating materials from which to fabricate high-level nuclear waste containers (hereafter called waste packages) for the potential repository at Yucca Mountain, Nevada. Because of their very good corrosion resistance in aqueous environments titanium alloys are considered for container materials. Consideration of titanium alloys is understandable since about one-third (in 1978) of all titanium produced is used in applications where corrosion resistance is of primary importance. Consequently, there is a considerable amount of data which demonstrates that titanium alloys, in general, but particularly the commercial purity and dilute {alpha} grades, are highly corrosion resistant. This report will discuss the corrosion characteristics of Ti Gr 2, 7, 12, and 16. The more highly alloyed titanium alloys which were developed by adding a small Pd content to higher strength Ti alloys in order to give them better corrosion resistance will not be considered in this report. These alloys are all two phase ({alpha} and {beta}) alloys. The palladium addition while making these alloys more corrosion resistant does not give them the corrosion resistance of the single phase {alpha} and near-{alpha} (Ti Gr 12) alloys.

  19. Biocompatibility and Inflammatory Potential of Titanium Alloys Cultivated with Human Osteoblasts, Fibroblasts and Macrophages

    Directory of Open Access Journals (Sweden)

    Jana Markhoff

    2017-01-01

    Full Text Available The biomaterials used to maintain or replace functions in the human body consist mainly of metals, ceramics or polymers. In orthopedic surgery, metallic materials, especially titanium and its alloys, are the most common, due to their excellent mechanical properties, corrosion resistance, and biocompatibility. Aside from the established Ti6Al4V alloy, shape memory materials such as nickel-titanium (NiTi have risen in importance, but are also discussed because of the adverse effects of nickel ions. These might be reduced by specific surface modifications. In the present in vitro study, the osteoblastic cell line MG-63 as well as primary human osteoblasts, fibroblasts, and macrophages were cultured on titanium alloys (forged Ti6Al4V, additive manufactured Ti6Al4V, NiTi, and Diamond-Like-Carbon (DLC-coated NiTi to verify their specific biocompatibility and inflammatory potential. Additive manufactured Ti6Al4V and NiTi revealed the highest levels of metabolic cell activity. DLC-coated NiTi appeared as a suitable surface for cell growth, showing the highest collagen production. None of the implant materials caused a strong inflammatory response. In general, no distinct cell-specific response could be observed for the materials and surface coating used. In summary, all tested titanium alloys seem to be biologically appropriate for application in orthopedic surgery.

  20. Tailoring the mechanical properties of titanium alloys via plasticity induced transformations

    NARCIS (Netherlands)

    Neelakantan, S.

    2010-01-01

    Titanium alloys possess good corrosion properties, high temperature stability and high strength-to-weight ratio. However, they fall short in providing the optimum strength-ductility relation in the most demanding structural applications, including the aerospace sector. Inspired by the possibility of

  1. Tailoring the Mechanical Properties of Titanium Alloys via Plasticity Induced Transformations

    NARCIS (Netherlands)

    Neelakantan, S.

    2010-01-01

    Titanium alloys possess good corrosion properties, high temperature stability and high strength-to-weight ratio. However, they fall short in providing the optimum strength-ductility relation in the most demanding structural applications, including the aerospace sector. Inspired by the possibility of

  2. Effect of high density electropulsing treatment on formability of TC4 titanium alloy sheet

    Institute of Scientific and Technical Information of China (English)

    SONG Hui; WANG Zhong-jin; GAO Tie-jun

    2007-01-01

    An annealed TC4 titanium alloy sheet was treated by high density electropulsing (Jmax=(5.09-5.26)×103A/mm2, tp=110 μs) under ambient conditions. The effect of electropulsing treatment(EPT) on the plastic deformation behavior of TC4 titanium alloy sheet was studied using uniaxial tension tests. The experimental results indicate that electropulsing treatment significantly changes the mechanical properties of sheet metal: the uniform elongation is increased by 35%, the yield stress is decreased by 19.8% and the yield to tensile ratio is decreased by 17.6%. It is of significant meaning to improve the formability of TC4 titanium alloy sheet. The optical microscope and scanning electron microscope(SEM) were used to examine the changes of the microstructure and the fracture morphology before and after the electropulsing treatment. It is found that recrystallization occurs in the sheet metal and dimples in fracture surface are large and deep after the electropulsing treatment. The research results show that the electropulsing treatment is an effective method to improve the formability of titanium alloy sheets.

  3. EFFECT OF TITANIUM-ALLOY PARTICLES ON EXPRESSION OF MEDIATING-RELATED GENES IN HUMAN OSTEOBLASTS

    Institute of Scientific and Technical Information of China (English)

    杨旭; 杨庆铭; 邓廉夫; 许福平; 张玥

    2004-01-01

    Objective To study mRNA expression of the mediating-related genes in osteoblasts after exposure to Titanium-alloy particles and cytochalasin-D. Methods Human osteoblasts were isolated from trabecular fragments and exposed to 0. 01% (v/v) titanium-alloy particles for 8h. Pretreatment of osteoblasts with cytochalasinD( 5μmol/L ) to prevent phagocytosis prior to the addition of Titanium-alloy particles, mRNA expression of RANKL,OPG, and IL-6 was semi-quantified by RT-PCR. Results Expressions of RANKL, OPG, and lL-6 mRNA at respective levels were found in osteoblasts under normal condition, which did not show significant changes in the samples treated with cytochalasin-D but without particles. Exposure of osteoblasts to particles after being treated with or without cytochalasin-D altered mRNA expression of these genes, however, an increase in the ratio of RANKL/ OPG mRNA was only found in samples without cytochalassin-D treatment. Conclusion Changes of expression of RANKL, OPG, and IL-6 mRNA in osteoblasts after exposure to titanium-alloy particles were independent of phagocytosis, whereas phagocytosis has a direct effect on their ability to stimulate osteoclast differentiation and function.

  4. Mechanical properties of ({alpha}+{beta})-titanium alloy at cryogenic temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ivasishin, O.M. [Institute for Metal Physics, 36 Vernadsky str, Kiev 252142 (Ukraine); Markovsky, P.E. [Institute for Metal Physics, 36 Vernadsky str, Kiev 252142 (Ukraine); Pakharenko, G.A. [Institute for Metal Physics, 36 Vernadsky str, Kiev 252142 (Ukraine); Shevchenko, A.V. [Institute for Metal Physics, 36 Vernadsky str, Kiev 252142 (Ukraine)

    1995-06-15

    The influence of microstructure, fine surface stress concentrators and weak surface gas saturation on the mechanical properties of high-strength ({alpha}+{beta})-titanium alloy at cryogenics temperatures was studied. The results are discussed in terms of a new microcleavage model of brittle fracture. (orig.)

  5. Cytotoxic, allergic and genotoxic activity of a nickel-titanium alloy

    NARCIS (Netherlands)

    Veldhuizen, AG; Sanders, MM; Schakenraad, JM; vanHorn, [No Value

    1997-01-01

    The nearly equiatomic nickel-titanium (NiTi) alloy is known for its shape memory properties. These properties can be put to excellent use in various biomedical applications, such as wires for orthodontic tooth alignment and osteosynthesis staples. The aim of this study was to evaluate the short-term

  6. Pelvic mass secondary to polyethylene and titanium alloy wear debris resulting in recurrent deep vein thrombosis.

    Science.gov (United States)

    Shilt, J S; Rozencwaig, R; Wilson, M R

    1997-12-01

    External venous compression can be a cause of deep vein thrombosis (DVT). This is an unusual case of acetabular component failure and resultant polyethylene and titanium alloy wear debris that presented as a pelvic mass and resulted in iliac vein compression and subsequent DVT.

  7. Fundamental Studies on Ambient Temperature Creep Deformation Behavior of Alpha and Alpha-Beta Titanium Alloys

    Science.gov (United States)

    2013-01-31

    Electron Microscope Elemental tin t time T Ta temperature Elemental Tantalum TEM Ti Transmission Electron Microscope Elemental titanium Ti...7 [45] and 8 [46]. The chemical compositions are actual chemical compositions of the alloys after fabrication as determined by the wet chemistry

  8. Investigation of Corrosion Behavior of Bioactive Coverings on Commercially Pure Titanium and its Alloys

    Directory of Open Access Journals (Sweden)

    M.Yu. Gazizova

    2015-12-01

    Full Text Available A microporous and macroporous bioactive coatings on boimedical titanium alloys (VT1-0, VT6, Ti-6Al-7Nb were formed by a micro-arc oxidation method. The effect of the phase composition of microporous and macroporous coatings on corrosion behavior titanium and its alloys was investigated. The results show that phase composition of the coatings microporous presented only titanium oxides: anatase and rutile, at that the phase composition macroporous coatings consists of anatase, rutile and calcium phosphate compounds: tricalcium phosphate (TCP α-Ca3(PO42 and calcium deficient hydroxyapatite Ca9HPO4(PO45OH. Corrosion behavior of MAO coatings was investigated in solution 0.9 % NaCl using potentiodynamic polarization tests. The microporous coatings exhibited a more highest corrosion resistance than macroporous coatings, it is connected with containing calcium phosphate compounds in macroporous coatings.

  9. Active screen plasma nitriding enhances cell attachment to polymer surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kaklamani, Georgia, E-mail: g.kaklamani@bham.ac.uk [University of Birmingham, College of Engineering and Physical Sciences, School of Metallurgy and Materials, Edgbaston, Birmingham B15 2TT (United Kingdom); Bowen, James; Mehrban, Nazia [University of Birmingham, College of Engineering and Physical Sciences, School of Chemical Engineering, Edgbaston, Birmingham B15 2TT (United Kingdom); Dong, Hanshan [University of Birmingham, College of Engineering and Physical Sciences, School of Metallurgy and Materials, Edgbaston, Birmingham B15 2TT (United Kingdom); Grover, Liam M. [University of Birmingham, College of Engineering and Physical Sciences, School of Chemical Engineering, Edgbaston, Birmingham B15 2TT (United Kingdom); Stamboulis, Artemis [University of Birmingham, College of Engineering and Physical Sciences, School of Metallurgy and Materials, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2013-05-15

    Active screen plasma nitriding (ASPN) is a well-established technique used for the surface modification of materials, the result of which is often a product with enhanced functional performance. Here we report the modification of the chemical and mechanical properties of ultra-high molecular weight poly(ethylene) (UHMWPE) using 80:20 (v/v) N{sub 2}/H{sub 2} ASPN, followed by growth of 3T3 fibroblasts on the treated and untreated polymer surfaces. ASPN-treated UHMWPE showed extensive fibroblast attachment within 3 h of seeding, whereas fibroblasts did not successfully attach to untreated UHMWPE. Fibroblast-coated surfaces were maintained for up to 28 days, monitoring their metabolic activity and morphology throughout. The chemical properties of the ASPN-treated UHMWPE surface were studied using X-ray photoelectron spectroscopy, revealing the presence of C-N, C=N, and C≡N chemical bonds. The elastic modulus, surface topography, and adhesion properties of the ASPN-treated UHMWPE surface were studied over 28 days during sample storage under ambient conditions and during immersion in two commonly used cell culture media.

  10. Prediction of the martensite start temperature for {beta} titanium alloys as a function of composition

    Energy Technology Data Exchange (ETDEWEB)

    Neelakantan, Suresh [Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft (Netherlands); Materials Innovation Institute, Kluyverweg 1, 2629 HS, Delft (Netherlands)], E-mail: s.neelakantan@tudelft.nl; Rivera-Diaz-del-Castillo, P.E.J.; Zwaag, Sybrand van der [Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft (Netherlands)

    2009-04-15

    A thermodynamics-based model to predict the martensite start temperature of {beta} titanium alloys is presented. The tendency of the {beta} phase to transform into martensite is estimated by applying the Ghosh-Olson approach to martensite nucleation modelling. The energetics and M{sub s} temperature for binary alloys are predicted with good accuracy. A succinct formula predicting M{sub s} temperature in multicomponent {beta} alloys is presented. The new equation is compared to the classical Mo equivalence criterion for assessing {beta} stability.

  11. Low cycle fatigue improvement of powder metallurgy titanium alloy through thermomechanical treatment

    Institute of Scientific and Technical Information of China (English)

    LIU Bin; LIU Yong; HE Xiao-yu; TANG Hui-ping; CHEN Li-fang

    2008-01-01

    A low-cost β type Ti-1.5Fe-6.8Mo-4.8Al-1.2Nd (mass fraction, %)(T12LCC) alloy was produced by blended elemental powder metallurgy(P/M) method and subsequent thermomechanical treatment. Low cycle fatigue(LCF) behavior of P/M T12LCC alloy before and after thermomechanical treatment was studied. The results show that the LCF resistance of P/M titanium alloy is significantly enhanced through the thermomechanical treatment. The mechanisms for the improvement of LCF behavior are attributed to the elimination of residual pores, the microstructure refining and homogenization.

  12. Pseudoelasticity and thermoelasticity of nickel-titanium alloys: a clinically oriented review. Part II: Deactivation forces.

    Science.gov (United States)

    Santoro, M; Nicolay, O F; Cangialosi, T J

    2001-06-01

    The purpose of this review was to organize a systematic reference to help orthodontists evaluate commonly used orthodontic nickel-titanium alloys. Part I of the article reviewed the data available in the literature regarding the temperature transitional ranges of the alloys. The thermomechanical behavior of these compounds is, in fact, strictly dependent upon the correlation between the temperature transitional range and the oral temperature range. Part II focuses on the mechanical characteristics of the alloys, such as the magnitude of the forces delivered and correlations with the temperature transitional range and oral temperature.

  13. Cytotoxicity and antibacterial property of titanium alloy coated with silver nanoparticle-containing polyelectrolyte multilayer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xinming [School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China); Li, Zhaoyang [School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin, 300072 (China); Yuan, Xubo [School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China); Cui, Zhenduo [School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin, 300072 (China); Bao, Huijing; Li, Xue; Liu, Yunde [School of Laboratory Medicine, Tianjin Medical University, Tianjin, 300203 (China); Yang, Xianjin, E-mail: xjyang@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin, 300072 (China)

    2013-07-01

    Silver nanoparticle (AgNP) was incorporated into dopamine-modified alginate/chitosan (DAL/CHI) polyelectrolyte multilayer to modify the surface of titanium alloy and improve its antibacterial property. Scanning electron microscopy showed that AgNP with the size of 50 nm embedded in DAL/CHI multilayers homogeneously. X-ray photoelectron spectroscopy analysis indicated that the nanoparticles were silver (0) with peaks at 368.4 and 374.4 eV, respectively. The formation of silver (0) without the addition of reductants was due to the self-polymerization of dopamine, which can reduce the silver cation into neutral metal. The polyelectrolyte multilayer coating enhanced the wettability of titanium alloy and promoted the fibroblast proliferation significantly, which could be attributed to the excellent biocompatibility of DAL/CHI. Despite the slight fall of L929 cell activity after AgNP incorporation, AgNP-DAL/CHI multilayer inhibited the growth of both Escherichia coli and Staphylococcus aureus. The above results demonstrate that dopamine decoration is a simple and effective way to induce the in-situ formation of AgNP within polyelectrolyte multilayer. Furthermore, the AgNP-containing multilayer considerably enhances the antibacterial activity of titanium alloy. The fabrication of AgNP-DAL/CHI multilayer on the surface of titanium implant might have great potential in orthopedic use. - Highlights: • Polyelectrolyte multilayer was fabricated through layer-by-layer assembly. • AgNP was formed in-situ and embedded within polyelectrolyte multilayer. • Surface of titanium was modified by AgNP-DAL/CHI multilayer with a facile method. • AgNP-DAL/CHI multilayer enhanced antibacterial activity of titanium alloy.

  14. Titanium

    DEFF Research Database (Denmark)

    Fage, Simon W; Muris, Joris; Jakobsen, Stig S

    2016-01-01

    Exposure to titanium (Ti) from implants and from personal care products as nanoparticles (NPs) is common. This article reviews exposure sources, ion release, skin penetration, allergenic effects, and diagnostic possibilities. We conclude that human exposure to Ti mainly derives from dental...... and medical implants, personal care products, and foods. Despite being considered to be highly biocompatible relative to other metals, Ti is released in the presence of biological fluids and tissue, especially under certain circumstances, which seem to be more likely with regard to dental implants. Although...... most of the studies reviewed have important limitations, Ti seems not to penetrate a competent skin barrier, either as pure Ti, alloy, or as Ti oxide NPs. However, there are some indications of Ti penetration through the oral mucosa. We conclude that patch testing with the available Ti preparations...

  15. Enhancement of Apoptosis by Titanium Alloy Internal Fixations during Microwave Treatments for Fractures: An Animal Study.

    Directory of Open Access Journals (Sweden)

    Gang Wang

    Full Text Available Microwaves are used in one method of physical therapy and can increase muscle tissue temperature which is useful for improving muscle, tendon and bone injuries. In the study, we sought to determine whether titanium alloy internal fixations influence apoptosis in tissues subjected to microwave treatments at 2,450 MHz and 40 W during the healing of fractures because this issue is not yet fully understood.In this study, titanium alloy internal fixations were used to treat 3.0-mm transverse osteotomies in the middle of New Zealand rabbits' femurs. After the operation, 30-day microwave treatments were applied to the 3.0 mm transverse osteotomies 3 days after the operation. The changes in the temperatures of the muscle tissues in front of the implants or the 3.0 mm transverse osteotomies were measured during the microwave treatments. To characterize the effects of titanium alloy internal fixations on apoptosis in the muscles after microwave treatment, we performed TUNEL assays, fluorescent real-time (quantitative PCR, western blotting analyses, reactive oxygen species (ROS detection and transmission electron microscopy examinations.The temperatures were markedly increased in the animals with the titanium alloy implants. Apoptosis in the muscle cells of the implanted group was significantly more extensive than that in the non-implanted control group at different time points. Transmission electron microscopy examinations of the skeletal muscles of the implanted groups revealed muscular mitochondrial swelling, vacuolization. ROS, Bax and Hsp70 were up-regulated, and Bcl-2 was down-regulated in the implanted group.Our results suggest that titanium alloy internal fixations caused greater muscular tissue cell apoptosis following 2,450 MHz, 40 W microwave treatments in this rabbit femur fracture models.

  16. Elastic stiffness and damping measurements in titanium alloys using atomic force acoustic microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kalyan Phani, M. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603102 Tamil Nadu (India); Kumar, Anish, E-mail: anish@igcar.gov.in [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603102 Tamil Nadu (India); Arnold, W. [Department of Materials and Materials Technology, Saarland University, Campus D 2.2, D-66123 Saarbrücken (Germany); 1. Physikalisches Institut, Georg-August-Universität, Friedrich Hund Platz 1, D-37077 Göttingen (Germany); Samwer, K. [1. Physikalisches Institut, Georg-August-Universität, Friedrich Hund Platz 1, D-37077 Göttingen (Germany)

    2016-08-15

    Atomic force acoustic microscopy (AFAM) has been used to study the distribution of elastic stiffness and damping properties across different phases, such as α &β phases in a β titanium alloy (Ti−10V−4.5Fe−1.5Al) and α, β and α′ phases in an α + β alloy (Ti−6Al−4V). Contact-resonance spectra were obtained with a 100 nm spatial resolution in various specimens of the two titanium alloys heat-treated at different temperatures. The study indicates that the metastable β phase has the minimum modulus and maximum damping followed by α′ and α-phases. Employing the rule of mixtures, the average modulus measured by AFAM was then compared with the modulus obtained by ultrasonic velocity measurements. The error in the average modulus values obtained by both techniques is discussed. - Highlights: • Mapping of elastic stiffness and damping across various phases in titanium alloys. • Influence of alloy chemistry and crystal orientation on the results are discussed. • β phase has the minimum modulus and maximum damping followed by α′ and α-phases. • Average modulus of sample calculated from AFAM measurements on individual phases.

  17. Interfacial reaction kinetics of coated SiC fibers with various titanium alloys

    Science.gov (United States)

    Gundel, D. B.; Wawner, F. E.

    1991-01-01

    The kinetics of the reaction between the silicon carbide fibers and the titanium-based alloy matrix was investigated at temperatures from 800 to 1000 C for several titanium-based alloys (including Ti-1100 alloy and BETA 21S) and unalloyed Ti, reinforced with coated silicon carbide fiber SCS-6. The reaction zone growth kinetics was studied by exposing vacuum encapsulated samples to temperatures from 700 to 1000 C for times up to 150 hrs, followed by SAM observations of samples which were polished perpendicular to the fiber axis and etched. It was found that the reaction zone growth kinetics of the alpha (hcp) and beta (bcc) phases of unalloyed titanium reacting with SCS-6 fibers exhibited different values of the apparent activation energy and of the preexponential factor. Additions of other metals to Ti was found to slow down the reaction kinetics. Among the alloys studied, the Ti-1100 was the slowest reacting conventional alloy and the Ti-14Al-21Nb (in wt pct) was the slowest overall.

  18. Potentiality of the "Gum Metal" titanium-based alloy for biomedical applications.

    Science.gov (United States)

    Gordin, D M; Ion, R; Vasilescu, C; Drob, S I; Cimpean, A; Gloriant, T

    2014-11-01

    In this study, the "Gum Metal" titanium-based alloy (Ti-23Nb-0.7Ta-2Zr-1.2O) was synthesized by melting and then characterized in order to evaluate its potential for biomedical applications. Thus, the mechanical properties, the corrosion resistance in simulated body fluid and the in vitro cell response were investigated. It was shown that this alloy presents a very high strength, a low Young's modulus and a high recoverable strain by comparison with the titanium alloys currently used in medicine. On the other hand, all electrochemical and corrosion parameters exhibited more favorable values showing a nobler behavior and negligible toxicity in comparison with the commercially pure Ti taken as reference. Furthermore, the biocompatibility tests showed that this alloy induced an excellent response of MC3T3-E1 pre-osteoblasts in terms of attachment, spreading, viability, proliferation and differentiation. Consequently, the "Gum Metal" titanium-based alloy processes useful characteristics for the manufacturing of highly biocompatible medical devices.

  19. Recrystallization behavior of Ti40 burn-resistant titanium alloy during hot working process

    Science.gov (United States)

    Lai, Yun-jin; Xin, She-wei; Zhang, Ping-xiang; Zhao, Yong-qing; Ma, Fan-jiao; Liu, Xiang-hong; Feng, Yong

    2016-05-01

    The recrystallization behavior of deformed Ti40 alloy during a heat-treatment process was studied using electron backscatter diffraction and optical microscopy. The results show that the microstructural evolution of Ti40 alloy is controlled by the growth behavior of grain-boundary small grains during the heating process. These small grains at the grain boundaries mostly originate during the forging process because of the alloy's inhomogeneous deformation. During forging, the deformation first occurs in the grain-boundary region. New small recrystallized grains are separated from the parent grains when the orientation between deformation zones and parent grains exceeds a certain threshold. During the heating process, the growth of these small recrystallized grains results in a uniform grain size and a decrease in the average grain size. The special recrystallization behavior of Ti40 alloy is mainly a consequence of the alloy's high β-stabilized elemental content and high solution strength of the β-grains, which partially explains the poor hot working ability of Ti-V-Cr-type burn-resistant titanium alloys. Notably, this study on Ti40 burn-resistant titanium alloy yields important information related to the optimization of the microstructures and mechanical properties.

  20. Improving the wear resistance of titanium alloys under high contact loads

    Energy Technology Data Exchange (ETDEWEB)

    Ivasishin, O.M.; Markovskii, P.E.; Mikulyak, O.V. [Inst. of Metal Physics, Kiev (Ukraine)] [and others

    1992-01-01

    One of the basic shortcomings of titanium alloys is their poor antifriction properties. The wear resistance of titanium alloys can be improved by applying special coatings to their surface by various methods. However, the formation of surface layers whose properties differ greatly from the properties of the metallic substrate is accompanied, as a rule, by considerable impairment of the ductile and fatigue characteristics of the alloy. Besides, the material of the coating or the technology of its application are not always able to ensure the required resistance under large contact loads, both of the coating itself and of the adjacent zones of the material of the substrate (which are often weakened by thermal or thermochemical effects). 8 refs., 1 fig.

  1. Evolution of Defect Structure of Two-Phase Titanium Alloy Under Active Load

    Science.gov (United States)

    Kunitsyna, T. S.; Teplyakova, L. A.; Kashin, A. D.

    2017-09-01

    The paper deals with the defect structure of two-phase VT6 titanium alloy and studies its evolution under plastic deformation within the wide range. It is found that the defect structure of this alloy before loading is a multi-level system with such scale-level elements as grain, colony, lamella, α- and β-lamellas, microtwins, and dislocation substructure. During plastic deformation, the evolution of the dislocation subsystem is observed. The sequence of substructural transformations with deformation is identified in this paper. The scalar dislocation density is measured in both phases and its dependence on the degree of deformation is detected. In particular, it is shown that the fracture of VT6 titanium alloy is caused by the similar value of scalar dislocation density achieved both in α- and β-phases.

  2. On the high-pressure phase stability and elastic properties of β-titanium alloys

    Science.gov (United States)

    Smith, D.; Joris, O. P. J.; Sankaran, A.; Weekes, H. E.; Bull, D. J.; Prior, T. J.; Dye, D.; Errandonea, D.; Proctor, J. E.

    2017-04-01

    We have studied the compressibility and stability of different β-titanium alloys at high pressure, including binary Ti-Mo, Ti-24Nb-4Zr-8Sn (Ti2448) and Ti-36Nb-2Ta-0.3O (gum metal). We observed stability of the β phase in these alloys to 40 GPa, well into the ω phase region in the P-T diagram of pure titanium. Gum metal was pressurised above 70 GPa and forms a phase with a crystal structure similar to the η phase of pure Ti. The bulk moduli determined for the different alloys range from 97  ±  3 GPa (Ti2448) to 124  ±  6 GPa (Ti-16.8Mo-0.13O).

  3. Biofilm formation on titanium alloy and anatase-Bactercline® coated titanium healing screws: an in vivo human study

    Directory of Open Access Journals (Sweden)

    Antonio Scarano

    2013-03-01

    Full Text Available Aim Bacterial adherence to implants is considered to be an important event in the pathogenesis of bacterial infections. In fact, this infection process is a first stage of peri-implant mucositis and peri-implantitis, and a positive correlation has been found between oral hygiene and marginal bone loss around implants in the edentulous mandible. Surface properties of transgingival implant components are important determinants in bacterial adhesion. The purpose of this study was to characterize the biofilm formation, in vivo, on healing screws made of titanium alloy or coated with a combination of anatase and Bactercline® product. Materials and methods Twenty-five patients, between 21- 37 years, in excellent systemic health, participated in this study. In each of the 25 participants, one anatase-Bactercline® coated healing screw (Test and one titanium alloy (TI6Al4V healing screw (Control were adapted to two different implants. Quantitative and qualitative biofilm formation on healing abutments was analyzed by culture method.Results Bacterial adherence to the two different healing screws used in this study were compared. Statistically significant differences were found between the Control and the Test group for both aerobic and anaerobic bacterial counts (p<0,05. The microflora consisted both of Gram-positive and Gram-negative bacteria, and displayed a high variability. The anaerobic S. intermedius, potentially “pathogenic”, was isolated only from the Control group. Both healing screws harbored primarily Gram-positive rods as Actinomyces spp, A. naeslundii, A. viscosus and the Gram-negative rods (Fusobacterium spp, Prevotella spp, Capnocythophaga spp were mostly found on the Control healing screws.Conclusion Anatase-Bactercline® coated healing screws reduce the number of initially adhering bacteria, formed mainly of Gram-positive microorgnisms, while, on the contrary, the microflora covering the titanium alloy healing screws was, for the

  4. Nanomechanical properties of surface-modified titanium alloys for biomedical applications.

    Science.gov (United States)

    Cáceres, D; Munuera, C; Ocal, C; Jiménez, J A; Gutiérrez, A; López, M F

    2008-09-01

    The mechanical properties of the oxide layers developed at elevated temperature on three vanadium-free titanium alloys of interest for biomedical applications were investigated by means of the nanoindentation technique. The as-received alloys (Ti-13Nb-13Zr, Ti-15Zr-4Nb and Ti-7Nb-6Al) and their oxide scales formed by reaction with air at 750 degrees C for several oxidation times were analysed comparatively. In particular, the hardness and the Young's modulus exhibit larger values for the thermally oxidized alloys than for the untreated specimens. However, the Ti-7Nb-6Al alloy shows a different tendency to that of the TiNbZr alloys, which seems to be related to a different oxide layer growth as a function of the oxidation time.

  5. Order/disorder in electrodeposited aluminum-titanium alloys

    Directory of Open Access Journals (Sweden)

    Stafford G.R.

    2003-01-01

    Full Text Available The composition, morphology, and crystallographic microstructure of Al-Ti alloys electrodeposited from two different chloroaluminate molten salt electrolytes were examined. Alloys containing up to 28 % atomic fraction Ti were electrodeposited at 150 °C from 2:1 AlCl3-NaCl with controlled additions of Ti2+. The apparent limit on alloy composition is proposed to be due to a mechanism by which Al3Ti forms through the reductive decomposition of [Ti(AlCl43]-. The composition of Al-Ti alloys electrodeposited from the AlCl3-EtMeImCl melt at 80 °C is limited by the diffusion of Ti2+ to the electrode surface. Alloys containing up to 18.4 % atomic fraction Ti are only obtainable at high Ti2+ concentrations in the melt and low current densities. Alloys electrodeposited from the higher temperature melt have an ordered L12 crystal structure while alloys of similar composition but deposited at lower temperature are disordered fcc. The appearance of antiphase boundaries in the ordered alloys suggests that the deposit may be disordered initially and then orders in the solid state, subsequent to the charge transfer step and adatom incorporation into the lattice. This is very similar to the disorder-trapping observed in rapidly solidified alloys. The measured domain size is consistent with a mechanism of diffusion-controlled doman growth at the examined deposition temperatures and times.

  6. Evaluation of Antibacterial Activity of Titanium Surface Modified by PVD/PACVD Process.

    Science.gov (United States)

    Ji, Min-Kyung; Lee, Min-Joo; Park, Sang-Won; Lee, Kwangmin; Yun, Kwi-Dug; Kim, Hyun-Seung; Oh, Gye-Jeong; Kim, Ji-Hyun; Lim, Hyun-Pil

    2016-02-01

    The aim of this study was to evaluate the response of Streptococcus mutans (S. mutans) via crystal violet staining assay on titanium surface modified by physical vapor deposition/plasma assisted chemical vapor deposition process. Specimens were divided into the following three groups: polished titanium (control group), titanium modified by DC magnetron sputtering (group TiN-Ti), and titanium modified by plasma nitriding (group N-Ti). Surface characteristics of specimens were observed by using nanosurface 3D optical profiler and field emission scanning electron microscope. Group TiN-Ti showed TiN layer of 1.2 microm in thickness. Group N-Ti was identified as plasma nitriding with X-ray photoelectron spectroscopy. Roughness average (Ra) of all specimens had values 0.05). Within the process condition of this study, modified titanium surfaces by DC magnetron sputtering and plasma nitriding did not influence the adhesion of S. mutans.

  7. Laser surface alloying of commercially pure titanium with boron and carbon

    Science.gov (United States)

    Makuch, N.; Kulka, M.; Dziarski, P.; Przestacki, D.

    2014-06-01

    Laser surface alloying with boron and carbon was applied to produce the composite layers, reinforced by the hard ceramic phases (titanium borides and titanium carbides), on commercially pure titanium. The external cylindrical surface of substrate material was coated by paste containing boron, boron and graphite, or graphite. Then, the laser re-melting was carried out with using the continuous-wave CO2 laser. This enabled the formation of laser-borided, laser-borocarburized, and laser-carburized layers. The microstructure or the re-melted zone consisted of the hard ceramic phases (TiB+TiB2, TiB+TiB2+TiC, or TiC) located in the eutectic mixture of Tiα'-phase with borides, borides and carbides, or carbides, respectively. All the composite layers were characterized by the sufficient cohesion. The significant increase in microhardness and in wear resistance of all the laser-alloyed layers was observed in comparison with commercially pure titanium. The percentage of hard ceramic phases in more plastic eutectic mixture influenced the measured microhardness values. The dominant wear mechanism (abrasive or adhesive) depended on the method of laser alloying, and the type of test used. The wear tests for longer duration, without the change in the counter specimen, created the favourable conditions for adhesive wear, while during the shorter tests the abrasive wear dominated, as a rule.

  8. Passive fit of frameworks in titanium and palladium-silver alloy submitted the laser welding.

    Science.gov (United States)

    de Sousa, S A; de Arruda Nobilo, M A; Henriques, G E P; Mesquita, M F

    2008-02-01

    This study evaluated the precision of fit of implant frameworks cast in titanium (cp Ti) and palladium-silver alloy (Pd-Ag), made by the one-piece cast and laser welding techniques. From a metal matrix with five implants, 20 master casts were obtained, to which replicas of implants were incorporated. On these masters 10 frameworks were made for each type of material (cp Ti and Pd-Ag alloy). Half of these were made by the one-piece cast technique and the other half by the laser welding technique. The implant/prosthesis interface was analysed and measured in the vestibular and lingual regions of the central and distal implants with the help of a measuring microscope. The results indicated that in the central cylinders, the Tukey test (Plaser-welded frameworks (34.73 microm) and those one-piece cast frameworks (151.39 microm), and as regards materials, the palladium-silver alloy (66.30 microm) showed better results than the titanium (119.83 microm). In the distal cylinders there was no significant difference between the frameworks cast in titanium and palladium-silver by the one-piece technique. However, after laser welding, there was a significant difference for the frameworks cast in titanium (31.37 microm) and palladium-silver (106.59 microm).

  9. Metallurgical response of an AISI 4140 steel to different plasma nitriding gas mixtures

    Directory of Open Access Journals (Sweden)

    Adão Felipe Oliveira Skonieski

    2013-01-01

    Full Text Available Plasma nitriding is a surface modification process that uses glow discharge to diffuse nitrogen atoms into the metallic matrix of different materials. Among the many possible parameters of the process, the gas mixture composition plays an important role, as it impacts directly the formed layer's microstructure. In this work an AISI 4140 steel was plasma nitrided under five different gas compositions. The plasma nitriding samples were characterized using optical and scanning electron microscopy, microhardness test, X-ray diffraction and GDOES. The results showed that there are significant microstructural and morphological differences on the formed layers depending on the quantity of nitrogen and methane added to the plasma nitriding atmosphere. Thicknesses of 10, 5 and 2.5 µm were obtained when the nitrogen content of the gas mixtures were varied. The possibility to obtain a compound layer formed mainly by γ'-Fe4N nitrides was also shown. For all studied plasma nitriding conditions, the presence of a compound layer was recognized as being the responsible to hinder the decarburization on the steel surface. The highest value of surface hardness - 1277HV - were measured in the sample which were nitrided with 3vol.% of CH4.

  10. Improving electrochemical properties of AISI 1045 steels by duplex surface treatment of plasma nitriding and aluminizing

    Energy Technology Data Exchange (ETDEWEB)

    Haftlang, Farahnaz, E-mail: f.haftlang@students.semnan.ac.ir [Department of Metallurgy and Materials Engineering, Faculty of Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Habibolahzadeh, Ali [Department of Metallurgy and Materials Engineering, Faculty of Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Sohi, Mahmoud Heydarzadeh [School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2015-02-28

    Highlights: • AlN coating was applied on AISI 1045 steel via plasma nitriding and aluminizing. • Plasma nitriding and post-aluminizing result in AlN single phase layer on the steel. • PN–Al coated steel had better corrosion resistance than Al–PN one. • Formation of oxide layer provided protection of PN–Al coated steel against corrosion. • Pitting and surface defects was the dominant corrosion mechanism in Al–PN coated steel. - Abstract: Improvement in electrochemical behavior of AISI 1045 steel after applying aluminum nitride coating was investigated in 3.5% NaCl solution, using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) analyses. Aluminum nitride coating was applied on the steel surface by duplex treatment of pack aluminizing and plasma nitriding. Some specimens were plasma nitrided followed by aluminizing (PN–Al), while the others were pack aluminized followed by plasma nitriding (Al–PN). Topological and structural studies of the modified surfaces were conducted using scanning electron microscope (SEM) equipped by energy dispersive X-ray spectroscope (EDS), and X-ray diffractometer (XRD). The electrochemical measurements showed that the highest corrosion and polarization (R{sub p}) resistances were obtained in PN–Al specimens, having single phase superficial layer of AlN. Pitting mechanism was dominant reason of lower corrosion resistance in the Al–PN specimens.

  11. Effect of topical fluoride application on titanium alloys: a review of effects and clinical implications.

    Science.gov (United States)

    Fragou, Stella; Eliades, Theodore

    2010-01-01

    The purposes of this review were to: summarize the currently available evidence on the effect of fluoride on titanium alloys; discuss the mechanisms involved; and assess the clinical relevance and validity of statements deriving from in vitro approaches. The spectrum of effects noted include: morphological variations, such as increased roughness with adverse effects on sliding mechanics; mechanical properties of the wires, which may entail effects on the superelastic plateau of nickel-titanium wires, or reduction in the strength of wires, which can result in frequent intraoral failures; and release of ions during service. Reduced nickel release rates have been documented, however, from retrieved nickel-titanium wires presumably due to the passive layer formed. In relevant research, forming oxide on titanium alloys has been proposed to provide immunity to further degradation and ionic release, since nickel ions must diffuse through this layer to be released. The described evidence of fluoride on titanium alloys derives mostly from in vitro research, which includes oversimplifications in simulating the oral environment. The reactivity in laboratory experiments is dramatically increased relative to the actual clinical conditions, which exaggerates the effects noted. The effects shown have not been validated in vivo, since the only available evidence on intraorally fractured nickel-titanium archwires did not support the implication of hydrogen embrittlement as a failure mechanism. Rather, fractures were found to be related to: (1) mechanical factors associated with loading of the wire in specific arch sites; and (2) the masticatory forces. Clinically, the use of fluoride varnishes at specific, caries-risk sites may provide protection while minimizing the potential risk of adverse effects.

  12. Microtwin formation in the {alpha} phase of duplex titanium alloys affected by strain rate

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yi-Hsiang; Wu, Shu-Ming [Department of Mechanical and Mechatronic Engineering, National Taiwan Ocean University, No. 2 Pei Ning Road, Keelung 20224, Taiwan (China); Kao, Fang-Hsin [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Wang, Shing-Hoa, E-mail: shwang@ntou.edu.tw [Department of Mechanical and Mechatronic Engineering, National Taiwan Ocean University, No. 2 Pei Ning Road, Keelung 20224, Taiwan (China); Yang, Jer-Ren [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Yang, Chia-Chih [Department of Mechanical and Mechatronic Engineering, National Taiwan Ocean University, No. 2 Pei Ning Road, Keelung 20224, Taiwan (China); Chiou, Chuan-Sheng [Department of Mechanical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan (China)

    2011-03-15

    Research highlights: {yields} The long and dense twins in {alpha} phase of SP700 alloy occurring at lower strain rates promote a good ductility. {yields} The deformation in SP700 alloy changed to micro twins-controlled mechanism in {alpha} as the strain rate decreases. {yields} The material has time to redistribute the deformed strain between {alpha} and {beta} as the strain rate decreases. - Abstract: The effect of tensile strain rate on deformation microstructure was investigated in Ti-6-4 (Ti-6Al-4V) and SP700 (Ti-4.5Al-3V-2Mo-2Fe) of the duplex titanium alloys. Below a strain rate of 10{sup -2} s{sup -1}, Ti-6-4 alloy had a higher ultimate tensile strength than SP700 alloy. However, the yield strength of SP700 was consistently greater than Ti-6-4 at different strain rates. The ductility of SP700 alloy associated with twin formation (especially at the slow strain rate of 10{sup -4} s{sup -1}), always exceeded that of Ti-6-4 alloy at different strain rates. It is caused by a large quantity of deformation twins took place in the {alpha} phase of SP700 due to the lower stacking fault energy by the {beta} stabilizer of molybdenum alloying. In addition, the local deformation more was imposed on the {alpha} grains from the surrounding {beta}-rich grains by redistributing strain as the strain rate decreased in SP700 duplex alloy.

  13. Corrosion Analysis of an Experimental Noble Alloy on Commercially Pure Titanium Dental Implants

    Science.gov (United States)

    Bortagaray, Manuel Alberto; Ibañez, Claudio Arturo Antonio; Ibañez, Maria Constanza; Ibañez, Juan Carlos

    2016-01-01

    Objective: To determine whether the Noble Bond® Argen® alloy was electrochemically suitable for the manufacturing of prosthetic superstructures over commercially pure titanium (c.p. Ti) implants. Also, the electrolytic corrosion effects over three types of materials used on prosthetic suprastructures that were coupled with titanium implants were analysed: Noble Bond® (Argen®), Argelite 76sf +® (Argen®), and commercially pure titanium. Materials and Methods: 15 samples were studied, consisting in 1 abutment and one c.p. titanium implant each. They were divided into three groups, namely: Control group: five c.p Titanium abutments (B&W®), Test group 1: five Noble Bond® (Argen®) cast abutments and, Test group 2: five Argelite 76sf +® (Argen®) abutments. In order to observe the corrosion effects, the surface topography was imaged using a confocal microscope. Thus, three metric parameters (Sa: Arithmetical mean height of the surface. Sp: Maximum height of peaks. Sv: Maximum height of valleys.), were measured at three different areas: abutment neck, implant neck and implant body. The samples were immersed in artificial saliva for 3 months, after which the procedure was repeated. The metric parameters were compared by statistical analysis. Results: The analysis of the Sa at the level of the implant neck, abutment neck and implant body, showed no statistically significant differences on combining c.p. Ti implants with the three studied alloys. The Sp showed no statistically significant differences between the three alloys. The Sv showed no statistically significant differences between the three alloys. Conclusion: The effects of electrogalvanic corrosion on each of the materials used when they were in contact with c.p. Ti showed no statistically significant differences. PMID:27733875

  14. METHODS OF COMPARATIVE APPRAISAL OF TITANIUM ALLOYS ABILITY TO THERMAL STRENGTHENING AS A RESULT OF HIGH-TEMPERATURE THERMOMECHANICAL PROCESSING

    Directory of Open Access Journals (Sweden)

    V. N. Fedulov

    2011-01-01

    Full Text Available The methods, enabing to produce the comparative appraisal of the titanium alloy ability to harden as a result of high-temperature thermal-mechanical processing depending on temperature and rate of deformation at forging, is developed.

  15. Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

    Institute of Scientific and Technical Information of China (English)

    GENG Duan-yang; ZUO Hong-fu; ZHENG Bai-zhan; XU Tong

    2006-01-01

    By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.

  16. Adhesion enhancement of titanium nitride coating on aluminum casting alloy by intrinsic microstructures

    Science.gov (United States)

    Nguyen, Chuong L.; Preston, Andrew; Tran, Anh T. T.; Dickinson, Michelle; Metson, James B.

    2016-07-01

    Aluminum casting alloys have excellent castability, high strength and good corrosion resistance. However, the presence of silicon in these alloys prevents surface finishing with conventional methods such as anodizing. Hard coating with titanium nitride can provide wear and corrosion resistances, as well as the aesthetic finish. A critical factor for a durable hard coating is its bonding with the underlying substrate. In this study, a titanium nitride layer was coated on LM25 casting alloy and a reference high purity aluminum substrate using Ion Assisted Deposition. Characterization of the coating and the critical interface was carried out by a range of complementing techniques, including SIMS, XPS, TEM, SEM/EDS and nano-indentation. It was observed that the coating on the aluminum alloy is stronger compared to that on the pure aluminum counterpart. Silicon particles in the alloy offers the reinforcement though mechanical interlocking at microscopic level, even with nano-scale height difference. This reinforcement overcomes the adverse effect caused by surface segregation of magnesium in aluminum casting alloys.

  17. Enhancement in mechanical properties of a β-titanium alloy by high-pressure torsion

    Directory of Open Access Journals (Sweden)

    Katarzyna Sharman

    2015-01-01

    Full Text Available Titanium alloys, mainly Ti–6Al–4V, are commonly used in biomedical applications as orthopedic implants. Due to the potential toxic influence of V and Al cations on health, a new alloy composition, Ti–24Nb–4Zr–8Sn, was introduced. However, Ti–24Nb–4Zr–8Sn has a much lower tensile strength by comparison with the Ti–6Al–4V alloy. The aim of this research was to determine whether high-pressure torsion (HPT can be an efficient method for obtaining the desired properties in the case of the Ti–24Nb–4Zr–8Sn β-titanium alloy. This paper presents an analysis of the microstructural and mechanical properties of the Ti–24Nb–4Zr–8Sn alloy processed by HPT with various processing parameters. The obtained microstructures were examined using transmission electron microscopy (TEM. Mechanical properties, such as hardness and tensile strength, were also measured. The study demonstrates that HPT of the Ti–24Nb–4Zr–8Sn alloy leads to a significant reduction of grain size and this grain refinement gives a major improvement in tensile strength and hardness.

  18. Tensile properties of cast titanium alloys: Titanium-6Al-4V ELI and Titanium-5Al-2.5Sn ELI

    Science.gov (United States)

    Billinghurst, E. E., Jr.

    1992-01-01

    This work was performed to determine the tensile properties of cast, hot isostatic pressed (HIP'ed), and annealed titanium alloys, Ti-6Al-4V ELI and Ti-5Al-2.5Sn ELI, that are candidate materials for the space transportation main engine (STME) liquid hydrogen turbopump impeller. Samples of the cast alloys were HIP'ed, annealed, and machined into tensile specimens. The specimens were tested in air at ambient temperature (70 F) and also at -423 F in liquid hydrogen. The Ti-6Al-4V alloy had an average ultimate strength of 129.1 ksi at 70 F and 212.2 ksi at -423 F. The Ti-5Al-2.5Sn alloy had an average ultimate strength of 108.4 ksi at 70 degrees F and 185.0 ksi at -423 F. The ductility, as measured by reduction of area, for the Ti-6Al-4V averaged 15.2 percent at 70 F and 8.7 percent at -423 F, whereas for the Ti-5Al-2.5Sn alloy average reduction of area was 24.6 percent at 70 F and 11.7 percent at -423 F.

  19. Fatigue of titanium alloys in a supersonic-cruise airplane environment

    Science.gov (United States)

    Imig, L. A.

    1976-01-01

    The test programs conducted by several aerospace companies and NASA, summarized in this paper, studied several titanium materials previously identified as having high potential for application to supersonic cruise airplane structures. These studies demonstrate that the temperature (560 K) by itself produced no significant degradation of the materials. However, the fatigue resistance of titanium-alloy structures, in which thermal and loading effects are combined, has been studied insufficiently. The predominant topic for future study of fatigue problems in Mach 3 structures should be the influences of thermal stress particularly, the effects of thermal stress on failure location.

  20. Building cross-platform apps using Titanium, Alloy, and Appcelerator cloud services

    CERN Document Server

    Saunders, Aaron

    2014-01-01

    Skip Objective-C and Java to get your app to market faster, using the skills you already have Building Cross-Platform Apps using Titanium, Alloy, and Appcelerator Cloud Services shows you how to build cross-platform iOS and Android apps without learning Objective-C or Java. With detailed guidance given toward using the Titanium Mobile Platform and Appcelerator Cloud Services, you will quickly develop the skills to build real, native apps- not web apps-using existing HTML, CSS, and JavaScript know-how. This guide takes you step-by-step through the creation of a photo-sharing app that leverages

  1. A low-cost hierarchical nanostructured beta-titanium alloy with high strength

    Science.gov (United States)

    Devaraj, Arun; Joshi, Vineet V.; Srivastava, Ankit; Manandhar, Sandeep; Moxson, Vladimir; Duz, Volodymyr A.; Lavender, Curt

    2016-01-01

    Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission. Working towards this goal we achieved high strength in a low cost β-titanium alloy, Ti–1Al–8V–5Fe (Ti185), by hierarchical nanostructure consisting of homogenous distribution of micron-scale and nanoscale α-phase precipitates within the β-phase matrix. The sequence of phase transformation leading to this hierarchical nanostructure is explored using electron microscopy and atom probe tomography. Our results suggest that the high number density of nanoscale α-phase precipitates in the β-phase matrix is due to ω assisted nucleation of α resulting in high tensile strength, greater than any current commercial titanium alloy. Thus hierarchical nanostructured Ti185 serves as an excellent candidate for replacing costlier titanium alloys and other structural alloys for cost-effective lightweighting applications. PMID:27034109

  2. Additive manufacturing of a high niobium-containing titanium aluminide alloy by selective electron beam melting

    Energy Technology Data Exchange (ETDEWEB)

    Tang, H.P., E-mail: thpfys@126.com [State Key Laboratory of Porous Metal Materials, Northwest Institute for Nonferrous Metal Research, Xi' an 710016 (China); Yang, G.Y.; Jia, W.P.; He, W.W.; Lu, S.L. [State Key Laboratory of Porous Metal Materials, Northwest Institute for Nonferrous Metal Research, Xi' an 710016 (China); Qian, M., E-mail: ma.qian@rmit.edu.au [State Key Laboratory of Porous Metal Materials, Northwest Institute for Nonferrous Metal Research, Xi' an 710016 (China); RMIT University, School of Aerospace, Mechanical and Manufacturing Engineering, Centre for Additive Manufacturing, Melbourne, VIC 3001 (Australia)

    2015-06-11

    Additive manufacturing (AM) offers a radical net-shape manufacturing approach for titanium aluminide alloys but significant challenges still remain. A study has been made of the AM of a high niobium-containing titanium aluminide alloy (Ti–45Al–7Nb–0.3W, in at% throughout the paper) using selective electron beam melting (SEBM). The formation of various types of microstructural defects, including banded structures caused by the vaporization of aluminum, was investigated with respect to different processing parameters. To avoid both micro- and macro-cracks, the use of higher preheating temperatures and an intermediate reheating process (to reheat each solidified layer during SEBM) was assessed in detail. These measures enabled effective release of the thermal stress that developed during SEBM and therefore the avoidance of cracks. In addition, the processing conditions for the production of a fine full lamellar microstructure were identified. As a result, the Ti–45Al–7Nb–0.3W alloy fabricated showed outstanding properties (compression strength: 2750 MPa; strain-to-fracture: 37%). SEBM can be used to fabricate high performance titanium aluminide alloys with appropriate processing parameters and pathways.

  3. Improved diffusion welding and roll welding of titanium alloys

    Science.gov (United States)

    Holko, K. H.

    1973-01-01

    Auto-vacuum cleaning technique was applied to titanium parts prior to welding. This provides oxide-free welding surfaces. Diffusion welding can be accomplished in as little as five minutes of hot pressing. Roll welding can be accomplished with only ten percent deformation.

  4. Surface characterization and cytotoxicity analysis of plasma sprayed coatings on titanium alloys.

    Science.gov (United States)

    Rahman, Zia Ur; Shabib, Ishraq; Haider, Waseem

    2016-10-01

    In the realm of biomaterials, metallic materials are widely used for load bearing joints due to their superior mechanical properties. Despite the necessity for long term metallic implants, there are limitations to their prolonged use. Naturally, oxides of titanium have low solubilities and form passive oxide film spontaneously. However, some inclusion and discontinuity spots in oxide film make implant to adopt the decisive nature. These defects heighten the dissolution of metal ions from the implant surface, which results in diminishing bio-integration of titanium implant. To increase the long-term metallic implant stability, surface modifications of titanium alloys are being carried out. In the present study, biomimetic coatings of plasma sprayed hydroxyapatite and titanium were applied to the surface of commercially pure titanium and Ti6Al4V. Surface morphology and surface chemistry were studied using scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. Cyclic potentiodynamic polarization and electrochemical impedance spectroscopy were carried out in order to study their electrochemical behavior. Moreover, cytotoxicity analysis was conducted for osteoblast cells by performing MTS assay. It is concluded that both hydroxyapatite and titanium coatings enhance corrosion resistance and improve cytocompatibility.

  5. Spectrophotometric determination of titanium with tannin and thioglycollic acid and its application to titanium-treated steels and ferrous and non-ferrous alloys.

    Science.gov (United States)

    Banerjee, S

    1986-04-01

    A sensitive spectrophotometric method for the determination of titanium by formation of its complex with tannin and thioglycollic acid at pH 4 has been developed. The intense yellow colour is measured at 400 nm and the system obeys Beer's law over the range 0.2-5 ppm titanium in the solution measured. The method is applicable to titanium-treated steels, stainless steels, permanent magnet alloys and duralumin alloys. The interference of Co, Ni, Cr, Mn, V, Mo and W can be eliminated by prior separation of titanium by controlled addition of cupferron in the presence of thioglycollic acid (TGA). Copper can be quantitatively separated by precipitation with TGA and determined complexometrically with EDTA, with PAN as indicator. Niobium interferes even in traces.

  6. Surface hardening of titanium alloys by oxygen-diffusion-permeation

    Institute of Scientific and Technical Information of China (English)

    马红岩; 王茂才; 张松; 辛公春; 魏政

    2003-01-01

    The surface oxygen-diffusion-permeation behaviors of Ti based alloys were investigated. MEF4A opticalmicroscopy and HMV-2000 micro-hardness tester were employed to characterize the microstructure and micro-hard-ness of the oxygen-permeated alloys. The results show that the micro-hardness of Ti based alloys are sharply en-hanced by the permeation of oxygen. The microstructure and micro-hardness of oxygen-permeated layer are stronglyrelated to the oxygen-diffusion-permeation techniques. The solid solution of oxygen in α phase can improve thetransformation temperature from α phase to β phase and enlarge the region of α phase so as to improve the micro-hardness of surface layer. Therefore, surface oxygen-diffusion-permeation would be a feasible method to reinforce Tibased alloys based on the solid solution of oxygen in α-Ti. At last, a diffusion-solution model was put forward.

  7. Influence of Tensile Stresses on α+β – Titanium Alloy VT22 Corrosion Resistance in Marine Environment

    Directory of Open Access Journals (Sweden)

    Yu. A. Puchkov

    2015-01-01

    Full Text Available Tensile stresses and hydrogen render strong influence on the titanic alloys propensity for delayed fracture. The protective film serves аs a barrier for penetration in hydrogen alloy. Therefore to study the stress effect on its structure and protective properties is of significant interest.The aim of this work is to research the tensile stress influence on the passivation, indexes of corrosion, protective film structure and reveal reasons for promoting hydrogenation and emerging propensity for delayed fracture of titanium alloy VТ22 in the marine air atmosphere.The fulfillеd research has shown that:- there is а tendency to reduce the passivation abilities of the alloy VТ22 in synthetic marine water (3 % solution of NaCl with increasing tensile stresses up to 1170 МPа, namely to reduce the potential of free corrosion and the rate of its сhange, thus the alloy remains absolutely (rather resistant;- the protective film consists of a titanium hydroxide layer under which there is the titanium oxide layer adjoining to the alloy, basically providing the corrosion protection.- the factors providing hydrogenation of titanium alloys and formation in their surface zone fragile hydrides, causing the appearing propensity for delayed fracture, alongside with tensile stresses are:- substances promoting chemisorbtion of hydrogen available in the alloy and on its surface;- the cathodic polarization caused by the coupling;- the presence of the structural defects promoting the formation of pitting and local аcidifying of the environment surrounding the alloy.

  8. Behavior of incorporated nitrogen in plasma-nitrided silicon oxide formed by chemical vapor deposition

    Science.gov (United States)

    Shinoda, Nao; Itokawa, Hiroshi; Fujitsuka, Ryota; Sekine, Katsuyuki; Onoue, Seiji; Tonotani, Junichi

    2016-04-01

    The behavior of nitrogen (N) atoms in plasma-nitrided silicon oxide (SiO2) formed by chemical vapor deposition (CVD) was characterized by physical analysis and from electrical properties. The changes in the chemical bonding and distribution of N in plasma-nitrided SiO2 were investigated for different subsequent processes. N-Si3, N-Si2O, and N2 are formed in a SiO2 film by plasma nitridation. N2 molecules diffuse out during annealing at temperatures higher than 900 °C. NH species are generated from N2 molecules and H in the SiO2 film with subsequent oxide deposition using O3 as an oxidant. The capacitance-voltage (C-V) curves of metal-oxide-semiconductor (MOS) capacitors are obtained. The negative shift of the C-V curve is caused by the increase in the density of positive fix charge traps in CVD-SiO2 induced by plasma nitridation. The C-V curve of plasma-nitrided SiO2 subjected to annealing shifts to the positive direction and that subjected to the subsequent oxide deposition shifts markedly to the negative direction. It is clarified that the density of positive charge fixed traps in plasma-nitrided SiO2 films decrease because the amount of N2 molecules is decreased by annealing, and that the density of traps increases because NH species are generated and move to the interface between SiO2 and the Si substrate with the subsequent oxide deposition.

  9. Effect of Indium Content on the Microstructure, Mechanical Properties and Corrosion Behavior of Titanium Alloys

    Directory of Open Access Journals (Sweden)

    Mi-Kyung Han

    2015-05-01

    Full Text Available Ti-xIn (x = 0, 5, 10, 15 and 20 wt% alloys were prepared to investigate the effect of indium on the microstructure, mechanical properties, and corrosion behavior of titanium with the aim of understanding the relationship between phase/microstructure and various properties of Ti-xIn alloys. The Ti-xIn alloys exhibited a lamellar α-Ti structure at an indium content of up to 20 wt%. High-resolution TEM images of the Ti-xIn alloys revealed that all the systems contained a fine, acicular martensitic phase, which showed compositional fluctuations at the nanoscopic level. The mechanical properties and corrosion behavior of Ti-xIn alloys were sensitive to the indium content. The Vickers hardness increased as the In content increased because of solid solution strengthening. The Ti-xIn alloys exhibited superior oxidation resistance compared to commercially pure Ti (cp-Ti. Electrochemical results showed that the Ti-xIn alloys exhibited a similar corrosion resistance to cp-Ti. Among the alloys tested, Ti-10In showed a potential for use as a dental material.

  10. 钛合金的研究进展与应用现状%Review on the Research Progress and Application of Titanium Alloys

    Institute of Scientific and Technical Information of China (English)

    彭昂; 毛振东

    2012-01-01

    This paper reviews the research progress of titanium alloys in China and other countries, especially aerospace titanium alloys, marine titanium alloys, and low-cost titanium alloys. It also briefly summaries the application of titanium alloys in the aerospace, naval ship and automobile and chemical industry, and gives the development trends of titanium alloys.%综述了国内外钛合金的研究进展和应用现状,具体介绍了航空用钛合金、船用钛合金及低成本钛合金的研究进展,简要概述了钛合金在航空航天、舰船及汽车和化工行业的应用现状,并对我国钛行业的发展进行了展望。

  11. Effects of pH on the electrochemical behaviour of titanium alloys for implant applications.

    Science.gov (United States)

    Souza, Maria E P; Lima, Lonetá; Lima, Carmo R P; Zavaglia, Cecília A C; Freire, Célia M A

    2009-02-01

    The electrochemical behaviour of two commercial titanium alloys Ti-6Al-4 V (ASTM F136) and Ti-13Nb-13Zr (ASTM F1713) was investigated in Ringer physiological solution at two pH values (5.5 and 7.0). The corrosion properties were examined by using electrochemical techniques: Potentiodynamic anodic polarization, cyclic polarization and electrochemical impedance spectroscopy (EIS). The electrochemical corrosion properties of both alloys at different conditions were measured in terms of corrosion potential (E (corr)), corrosion current density (i (corr)) and passivation current density (i (pass)). Equivalent electrical circuits were used to modulate EIS data, in order to characterize alloys surface and better understanding the pH effect on the interface alloy/solution.

  12. Structure of (alpha + beta)-titanium alloys subjected to laser heating

    Energy Technology Data Exchange (ETDEWEB)

    Ivasishin, O.M.; Markovskii, P.E.; Svechnikov, V.L.; Krasavin, A.P.; Oshkaderov, S.P. (Institut Metallofiziki, Kiev (Ukrainian SSR))

    1990-02-01

    The structure of surface layers formed in the industrial (alpha + beta)-titanium alloys subjected to pulse-laser treatment with energy density of 5 J/mm is examined. It is shown that as the temperature in the alloys increases, the following sequence of processes occurs: nondiffusion alpha-to-beta transformation; the diffusion redistribution of alloying components in the chemically inhomogeneous beta-phase; and melting and homogenization of the melt. The effect of the initial state of alloys and elastic stresses on the final structure is examined. It is established that the laser treatment with melting, combined with subsequent annealing in the (alpha + beta) region, makes it possible to create the dispersed high-strength state in the surface layer. 11 refs.

  13. Microstructure evolution model based on deformation mechanism of titanium alloy in hot forming

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-li; LI Miao-quan

    2005-01-01

    The microstructure evolution in hot forming will affect the mechanical properties of the formed product.However, the microstructure is sensitive to the process variables in deformation process of metals and alloys. A microstructure evolution model of a titanium alloy in hot forming, which included dislocation density rate and primary α phase grain size, was presented according to the deformation mechanism and driving forces, in which the effect of the dislocation density rate on the grain growth was studied firstly. Applying the model to the high temperature deformation process of a TC6 alloy with deformation temperature of 1 133 - 1 223 K, strain rate of 0.01 -50 s-1 and height reduction of 30%, 40% and 50%, the material constants in the present model were calculated by the genetic algorithm(GA) based objective optimization techniques. The calculated results of a TC6 alloy are in good agreement with the experimental ones.

  14. A yttrium-containing high-temperature titanium alloy additively manufactured by selective electron beam melting

    Institute of Scientific and Technical Information of China (English)

    逯圣路; 汤慧萍; 马前; 洪权; 曾立英

    2015-01-01

    A yttrium-containing high-temperature titanium alloy (Ti-6Al-2.7Sn-4Zr-0.4Mo-0.45Si-0.1Y, mass fraction, %) has been additively manufactured using selective electron beam melting (SEBM). The resulting microstructure and textures were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and electron backscattered diffraction (EBSD) and compared with the conventionally manufactured form. A notable distinct difference of microstructures is that additive manufacturing by SEBM enables homogeneous precipitation of fine Y2O3 dispersoids in the size range of 50−250 nm throughout the as-fabricated alloy, despite the presence of just trace levels of oxygen (7×10−4, mass fraction) and yttrium (10−3, mass fraction) in the alloy. In contrast, the conventionally manufactured alloy shows inhomogeneously distributed coarse Y2O3 precipitates, including cracked or debonded Y2O3 particles.

  15. A comparative study of the cytotoxicity and corrosion resistance of nickel-titanium and titanium-niobium shape memory alloys.

    Science.gov (United States)

    McMahon, Rebecca E; Ma, Ji; Verkhoturov, Stanislav V; Munoz-Pinto, Dany; Karaman, Ibrahim; Rubitschek, Felix; Maier, Hans J; Hahn, Mariah S

    2012-07-01

    Nickel-titanium (NiTi) shape memory alloys (SMAs) are commonly used in a range of biomedical applications. However, concerns exist regarding their use in certain biomedical scenarios due to the known toxicity of Ni and conflicting reports of NiTi corrosion resistance, particularly under dynamic loading. Titanium-niobium (TiNb) SMAs have recently been proposed as an alternative to NiTi SMAs due to the biocompatibility of both constituents, the ability of both Ti and Nb to form protective surface oxides, and their superior workability. However, several properties critical to the use of TiNb SMAs in biomedical applications have not been systematically explored in comparison with NiTi SMAs. These properties include cytocompatibility, corrosion resistance, and alterations in alloy surface composition in response to prolonged exposure to physiological solutions. Therefore, the goal of the present work was to comparatively investigate these aspects of NiTi (49.2 at.% Ti) and TiNb (26 at.% Nb) SMAs. The results from the current studies indicate that TiNb SMAs are less cytotoxic than NiTi SMAs, at least under static culture conditions. This increased TiNb cytocompatibility was correlated with reduced ion release as well as with increased corrosion resistance according to potentio-dynamic tests. Measurements of the surface composition of samples exposed to cell culture medium further supported the reduced ion release observed from TiNb relative to NiTi SMAs. Alloy composition depth profiles also suggested the formation of calcium phosphate deposits within the surface oxide layers of medium-exposed NiTi but not of TiNb. Collectively, the present results indicate that TiNb SMAs may be promising alternatives to NiTi for certain biomedical applications. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. Aging response of coarse- and fine-grained {beta} titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ivasishin, O.M. [G.V.Kurdyumov Institute for Metal Physics, National Academy of Sciences, 03142 Kyiv (Ukraine)]. E-mail: ivas@imp.kiev.ua; Markovsky, P.E. [G.V.Kurdyumov Institute for Metal Physics, National Academy of Sciences, 03142 Kyiv (Ukraine); Semiatin, S.L. [Air Force Research Laboratory, AFRL/ML, Wright-Patterson Air Force Base, OH 45433-7817 (United States); Ward, C.H. [Air Force Research Laboratory, AFRL/ML, Wright-Patterson Air Force Base, OH 45433-7817 (United States)

    2005-09-25

    The effect of heating rate to aging temperature and {beta} grain size on the aging behavior of three metastable {beta} titanium alloys, TIMETAL-LCB, VT22 and Ti-15-3-3-3 ('Ti-15-3'), was established using in situ resistivity measurements, X-ray diffraction, optical microscopy, SEM, TEM and STEM characterization. The results revealed the alloys could be divided into two classes based on their aging behavior. TIMETAL-LCB and VT-22 formed fine plate-like {alpha} at slow heating rates to the aging temperature. This behavior was determined to be due to the precipitation of isothermal {omega} at low temperatures, which serves as nucleation sites for {alpha}. The slow heating rate yielded the best balance of strength and ductility, particularly in alloys with a fine ({approx}10 {mu}m) {beta} grain size. At high heating rates, the formation of isothermal {omega} was avoided, leading to coarse, plate-like {alpha} microstructures with less desirable properties. Ti-15-3, on the other hand, exhibited {beta} phase separation during isothermal aging rather than isothermal {omega} formation. Much slower cooling rates were required to form fine {alpha} laths in Ti-15-3 compared to the other two alloys. The importance of specifying heating rate and aging temperature for the industrial heat treatment of {beta} titanium alloys was thus established.

  17. Hidroxyapatite Coating on CoCrMo Alloy Titanium Nitride Coated Using Biomimetic Method

    Science.gov (United States)

    Charlena; Sukaryo, S. G.; Fajar, M.

    2016-11-01

    Bone implants is a way to cure broken bones which is being developed. The implants can be made of metals, ceramics and polymers. Metallic materials commonly used are titanium (Ti), stainless steel, and metal alloys. This study used Co-based alloys, i.e. CoCrMo coated with titanium nitride (TiN) which was then coated on hidroxyapatite (HAp). The HAp coating on the surface of CoCrMo alloy was done by biomimetic methods, first by soaking the metal alloys in simulated body fluid (SBF) solution for 18, 24, and 36 hours. The immersion in the SBF solution produced white coat on the surface of the metal alloy. The layers formed were analyzed by scanning electron microscope (SEM) and characterized by x-ray diffractometer (XRD). Based on the SEM results of 36 hours treatment, the morphology of apatite crystal formed fine grains. According to XRD result, there were HAp peaks at angles 2θ 31.86, 32.25, dan 39.48. However, there were also CaCO3 peaks at angles 2θ 29.46, 36.04, and 46.79. It indicated the pure HAp is not yet formed.

  18. Recrystallization behavior of Ti40 burn-resistant titanium alloy during hot working process

    Institute of Scientific and Technical Information of China (English)

    Yun-jin Lai; She-wei Xin; Ping-xiang Zhang; Yong-qing Zhao; Fan-jiao Ma; Xiang-hong Liu; Yong Feng

    2016-01-01

    The recrystallization behavior of deformed Ti40 alloy during a heat-treatment process was studied using electron backscatter dif-fraction and optical microscopy. The results show that the microstructural evolution of Ti40 alloy is controlled by the growth behavior of grain-boundary small grains during the heating process. These small grains at the grain boundaries mostly originate during the forging proc-ess because of the alloy’s inhomogeneous deformation. During forging, the deformation first occurs in the grain-boundary region. New small recrystallized grains are separated from the parent grains when the orientation between deformation zones and parent grains exceeds a certain threshold. During the heating process, the growth of these small recrystallized grains results in a uniform grain size and a decrease in the av-erage grain size. The special recrystallization behavior of Ti40 alloy is mainly a consequence of the alloy’s highβ-stabilized elemental con-tent and high solution strength of theβ-grains, which partially explains the poor hot working ability of Ti-V-Cr-type burn-resistant titanium alloys. Notably, this study on Ti40 burn-resistant titanium alloy yields important information related to the optimization of the microstruc-tures and mechanical properties.

  19. The Microstructure and Capacitance Characterizations of Anodic Titanium Based Alloy Oxide Nanotube

    Directory of Open Access Journals (Sweden)

    Po Chun Chen

    2013-01-01

    Full Text Available This paper presents a simple anodization process to fabricate ordered nanotubes (NTs of titanium and its alloys (Ti-Mo and Ti-Ta. TiO2, MoO3, and Ta2O5 are high dielectric constant materials for ultracapacitor application. The anodic titanium oxide contains a compact layer on the NT film and a barrier layer under the NT film. However, the microstructure of oxide films formed by anodic Ti-Mo and Ti-Ta alloys contains six layers, including a continuous compact layer, a continuous partial porous layer, a porous layer, a net layer, an ordering NT film, and an ordering compact barrier layer. There are extra layers, which are a partial porous layer and a porous layer, not presented on the TiO2 NT film. In this paper, we fabricated very high surface area ordered nanotubes from Ti and its alloys. Based on the differences of alloys elements and compositions, we investigated and calculated the specific capacitance of these alloys oxide nanotubes.

  20. [Effect of titanium nitride coating on bacterial corrosion resistance of dental Co-Cr alloy].

    Science.gov (United States)

    Zou, Jie; Chen, Jie; Hu, Bin

    2010-04-01

    To study the influence of titanium nitride(TiN) coating on bacterial corrosion resistance of clinically used Co-Cr alloy. The Co-Cr alloy commonly used for casting metal full crown was casted with specimen 10mm x 10mm x 3mm in size. The specimen was coated with a thickness of 2.5 microm TiN coating on the surface by multi-arc physical vapor deposition. Then the specimen before and after coating titanium nitride were exposed to TSB media with S.mutans or Actinomyces viscosus,while pure media,as control.After inoculated for 24 hours, the Tafel polarization curves of the specimen were measured by electrochemical station. From the Tafel polarization curves, the non-coated Co-Cr alloy showed that corrosion potential moved to the negative way in presence of oral bacteria,and passivation interval got shorter.While the polarization curves of the specimen after coating TiN changed slightly in presence of oral microorganism. The TiN significantly weakened the corrosion action of bacteria on the alloy. These results demonstrate that the TiN coating with better tolerance to the bacterial action can improve bacterial corrosion resistance of Co-Cr alloy.Supported by Research Fund of Science and Technology Commission of Shanghai Municipality(Grant No.08DZ2271100) and Shanghai Leading Academic Discipline Project (Grant No. S30206).

  1. The Solidification Velocity of Undercooled Nickel and Titanium Alloys with Dilute Solute

    Science.gov (United States)

    Algoso, Paul R.; Altgilbers, A. S.; Hofmeister, William H.; Bayuzick, Robert J.

    2003-01-01

    The study of solidification velocity is important for two reasons. First, understanding the manner in which the degree of undercooling of the liquid and solidification velocity affect the microstructure of the solid is fundamental. Second, there is disagreement between theoretical predictions of the relationship between undercooling and solidification velocity and experimental results. Thus, the objective of this research is to accurately and systematically quantify the solidification velocity as a function of undercooling for dilute nickel-and titanium-based alloys. The alloys chosen for study cover a wide range of equilibrium partition coefficients, and the results are compared to current theory.

  2. High strength microstructural forms developed in titanium alloys by rapid heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Ivasishin, O.M. [Institute of Metal Physics, Kiev (Ukraine)

    2001-09-01

    It is shown that rapid heat treatment of alpha+beta and beta titanium alloys, which includes rapid heating of alloys with initial equiaxed microstructure into single-phase beta field is able to produce microstructural forms in which high strength can be well balanced with other mechanical properties. Main advantage of rapid heating approach comes from the possibility to extend the level of ''useful'' strength. Desirably high strength is provided by intragranular morphology and microchemistry while beta-grain refinement permits a reliability of such high strength conditions. (orig.)

  3. Loss of coherency of the alpha/beta interface boundary in titanium alloys during deformation

    Science.gov (United States)

    Zherebtsov, Sergey; Salishchev, Gennady; Semiatin, S. Lee

    2010-12-01

    The loss of coherency of interphase boundaries in two-phase titanium alloys during deformation was analyzed. The energy of the undeformed interphase boundary was first determined by means of the van der Merwe model for stepped interfaces. The subsequent loss of coherency was ascribed to the increase of interphase energy due to absorption of lattice dislocations and was quantified by a relation similar to the Read-Shockley equation for low-angle boundaries in single-phase alloys. It was found that interphase boundaries lose their coherency by a strain of approximately 0.5 at T = 800°C.

  4. Microstructural Characterization Of Quenched And Plastically Deformed Two-Phase α+β Titanium Alloys

    Directory of Open Access Journals (Sweden)

    Motyka M.

    2015-09-01

    Full Text Available Development of microstructure in two-phase α+β titanium alloys is realized by thermomechanical processing – sequence of heat treatment and plastic working operations. Analysis of achieved results indicates that hot plastic deformation – depending on deformation degree – causes significant elongation of α phase grains. Following heat treatment and plastic deformation processes lead to their fragmentation and spheroidization. Characterization of microstructure morphology changes during thermomechanical processing of quenched Ti-6Al-4V and Ti-6Al-2Mo-2Cr alloys is presented in the paper. The effect of martensitic phase α’(α” on microstructure development in plastic deformation process was confirmed.

  5. Study of the structure of passivated vanadium-titanium alloys and their semiconductor properties.

    Science.gov (United States)

    Bachmann, T; Vonau, W; John, P

    2002-10-01

    The possibility of investigating the photocurrent behavior and structure of electrochemically prepared passive films on metallic titanium and on binary vanadium-titanium alloys has been demonstrated. The semiconductor properties were characterized by measuring the dependence of the photocurrent on the wavelength of the incident light and on the electrode potential. The results showed the oxide layers to be n-type semiconductors with a bandgap between 2.6 and 3.3 eV and a flatband potential of approximately -300 to +400 mV (relative to the SCE). The results were interpreted in terms of the corrosion characteristics of the materials. XPS measurements on pure vanadium and some alloys are presented. Several properties were used to characterize the passive surface of these materials. The V(2)O(5) and TiO(2) content decreases with increasing depth.

  6. Titanium alloys as fixation device material for cranioplasty and its safety in electroconvulsive therapy.

    Science.gov (United States)

    Kaido, Takanobu; Noda, Takamasa; Otsuki, Taisuke; Kaneko, Yuu; Takahashi, Akio; Nakai, Tetsuji; Nabatame, Maki; Tani, Mariko

    2011-03-01

    Here, we report the case of a patient successfully treated by a series of electroconvulsive therapy (ECT) who had implanted skull fixation devices made of titanium alloy. The patient was a 57-year-old man with bipolar I disorder. He was hospitalized for the treatment of manic symptoms of bipolar I disorder with pharmacotherapy and ECT. He sustained a fall and hit his head hard on the ground. Acute subdural hematoma developed, and emergent surgery to remove the hematoma was carried out. Cranioplasty was performed using fixation devices made of titanium alloy (Ti 6Al-4V). In order to control his manic symptoms, a series of ECT was readministered from 1 week after surgery. No adverse effects occurred. Devices must be investigated and chosen very carefully for permanent implantation, especially in patients during a course of ECT.

  7. Mechanical behaviour of pressed and sintered titanium alloys obtained from prealloyed and blended elemental powders.

    Science.gov (United States)

    Bolzoni, L; Esteban, P G; Ruiz-Navas, E M; Gordo, E

    2012-10-01

    The applicability of irregular prealloyed Ti-6Al-4V powder for the fabrication of titanium products by pressing and sintering and its employment as a master alloy to obtain the Ti-3Al-2.5V alloy was studied. To this end, the starting powders were characterised by dilatometry, differential thermal analysis and XRD. Green samples were obtained by cold uniaxial pressing, and the evolution of the microstructure over the sintering temperature range 900-1400°C was studied. The variation of the final density and mechanical properties with the sintering temperature was considered. Based on the study carried out, it can be stated that more reliable powders are needed to open the titanium market to new applications. A relative density of 95% and diverse microstructural features and mechanical properties equivalent to those of biomedical devices can be obtained by the pressing and sintering route.

  8. Dynamic Analysis of the Titanium Alloy Plate under Thermal-acoustic Loadings

    Directory of Open Access Journals (Sweden)

    Zou Xuefeng

    2015-01-01

    Full Text Available Hypersonic vehicles structures suffer complex combined loadings generally. For the thin-walled structures and thermal protection systems of the aircraft, high temperature and intensity acoustic loadings are the significant factors that leading to their break. The object of this paper is typical simply supported titanium alloy plate, the finite element method was adopted to calculate the critical thermal buckling temperature the ordinal coupling method and Newmark method were adopted to calculate the thermal-acoustic dynamic response. Based on the FEM analysis, the power spectrum densities (PSD of center point was presented. Research results show that the thermal buckling of the typical simply supported titanium alloy plate occurs easily because of the low critical thermal buckling temperature, dynamic response of the thermal buckled plate suffering acoustic loads performs strong nonlinear characteristics and complex forms of exercise.

  9. Finishing of additively manufactured titanium alloy by shape adaptive grinding (SAG)

    Science.gov (United States)

    Beaucamp, Anthony T.; Namba, Yoshiharu; Charlton, Phillip; Jain, Samyak; Graziano, Arthur A.

    2015-06-01

    In recent years, rapid prototyping of titanium alloy components for medical and aeronautics application has become viable thanks to advances in technologies such as electron beam melting (EBM) and selective laser sintering (SLS). However, for many applications the high surface roughness generated by additive manufacturing techniques demands a post-finishing operation to improve the surface quality prior to usage. In this paper, the novel shape adaptive grinding process has been applied to finishing titanium alloy (Ti6Al4V) additively manufactured by EBM and SLS. It is shown that the micro-structured surface layer resulting from the melting process can be removed, and the surface can then be smoothed down to less than 10 nm Ra (starting from 4-5 μm Ra) using only three different diamond grit sizes. This paper also demonstrates application of the technology to freeform shapes, and documents the dimensional accuracy of finished artifacts.

  10. Hydroxyapatite coating by biomimetic method on titanium alloy using concentrated SBF

    Indian Academy of Sciences (India)

    S Bharati; M K Sinha; D Basu

    2005-10-01

    This article reports a biomimetic approach for coating hydroxyapatite on titanium alloy at ambient temperature. In the present study, coating was obtained by soaking the substrate in a 5 times concentrated simulated body fluid (5XSBF) solution for different periods of time with and without the use of CaO–SiO2 based glass as a possible source of nucleating agent of apatite formation. Optical microscopic and SEM observations revealed the deposition of Ca–P layer on the titanium alloy by both the methods. Thickness of coating was found to increase with the increase in immersion time. The use of glass did not help the formation of apatite nuclei on the substrate and the coating obtained by this method was also not uniform. EDX analysis indicated that the coating consisted of Ca–P based apatite globules, mostly in agglomerated form, and its crystallinity was poor as revealed by XRD.

  11. Structural investigation of the zirconium-titanium based amino trimethylene phosphonate hybrid coating on aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Shuanghong WANG; Changsheng LIU; Fengjun SHAN

    2009-01-01

    A zirconium-titanium based amino trimethylene phosphonate hybrid coating on AA6061 aluminum alloys was formed by dipping in a fluorotitanate/zirconate acid and amino trimethylene phosphonic acid (ATMP) solution for improving the lacquer adhesion and corrosion resistance as a substitute of chromate coatings. The morphol-ogy and structure of the hybrid coating were studied by means of scanning electror microscopy (SEM) and atomic force microscopy (AFM). The surface compositior and structure characteristics were also investigated by means of X-ray photoelectron spectroscopy (XPS) and Fourier transformation infra-red spectroscopy (FTIR). The results of SEM and AFM show that the hybrid coating present piece particle distrib-ution which is much denser than that of the zirconium-titanium coating. The results of XPS and FTIR indicate that the hybrid coating is a hybrid composite structure composed of both the zirconium-titanium and amino trimethylene phosphonate coat-ings.

  12. Additive manufacturing of titanium alloys state of the art, challenges and opportunities

    CERN Document Server

    Dutta, Bhaskar

    2016-01-01

    Additive Manufacturing of Titanium Alloys: State of the Art, Challenges and Opportunities provides alternative methods to the conventional approach for the fabrication of the majority of titanium components produced via the cast and wrought technique, a process which involves a considerable amount of expensive machining. In contrast, the Additive Manufacturing (AM) approach allows very close to final part configuration to be directly fabricated minimizing machining cost, while achieving mechanical properties at least at cast and wrought levels. In addition, the book offers the benefit of significant savings through better material utilization for parts with high buy-to-fly ratios (ratio of initial stock mass to final part mass before and after manufacturing). As titanium additive manufacturing has attracted considerable attention from both academicians and technologists, and has already led to many applications in aerospace and terrestrial systems, as well as in the medical industry, this book explores the un...

  13. Tribological and Impact Fatigue Behaviors of Pure Titanium Treated by Plasma Ni Alloying

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenxia; HE Zhiyong; WANG Yingqin; LIU Xiaoping; TANG Bin

    2012-01-01

    Ni modified layer is prepared on the surface of pure titanium by plasma surface alloying technique.Surface appearance,micro-structure morphology,composition distribution,phase structure and microhardness of Ni modified layer are analyzed.Tribological performance and fatigue behaviors of Ni modified layer of pure titanium are observed using Pin-on-disc tribometer and repeated impact test.The results indicate that the surface mean Ni concentration of Ni modified layer is nearly 18% which is composed of TiNi,Ti2Ni and Ti phase.The maximum surface microhardness of Ni modified layer is approximately 580 HV which is almost two-fold of the hardness of the substrate.The wear resistance of Ni modified layer is improved obviously.The wear mechanism of Ni modified layer shows slight abrasion wearing,while pure titanium is abrasion and adhesion wearing.Ni modified layer presents better impact fatigue strength.

  14. The use of titanium alloys for dynamic risers: a literature review

    Energy Technology Data Exchange (ETDEWEB)

    Torster, F.; Kocak, M.; Santos, J.F. dos [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung; Hutt, G. [Stolt Comex Seaway Ltd., Aberdeen, (Scotland)

    1997-12-31

    The main topic of this short literature review is to describe the material related aspects concerning the production and purpose of flexible titanium risers for offshore oil and gas production. Metallurgy and alloying of titanium are briefly introduced. The review concentrates on the materials properties that are relevant for the intended use in marine environment. The focus is put on {alpha}+{beta} Ti-alloys, because earlier investigations have shown that this alloy family is the most suitable one for this purpose. Further topics which are taken into account are welding processes for titanium, weld properties and aspects of the associated weld defects as well. This literature review has been carried out at GKSS-Forschungszentrum Geesthacht GmbH within the framework of the project `Titanium Risers for Deepwater Developments (contract nr. OG/175/95), supported by the THERMIE-JOULE Programme of the European Commission. The project consortium is formed by Stolt Comex Seaway Ltd. (UK), Seaflex AS (Norway) and GKSS (Germany). (orig.) [Deutsch] Die vorliegende kurze Literaturrecherche befasst sich vorrangig mit den materialbezogenen Aspekten der Produktion und des Einsatzes von flexiblen `Risern` aus Titanlegierungen fuer die Oel- und Gasfoerderung auf See. Die Metallurgie und das Legieren von Titan werden kurz vorgestellt. Die Recherche konzentriert sich im weiteren auf die Materialeigenschaften, die fuer den vorgesehenen Einsatz in mariner Umgebung von besonderer Bedeutung sind. In erster Linie wird dabei auf {alpha}+{beta}-Titanlegierungen eingegangen, da vorausgegangene Untersuchungen gezeigt haben, dass diese Legierungsfamilie die guenstigsten Eigenschaften fuer das vorgesehene Einsatzgebiet aufweist. Im weiteren werden die Schweissprozesse, die bei Titanlegierungen eingesetzt werden, vorgestellt und die Eigenschaften und moeglichen Schweissfehler der hergestellten Schweissverbindungen gegenuebergestellt. Diese Literaturrecherche wurde im GKSS-Forschungszentrum im

  15. Development of new ferritic alloys reinforced by nano titanium nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Mathon, M.H., E-mail: marie-helene.mathon@cea.fr [Laboratoire Léon Brillouin, CEA-CNRS, CEA/Saclay, 91191 Gif-sur-Yvette (France); Perrut, M., E-mail: mikael.perrut@onera.fr [Laboratoire Léon Brillouin, CEA-CNRS, CEA/Saclay, 91191 Gif-sur-Yvette (France); Poirier, L., E-mail: poirier@nitruvid.com [Bodycote France and Belgium, 9 r Jean Poulmarch, 95100 Argenteuil (France); Ratti, M., E-mail: mathieu.ratti@snecma.fr [CEA, DEN, Service de Recherches Métallurgiques Appliquées, F91191 Gif-sur-Yvette (France); Hervé, N., E-mail: nicolas.herve@cea.fr [CEA, DRT, LITEN, F38054 Grenoble (France); Carlan, Y. de, E-mail: yann.decarlan@cea.fr [CEA, DEN, Service de Recherches Métallurgiques Appliquées, F91191 Gif-sur-Yvette (France)

    2015-01-15

    Nano-reinforced steels are considered for future nuclear reactors or for application at high temperature like the heat exchangers tubes or plates. Oxide Dispersion Strengthened (ODS) alloys are the most known of the nano-reinforced alloys. They exhibit high creep strength as well as high resistance to radiation damage. This article deals with the development of new nano reinforced alloys called Nitride Dispersed Strengthened (NDS). Those are also considered for nuclear applications and could exhibit higher ductility with a simplest fabrication way. Two main fabrication routes were studied: the co-milling of Fe–18Cr1W0.008N and TiH{sub 2} powders and the plasma nitration at low temperature of a Fe–18Cr1W0.8Ti powder. The materials were studied mainly by Small Angle Neutron Scattering. The feasibility of the reinforcement by nano-nitride particles is demonstrated. The final size of the nitrides can be similar (few nanometers) to the nano-oxides observed in ODS alloys. The mechanical properties of the new NDS show an amazing ductility at high temperature for a nano-reinforced alloy.

  16. [Biologic age as a criterion for work evaluation (exemplified by titanium alloys production)].

    Science.gov (United States)

    Afanas'eva, R F; Prokopenko, L V

    2009-01-01

    The article deals with results of studies concerning biologic age of workers (males) under occupational hazards of titanium alloys (jeopardy classes 3.3, 3.4.4) in Verkhne-Saldinsky metallurgic production association. Based on mathematic statistic analysis, the authors worked out an equation of multiple regression for ageing pace to forecast the ageing with consideration of age, length of service, occupation. The authors determined occupational groups characterized by premature ageing and increased risk of health disorders.

  17. Experimental and simulation study on the microstructure of TA15 titanium alloy laser beam welded joints

    Science.gov (United States)

    Zhan, Xiaohong; Peng, Qingyu; Wei, Yanhong; Ou, Wenmin

    2017-09-01

    Laser beam welding technique offers obvious advantages over other fusion welding processes in terms of joining titanium alloy. The microstructure of welded seam and heat affected zone resulted from diverse welding speeds and laser powers were investigated after simulating welding heat treatment. The analysis of the thermal transport properties successfully explained the morphology. Optimal process parameters were obtained. The simulation results were consistent with the corresponding experimental observations.

  18. Analyses of heterogeneous deformation and subsurface fatigue crack generation in alpha titanium alloy at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Umezawa, Osamu [Department of Mechanical Engineering and Materials Science, Yokohama National University 79-5 Tokiwadai, Hodogaya, Yokohama, 240-8501 (Japan); Morita, Motoaki [Department of Mechanical Engineering and Materials Science, Yokohama National University 79-5 Tokiwadai, Hodogaya, Yokohama, 240-8501, Japan and Now Tokyo University of Marine Science and Technology, Koto-ku, Tokyo 135-8533 (Japan); Yuasa, Takayuki [Department of Mechanical Engineering and Materials Science, Yokohama National University 79-5 Tokiwadai, Hodogaya, Yokohama, 240-8501, Japan and Now Nippon Steel and Sumitomo Metal, Kashima, 314-0014 (Japan); Morooka, Satoshi [Department of Mechanical Engineering and Materials Science, Yokohama National University 79-5 Tokiwadai, Hodogaya, Yokohama, 240-8501, Japan and Now Tokyo Metropolitan University, Hino, Tokyo 191-0065 (Japan); Ono, Yoshinori; Yuri, Tetsumi; Ogata, Toshio [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, 305-0047 (Japan)

    2014-01-27

    Subsurface crack initiation in high-cycle fatigue has been detected as (0001) transgranular facet in titanium alloys at low temperature. The discussion on the subsurface crack generation was reviewed. Analyses by neutron diffraction and full constraints model under tension mode as well as crystallographic identification of the facet were focused. The accumulated tensile stress along <0001> may be responsible to initial microcracking on (0001) and the crack opening.

  19. Study of preparation of BG/HA gradient coating on titanium alloy by electrophoretic deposition method

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-ming; HAN Qing-rong; LI Shi-pu; XU Chuan-bo

    2001-01-01

    In this paper, a gradient bioactive coating made from modified bioglass (BG) and hydroxyapatite (HA) was prepared by electrophoretic deposition method(EPD)on the surface of titanium alloy. Strong bonding between the matrix and BG/HA gradient coating was got by sintering. Crystal composition of the coating was analyzed by XRD. The characteristics of surface and cross section of the coating were observed by SEM. Adhesive strength of the coating was tested by pull method. The optimizing technological parameters were determined.

  20. Surface integrity after pickling and anodization of Ti–6Al–4V titanium alloy

    OpenAIRE

    Vermesse, Eric; Mabru, Catherine; Arurault, Laurent

    2013-01-01

    International audience; The surface integrity of Ti–6Al–4V titanium alloy was studied at different stages of surface treatments, especially pickling and compact anodization, through surface characteristics potentially worsening fatigue resistance. No significant changes of the equiaxe microstructure were detected between sample core and surface, or after the pickling and anodization steps. Surface hydrogen and oxygen superficial contents were found to remain unchanged. Roughness characteristi...

  1. Micromechanical Characterization and Texture Analysis of Direct Cast Titanium Alloys Strips

    Science.gov (United States)

    2000-01-01

    This research was conducted to determine a post-processing technique to optimize mechanical and material properties of a number of Titanium based alloys and aluminides processed via Melt Overflow Solidification Technique (MORST). This technique was developed by NASA for the development of thin sheet titanium and titanium aluminides used in high temperature applications. The materials investigated in this study included conventional titanium alloy strips and foils, Ti-1100, Ti-24Al-11Nb (Alpha-2), and Ti-48Al-2Ta (Gamma). The methodology used included micro-characterization, heat-treatment, mechanical processing and mechanical testing. Characterization techniques included optical, electron microscopy, and x-ray texture analysis. The processing included heat-treatment and mechanical deformation through cold rolling. The initial as-cast materials were evaluated for their microstructure and mechanical properties. Different heat-treatment and rolling steps were chosen to process these materials. The properties were evaluated further and a processing relationship was established in order to obtain an optimum processing condition. The results showed that the as-cast material exhibited a Widmanstatten (fine grain) microstructure that developed into a microstructure with larger grains through processing steps. The texture intensity showed little change for all processing performed in this investigation.

  2. LASER Additive Manufacturing of Titanium-Tantalum Alloy Structured Interfaces for Modular Orthopedic Devices

    Science.gov (United States)

    Fuerst, Jacob; Medlin, Dana; Carter, Michael; Sears, James; Vander Voort, George

    2015-04-01

    Tantalum is recognized to have better biocompatibility and osseointegrative properties than other more commonly used orthopedic grade alloys. There are several novel methods that tantalum or tantalum-titanium could be used to augment orthopedic implants. A tantalum or tantalum-titanium alloy at the bone/implant or modular component interfaces would substantially increase the longevity and performance of modular devices. Bonding a functional tantalum coating to a titanium orthopedic device is inherently difficult because of the small difference between the melting temperature of tantalum, 3017°C, and the boiling point of titanium, 3287°C. LASER powder deposition (LPD) is a fusion operation using an Nd:YAG to melt a small volume of substrate into which metal powder is sprayed achieving high temperature with a high solidification rate. LPD of Ti-Ta onto a Ti-6Al-4V substrate produced both a solid surface and structured coating with a pore size in the optimal 350-500 μm range.

  3. Near-Net Shape Fabrication Using Low-Cost Titanium Alloy Powders

    Energy Technology Data Exchange (ETDEWEB)

    Dr. David M. Bowden; Dr. William H. Peter

    2012-03-31

    The use of titanium in commercial aircraft production has risen steadily over the last half century. The aerospace industry currently accounts for 58% of the domestic titanium market. The Kroll process, which has been used for over 50 years to produce titanium metal from its mineral form, consumes large quantities of energy. And, methods used to convert the titanium sponge output of the Kroll process into useful mill products also require significant energy resources. These traditional approaches result in product forms that are very expensive, have long lead times of up to a year or more, and require costly operations to fabricate finished parts. Given the increasing role of titanium in commercial aircraft, new titanium technologies are needed to create a more sustainable manufacturing strategy that consumes less energy, requires less material, and significantly reduces material and fabrication costs. A number of emerging processes are under development which could lead to a breakthrough in extraction technology. Several of these processes produce titanium alloy powder as a product. The availability of low-cost titanium powders may in turn enable a more efficient approach to the manufacture of titanium components using powder metallurgical processing. The objective of this project was to define energy-efficient strategies for manufacturing large-scale titanium structures using these low-cost powders as the starting material. Strategies include approaches to powder consolidation to achieve fully dense mill products, and joining technologies such as friction and laser welding to combine those mill products into near net shape (NNS) preforms for machining. The near net shape approach reduces material and machining requirements providing for improved affordability of titanium structures. Energy and cost modeling was used to define those approaches that offer the largest energy savings together with the economic benefits needed to drive implementation. Technical

  4. Effect of contact with titanium alloys on the proliferation of mouse osteoblastic cells in culture.

    Science.gov (United States)

    Onuki, Hiroyuki; Sakagami, Hiroshi; Kobayashi, Masahiko; Hibino, Yasushi; Yokote, Yoshiko; Nakajima, Hiroshi; Shimada, Jun

    2010-01-01

    This study was aimed at studying the effect of contact with titanium alloy plates of different surface textures on the proliferative capability of mouse osteoblastic MC3T3-E1 cells. First, the proliferation characteristics of MC3T3-E1 cells were investigated. MC3T3-E1 cells showed a high capacity for proliferation and survived for a long period even under nutritionally starved conditions. During logarithmic cell growth, the consumption of Ser, Gln, Val, Ile and Leu increased time-dependently. Contact with an hydoxyapatite (HA)-coated titanium alloy plate resulted in the increase in the recovery of cells from the plate by trypsin, and an increase in the consumption of these amino acids, suggesting enhanced cell proliferation. On the contrary, contact with the sandblasted and anodized titanium alloy plates resulted in the reduction of the recovery of the cells from the plate, but a slight increase in the amino acid consumption, suggesting the tight adhesion of the cells to the plates. This study demonstrates that the present method, based on the amino acid consumption of the cells, is useful for monitoring the cell proliferative capability, without detachment of the cells from the plate. This method may be applicable to the study of the interaction between cells and metal plates.

  5. Fabrication and biocompatibility in vitro of potassium titanate biological thin film/titanium alloy biological composite

    Institute of Scientific and Technical Information of China (English)

    QI Yumin; HE Yun; CUI Chunxiang; LIU Shuangjin; WANG Huifen

    2007-01-01

    A potassium titanate biological thin film/titanium alloy biological composite was fabricated by way of bionic chemistry.The biocompatibility fn vitro of Ti-15Mo-3Nb and the potassium titanate biological thin film/titanium alloy was studied using simulated body fluid cultivation,kinetic clotting of blood and osteoblast cell cultivation experiments in vitro.By comparing the biological properties of both materials,the following conclusions can be obtained:(1)The deposition of a calcium phosphate layer was not found on the surface of Ti-15Mo-3Nb,so it was bioinert.Because the network of potassium titanate biological thin film could induce the deposition of a calcium phosphate layer,this showed that it had excellent bioactivity.(2)According to the values of kinetic clotting,the blood coagulation time of the potassium titanate biological thin film was more than that of Ti-15Mo-3Nb.It was obvious that the potassium titanate biological thin film possessed good hemocompatibility.(3)The cell compatibility of both materials was very good.However,the growth trend and multiplication of osteoblast cells on the surface of potassium titanate biological thin film was better,which made for the concrescence of wounds during the earlier period.As a result,the potassium titanate biological thin film/titanium alloy showed better biocompatibility and bioactivity.

  6. Surface characterization and biocompatibility of titanium alloys implanted with nitrogen by Hardion+ technology.

    Science.gov (United States)

    Gordin, D M; Gloriant, T; Chane-Pane, V; Busardo, D; Mitran, V; Höche, D; Vasilescu, C; Drob, S I; Cimpean, A

    2012-12-01

    In this study, the new Hardion+ micro-implanter technology was used to modify surface properties of biomedical pure titanium (CP-Ti) and Ti-6Al-4V ELI alloy by implantation of nitrogen ions. This process is based on the use of an electron cyclotron resonance ion source to produce a multienergetic ion beam from multicharged ions. After implantation, surface analysis methods revealed the formation of titanium nitride (TiN) on the substrate surfaces. An increase in superficial hardness and a significant reduction of friction coefficient were observed for both materials when compared to non-implanted samples. Better corrosion resistance and a significant decrease in ion release rates were observed for N-implanted biomaterials due to the formation of the protective TiN layer on their surfaces. In vitro tests performed on human fetal osteoblasts indicated that the cytocompatibility of N-implanted CP-Ti and Ti-6Al-4V alloy was enhanced in comparison to that of the corresponding non treated samples. Consequently, Hardion+ implantation technique can provide titanium alloys with better qualities in terms of corrosion resistance, cell proliferation, adhesion and viability.

  7. Titanium Alloy Cage Implantation for the Treatment of Ischemic Necrosis of Femoral Head in Dogs

    Institute of Scientific and Technical Information of China (English)

    Ruiying WANG; Yan GAO; Shuhua YANG; Cao YANG

    2008-01-01

    To study the effect of titanium alloy cage on the treatment of the ischemic necrosis of femoral head in dog, the model of the ischemic necrosis of femoral head was made with the liquid nitrogon in 15 hybrid adult dogs. The titanium alloy cage made of a hollow cylinder was driven into the subchondral bone of necrotic femoral head via central channel. The dogs were divided into 3 groups, each group was sacrificed 3, 6, 12 weeks after the operation respectively. No collapse of femoral head was observed after the operation. The position of the cages was good on radiograph. Microscopically, the cancellous bone of necrotic femoral head rebuilt gradually and grew into cage. After 12 weeks of creeping substitution, the cancellous bone filled up the hollow cavity and holes of the cages. It is concluded that the titanium alloy cage can provide structural support for the subchondral bone and prevent collapse and can be used for the treatment of the ischemic necrosis of femoral head.

  8. Experimental investigation of laser peening on Ti17 titanium alloy for rotor blade applications

    Energy Technology Data Exchange (ETDEWEB)

    Hongchao, Qiao, E-mail: hcqiao@sia.cn

    2015-10-01

    Highlights: • Laser peening on Ti17 titanium alloys is investigated. • Roughness and residual stress value were grown on laser energy and impact times. • Hardened layer depth increases significantly with laser peening impact times. • Laser peening is effectively in lower fatigue stress level. • Laser peening makes the microstructures evolution. - Abstract: Laser peening is an innovative surface treatment technique, and can significantly improve the mechanical performance of metallic components. To investigate the fatigue life of Ti17 titanium alloy by laser peening, laser peening experiment was undertaken using Nd:YAG laser system with the pulse-width of 15 ns and max pulse-energy of 7 J. Firstly, the mechanical properties and microstructure with different laser peening parameters were investigated, which were measured and observed by Vickers indenter, X-ray diffraction, scanning electron microscope and transmission electron microscope. Micro-hardness and compressive residual stress distribution was remarkably improved. High-density dislocations and fine-grains were observed in the surface layer. Then, several stress levels were chosen to be applied on the tension and compression fatigue specimens. The fatigue life and fracture mechanism of the specimens without- and with-laser peened were compared, and the strengthening mechanism was indicated by analyzing the effects on the microstructure and residual stress evolution. The results demonstrate that laser peening could effectively improve the fatigue life of Ti17 titanium alloy.

  9. Brazing of zirconia to titanium using Ag-Cu and Au-Ni filler alloys

    Directory of Open Access Journals (Sweden)

    Jean S. Pimenta

    2013-12-01

    Full Text Available Advanced ceramic is usually joined to metal by the well-known direct brazing process, where costly active filler alloys can be considered a limitation. Brazing using active-metal-free filler alloy as insert between the joint components is an attempt to overcome it. The active metal diffusion from the titanium member through the bulk of molten filler to the ceramic was responsible to produce an active filler alloy in loco and promote reduction of the zirconium oxide to improve wetting on the ceramic surface. Unalloyed titanium was joined in a high-vacuum furnace (<3x10-5 mbar to yttria-tetragonal zirconia polycristals (Y-TZP and zirconia partially stabilized with magnesia (Mg-PSZ, where commercial fillers Ag-28Cu and Au-18Ni with respective thermal cycles were evaluated. Helium gas leak detection test was performed at the ceramic/metal interface at room temperature; samples from reliable vacuum tight joints were examined by microstructural analysis techniques and energy dispersive X-ray analysis at the joint cross-section. Tight joints were produced with eutectic Ag-Cu filler, revealing an intermetallic layer and a dark reaction layer near the ceramic surface; titanium diffusion was efficient for superficial chemical interactions between individual components. Brazing joints were also tested using three-point flexure testing.

  10. Bactericidal and antimicrobial effects of pure titanium and titanium alloy treated with short-term, low-energy UV irradiation

    Science.gov (United States)

    Narita, K.; Ono, A.; Wada, K.; Tanaka, T.; Kumagai, G.; Yamauchi, R.; Nakane, A.; Ishibashi, Y.

    2017-01-01

    Objectives The surface of pure titanium (Ti) shows decreased histocompatibility over time; this phenomenon is known as biological ageing. UV irradiation enables the reversal of biological ageing through photofunctionalisation, a physicochemical alteration of the titanium surface. Ti implants are sterilised by UV irradiation in dental surgery. However, orthopaedic biomaterials are usually composed of the alloy Ti6Al4V, for which the antibacterial effects of UV irradiation are unconfirmed. Here we evaluated the bactericidal and antimicrobial effects of treating Ti and Ti6Al4V with UV irradiation of a lower and briefer dose than previously reported, for applications in implant surgery. Materials and Methods Ti and Ti6Al4V disks were prepared. To evaluate the bactericidal effect of UV irradiation, Staphylococcus aureus 834 suspension was seeded onto the disks, which were then exposed to UV light for 15 minutes at a dose of 9 J/cm2. To evaluate the antimicrobial activity of UV irradiation, bacterial suspensions were seeded onto the disks 0, 0.5, one, six, 24 and 48 hours, and three and seven days after UV irradiation as described above. In both experiments, the bacteria were then harvested, cultured, and the number of colonies were counted. Results No colonies were observed when UV irradiation was performed after the bacteria were added to the disks. When the bacteria were seeded after UV irradiation, the amount of surviving bacteria on the Ti and Ti6Al4V disks decreased at 0 hours and then gradually increased. However, the antimicrobial activity was maintained for seven days after UV irradiation. Conclusion Antimicrobial activity was induced for seven days after UV irradiation on both types of disk. Irradiated Ti6Al4V and Ti had similar antimicrobial properties. Cite this article: T. Itabashi, K. Narita, A. Ono, K. Wada, T. Tanaka, G. Kumagai, R. Yamauchi, A. Nakane, Y. Ishibashi. Bactericidal and antimicrobial effects of pure titanium and titanium alloy treated with

  11. Influence of thermal and mechanical cycling on the flexural strength of ceramics with titanium or gold alloy frameworks

    NARCIS (Netherlands)

    Oyafuso, Denise Kanashiro; Ozcan, Mutlu; Bottino, Marco Antonio; Itinoche, Marcos Koiti

    2008-01-01

    Objectives. The aim of this study was to evaluate the effect of thermal and mechanical cycling alone or in combination, on the flexural strength of ceramic and metallic frameworks cast in gold alloy or titanium. Methods. Metallic frameworks (25 mm x 3 mm x 0.5 mm) (N = 96) cast in gold alloy or comm

  12. Influence of thermal and mechanical cycling on the flexural strength of ceramics with titanium or gold alloy frameworks

    NARCIS (Netherlands)

    Oyafuso, Denise Kanashiro; Ozcan, Mutlu; Bottino, Marco Antonio; Itinoche, Marcos Koiti

    Objectives. The aim of this study was to evaluate the effect of thermal and mechanical cycling alone or in combination, on the flexural strength of ceramic and metallic frameworks cast in gold alloy or titanium. Methods. Metallic frameworks (25 mm x 3 mm x 0.5 mm) (N = 96) cast in gold alloy or

  13. Functional and structural fatigue of titanium tantalum high temperature shape memory alloys (HT SMAs)

    Energy Technology Data Exchange (ETDEWEB)

    Niendorf, T., E-mail: Thomas.Niendorf@iwt.tu-freiberg.de [Institute of Materials Engineering, Technische Universität Bergakademie Freiberg, 09599 Freiberg (Germany); Krooß, P. [Lehrstuhl für Werkstoffkunde (Materials Science), University of Paderborn, 33098 Paderborn (Germany); Batyrsina, E. [Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, 30823 Garbsen (Germany); Paulsen, A.; Motemani, Y.; Ludwig, A.; Buenconsejo, P.; Frenzel, J.; Eggeler, G. [Institut für Werkstoffe, Ruhr-Universität Bochum, 44801 Bochum (Germany); Maier, H.J. [Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, 30823 Garbsen (Germany)

    2015-01-03

    Due to their high work output and good mechanical properties, actuators made from shape memory alloys (SMAs) are used in numerous applications. Unfortunately, SMAs such as nickel–titanium (Ni–Ti) can only be employed at temperatures up to about 100 °C. Lately, high-temperature shape memory alloys (HT SMAs) have been introduced to overcome this limitation. Ternary systems based on Ni–Ti have been intensively characterized and alloys are available that can operate at elevated temperatures. However, these alloys either contain substantial amounts of expensive noble elements like platinum and palladium, or the materials are brittle. The titanium–tantalum (Ti–Ta) system has been developed to overcome these issues. Binary Ti–Ta provides relatively high M{sub S} temperature combined with excellent workability, but it suffers from fast cyclic degradation. By alloying with third elements this drawback can be overcome: The ternary Ti–Ta–Al alloy shows overall promising properties as will be shown in the present work. In-situ thermo-mechanical cycling experiments were conducted and allowed for evaluation of the factors affecting the functional and structural fatigue of this alloy. Functional fatigue is dominated by ω-phase evolution, while structural fatigue is triggered by an interplay of ω-phase induced embrittlement and deformation constraints imposed by unsuitable texture. In addition, a concept for fatigue life extension proposed very recently for binary Ti–Ta, is demonstrated to be also applicable for the ternary Ti–Ta–Al.

  14. The effect of aging on hydrogen trapping in [beta]-titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Pound, B.G. (SRI International, Menlo Park, CA (United States). Materials Research Center)

    1994-05-01

    The ingress of hydrogen in three [beta]-titanium alloys (Beta-C, Ti-10V-2Fe-3Al, and Ti-13V-11Cr-3Al) and an [alpha]-[beta] titanium alloy (Ti-6Al-4V) was investigated with a view to characterizing their interaction with hydrogen. A technique referred to as hydrogen ingress analysis by potentiostatic pulsing (HIAPP) was used to obtain anodic current transients for the unaged and aged [beta]-Ti alloys and as-received Ti-6-4 in an acetate buffer (1 mol L[sup [minus]1] HAc/l mol L[sup [minus]1] NaAc, where Ac = acetate). The transients were analyzed using a diffusion/trapping model under interface control conditions to evaluate the trapping constants and hydrogen entry flux in each case. A marked increase in irreversible trapping was observed for the [beta]-titanium alloys with aging and was attributed to precipitation of secondary [alpha] phase. Aging also induced changes in the passive film and hence the hydrogen entry flux. Ti-13-11-3 and Ti-10-2-3 are predicted to become less resistant to hydrogen embrittlement with aging as a result of increase in both the trapping constant (at least for Ti-13-11-3) and the flux. In contrast, the change in resistance of Beta-C Ti with aging is subject to the opposing effects of a reduced flux and an enhanced trapping capability, though the latter appears to have the primary effect, rendering aged Beta-C Ti less resistance to hydrogen embrittlement than the unaged alloy.

  15. Flux Pinning in Superconducting Niobium-Titanium Alloys

    Science.gov (United States)

    McKinnell, James Charles

    1990-01-01

    By studying Nb-Ti alloys from Nb44wt%Ti to Nb62wt%Ti the low field (2T) current density has been raised from 6500A/mm^2 (4.2^ circK) with standard Nb46.5wt%Ti to 7400A/mm ^2 with Nb58wt%Ti. When standard processing sequences were used, the alloys containing more than 46.5wt%Ti exhibited non-uniform microstructures following a precipitation heat treatment and the hardness rose from 200 DPN to over 300 DPN. By increasing the cold work prior to heat treatment the non-uniform precipitation was avoided. The amount of cold work needed prior to heat treatment to suppress non-uniform precipitation increased as the Ti content of the alloy increased. The volume fraction of precipitate produced during a given heat treatment also increased as the Ti content of the alloy increased. As the Ti content increased, the peak in the reduced pinning force curve shifted from b = 0.5 to b = 0.25. In order to determine whether the change in the flux pinning properties was due to the change in microstructure or due to enhanced Delta H_{c} pinning as the Ti content was increased, a set of wires with similar microstructures was developed. Their flux pinning behavior showed that the higher Ti alloys have pinning force curves which peak at progressively lower reduced fields. Thus Delta H_{c} pinning becomes the dominant pinning mechanism as the Ti content is increased.

  16. [The effect on anti-acid corrosion resistance of Ni-Cr alloy coating titanium].

    Science.gov (United States)

    Hu, Bin; Zhang, Fu-qiang

    2003-04-01

    The aim of this study was to investigate the variation of the corrosion resistance of Ni-Cr alloy in acid environment before and after coating titanium in vitro. 1. Surface treatment using sol-gel technique of coating titanium. The steps were as follows: (1) Pre-treatment: sanding, washing and activation in order to remove the oxidative product; (2) The preparation of sol: some small charged particles produced by the hydrolytic reaction, and formed sol. These particles would congeal into extremely small ones (diameter usually is 5 microns); (3) Coating; (4) Heat treatment: The organism was resolved and volatilizeed at high temperature, and the atoms of Ti were left. These atoms of Ti were very active and could combine firmly with the atoms on the surface awaiting of treatment. 2. artificial saliva; pH = 7.0 and pH = 5.6; temperature: 36.5 degrees C 3. Electrochemical test: polarization curve; instrument: ZF-3 poteniostat. Before coating titanium, when pH was 7.0, the electrode potential of Ni-Cr alloy was -160 mV, and the self-corrosion current density was 0.262 microA cm-2; when pH = 5.6, the data were -182 mV and 0.352 microA cm-2, respectively. This result showed that when pH value reduced, the potential and current density descended, too. This indicated that the material was easy to be corroded. After coating titanium, when pH value was 7.0, the potential was -71 mV, the self-corrosion current density was 0.152 microA cm-2; when pH = 5.6, the data were -89 mV and 0.174 microA cm-2. This indicated that the corrosion rate of material descended evidently after coating titanium in acid environment. (1) Not only before coating Ti but also after coating, the corrosion resistance of Ni-Cr alloy would descend in acid environment;(2) In acid environment, the corrosion resistance of Ni-Cr alloy after coating titanium was superior to that of the material before coating. So was in neutral environment.

  17. New developments and applications in the field of plasma-nitrides and plasma nitrocarburizing; Neue Entwicklungen und Anwendungen des Plasmanitrierens und Plasmanitrocarburierens

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, S.; Oppel, W.; Kloeckner, R.

    1995-12-31

    The large number of different applications has even further increased due to the constructive properties of plasma nitrides and due to the possibility of an economic and environmentally harmless process technique. The demand on multi-functional component properties has recently led to the combination of plasma nitrides with surface coating methods, such as the PVD-method. The successful combination of a TiN hard material layer at the surface thickness 2-4{mu}m with the adjacent plasma nitride layer, that functions as supporting layer, has fully proved up to the mark for components which are exposed to strong tribological effects in case of high surface pressures. Another field of application of plasma nitrides is the generation of nitride layers in non-ferrous metals, e.g. titan or aluminium alloys. The improvement of the tribological properties, such as high temperature stability, abrasive wear resistance and corrosive properties result in numerous applications in the fields of air and space travel, energy technology and the construction of chemical plants. Thus surface hardness numbers of approx. 1200 HV0.1 are achieved at the manufacture of plasma-nitrated turbine blades made of the material TiAl5Zr. (orig.) [Deutsch] Aufgrund der beschriebenen verfahrenstechnischen und konstruktiven Merkmale des Plasmanitrierens einerseits und des Angebots wirtschaftlicher und umweltfreundlicher Verfahrenstechnik andererseits wird die bereits sehr breite Anwendungsvielfalt zunehmend erweitert. Die Forderung nach multifunktionalen Bauteileigenschaften fuehrt in juengster Zeit zur Kombination des Plasmanitrierens mit Oberflaechenbeschichtungsverfahren, z.B. dem PVD-Verfahren. Diese sehr erfolgversprechende Kombination einer 2-4 {mu}m dicken TiN-Hartstoffschicht an der Oberflaeche mit einer darunter anschliessenden Plasmanitrierschicht, die als Stuetzschicht fungiert, hat sich besonders bei hohen Flaechenpressungen stark tribologisch beanspruchter Bauteile bewaehrt. Ein weiteres

  18. Titanium alloys (AoN) and their involvement in osseointegration.

    Science.gov (United States)

    Danza, Matteo; Zollino, Ilaria; Candotto, Valentina; Cura, Francesca; Carinci, Francesco

    2012-12-01

    Osseointegration is essential for a long-term successful and inflammation-free dental implant. Such a result depends on osteoblastic cells growth and differentiation at the tissue-implant interface. The aim of this study was to compare two different AoN titanium layers (GR4 and GR5) to investigate which one had a greater osteoconductive power using human osteoblasts (HOb) culture at two different time-points. The expression levels of some bone-related (ALPL, COL1A1, COL3A1, SPP1, RUNX2, and SPARC) were analyzed using real time reverse transcription-polymerase chain reaction (real time RT-PCR). Real-time RT-PCR data showed that after 3 days of treatment with TiA4GR, the genes up-regulated were COL3A1, ALPL, SPP1, and RUNX2. Moreover, no difference in gene expression was noticed 4 days later. On the other hand, the genes that overexpressed after 3 days of treatment with AoN5GR were ALPL, SPP1, and RUNX2. In both cases, the expression of COL1A1 and SPARC was negatively regulated. Our data showed that both titanium surfaces led to osteoblasts recruitment, maturation, and differentiation, thus promoting osseointegration at the tissue-implant interface.

  19. Effect of Plasma Nitriding Process Conditions on Corrosion Resistance of 440B Martensitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    Łępicka Magdalena

    2014-09-01

    Full Text Available Martensitic stainless steels are used in a large number of various industrial applications, e.g. molds for plastic injections and glass moldings, automotive components, cutting tools, surgical and dental instruments. The improvement of their tribological and corrosion properties is a problem of high interest especially in medical applications, where patient safety becomes a priority. The paper covers findings from plasma nitrided AISI 440B (PN-EN or DIN X90CrMoV18 stainless steel corrosion resistance studies. Conventionally heat treated and plasma nitrided in N2:H2 reaction gas mixture (50:50, 65:35 and 80:20, respectively in two different temperature ranges (380 or 450°C specimens groups were examined. Microscopic observations and electrochemical corrosion tests were performed using a variety of analytical techniques. As obtained findings show, plasma nitriding of AISI 440B stainless steel, regardless of the process temperature, results in reduction of corrosion current density. Nevertheless, applying thermo-chemical process which requires exceeding temperature of about 400°C is not recommended due to increased risk of steel sensitization to intergranular and stress corrosion. According to the results, material ion nitrided in 450°C underwent leaching corrosion processes, which led to significant disproportion in chemical composition of the corroded and corrosion-free areas. The authors suggest further research into corrosion process of plasma nitrided materials and its degradation products.

  20. Phase formation in selected surface-roughened plasma-nitrided 304 austenite stainless steel

    Directory of Open Access Journals (Sweden)

    Gajendra Prasad Singh et al

    2008-01-01

    Full Text Available Direct current (DC glow discharge plasma nitriding was carried out on three selected surface-roughened AISI 304 stainless steel samples at 833 K under 4 mbar pressures for 24 h in the presence of N2:H2 gas mixtures of 50 : 50 ratios. After plasma nitriding, the phase formation, case depth, surface roughness, and microhardness of a plasma-nitrided layer were evaluated by glancing angle x-ray diffractogram, optical microscope, stylus profilometer, and Vickers microhardness tester techniques. The case depth, surface hardness, and phase formation variations were observed with a variation in initial surface roughness. The diffraction patterns of the plasma-nitrided samples showed the modified intensities of the α and γ phases along with those of the CrN, Fe4N, and Fe3N phases. Hardness and case depth variations were observed with a variation in surface roughness. A maximum hardness of 1058 Hv and a case depth of 95 μm were achieved in least surface-roughened samples.

  1. Phase formation in selected surface-roughened plasma-nitrided 304 austenite stainless steel.

    Science.gov (United States)

    Singh, Gajendra Prasad; Joseph, Alphonsa; Raole, Prakash Manohar; Barhai, Prema Kanta; Mukherjee, Subroto

    2008-04-01

    Direct current (DC) glow discharge plasma nitriding was carried out on three selected surface-roughened AISI 304 stainless steel samples at 833 K under 4 mbar pressures for 24 h in the presence of N2:H2 gas mixtures of 50 : 50 ratios. After plasma nitriding, the phase formation, case depth, surface roughness, and microhardness of a plasma-nitrided layer were evaluated by glancing angle x-ray diffractogram, optical microscope, stylus profilometer, and Vickers microhardness tester techniques. The case depth, surface hardness, and phase formation variations were observed with a variation in initial surface roughness. The diffraction patterns of the plasma-nitrided samples showed the modified intensities of the α and γ phases along with those of the CrN, Fe4N, and Fe3N phases. Hardness and case depth variations were observed with a variation in surface roughness. A maximum hardness of 1058 Hv and a case depth of 95 μm were achieved in least surface-roughened samples.

  2. Chimeric Peptides as Implant Functionalization Agents for Titanium Alloy Implants with Antimicrobial Properties

    Science.gov (United States)

    Yucesoy, Deniz T.; Hnilova, Marketa; Boone, Kyle; Arnold, Paul M.; Snead, Malcolm L.; Tamerler, Candan

    2015-04-01

    Implant-associated infections can have severe effects on the longevity of implant devices and they also represent a major cause of implant failures. Treating these infections associated with implants by antibiotics is not always an effective strategy due to poor penetration rates of antibiotics into biofilms. Additionally, emerging antibiotic resistance poses serious concerns. There is an urge to develop effective antibacterial surfaces that prevent bacterial adhesion and proliferation. A novel class of bacterial therapeutic agents, known as antimicrobial peptides (AMPs), are receiving increasing attention as an unconventional option to treat septic infection, partly due to their capacity to stimulate innate immune responses and for the difficulty of microorganisms to develop resistance towards them. While host and bacterial cells compete in determining the ultimate fate of the implant, functionalization of implant surfaces with AMPs can shift the balance and prevent implant infections. In the present study, we developed a novel chimeric peptide to functionalize the implant material surface. The chimeric peptide simultaneously presents two functionalities, with one domain binding to a titanium alloy implant surface through a titanium-binding domain while the other domain displays an antimicrobial property. This approach gains strength through control over the bio-material interfaces, a property built upon molecular recognition and self-assembly through a titanium alloy binding domain in the chimeric peptide. The efficiency of chimeric peptide both in-solution and absorbed onto titanium alloy surface was evaluated in vitro against three common human host infectious bacteria, Streptococcus mutans, Staphylococcus epidermidis, and Escherichia coli. In biological interactions such as occur on implants, it is the surface and the interface that dictate the ultimate outcome. Controlling the implant surface by creating an interface composed chimeric peptides may therefore

  3. Unified constitutive modelling for two-phase lamellar titanium alloys at hot forming conditions

    Directory of Open Access Journals (Sweden)

    Yang Lei

    2016-01-01

    Full Text Available In this paper, a set of mechanism based unified viscoplastic constitutive equations have been established for two-phase titanium alloys with initial lamellar microstructure, which models the softening mechanisms of the alloys in hot forming conditions. The dislocation density, rotation and globularization of lamellar α-phase and their effects on flow behaviour can also be modelled. The values of material constants in the equation set have been calibrated, according to stress-strain curves and globularization fractions of lamellar α-phase obtained from compression tests at a range of temperatures and strain rates, using a genetic algorithm (GA based optimisation method. Based on the determined constitutive equations, flow stress and globularization evolution of Ti-17 and TA15 alloys at different temperatures and strain rates were predicted. Good agreements between the experimental and computed results were obtained.

  4. Joining of dissimilar metals by diffusion bonding. Titanium alloy with aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Akca, Enes [International Univ. of Sarajevo (Bosnia and Herzegovina). Research and Development Center; International Univ. of Sarajevo (Bosnia and Herzegovina). Dept. of Mechanical Engineering; Gursel, Ali [International Univ. of Sarajevo (Bosnia and Herzegovina). Dept. of Mechanical Engineering

    2017-05-01

    This paper presents a novel diffusion bonding process of commercially pure aluminum to Ti-6Al-4V alloy at 520, 560, 600 and 640 C for 30, 45 and 60 minutes under argon gas shielding without the use of interlayer. The approach is to overcome the difficulties in fusion welding of dissimilar alloys. Diffusion bonding is a dissimilar metal welding process which can be applied to the materials without causing any physical deformations. Processed samples were metallographically prepared, optically examined followed by Vickers microhardness test and subjected to tensile test in order to determine joint strength. Scanning electron microscopy and energy dispersive spectroscopy were used in this work to investigate the compositional changes across the joint region. Elemental composition of the region has been successfully defined between titanium alloy and aluminum. The maximum tensile strength was obtained from the samples bonded at the highest temperatures of 600 and 640 C.

  5. Aging properties and microstructures of Ti-B20 titanium alloy

    Institute of Scientific and Technical Information of China (English)

    GE Peng; ZHAO Yong-qing; ZHOU Lian

    2006-01-01

    A new metastable beta titanium alloy of Ti-Al-Mo-V-Cr-Fe-Zr-Sn system was designed and named Ti-B20. In order to investigate the aging properties and microstructures of the new alloy subjected to different solution treatments, the tensile and Vickers hardness tests were carried out and the optical microscope and scanning electron microscope analysis were performed. The results show that the new alloy displays rapid aging response, high age strengthening effect and fine deposition. In addition, beta solution results in ultra high age hardening effect with low tensile ductility, whereas excellent combination of aging strength and ductility can be obtained after solution treated below beta transus temperature.

  6. Fatigue Life of Cast Titanium Alloys Under Simulated Denture Framework Displacements

    Science.gov (United States)

    Koike, Mari; Chan, Kwai S.; Hummel, Susan K.; Mason, Robert L.; Okabe, Toru

    2013-02-01

    The objective of the study was to evaluate the hypothesis that the mechanical properties and fatigue behavior of removable partial dentures (RPD) made from cast titanium alloys can be improved by alloying with low-cost, low-melting elements such as Cu, Al, and Fe using commercially pure Ti (CP-Ti) and Ti-6Al-4V as controls. RPD specimens in the form of rest-shaped, clasp, rectangular-shaped specimens and round-bar tensile specimens were cast using an experimental Ti-5Al-5Cu alloy, Ti-5Al-1Fe, and Ti-1Fe in an Al2O3-based investment with a centrifugal-casting machine. The mechanical properties of the alloys were determined by performing tensile tests under a controlled displacement rate. The fatigue life of the RPD specimens was tested by the three-point bending in an MTS testing machine under a cyclic displacement of 0.5 mm. Fatigue tests were performed at 10 Hz at ambient temperature until the specimens failed into two pieces. The tensile data were statistically analyzed using one-way ANOVA (α = 0.05) and the fatigue life data were analyzed using the Kaplan-Meier survival analysis (α = 0.05). The experimental Ti-5Al-5Cu alloy showed a significantly higher average fatigue life than that of either CP-Ti or Ti-5Al-1Fe alloy ( p casting pores. Among the alloys tested, the Ti-5Al-5Cu alloy exhibited favorable results in fabricating dental appliances with an excellent fatigue behavior compared with other commercial alloys.

  7. Ordered nano-scale dimple pattern formation on a titanium alloy (Ti-6Al-4V

    Directory of Open Access Journals (Sweden)

    Yue Wang

    2012-09-01

    Full Text Available Due to the many applications of nanostructured surfaces – including in biomaterials – there is a strong interest in cost- and time-efficient methods for their fabrication. Previously, our group established a simple electrochemical method generating nanoscale patterns on large areas of a number of different metal surfaces. They consist of dimples that are around 6-10 nm deep and hexagonally closed packed with a tunable periodicity of around 50 nm. Ordering requires careful tuning of the surface chemistry, which makes the translation of these findings to multi-component alloys non-obvious. Here, we demonstrate for the first time that such a pattern can also be achieved on the surface of an alloy, namely Ti-6Al-4V. This alloy is of particular interest for biomedical implants. While dimple formation on the main component metals titanium and aluminum has previously been reported (albeit under conditions that differ from each other, we now also report dimple formation on pure vanadium surfaces to occur under very different conditions. Dimple formation occurs preferentially on the (dominant α-phase grains of the alloy. The size of dimples of the alloy material is subject to the electropolishing potential, electrolyte concentration and surface chemical composition, which gives us the opportunity to control the surface features. Since a main application of this alloy are biomedical implants, this level of control will be an important tool for accommodating cell growth.

  8. Composition and Performance of Nanostructured Zirconium Titanium Conversion Coating on Aluminum-Magnesium Alloys

    Directory of Open Access Journals (Sweden)

    Sheng-xue Yu

    2013-01-01

    Full Text Available Nanostructured conversion coating of Al-Mg alloy was obtained via the surface treatment with zirconium titanium salt solution at 25°C for 10 min. The zirconium titanium salt solution is composed of tannic acid 1.00 g·L−1, K2ZrF6 0.75 g·L−1, NaF 1.25 g·L−1, MgSO4 1.0 g/L, and tetra-n-butyl titanate (TBT 0.08 g·L−1. X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, and Fourier transform infrared spectrum (FT-IR were used to characterize the composition and structure of the obtained conversion coating. The morphology of the conversion coating was obtained by atomic force microscopy (AFM and scanning electron microscopy (SEM. Results exhibit that the zirconium titanium salt conversion coating of Al-Mg alloy contains Ti, Zr, Al, F, O, Mg, C, Na, and so on. The conversion coating with nm level thickness is smooth, uniform, and compact. Corrosion resistance of conversion coating was evaluated in the 3.5 wt.% NaCl electrolyte through polarization curves and electrochemical impedance spectrum (EIS. Self-corrosion current density on the nanostructured conversion coating of Al-Mg alloy is 9.7×10-8A·cm-2, which is only 2% of that on the untreated aluminum-magnesium alloy. This result indicates that the corrosion resistance of the conversion coating is improved markedly after chemical conversion treatment.

  9. The electrochemical properties of four dental casting suprastructure alloys coupled with titanium implants

    Directory of Open Access Journals (Sweden)

    Suleyman Hakan Tuna

    2009-10-01

    Full Text Available OBJECTIVES: As the choice of suprastructure alloy to be combined with titanium for the oral cavity is still a much debated issue, the aim of this study was to investigate the electrochemical interaction of the suprastructure/implant couples under the determined experiment conditions. MATERIAL AND METHODS: The potentiodynamic polarization curves and open-circuit potentials (OCP of four UCLA type suprastructures coupled with straight Swiss Plus implant fixtures were taken in Afnor type artificial saliva solution at 37°C. The concentration of ions leached into artificial saliva solutions was estimated with ICP-MS. SEM images of the margins of suprastructure/implant couples were obtained before and after the electrochemical tests. RESULTS: The OCP value of titanium became passive at the most negative potential. The lowest difference between the initial and constant OCP value was exhibited by the Au based suprastructure. Suprastructures made greater contributions to the potentiodynamic polarization curves of the implant/suprastructure couples. According to the ICP-MS results, Pd based and Au based couples dissolved less than Co-Ni based and Co-Cr based couples. CONCLUSIONS: Within the conditions this study, it may be concluded that the titanium implant forms a stable passive oxide layer in artificial saliva exposed to open air and does not affect the corrosion properties of the suprastructures. Pd based and Au based couples have been found to be more corrosion-resistant than base alloy couples.

  10. Thermoforming Mold for Titanium Alloy%钛合金热成形模具

    Institute of Scientific and Technical Information of China (English)

    李鹏亮; 张志

    2012-01-01

    由于钛合金在力学性能上具有屈强比高、弹性模量小等特点,成形上表现为变形范围窄、易开裂、回弹大和尺寸精度难于保.证为克服上述钛合金成形难点,一般需将其加热到较高的温度进行成形.本文重点讨论了钛合金热成形模具的材料选择及设计,并提出了热成形模具标准化是未来的重点发展方向.%Since the titanium alloy having a high yield ratio, a low elastic modulus and other characteristics on the mechanical properties, it causes narrow deformation range, easily cracking, large springback and difficulty to ensure dimension accuracy. To overcome the above difficulties, it is generally necessary for titanium alloy forming to be heated to a high temperature, the titanium altoy thermoforming mold material selection and design are focused on. It is also proposed that the standardization of thermoforming mold is the future development tendency.

  11. Surface characterization and cytotoxicity analysis of plasma sprayed coatings on titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Zia ur; Shabib, Ishraq [School of Engineering and Technology, Central Michigan University, Mount Pleasant, MI 48859 (United States); Science of Advanced Materials, Central Michigan University, Mount Pleasant, MI 48859 (United States); Haider, Waseem, E-mail: haide1w@cmich.edu [School of Engineering and Technology, Central Michigan University, Mount Pleasant, MI 48859 (United States); Science of Advanced Materials, Central Michigan University, Mount Pleasant, MI 48859 (United States)

    2016-10-01

    In the realm of biomaterials, metallic materials are widely used for load bearing joints due to their superior mechanical properties. Despite the necessity for long term metallic implants, there are limitations to their prolonged use. Naturally, oxides of titanium have low solubilities and form passive oxide film spontaneously. However, some inclusion and discontinuity spots in oxide film make implant to adopt the decisive nature. These defects heighten the dissolution of metal ions from the implant surface, which results in diminishing bio-integration of titanium implant. To increase the long-term metallic implant stability, surface modifications of titanium alloys are being carried out. In the present study, biomimetic coatings of plasma sprayed hydroxyapatite and titanium were applied to the surface of commercially pure titanium and Ti6Al4V. Surface morphology and surface chemistry were studied using scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. Cyclic potentiodynamic polarization and electrochemical impedance spectroscopy were carried out in order to study their electrochemical behavior. Moreover, cytotoxicity analysis was conducted for osteoblast cells by performing MTS assay. It is concluded that both hydroxyapatite and titanium coatings enhance corrosion resistance and improve cytocompatibility. - Highlights: • Surface morphology and surface chemistry were studied using scanning electron microscopy and X-ray photoelectron spectroscopy. • The cyclic polarization tests revealed noticeable improvement towards the positive potentials for both Tip coatings. • CpTi-Hap and Ti6Al4V-Hap both demonstrate similar corrosion rate. • High cytotoxicity was observed for Mp when compared with Tip and Hap after 21 days of immersion. • Both Tip and Hap coatings promoted the osteoblast cell adhesion and exhibited stellar morphology.

  12. Cooperative effect of silicon and other alloying elements on creep resistance of titanium alloys: insight from first-principles calculations.

    Science.gov (United States)

    Li, Yang; Chen, Yue; Liu, Jian-Rong; Hu, Qing-Miao; Yang, Rui

    2016-07-28

    Creep resistance is one of the key properties of titanium (Ti) alloys for high temperature applications such as in aero engines and gas turbines. It has been widely recognized that moderate addition of Si, especially when added together with some other elements (X), e.g., Mo, significantly improves the creep resistance of Ti alloys. To provide some fundamental understandings on such a cooperative effect, the interactions between Si and X in both hexagonal close-packed α and body-centered cubic β phases are systematically investigated by using a first-principles method. We show that the transition metal (TM) atoms with the number of d electrons (Nd) from 3 to 7 are attractive to Si in α phase whereas those with Nd > 8 and simple metal (SM) alloying atoms are repulsive to Si. All the alloying atoms repel Si in the β phase except for the ones with fewer d electrons than Ti. The electronic structure origin underlying the Si-X interaction is discussed based on the calculated electronic density of states and Bader charge. Our calculations suggest that the beneficial X-Si cooperative effect on the creep resistance is attributable to the strong X-Si attraction.

  13. Cooperative effect of silicon and other alloying elements on creep resistance of titanium alloys: insight from first-principles calculations

    Science.gov (United States)

    Li, Yang; Chen, Yue; Liu, Jian-Rong; Hu, Qing-Miao; Yang, Rui

    2016-07-01

    Creep resistance is one of the key properties of titanium (Ti) alloys for high temperature applications such as in aero engines and gas turbines. It has been widely recognized that moderate addition of Si, especially when added together with some other elements (X), e.g., Mo, significantly improves the creep resistance of Ti alloys. To provide some fundamental understandings on such a cooperative effect, the interactions between Si and X in both hexagonal close-packed α and body-centered cubic β phases are systematically investigated by using a first-principles method. We show that the transition metal (TM) atoms with the number of d electrons (Nd) from 3 to 7 are attractive to Si in α phase whereas those with Nd > 8 and simple metal (SM) alloying atoms are repulsive to Si. All the alloying atoms repel Si in the β phase except for the ones with fewer d electrons than Ti. The electronic structure origin underlying the Si-X interaction is discussed based on the calculated electronic density of states and Bader charge. Our calculations suggest that the beneficial X-Si cooperative effect on the creep resistance is attributable to the strong X-Si attraction.

  14. Effects of alloying elements on nitrogen diffusion behavior around TiN/Ti interface α region in as-cast titanium alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To characterize the effects of alloying elements on inclusion dissolution of titanium nitride, the content profiles of elements around TiN/Ti boundary α phase regions in liquid titanium alloys have been experimentally carried out. Four kinds of commercial alloys of CpTi, Ti64, Ti17 and Ti6242 containing different α-stabilizing or β-stabilizing elements are examined through artificially embedding the TiN sponge particle into liquid alloys in VAR conditions. The content profiles of nitrogen and alloying elements around TiN/Ti boundary were measured by WDX and microprobe for as-cast samples. The content profiles of nitrogen and alloying elements around N-containing solid in αTi region of these alloys show a common features of a steep change. In particular, the content profiles of elements for Ti6242 demonstrate unique change of a more gentle change tendency and further deeper into the alloy matrix. The experiment results show that, the differences among composite effects of alloying elements in different alloys within nitrogen-induced diffusion α region result in different dissolution and diffusion behaviors to overcome the α phase region barriers.

  15. Isothermal α″ formation in β metastable titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Aeby-Gautier, E., E-mail: Elisabeth.Gautier@mines.inpl-nancy.fr [Institut Jean Lamour, UMR CNRS Nancy Université, UPVM 7198, Nancy (France); Settefrati, A. [Institut Jean Lamour, UMR CNRS Nancy Université, UPVM 7198, Nancy (France); Airbus Operations, Materials and Processes, Toulouse (France); Bruneseaux, F. [Institut Jean Lamour, UMR CNRS Nancy Université, UPVM 7198, Nancy (France); Appolaire, B. [Laboratoire d’Etudes des Microstructures ONERA – CNRS Chatillon (France); Denand, B.; Dehmas, M.; Geandier, G.; Boulet, P. [Institut Jean Lamour, UMR CNRS Nancy Université, UPVM 7198, Nancy (France)

    2013-11-15

    Highlights: ► Isothermal kinetics of orthorhombic α″ formation is characterized by HEXRD. ► Cell parameters of parent and product phases are obtained. ► Partitioning of solutes during the transformation and the ageing is discussed. -- Abstract: Thanks to time resolved high energy X-ray diffraction, isothermal decomposition of β metastable phase was studied, directly after solution treatment in the β temperature range, for temperatures ranging from 300 to 450 °C for two beta metastable alloys (Ti 17 and Ti 5553). The formation of an orthorhombic α″ phase is clearly identified at the beginning of the transformation whatever the alloy studied. If transformation occurs at the higher temperature an evolution of α″ is observed toward the hexagonal α phase. The phase amounts and the mean cell parameters of each phase were quantified by the Rietveld refinement method. The obtained cell parameters evolutions and the orthorhombicity of α″ are discussed. Moreover, the orthorhombicity of α″ compared to that obtained for stress induced martensite may indicate a slight partitioning of solutes in isothermal α″.

  16. Research Progress of Biomedical Titanium Alloys%生物医用钛合金的研究进展

    Institute of Scientific and Technical Information of China (English)

    李红梅; 雷霆; 方树铭; 黄光明

    2011-01-01

    钛合金具有较低的弹性模量、优异的耐腐蚀性能和生物相容性,是理想的生物医用材料.综述了医用钛合金的发展过程及新型医用β钛合金的研究现状,以及开发的新合金系列.目前开发的医用钛合金中,Ti-35Nb-7Zr-5Ta和Ti-29Nb-13Ta-7.1Zr合金的弹性模量为55 GPa,与致密骨的弹性模量很接近,与人体骨有较好的力学相容性.%Titanium alloys offering lower elastic modulus,excellent corrosion resistance and enhanced bioeompatibility are ideal biomedical materials. The development history of medical titanium alloys and research status of new β-type titanium alloys and developed new alloy system are summarized. Among current developed biomedical titanium alloys, the modulus of elasticity of Ti-35Nb-7Zr-5Ta and Ti-29Nb-13Ta-7. 1Zr alloys is 55GPa , very near the modulus of density bone , and have better mechanical compatibility with natural bone.

  17. Phenomena of nanotube nucleation and growth on new ternary titanium alloys.

    Science.gov (United States)

    Choe, Han-Cheol; Jeong, Yong-Hoon; Brantley, William A

    2010-07-01

    Ti-30Nb-xZr and Ti-30Ta-xNb alloys have been investigated using various methods of surface nanotube formation. Ternary Ti-30Nb-xZr (x = 3 and 15 wt%) and Ti-30Ta-xNb (x = 3 and 15 wt%) alloys were prepared by using high-purity sponge Ti (Grade 4, G&S Titanium, USA), Ta, Zr and Nb spheres. The two groups of ternary Ti alloys were prepared using a vacuum arc melting furnace. Nanotube formation was carried out with a conventional three-electrode configuration with the Ti alloy specimen, a platinum counterelectrode, and a saturated calomel (SCE) reference electrode. Experiments were performed in 1 M H3PO4 with small additions of NaF (0.1-0.8 wt%), using a potentiostat. Nanotubes formed on the surfaces of the two ternary Ti alloys were examined by field emission scanning electron microscopy, EDS and XRD. The Ti-30Ta-xZr alloys had microstructure with entirely needle-like constituents; the thickness of the needle-like alpha-phase increased as the Zr content increased. The Ti-30Nb-xZr alloys had equiaxed microstructures of the beta-phase, and increasing amounts of the needle-like alpha phase appeared at the grain boundaries of the beta-phase as the Zr content increased. The nanotubes were nucleated and grew mainly on the beta phase for the Ti-30Ta-3Zr and Ti-30Nb-3Zr alloys, which had nanotubes with uniform shape, but the nanotubes were nucleated at the alpha phase for the Ti-30Ta-15Zr and Ti-30Nb-15Zr alloys, which had nanotubes with irregular shape and diameters of two sizes. The diameter and depth of the nanotubes could be controlled, depending upon the alloy composition and composition of the surface oxide films (TiO2, Nb2O5, Ta2O5, and ZrO2). It is concluded that this research that selection of the appropriate alloying element can allow significant control of the nanotopography of these Ti alloy surfaces and that it is possible to control the surface nanotube size to promote long-term osseointegration for clinical dental or orthopedic use.

  18. Electrochemical & osteoblast adhesion study of engineered TiO{sub 2} nanotubular surfaces on titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Zia Ur [School of Engineering and Technology, Central Michigan University, Mt. Pleasant, MI (United States); Haider, Waseem, E-mail: haide1w@cmich.edu [School of Engineering and Technology, Central Michigan University, Mt. Pleasant, MI (United States); Pompa, Luis [Department of Mechanical Engineering, University of Texas–Pan American, Edinburg, TX (United States); Deen, K.M. [Department of Metallurgy & Materials Engineering, CEET, University of the Punjab, 54590 Lahore (Pakistan); Department of Materials Engineering, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada)

    2016-01-01

    TiO{sub 2} nanotubes were grafted on the surface of cpTi, Ti6Al4V and Ti6Al4V-ELI with the aim to provide a new podium for human pre-osteoblast cell (MC3T3) adhesion and proliferation. The surface morphology and chemistry of these alloys were examined with scanning electron microscopy and energy dispersive x-ray spectroscopy. TiO{sub 2} nanotubes were further characterized by cyclic potentiodynamic polarization tests and electrochemical impedance spectroscopy. The vertically aligned nanotubes were subjected to pre-osteoblast cell proliferation in order to better understand cell–material interaction. The study demonstrated that these cells interact differently with nanotubes of different titanium alloys. The significant acceleration in the growth rate of pre-osteoblast cell adhesion and proliferation is also witnessed. Additionally, the cytotoxicity of the leached metal ions was evaluated by using a tetrazolium-based bio-assay, MTS. Each group of data was operated for p < 0.05, concluded one way ANOVA to investigate the significance difference. - Highlights: • TiO{sub 2} nanotubes were grafted on cpTi, Ti6Al4V and Ti6Al4V-ELI via anodization. • MC3T3 cells interact differently with nanotubes of different titanium alloys. • TiO{sub 2} nanotubes have a positive impact on the osteoblast cell viability.

  19. Characterization of Coatings Created on Selected Titanium Alloys by Plasma Electrolytic Oxidation

    Directory of Open Access Journals (Sweden)

    Rokosz K.

    2016-03-01

    Full Text Available The SEM and EDS results of coatings obtained on pure niobium and titanium alloys (NiTi and Ti6Al4V by Plasma Electrolytic Oxidation in the electrolytes containing of 300 g and 600 g copper nitrate in 1 litre of concentrated phosphoric acid at 450 V for 3 minutes, are presented. The obtained coatings are porous and consist mainly of phosphorus within titanium and copper. For each coating, the Cu/P ratios were calculated. The maximum of that coefficient was found for niobium and Ti6Al4V alloy oxidised in the electrolyte containing 600 g of Cu(NO32 in 1 dm3 of H3PO4 and equaling to 0.22 (wt% | 0.11 (at%. The minimum of Cu/P ratio was recorded for NiTi and Ti6Al4V alloys oxidised by PEO in electrolyte consisting of 300 g of copper nitrate in 1 dm3 of concentrated phosphoric acid and equals to 0.12 (wt% | 0.06 (at%. The middle value of that ratio was recorded for NiTi and it equals to 0.16 (wt% | 0.08 (at%.

  20. Production of a low young modulus titanium alloy by powder metallurgy

    Directory of Open Access Journals (Sweden)

    Dalcy Roberto dos Santos

    2005-12-01

    Full Text Available Titanium alloys have several advantages over ferrous and non-ferrous metallic materials, such as high strengthto-weight ratio and excellent corrosion resistance. A blended elemental titanium powder metallurgy process has been developed to offer low cost commercial products. The process employs hydride-dehydride (HDH powders as raw material. In this work, results of the Ti-35Nb alloy sintering are presented. This alloy due to its lower modulus of elasticity and high biocompatibility is a promising candidate for aerospace and medical use. Samples were produced by mixing of initial metallic powders followed by uniaxial and cold isostatic pressing with subsequent densification by isochronal sintering between 900 up to 1600 °C, in vacuum. Sintering behavior was studied by means of microscopy and density. Sintered samples were characterized for phase composition, microstructure and microhardness by X-ray diffraction, scanning electron microscopy and Vickers indentation, respectively. Samples sintered at high temperatures display a fine plate-like alpha structure and intergranular beta. A few remaining pores are still found and density above 90% for specimens sintered in temperatures over 1500 °C is reached.

  1. Experimental study on dieless drawing of Nickel-Titanium alloy.

    Science.gov (United States)

    Twohig, E; Tiernan, P; Tofail, S A M

    2012-04-01

    The effect of a dieless drawing process on commercial grade Nickel-Titanium rods, of 5 mm diameter, was investigated by varying the established critical process parameters of temperature, cooling rate, drawing velocity, and heating/cooling velocity. The rods were successfully dieless drawn with a maximum steady state reduction in cross-sectional area of 54%. The thermal and mechanical loading profiles of the rod during processing, and the resulting changes in microstructure and hardness, have been investigated. Uniform levels of stress and strain resulted in uniform reduction of the rod cross-sectional area. The grain structure was highly deformed in the drawing direction and increased porosity was observed as a result of the process. The longitudinal section hardness of the rod was significantly reduced as a result of the dieless drawing process. Any failures that arose were due to discontinuities within the material microstructure caused by a high necking rate, shorter exposure time to the process temperature and low heating and cooling rates. A uniform oxidation layer was observed on the surface of the processed rods as a result of processing in atmospheric conditions. This oxidation layer has the potential to aid in the lubrication of subsequent cold working operations of the dieless drawn rods. Coupling the thermomechanical effects of the dieless drawing process with a cold drawing processing step has the potential to produce a NiTi wire in fewer passes, and therefore at a reduced cost. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Bioactive titanate layers formed on titanium and its alloys by simple chemical and heat treatments.

    Science.gov (United States)

    Kokubo, Tadashi; Yamaguchi, Seiji

    2015-01-01

    To reveal general principles for obtaining bone-bonding bioactive metallic titanium, Ti metal was heat-treated after exposure to a solution with different pH. The material formed an apatite layer at its surface in simulated body fluid when heat-treated after exposure to a strong acid or alkali solution, because it formed a positively charged titanium oxide and negatively charged sodium titanate film on its surface, respectively. Such treated these Ti metals tightly bonded to living bone. Porous Ti metal heat-treated after exposure to an acidic solution exhibited not only osteoconductive, but also osteoinductive behavior. Porous Ti metal exposed to an alkaline solution also exhibits osteoconductivity as well as osteoinductivity, if it was subsequently subjected to acid and heat treatments. These acid and heat treatments were not effective for most Ti-based alloys. However, even those alloys exhibited apatite formation when they were subjected to acid and heat treatment after a NaOH treatment, since the alloying elements were removed from the surface by the latter. The NaOH and heat treatments were also not effective for Ti-Zr-Nb-Ta alloys. These alloys displayed apatite formation when subjected to CaCl2 treatment after NaOH treatment, forming Ca-deficient calcium titanate at their surfaces after subsequent heat and hot water treatments. The bioactive Ti metal subjected to NaOH and heat treatments has been clinically used as an artificial hip joint material in Japan since 2007. A porous Ti metal subjected to NaOH, HCl and heat treatments has successfully undergone clinical trials as a spinal fusion device.

  3. Effect of Microstructure on Creep Crack Growth Behavior of a Near- α Titanium Alloy IMI-834

    Science.gov (United States)

    Satyanarayana, D. V. V.; Omprakash, C. M.; Sridhar, T.; Kumar, Vikas

    2009-01-01

    In the present study, the effect of microstructure ( i.e., α + β and transformed β) on creep crack growth (CCG) behavior of a near-alpha (IMI 834) titanium alloy has been explored at temperatures 550 °C and 600 °C. For characterizing the CCG behavior of the alloy, both stress intensity factor ( K) and energy integral parameter ( C t ) were used in the present investigation. The use of stress intensity factor ( K) as crack-tip parameter is not appropriate in the present study as no unique correlation between crack growth rate and K could be obtained from the observed trend due to transients in the creep crack rate data. On the other hand, C t parameter for both microstructural conditions consolidates CCG data into a single trend. The alloy with fully transformed β microstructure exhibits better CCG resistance as compared to bimodal ( α + β) microstructure. This is consistent with the fact that the transformed β structure offers superior creep resistance as compared to α + β microstructure. Microstructural examination has revealed that CCG for both microstructural conditions is accompanied by formation of damage zone in the form of numerous environmental-assisted secondary surface cracks (perpendicular to the stress axis) ahead of the main crack tip. For α + β microstructure of the alloy, the surface creep cracks were formed by growth and coalescence of microcracks nucleated by fracture of primary α particles. While in the interior of the specimens, CCG occurred by growth and coalescence of microvoids nucleated at primary α/transformed β (matrix) interfaces. For β microstructure of the alloy, while the surface creep cracks formed by growth and coalescence of microvoids nucleated at titanium enriched surface oxide particles, in the interior CCG occurred by nucleation of intergranular cavities.

  4. In situ high temperature microscopy study of the surface oxidation and phase transformations in titanium alloys.

    Science.gov (United States)

    Malinov, S; Sha, W; Voon, C S

    2002-09-01

    Two popular commercial titanium alloys, Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo-0.08Si, were used for in situ high temperature microscopy study. The experiments were performed on an optical microscope equipped with high temperature stage using both normal and florescence lights. Two kinds of experiments were performed, at continuous heating/cooling with different rates and in isothermal conditions at different temperatures. The changes taking place on the sample surface during the experiments were monitored. The morphology of the alpha ==> beta ==> alpha phase transformation was recorded at different heat treatment conditions using the effect of thermal etching. An effect of sample surface oxidation and deoxidation was observed during continuous heating. The appearance and disappearance of ordered titanium oxides Ti3O and Ti2O are discussed based on the phase equilibrium diagram. The kinetics of the surface oxidation was monitored in both isothermal and continuous cooling conditions.

  5. [Use of nickel-titanium alloys in plasty of the anterior abdominal wall].

    Science.gov (United States)

    Veronskiĭ, G I; Zotov, V A

    2000-01-01

    The work presents results of the surgical treatment of postoperative hernias of the abdominal wall using explants of titanium nickelide in 48 patients. Data of biopsy of the anterior abdominal wall muscles in these patients are given. The anatomo-morphological and functional incompetence is shown. A method of preparing the patients with giant hernias to operation with the help of dynamic pneumocompression is described. The indications to using the explants in hernioplasty are determined by the methods of somatometry and intraoperative dynamometry. The data of three methods of combined hernioplasty are presented: with the use of a superelastic network from a nickelide-titanium alloy; explant with tractional properties, effect of the "shape memory"; method of extracorporeal extension of the abdominal wall at the postoperative period. The nearest and long-term results followed-up during 3 years are shown.

  6. Application of gas-fluid atomization technology in ultrosonic vibration cutting titanium alloy workpiece

    Science.gov (United States)

    Zhou, Zhimin; Zhang, Yuangliang; Li, Xiaoyan; Sun, Baoyuan

    2009-11-01

    To further improve machined surface quality of diamond cutting titanium workpiece and reduce diamond tool wear, it puts forward a kind of machining technology with mixture of carbon dioxide gas, water and vegetable oil atomized mist as cooling media in the paper. The cooling media is sprayed to cutting area through gas-liquid atomizer device to achieve purpose of cooling, lubricating, and protecting diamond tool. Experiments indicate that carbon dioxide gas can touch cutting surface more adequately through using gas-liquid atomization technology, which makes iron atoms of cutting surface cause a chemical reaction directly with carbon in carbon dioxide gas and reduce graphitizing degree of diamond tool. Thus, this technology of using gas-liquid atomization and ultrasonic vibration together for cutting Titanium Alloy is able to improve machined surface quality of workpiece and slow of diamond tool wear.

  7. Adherence of extracellular matrix components to modified surfaces of titanium alloys

    Science.gov (United States)

    Stelzer, C.; Uhlmann, E.; Meinke, M.; Lademann, J.; Hansen, U.

    2009-04-01

    The adherence of biological materials on metal surfaces is of special importance in biology and medicine. The underlying interactions between surface and biological materials (e.g. extracellular matrix components or cells) are responsible for the application as a medical device. Numerous products are made of pure titanium and titanium alloys. This paper shows the influence of a laser production technology on machined surfaces of TiAl6V4 and the resulting adherence of biological material on the basis of the surface characterisation. In this study, different machined TiAl6V4 surfaces were used for coatings with extracellular matrix components. For this process, different coating with collagen I monomers and a complex mixture of extracellular matrix proteins derived from the dermal-epidermal basement membrane zone were analysed. The efficiency of the coating was analysed by different methods and the results are presented in this paper.

  8. Numerical simulation and its application of rheological forming of titanium alloy vane disk

    Institute of Scientific and Technical Information of China (English)

    YU Min; LUO Ying-she; PENG Xiang-hua; QIN Yin-hui

    2006-01-01

    The hot rheological forming method was proposed to form the second titanium alloy vane disk. The hot rheological forming process of the TC11 titanium vane disk under a certain temperature and different strain rates was investigated by using the bulk forming software of DEFORM 3D. A series of results including temperature field,equivalent strain distribution,load-stroke curve and rheology procedure were obtained by this finite element method. The rheological forming characteristics were well realized and the forming parameters were determined. The results and analysis show that with decreasing strain rate,the metal flow more equably and the filling of the vane shape is also better. Moreover,the mechanical properties and microstructures of the products produced by this new technique are improved evidently compared with that produced by traditional method.

  9. The Influence of Process Parameters on Properties of Conversion Coatings Deposited on Titanium Alloy

    Directory of Open Access Journals (Sweden)

    Karaś M.

    2016-03-01

    Full Text Available The effect of process parameters of conversion coatings on the corrosion resistance was investigated. To produce anodic coatings, the solutions of H2SO4 of 0.5 and 1 M concentrations and current densities of 0.5 and 1 A/dm2 were applied. The coatings were deposited by galvanostatic technique on titanium Grade 1. The result of the study was comparison of the corrosion resistance of coatings produced under varying parameters such as: the anodic current density, the electrolyte concentration, and the speed of reaching the preset voltage. Corrosion tests performed by potentiodynamic polarization test have shown that even nanometric anodic films of amorphous structure improve the corrosion resistance of titanium alloy. The lowest corrosion current and the corrosion potential of the most cathodic nature were observed in the sample with anodic coating produced at J = 1 A/dm2 in a 0.5 M H2SO4 electrolyte concentration.

  10. Study on arc-ultrasonic TIG welding of titanium alloy

    Institute of Scientific and Technical Information of China (English)

    周荣林; 郭德伦; 李从卿; 张银根

    2004-01-01

    TC4 alloy was welded by conventional TIG welding and arc-ultrasonic TIG welding respectively. The microstructure of joint was analyzed by means of optical-microscope, scanning electron microscope in order to study the relationship between the macro-properties of joint and the microstructure. The results show that the joints were all welded successfully by conventional TIG welding and arc-ultrasonic TIG welding. With the increment of ultrasonic frequency and activated voltage, the width of joint became narrow step by step. The microstructure became more and more fine and was inclined to equiaxed crystal. Moreover, the dendrite depredation was not observed obviously. The properties of welded joint were improved markedly compared with that of conventional TIG welding.

  11. NUMERICAL SIMULATION OF INDUCTION SKULL MELTING PROCESS FOR TITANIUM-ALUMINIUM BASE ALLOY

    Institute of Scientific and Technical Information of China (English)

    Z.Y. Chen; L.J. Xu; F.T. Kong; Q. Shu; Y.Y. Chen

    2004-01-01

    The mathematics model for temperature field of water-cooling copper crucible induction skull melting process was established. The program for simulating temperature field of melting process was developed with finite element method. The temperature field of the melting process for Ti-47Al-2Cr-2Nb alloy was calculated. During melting period, the temperature is raised gradually along radius augmentation direction. The elements of the charge near the crucible wall are molten first. The center elements of the charge are molten last. The melting time of the center element is just that of all the charge melting. The melting time of Ti-47Al-2Cr-2Nb alloy is 15min. In which, the charge was heated by low power 80kW for 9min and by high power 300kW for 6min. When melting Ti-47Al-2Cr-2Nb alloy,the loading power is nearly direct proportion to melt temperature. Increasing loading power may raise melt temperature. The best melting power of Ti-47Al-2Cr-2Nb alloy is 305-310kW. This is identical with the melting test and has guidance sense to the melting process of actual titanium alloy.

  12. Electrochemical behaviour of commercially pure titanium and Co-Cr alloy in Ringer's solution

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The electrochemical behaviors of commercially pure titanium (CP Ti) and Co-Cr alloy in Ringer's solution have been investigated. The results indicate that the electric potential of passive region for CP Ti is up to 3000 mV, and its passive current density is 3.078 (A/cm2. The excellent corrosion resistance of CP Ti can be attributed to the formation of TiO2 oxide film. The passive region of Co-Cr alloy is 770 mV, which is narrower than that of CP Ti. However, no hysteresis loops are found in the reverse scanning curves of Cu-Cr alloy. A complex oxide film of Co3O4, Co2O3, and Cr2O3 formed on the surface provides Co-Cr alloy with a stable electrochemistry property. The corrosion rates of the crevice samples increase with the pH value of medium decreasing. The electron probe microanalyzer (EPMA) analysis indicates that Ti in CP Ti and Co, Cr in Co-Cr alloy dissolve in crevice area due to the Sealed-Cell effect.

  13. Influence of heating rate on the temperature of the (alpha+beta)-beta transformation of titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gridnev, V.N.; Ivasishin, O.M.; Markovskii, P.E.

    1985-07-01

    Results of a systematic experimental study of the effect of the heating rate, composition, and structure on the temperature of the (alpha+beta)-beta transformation in titanium alloys VT6, VT14, VT3-1, VT23, and VT22 are presented. It is shown that the transformation temperature of the alloys increases proportionally to the coefficient k-beta, which characterizes the alloy content, and to the size of the alpha-phase grains in the original structure. All other conditions being equal, the transformation is completed sooner in alloys with a spheroidal structure. 8 references.

  14. Gelatin functionalised porous titanium alloy implants for orthopaedic applications

    Energy Technology Data Exchange (ETDEWEB)

    Vanderleyden, E. [Polymer Chemistry and Biomaterials Research Group, Department of Organic Chemistry, University of Ghent, Krijgslaan 281 S4, 9000 Ghent (Belgium); Van Bael, S. [Prometheus, Division of Skeletal Tissue Engineering, Katholieke Universiteit Leuven, O and N 1, Herestraat 49, Box 813, 3000 Leuven (Belgium); Department of Mechanical Engineering, Division of Production Engineering, Machine Design and Automation, Katholieke Universiteit Leuven, Celestijnenlaan 300b, 3001 Leuven (Belgium); Department of Mechanical Engineering, Division of Biomechanics and Engineering Design, Katholieke Universiteit Leuven, Celestijnenlaan 300c, Box 2419, 3001 Heverlee (Belgium); Chai, Y.C. [Prometheus, Division of Skeletal Tissue Engineering, Katholieke Universiteit Leuven, O and N 1, Herestraat 49, Box 813, 3000 Leuven (Belgium); Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Center, Katholieke Universiteit Leuven, O and N 1, Herestraat 49, Box 813, 3000 Leuven (Belgium); Kruth, J.-P. [Department of Mechanical Engineering, Division of Production Engineering, Machine Design and Automation, Katholieke Universiteit Leuven, Celestijnenlaan 300b, 3001 Leuven (Belgium); Schrooten, J. [Prometheus, Division of Skeletal Tissue Engineering, Katholieke Universiteit Leuven, O and N 1, Herestraat 49, Box 813, 3000 Leuven (Belgium); Department of Metallurgy and Materials Engineering, Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, Bus 2450, 3001 Leuven (Belgium); Dubruel, P., E-mail: pbmugent@gmail.com [Polymer Chemistry and Biomaterials Research Group, Department of Organic Chemistry, University of Ghent, Krijgslaan 281 S4, 9000 Ghent (Belgium)

    2014-09-01

    In the present work, we studied the immobilisation of the biopolymer gelatin onto the surface of three dimensional (3D) regular Ti6Al4V porous implants to improve their surface bio-activity. The successful immobilisation of the gelatin coating was made possible by a polydopamine interlayer, a polymer coating inspired by the adhesive nature of mussels. The presence of both coatings was first optimised on two dimensional titanium (2D Ti) substrates and confirmed by different techniques including X-ray photelectron spectroscopy, contact angle measurements, atomic force microscopy and fluorescence microscopy. Results showed homogeneous coatings that are stable for at least 24 h in phosphate buffer at 37 °C. In a next step, the coating procedure was successfully transferred to 3D Ti6Al4V porous implants, which indicates the versatility of the applied coating procedure with regard to complex surface morphologies. Furthermore, the bio-activity of these stable gelatin coatings was enhanced by applying a third and final coating using the cell-attractive protein fibronectin. The reproducible immobilisation process allowed for a controlled biomolecule presentation to the surrounding tissue. This newly developed coating procedure outperformed the previously reported silanisation procedure for immobilising gelatin. In vitro cell adhesion and culture studies with human periosteum-derived cells showed that the investigated coatings did not compromise the biocompatible nature of Ti6Al4V porous implants, but no distinct biological differences between the coatings were found. - Highlights: • Ti6Al4V porous implants were produced by selective laser melting. • A procedure to obtain a stable gelatin coating was developed. • Successful transfer of the coating procedure from 2D to 3D Ti6Al4V porous implants. • In vitro cell studies showed that the developed coatings supported cell growth.

  15. Prediction of Failure Due to Thermal Aging, Corrosion and Environmental Fracture in Amorphous and Titanium Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J C

    2003-04-15

    DARPA is exploring a number of advanced materials for military applications, including amorphous metals and titanium-based alloys. Equipment made from these materials can undergo degradation due to thermal aging, uniform corrosion, pitting, crevice corrosion, denting, stress corrosion cracking, corrosion fatigue, hydrogen induced cracking and microbial influenced corrosion. Amorphous alloys have exceptional resistance to corrosion, due in part to the absence of grain boundaries, but can undergo crystallization and other phase instabilities during heating and welding. Titanium alloys are extremely corrosion resistant due to the formation of a tenacious passive film of titanium oxide, but is prone to hydrogen absorption in crevices, and hydrogen induced cracking after hydrogen absorption. Accurate predictions of equipment reliability, necessary for strategic planning, requires integrated models that account for all relevant modes of attack, and that can make probabilistic predictions. Once developed, model parameters must be determined experimentally, and the validity of models must be established through careful laboratory and field tests. Such validation testing requires state-of-the-art surface analytical techniques, as well as electrochemical and fracture mechanics tests. The interaction between those processes that perturb the local environment on a surface and those that alter metallurgical condition must be integrated in predictive models. The material and environment come together to drive various modes of corrosive attack (Figure 1). Models must be supported through comprehensive materials testing capabilities. Such capabilities are available at LLNL and include: the Long Term Corrosion Test Facility (LTCTF) where large numbers of standard samples can be exposed to realistic test media at several temperature levels; a reverse DC machine that can be used to monitor the propagation of stress corrosion cracking (SCC) in situ; and banks of potentiostats with

  16. Investigation of photocatalytic activity of titanium dioxide coating deposited on aluminium alloy substrate by plasma technique

    DEFF Research Database (Denmark)

    Daviðsdóttir, Svava; Soyama, Juliano; Dirscherl, Kai

    2011-01-01

    . Literature consists of large number of publications on titanium dioxide coating for self-cleaning applications, with glass as the main substrate. Only little work is available on TiO2 coating of metallic alloys used for engineering applications. Engineering materials, such as light-weight aluminium and steel...... of the coating strongly influences the photocatalytic properties. In general, the photocatalytic activity increased with thickness. Quantification of images scanned with Atomic Force Microscope (AFM) revealed that there is a linear relationship between the thickness of the coating and the average cell size...

  17. Stability analysis of titanium alloy milling by multiscale entropy and Hurst exponent

    Science.gov (United States)

    Rusinek, Rafał; Borowiec, Marek

    2015-10-01

    This paper discusses the problem of stability in a milling process for titanium super-alloy Ti6242. The phenomenon of chatter vibration is analysed by the multiscale entropy method and Hurst exponent. Although this problem is often considered based on stability lobe diagrams, theoretical findings do not always agree with experimental results. First, a stability lobe diagram is created based on parameters determined by impact testing. Next, cutting forces are measured in an experiment where the axial cutting depth is gradually increased. Finally, the obtained experimental signals are investigated with respect to stability using the multiscale entropy method and Hurst exponent.

  18. A fundamental approach to adhesion: Synthesis, surface analysis, thermodynamics and mechanics. [titanium alloys

    Science.gov (United States)

    Chen, W.; Dwight, D. W.; Wightman, J. P.

    1978-01-01

    Various surface preparations for titanium 6-4 alloy were studied. An anodizing method was investigated, and compared with the results of other chemical treatments, namely, phosphate/fluoride, Pasa-Jell and Turco. The relative durability of the different surface treatments was assessed by monitoring changes in surface chemistry and morphology occasioned by aging at 505 K (450 F). Basic electron spectroscopic data were collected for polyimide and polyphenylquinoxaline adhesives and synthetic precursors. Fractographic studies were completed for several combinations of adherend, adhesive, and testing conditions.

  19. A low-cost hierarchical nanostructured beta-titanium alloy with high strength

    OpenAIRE

    Devaraj, Arun; Joshi, Vineet V.; Srivastava, Ankit; Manandhar, Sandeep; Moxson, Vladimir; Duz, Volodymyr A.; Lavender, Curt

    2016-01-01

    Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission. Working towards this goal we achieved high strength in a low cost β-titanium alloy, Ti–1Al–8V–5Fe (Ti185), by hierarchical nanostructure consisting of homogenous distribution of micron-scale and nanoscale α-phase precipitates within the β-phase matrix. The sequence of phase transformation leading to this hierarchical na...

  20. Equations of state for titanium and Ti6A14V alloy.

    Energy Technology Data Exchange (ETDEWEB)

    Kerley, Gerald Irwin (Kerley Technical Services, Appomattox, VA)

    2003-10-01

    The PANDA code is used to build tabular equations of state (EOS) for titanium and the alloy Ti4Al6V. Each EOS includes solid-solid phase transitions, melting, vaporization, and thermal electronic excitation. Separate EOS tables are constructed for the solid and fluid phases, and the PANDA phase transition model is used to construct a single multiphase table. The model explains a number of interesting features seen in the Hugoniot data, including an anomalous increase in shock velocity, recently observed near 200 GPa in Ti6Al4V. These new EOS tables are available for use with the CTH code and other hydrocodes that access the CTH database.