Papers by Keyword: Titanium Alloy

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Authors: Qiu Lin Niu, Guo Giang Guo, Xiao Jiang Cai, Zhi Qiang Liu, Ming Chen
Abstract: As two kinds of advanced titanium alloys, TC18 and TA19 were introduced in this paper. The machinabilities of TC18 and TA19 alloys were described in the grinding process. Grinding experiments were completed using green silicon carbide grinding wheel with the coarser 100 grit. Grinding forces and specific energy in surface grinding were investigated. And then, for studying the grinding characteristic, SEM images of the workpiece material were obtained. The results indicated that specific chip formation had the great effect on the mechanism of grinding TC18 and TA19 alloys, and the scratch was the main characteristic of surface grinding. TC18 alloy had the poor grinding performance compared to TA19 alloy.
Authors: Swapan Barman, Asit Baran Puri, Nagahanumaiah
Abstract: Efficiency of any machining process depends on the effectiveness of final outcomes. Surface integrity plays an important role in functional performance of a part or component. Traditionally, surface roughness is considered to be the principal parameter to assess the surface integrity of a machined surface. In this paper, the influences of machining parameters like gap voltage, capacitance and depth of hole on the surface finish parameters like Ra and Sa of micro holes have been studied in micro electrical discharge drilling. The high aspect ratio blind micro holes were drilled on titanium alloy (Ti-6Al-4V) with cylindrical tungsten tool electrodes. The experimentation was carried out adopting a full factorial design (33). The simultaneous effects of machining parameters on responses were analysed using response surface methodology. Multiple linear regression models were developed for responses to obtain the correlation between machining parameters and machining outputs. Multi-objective optimization has been performed with the aid of the desirability function approach.
Authors: Yu Hai Yang, Jian Ye Guo, Chao Yu
Abstract: This paper took a titanium alloy thin-wall splined tube as the object of research, and mainly analyzed the influences of cutting force to machining deformation of part in turning process. The paper first introduced the structure composition and characteristic of splined tube, then established the mathematical model of cutting force in turning process according to the orthogonal experiment method and the multiple regression algorithm, and finally the influences of cutting force to machining deformation of splined tube was carried on the simulation analysis with the aid of the finite element analysis software under the different cutting conditions. The conclusions of research in this paper will have important practical significance to reduce the machining deformation of thin-wall part and optimize the cutting parameters of difficult-to-machine material.
Authors: Dai Yamamoto, Kensuke Kuroda, Ryoichi Ichino, Masazumi Okido
Abstract: Titanium and Ti alloys are widely used as substitutional materials for natural bone because of their good biocompatibility, high strength, and high corrosion resistance. In our previous studies, TiO2 coating on Ti with Ra (arithmetical means of roughness) < 0.1 μm formed by anodizing had much higher osteoconductivity than that of pure Ti. It can be expected that TiO2 coating with fine surface can improve the osteoconductivity of Ti alloys. In this study, the effects on the osteoconductivity of TiO2 coatings on different kinds of Ti alloys were investigated by in vivo study. TiO2 coatings with Ra < 0.1 μm were formed on 4 kinds of Ti alloys (Ti-6Al-4V (Ti64), Ti-6Al-7Nb (Ti67), Ti-29Nb-13Ta-4.6Zr (TNTZ), Ti-13Cr-1Fe-3Al (TCFA)) using anodizing in H3PO4 aqueous solution. Surface properties of these coatings were evaluated using SEM, XRD, and XPS. In in vivo study, samples were implanted in rats’ tibia for 14 days, and then removed. Cross section of the sample was observed with optical microscope and bone-implant contact ratio (RB-I) at the interface between body tissue and bone was used as a parameter of osteoconductivity. Anatase type TiO2 coatings with Ra < 0.1 μm were uniformly formed on all of the Ti alloys by anodizing at low voltage. These oxide coatings contained the ions of other alloy elements. TiO2 coatings on Ti64 and Ti67 indicated high osteoconductivity similar to that of TiO2 coating on pure Ti. On the contrary, TiO2 coating on TNTZ and TCFA showed low osteoconductivity. It was thought that ions of alloy elements brought bad influence on the osteoconductivity of TiO2.
Authors: Ana Lucia do Amaral Escada, Cristiane Aparecida Pereira, Antonio Olavo Cardoso Jorge, Ana Paula Rosifini Alves Claro
Abstract: In the present work, the efficacy of the Ti–7.5Mo alloy nanotube and Ti–7.5Mo alloy nanotube with chlorhexidine against bacterial biofilm formation was evaluated. Nanotubes were processed using anodization in 0.25% NH4F electrolyte solution. Biofilms were cultured in discs immersed in sterile brain heart infusion broth (BHI) containing 5% sucrose, inoculated with microbial suspension (106 cells/ml) and incubated for 5 days. Next, the discs were placed in tubes with sterile physiological solution 0.9% sodium chloride (NaCl) and sonicated to disperse the biofilms. Tenfold serial dilutions were carried and aliquots seeded in selective agar, which were then incubated for 48 h. Then, the numbers CFU/ml (log 10) were counted and analyzed statistically. Scanning electron microscopy (SEM) on discs with biofilms groups and contact angle was carried out. The results show that there is no difference in bacterial adhesion between of the Ti–7.5Mo alloy nanotube and Ti–7.5Mo alloy nanotube with chlorhexidine.
Authors: Pavlo E. Markovsky
Abstract: Local Rapid Heat Treatment (LRHT) based on induction-heating methods can be used to form unique location-specific microstructures and properties in commercial titanium alloys while maintaining the bulk of the material in an initial, non-heat-treated condition. The present work is focused on practical aspects of LRHT application for microstructure/ mechanical properties improvement of some parts made of commercial titanium alloys. It is shown, that LRHT application could improve mechanical properties of such complicated part like turbine engine compressor blades, and two made of Ti-6Al-4V and VT22 titanium alloys goods after repair with Electron Beam Physical Vapor Deposition as well as with Build-up Welding.
Authors: A. Ramamurthy, R. Sivaramakrishnan, S. Venugopal, T. Muthuramalingam
Abstract: It is very tedious process to find the optimum multiple performance measures of wire EDM process parameters and role of each parameter to attain the better performance characteristics. Since the WEDM process involves more one than machining characteristics, it is important to carry out the multi-response optimization methodology. In the present study, an attempt has been made to find the optimum process parameters using Taguchi-Grey relational analysis. The machining experiments have been conducted with different levels of input factors such as voltage, peak current, pulse on time, and pulse off time and wire material based on Taguchi L18 orthogonal table. Experimental results have indicated that the multi-response characteristic such material removal rate and surface roughness can be enhanced by 1.2% effectively through grey relational analysis.
Authors: Artemiy A. Popov, A.G. Illarionov, S.V. Grib
Abstract: A possibility of using the electron concentration calculation method to evaluate Acm and Ac3 temperatures in the Ti-Cr system alloys with different hydrogen content (0.15-0.93 wt %) is considered. It is found that the proposed method gives results similar to the experimental data only in the case of low hydrogen concentrations since it does not take into account the degree of hydrogen ion screening by electrons.
Authors: Cristina Ileana Pascu, Stefan Gheorghe, Ilie Dumitru, Claudiu Nicolicescu
Abstract: For this study with high originality, some aspects about the sintering behaviour of Titanium based alloy used for automotive components are presented. This paper presents the experimental results concerning the processing of Ti based alloy by Powder Metallurgy (PM) technology. The initial powder mixture consists in TiH2 micrometric powder particles that have been combined with some metallic powders for improving the final mechanic-chemicals and functional properties for using in the automotive industry. The classical PM route have been applied for obtaining a low-cost Ti- alloy.As a result it was compulsory to study the parameters that influence the densification process and the sintered properties, depending on the sintering temperature. The experimental test results were processed using the STATISTICA program. Therefore the influence of these sintering temperatures on the height and diameter shrinkages, density and hardness for the alloys based on Ti micrometric powders has been studied.
Authors: A.N. Mustafizul Karim, M. Ikram, H.M. Emrul Kays, M. Abdesselam, T.L. Ginta
Abstract: Past few decades have been marked by significant achievements in the development of cutting tools and machining processes. End-milling operation with Polycrystalline Diamond (PCD) cutting tool insert presents a good technical solution for machining difficult-to-cut materials. However, the cost of each technical or technological solution is a major concern in the decision making process. It is quite common for a solution developer to encounter a question like How much will this new method cost? before proceeding for implementation. PCD insert applied as a cutting tool is a recent development and evaluation of economic performance of this cutting tool insert in end-milling of a-difficult-to-cut material such as Ti-6Al-4V titanium alloy can be of significant importance to the manufacturer. However, cost economy depends significantly on the correct choice of cutting conditions especially in the context of cutting parameters. To determine the economically desired levels of the cutting parameters for PCD insert to end-mill Titanium alloy we have presented a RSM-based mathematical model which would help to estimate the cost of removing unit volume of material and to find out the optimum cutting conditions leading to minimum machining cost.
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