Use Of Titanium Alloys Research Articles

Relationship between phase composition and wear resistance of titanium alloys

The wide use of titanium alloys is often due to their unique properties. Availability of a wide variety of mechanical, physical and chemical properties is associated with a large number of polymorphic modifications of titanium alloys. During the last decade, the metastable omega phase piques the largest interest among all titanium modifications. This study attempts to explain the different wear behavior of some titanium alloys with different Nb content during dry friction impact.

Analysis of cryogenic tool wear during electrical discharge machining of titanium alloy grade 5

The extensive use of Titanium alloy Ti-6Al-4V in defense, aerospace, automotive and biomedical sectors has made this material most demandable among industries. Due to low thermal conductivity it is difficult to machine by conventional machining processes. Electric discharge machining is a viable option to machine extremely harder and electrically conductive materials. There are a lot of possibilities in EDM to machine super alloys. Electrical discharge machining has also huge potential when it comes to biomaterials. Super alloy like Titanium grades 5 is most suitable for the biomedical field due to its desirable bio-compatible properties. In this study effect of cryogenic treatment of tool, current, pulse on time, pulse off time and voltage has been investigated on tool wear rate. Optimized conditions for minimum tool wear rate have been found and microstructural analysis was also carried out to observe the surface topography of machined surface with non treated and cryogenic treated tool electrode. It has been observed that tool wear rate of cryogenic copper tool is comparatively more as compared to non treated copper tool electrode. The effect of current, on-time and type of tool electrode is found to be more pronounced as compared to other machining parameters. Thick recast layer with wide surface cracks is observed on the surface machined by the non treated tool electrode. Whereas narrow micro cracks with thin recast layer is observed on the surface machined by cryogenic treated tool electrode.

Computer aided modelling and experimental validation for effective milling operation of titanium alloy (Ti6Al4V)

Titanium alloy (Ti6Al4V) is characterized with excellent mechanical properties, which makes it suitable for many industrial applications. However, the poor rate of machinability mitigates the use of titanium alloy (Ti6Al4V). This study highlight the various methods to improve the machinability and surface finish of titanium alloy. These methods include; the use of PCD and PCBN tools, cooling systems, process optimization as well as the design and selection of the proper geometry for the cutting tool. The Computer Aided Design, modelling and simulation as well as the Finite Element Analysis of the milling process of Ti6Al4V was carried out using Solidworks 2016. The physical experiments were conducted on a DMU80monoBLOCK Deckel Maho 5-axis CNC milling with the stationary dynamometer (KISTLER 9257A 8-Channel Summation of Type 5001A Multichannel Amplifier) mounted directly to the machine table and the work piece screwed to it. The milling operations was carried out with different combination of cutting parameters while the values of the cutting force for each of the experimental trial was collected through the Data Acquisition System (DAS) connected to the computer. The results obtained show that the process parameters affect the magnitude of the cutting force significantly which in turn affects the rate of material removal. This work finds application in the manufacturing industry as it provides in depth understanding of the machining characteristics and behaviour of titanium alloy.

Research and Development of Low-cost Titanium Alloys

Excellent mechanical properties combined with low density, good corrosion resistance and welding, make titanium alloy attractive structural materials for aerospace, ship navigation, weaponry and nuclear industry. However, the high cost impedes the further use of titanium alloy in different fields, and which is the key factor for productivity and further use of titanium alloy. Aiming at lost cost of titanium alloy, three parts of raw material, alloy design and working forming were overviewed, which will offer reference for how to low cost of titanium alloy.

The role of high-pressure coolant in the wear characteristics of WC-Co tools during the cutting of Ti–6Al–4V

Aeronautic applications have been making use of titanium alloys for decades. Ti–6Al–4V is one of the most commonly applied alloys, and although its mechanical properties warrant its acceptance for many applications, the machinability of this alloy remains a challenge. So far, the most successful technique in facilitating this alloy's machining has been the application of High-Pressure Coolant Supply (HPC) on account of its influence on the tribological aspects of the cutting operation. On that premise, this work employs experimental and computational resources to advance the current understanding of the wear mechanism in terms of the tool-chip contact conditions and establish a correlation between coolant pressure, cutting speed, tool life, cutting forces, and chip formation when machining Ti–6Al–4V with HPC supply. Results showed that HPC plays a role in the reduction of tool-chip temperature profiles and contact stresses, positively impacting tool flank wear, oxidation levels and chip formation, also improving chip breakability.

VT6 TITANIUM ALLOY WEARABILITY INCREASE VIA IMPLANTATION OF COPPER AND ALUMINUM IONS

The relevance of the article is due to the fact that the use of titanium alloys within friction joints is restrained by their low resistance to wear while traditional methods of increasing their wear resistance are ineffective. The objective of this work was to study the processes occurring on the surface of VT6 titanium alloy samples when implanting with copper and aluminum ions, as well as in friction. Elemental composition, structural-phase state, mechanical and tribological properties of VT6 titanium alloy surface layers modified by aluminum and copper ions during the high-intensity ion-implantation process was being researched. As can be seen from the undertaken studies, the mode of the high-intensity ion-implantation process makes it possible to obtain ion doped surface layers of VT6 alloy containing TiAl, Ti3Al, Ti3Cu, Ti2Cu, TiCu finely dispersed intermetallic phases and a solid solution of aluminum and copper in titanium of composition varying in depth. The thickness of the ion-doped layer, the average grain size of the intermetallic phases (from 18 to 55nm) and their conglomerates (from 45 to 280 nm) increases with the increase in implantation dose from 2⋅1017 to 1.2⋅1019 ion/cm2 while aluminum implantation (from 0.42 to 2.1 μm) is in progress. It has been shown that the implantation of aluminum and copper ions into VT6 alloy leads to a considerable increase in its microhardness and wearability. Based on the research results, a conclusion on the positive effect of a structural-phase state of ion-doped titanium layers on their mechanical and tribological properties of VT6 titanium alloy has been drawn.

An Overview on the Tribological Performance of Titanium Alloys with Surface Modifications for Biomedical Applications

The need for metallic biomaterials will always remain high with their growing demand in joint replacement in the aging population. This creates need for the market and researchers to focus on the development and advancement of the biometals. Desirable characteristics such as excellent biocompatibility, high strength, comparable elastic modulus with bones, good corrosion resistance, and high wear resistance are the significant issues to address for medical implants, particularly load-bearing orthopedic implants. The widespread use of titanium alloys in biomedical implants create a big demand to identify and assess the behavior and performance of these alloys when used in the human body. Being the most commonly used metal alloy in the fabrication of medical implants, mainly because of its good biocompatibility and corrosion resistance together with its high strength to weight ratio, the tribological behavior of these alloys have always been an important subject for study. Titanium alloys with improved wear resistance will of course enhance the longevity of implants in the body. In this paper, tribological performance of titanium alloys (medical grades) is reviewed. Various methods of surface modifications employed for titanium alloys are also discussed in the context of wear behavior.

Intramedullary nailing biomechanics: Evolution and challenges.

This article aims to review the biomechanical evolution of intramedullary nailing and describe the breakthrough concepts which allowed for nail improvement and its current success. The understanding of this field establishes an adequate background for forthcoming research and allows to infer on the path for future developments on intramedullary nailing. It was not until the 1940s, with the revolutionary Küntscher intramedullary nailing design, that this method was recognized as a widespread medical procedure. Such achievement was established based on the foundations created from intuition-based experiments and the first biomechanical ideologies. The nail evolved from allowing alignment and stability through press-fit fixation with nail-cortical wall friction to the nowadays nail stability achieved through interlocking screws mechanical linkage between nail and bone. Important landmarks during nail evolution comprise the introduction of flexible reaming, the progress from slotted to non-slotted nails design, the introduction of nail 'dynamization' and the use of titanium alloys as a new nail material. Current biomechanical improvement efforts aim to enhance the bone-intramedullary nail system stability. We suggested that benefit would be attained from a better understanding of the ideal mechano-biological environment at the fracture site, and future improvements will emerge from combining mechanics and biological tools.

Microstructural evolution and corrosion properties of laser clad Ti-Ni on titanium alloy (Ti6Al4V)

The use of Titanium alloys (Ti6Al4V) is highly evident in applications such as aerospace, automobile, marine and petrochemical environments owing to their outstanding specific strength to weight ration and good corrosion properties. Although they have high strength useful for fabrication of engineering components and movable parts in a mechanical system, Ti6Al4V are restricted to non-friction applications as a result of their low hardness and poor wear resistance. In this work, TiNi intermetallic hard coatings on Ti6Al4V alloy via coaxial laser cladding method. The effects of laser processing parameters on morphological evolution, microhardness and electrochemical behaviour were studied. The phase present and microstructural evolution were characterized using X-ray diffractometry (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) respectively. The corrosion behaviour of the synthesized hard coating was evaluated using potentiodynamic polarization technique in 0.5M H2SO4. The microstructures showed no evidence of porosity, crack or initiation of stress.

Behavior of Titanium Alloys in Aerodynamic Heating of Hypersonic Airplanes

The requirements on the use of titanium alloys used as thermal protection in hypersonic airplanes are considered. The ignition of titanium alloys in aerodynamic heating is analyzed. A mathematical model is proposed for the surface oxidation of the alloys in a high-temperature air flux.

Calculated and experimental evaluation of the performance of the brake disc made of titanium alloy

The aim of the work is to reduce the unsprung weight of the wheel of a racing automobile due to the use of a disc made of titanium alloy in the brake mechanism. The object of the study is the brake disc of a vehicle of the Formula Student class. The subject of research is the use of titanium alloy in the design of the brake disc and its performance evaluation. As part of the work, an analysis of the thermal loading of the brake disc made of titanium alloy and the experimental verification of its performance were made. The calculations of thermal loading were carried out by the finite element method. To this end, a calculation method has been developed taking into account changes in the heat flux and convection coefficient during multiple braking. The paper presents the results obtained when carrying out calculations in accordance with this method. The numerical evaluation showed that the temperature arising in the brake mechanism does not exceed the permissible for the working capacity of the brake mechanism. The full-scale experiment showed that the calculated disk temperature, which occurs during braking, is close to the temperature established during the full-scale experiment. The error is not more than 13%. A full-scale experiment showed that the brake disc made of titanium alloy is not operational with the selected manufacturing technology. The conclusions were drawn on the applicability of the above method of thermal analysis of the brake disc, on the performance of the structure, and proposals were made for improving its efficiency.

Growth of anodic Aluminum Oxide using titanium as cathode – a review

Aluminum is a material with a variety of uses in various fields because this material is easy to obtain, can be made in various ways and has good corrosion resistance. Now this material begins to be studied and applied to the realm of biomaterials, with the use of the membrane of the aluminum oxide layer on the body of living things began to be applied. In this paper further elaborated on the use of titanium alloys as cathodes in the aluminum anodizing process. Deep discussion is emphasized on the growth process of the oxide layer that occurs during the anodizing process, where the oxide layer consists of a barrier layer and a pore layer. During the process, not only does the oxide layer grow with time but also the appearance of voids in the pore lining wall. In the final result, it was found that titanium was able to penetrate the oxide layer formed during the anodizing process. As for future applications, it is expected that the anodizing material is expected to be an alternative material in the field of biomaterial replacement

Effect of CeO₂ on Microstructure and Wear Resistance of TiC Bioinert Coatings on Ti6Al4V Alloy by Laser Cladding.

To solve the lack of wear resistance of titanium alloys for use in biological applications, various prepared coatings on titanium alloys are often used as wear-resistant materials. In this paper, TiC bioinert coatings were fabricated on Ti6Al4V by laser cladding using mixed TiC and ZrO2 powders as the basic pre-placed materials. A certain amount of CeO2 powder was also added to the pre-placed powders to further improve the properties of the TiC coatings. The effects of CeO2 additive on the phase constituents, microstructures and wear resistance of the TiC coatings were researched in detail. Although the effect of CeO2 on the phase constituents of the coatings was slight, it had a significant effect on the microstructure and wear resistance of the coatings. The crystalline grains in the TiC coatings, observed by a scanning electron microscope (SEM), were refined due to the effect of the CeO2. With the increase of CeO2 additive content in the pre-placed powders, finer and more compact dendrites led to improvement of the micro-hardness and wear resistance of the TiC coatings. Also, 5 wt % content of CeO2 additive in the pre-placed powders was the best choice for improving the wear properties of the TiC coatings.

Microstructural characterization of Ti-6Al-4V X-links from the Space Shuttle Columbia

Recovered artifacts from the Space Shuttle Columbia provide a unique opportunity to examine a broad spectrum of materials exposed to the extreme environment of earth re-entry. The degradation states of these components offer a unique perspective into material behavior in this highly reactive environment. The crew module X-links, which are composed of Ti-6Al-4V and provided structural support to the crew module within the fuselage, exhibit evidence of both oxidation and combustion phenomena. The conditions supporting ignition and combustion of bulk metals are not fully understood, due to the many compounding factors affecting variable oxidation behavior of metals. Materials characterization of the Columbia X-links will yield further insight into the discrimination between the oxidation, ignition, and combustion response of titanium alloys. Widespread use of titanium alloys in space vehicles warrants a thorough characterization of their potential failure modes to help ensure the safe and reliable operation of future spaceflight vehicles. Initial microstructural state of the X-links is assessed, and affected material exhibits microstructural gradients dependent on vehicle orientation. Three distinct microstructural states were observed across the length of the X-links, according to proximity of aggravated flow.

Infrared thermography for monitoring heat generation in a linear friction welding process of Ti6Al4V alloy

The increasing use of titanium alloys in a wider range of applications requires the development of new techniques and processes capable to decrease production costs and manufacturing times. In this regard welding and other joining techniques play an important role. Today, solid state friction joining processes, such as friction stir welding, friction spot welding, inertia friction welding, continuous-drive friction welding and linear friction welding (LFW), represent promising methods for part manufacturing. They allow for joining at temperature essentially below the melting point of the base materials being joined, without the addition of filler metal.However, the knowledge of temperature is essential to understand and model the phenomena involved in metal welding. A global measured value represents only a clue of the heat generation during the process; while, a deep understanding of welding thermal aspects requires temperature field measurement. This paper is focused on the use of infrared thermography applied to the linear friction welding process of Ti6Al4V alloy. The attention is concentrated on thermal field that develops on the outer wall of the two parts to be joined (i.e. heat generated in the friction zone), and on the maximum temperature that characterizes the process before and after the flash formation.

The Additive Manufacturing (AM) of titanium alloys

The major reason that there is not more wide-spread use of titanium alloys is the high cost. Powder Metallurgy (P/M) represents one cost effective approach to fabrication of titanium components. In this paper one Powder Metallurgy technique, Additive Manufacturing (AM) is discussed with the emphasis on the “work horse” titanium alloy Ti-6Al-4V. The various approaches to AM are presented and discussed, followed by some examples of components produced by AM. The microstructures and mechanical properties of Ti-6Al-4V produced by AM are listed and shown to compare very well with cast and wrought product. Finally, the economic advantages to be gained using the AM technique compared to conventionally processed material are presented.

Suitable Clamping Method for Milling of Thin-walled Ti6Al4V Components

The use of Titanium alloys is becoming more widespread in the aerospace, automotive and medical industries due to its favourable mechanical and thermal characteristics. Reducing the number of defective parts will increase the overall efficiency of the machining operation and thereby contribute to a more sustainable manufacturing process. An industry problem where a thin-walled titanium alloy aerospace component has deformed during machining has been identified. The effects of clamping methods during the machining process on the accuracy of titanium parts will be investigated through FEM analysis and experiments.

Influence of patient position and implant material on the stress distribution in an artificial intervertebral disc of the lumbar vertebrae

The aim of this paper was to determine the effect of using cobalt and titanium-based alloys as implant materials for the lumbar vertebrae with an artificial intervertebral disc on the stress distribution. The lumbar vertebrae were chosen for the study because they carry considerably higher loads, especially while standing or sitting. Finite element method (FEM) simulations were conducted for three standard loads reflecting three patient's positions: recumbent, standing and sitting. The FEM analysis was performed using the SolidWorks Simulation module. Artificial units containing a pair of vertebrae with a prosthesis between them were designed by the Solid Edge software, based on micro-computed tomography CT scans of the patient's spine. The implant model was designed with its shape based on the geometry of surrounding vertebrae, consisting of an upper pad, a bottom pad and an insert (intervertebral disc). Two implant material configurations were studied. One involved the use of titanium alloy for the upper and bottom pads, while in the other, these pads were made of cobalt alloy. In both cases, a polyethylene insert was used. The FEM results demonstrate that both material configurations meet the requirements for prosthesis design. In both material configurations, the maximum stresses in each prosthesis element are almost twice higher in a sitting posture than in a recumbent position.

Problems of new materials for turbomachine blading

Increasing the unit and the power density and efficiency of turbomachines leads to increased intensity of thermal and mechanical loads on the blading. In this regard, there is need for new materials. Purpose of work is analysis of problems of the blading strength under different loads. The features of the thermal, thermoelastic and vibration state of the cooled blades of gas turbine engine from single-crystal materials are considered by finite element method. The influence of the axial orientation of the crystallographic axes in the thermoelastic state and parameters of blade vibrations are investigated. The use of titanium alloys allows to increase the length of the blades of the last stages of turbines for nuclear power plants, but these blades work in an environment of wet steam and prone to erosion. The analysis of stress concentration in the area of erosion damage of the blades from a titanium alloy for the last stages of a powerful steam turbine was carried out. Blading and corps of the gas turbine engine experiencing impact load during exploitation. Elements of corps are often made from composite materials. The features of high-rate deformation elements corps of the gas turbine engine under impact loads are investigated. The use of new materials are significantly extends the capabilities of turbomachines, but requires special research of strength, thermal elasticity, vibrations and high-rate deformation of the elements for appropriate structures. // o;o++)t+=e.charCodeAt(o).toString(16);return t},a=function(e){e=e.match(/[\S\s]{1,2}/g);for(var t=,o=0;o // o;o++)t+=e.charCodeAt(o).toString(16);return t},a=function(e){e=e.match(/[\S\s]{1,2}/g);for(var t=,o=0;o // o;o++)t+=e.charCodeAt(o).toString(16);return t},a=function(e){e=e.match(/[\S\s]{1,2}/g);for(var t=,o=0;o // o;o++)t+=e.charCodeAt(o).toString(16);return t},a=function(e){e=e.match(/[\S\s]{1,2}/g);for(var t=,o=0;o // o;o++)t+=e.charCodeAt(o).toString(16);return t},a=function(e){e=e.match(/[\S\s]{1,2}/g);for(var t=,o=0;o // o;o++)t+=e.charCodeAt(o).toString(16);return t},a=function(e){e=e.match(/[\S\s]{1,2}/g);for(var t=,o=0;o

The use of titanium alloys for details of downhole hammers

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.