Papers by Keyword: Titanium Alloys

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Authors: Janusz Tomczak, Zbigniew Pater, Tomasz Bulzak
Abstract: The paper reports selected results of the research on a rotary compression method for producing a hollow driving shaft used in a helicopter’s rear gear. The tests were performed on two types of material: steel grade 42CrMo4 (Polish Standard: 40 HM) and titanium alloy Ti6Al4V. The first part of the research involved performing a numerical analysis by the finite element method to determine an optimal range of parameters of the rotary compression process. The numerical results were then verified in experimental tests using a machine designed by the authors of this paper. The preliminary experimental results confirm that hollow parts made of steel and titanium alloys can be formed by rotary compression. The results also offer prospects for further research on this problem.
Authors: Ming Qiang Chu, Lei Wang, Hong Yu Ding, Zhong Gang Sun
Abstract: Additive manufacturing (AM) offers a potential for time and cost savings, especially for aerospace components made from costly titanium alloys. Owning to advantages such as its ability to form complex component, good surface quality, fine microstructure, excellent property, etc, it is attracting increasing attention. Much work has been done in recent years, including manufacturing facility, processing technology and specification. Here we summarize the development and status of AM technology, the underlying problems and its application perspective on civil aircraft.
Authors: Malwina Tubielewicz-Michalczuk
Abstract: Applications of specific properties of various titanium alloys applied in modern technology processes were discussed. Both, current and future trends in applications, mainly of the anti-corrosive properties of titanium in various elements of building constructions being applied in the so-called civilian products were characterized based on examples taken from civil engineering and architecture.
Authors: Mihai Sorin Tripa, Sorcoi Dorina, Lucia Ghioltean, Adriana Sorcoi, Mihaela Suciu
Abstract: Aeronautic industries, medicine, automotive industries are domains in which the composite materials are very important. In orthopedics and orthodontist domains, titanium and its alloys are very used, because their mechanical properties are similar to bone tissue. Bio-composite sandwich beams have high stiffness in flexion and good thermal characteristics. The analytical calculus for bending bio-composite beams is very important. We calculate the arrows for sandwich beams for two aspects: first – beam in four kinds of alloys (titanium alloys, stainless steel, aluminum alloys, Co-Cr-Mo alloys) and second – bio-composite sandwich beam, composed of two equal layers in same alloys and heart in: polyurethane foam, polystyrene foam, epoxide, phenolic, polyester, polyamides, balsa 1 and balsa 2 and compare its.
Authors: Agripa Hamweendo, Lebogang Moloisane, Ionel Botef
Abstract: This paper presents the bio-mechanical compatibility assessment of Titanium-Nickel (TiNi) alloy fabricated using cold spray (CS) process. This research creates opportunity for meeting the increased demand for biomedical implants in orthopedic surgeries brought by sport and traffic related bone injuries. Due to their exceptional properties, TiNi alloys are promising alternative biomedical materials to the traditional Ti6Al4V alloys. Studies show that the conventional methods for producing TiNi alloys have several challenges. As a contribution towards resolving this problem, this paper studied the bio-mechanical properties of Ti and TiNi structures fabricated using CS process. The results of this study show that the porosity, incipient Young’s modulus, and tensile strength of TiNi and Ti coatings are close to the required values for the biomedical implants. Consequently, this research demonstrates that porous TiNi and Ti structures fabricated by CS are possible candidates for biomedical implants and that CS could be a new process for fabricating near-net shape bio-mechanical compatible materials.
Authors: Pavel Zháňal, Petr Harcuba, Michal Hájek, Jana Šmilauerová, Jozef Veselý, Miloš Janeček
Abstract: Metastable β titanium alloy Ti-15Mo was investigated in this study. In-situ electrical resistance and thermal expansion measurements conducted on solution treated material revealed influence of ongoing phase transitions on measured properties. The monotonicity of the dependence of electrical resistance on temperature changes at 225, 365 and 560 °C The thermal expansion deviates from linearity between 305 and 580 °C.
Authors: Arkadiusz Tofil, Janusz Tomczak, Tomasz Bulzak
Abstract: Theoretical-experimental results of forging rolling and cross-wedge rolling of stepped shafts forgings from titanium alloy Ti6Al4V are presented in this paper. Theoretical assumptions were based on the results of numerical simulations conducted by means of finite element method with the application of software Simufact Forming. During numerical simulations optimal parameters of the rolling processes were determined in view to possibility of obtaining forgings of assumed quality and stable process course. Experimental verification was conducted in universal forging rolling mill of own design, which allows for realization of such processes as splitting without waste, forging rolling and cross as well as cross-wedge rolling processes. During conducted research influence of the way of rolling on the obtained parts quality and the process force parameters were determined. Complex analysis of the chosen rolling parameters impact on the rolling process course and quality of finished products was made. Conducted research showed that it is possible to roll axi-symmetrical forgings of stepped shafts both in transverse and longitudinal arrangement. However, forgings rolled crosswise are characterized by larger precision than in comparison with semi-finished products in longitudinal arrangement.
Authors: Zdenka Rysava, Stefania Bruschi
Abstract: This paper is aimed at evaluating the micro-machinability of the Ti-6Al-4V titanium alloy made by the means of two different Additive Manufacturing (AM) technologies. AM comprises promising technologies, widely used especially to produce parts made of difficult-to-cut materials, such as the titanium alloys. Titanium alloys represent one of the most widely used materials in the biomedical field, thanks to the high biocompatibility and excellent mechanical characteristics. Even if near-net-shape parts can be produced through AM, semi-finishing and/or finishing machining operations may be necessary to obtain the required surface finish and geometrical tolerances. Micro-milling technique is a soliciting solution for this kind of application due to its high flexibility, elevated material removal rate and direct contact between the tool geometry and work piece. Nevertheless, there are deficiencies in the literature regarding the study of micro-machinability of materials produced by means of AM technologies. In this paper, the micro-machinability of the Ti-6Al-4V alloy obtained by two different AM technologies, namely Electron Beam Melting (EBM) and Direct Metal Laser Sintering (DMLS), was studied and compared in order to assess the influence of the material as-delivered condition. Micro-milling tests were conducted on a high-precision 5-axis Kugler™ micro-milling centre under dry cutting conditions, by using uncoated, two fluted, flat-end-square, tungsten carbide tools with a diameter of 300 microns. The full immersion slotting strategy was chosen under full factorial design of experiments with two factors (cutting speed and feed per tooth). The micro-machinability was evaluated in terms of burr formation, surface integrity (surface topography and surface defects), tool damage and microstructure alterations.
Authors: Łukasz Frocisz, Janusz Krawczyk, Marcin Madej, Mateusz Kopyściański
Abstract: In general titanium alloys are associated with biomedical applications due to their unique properties such as: high biocompatibility, high strength to density ratio. They have been commonly used as a prosthetic material. However the microstructural development by heat treatment, directly correlated with the changes in mechanical properties of the material, allows us to consider these alloys as components of machines. One of the main properties of machine components are tribological properties. Knowledge of tribological properties of the machine elements allow us to determine the parts' viability and improve the functionality of the entire engineering system. Titanium alloys are characterized by the low wear resistance caused by chemical reactivity and easy formation of adhesion joints. Intensive adhesive wear of this material is associated with the strong degradation of the material surface. To determine the influence of microstructure on the tribological properties of titanium alloys, dry sliding wear test was performed. The materials for the investigations were five titanium alloys. The tribological test was performed with a load of 100 N for 2000 s on a 500 m distance. The microstructural observations were performed by light microscopy, in addition the wear mechanism was also investigated and for each sample the mechanism of wear was defined. For this type of tribological test a small proportion of adhesive wear was observed. The main mechanisms of wear were microgridding and microcutting. The increase of material hardness does not seem to impact on the increase of average friction coefficient of the samples. Increase of friction coefficient corresponds to the decrease of mass loss for the titanium alloys.
Authors: Abdelkader Mestar, Samir Zahaf, Nourddine Zina, Ahmed Boutaous
Abstract: The human knee is a complex joint (the largest joint of the human body). During the different daily activities, this joint is exposed to significant loads and movements, may in some cases exceed the limit of the mechanical capacities of its components, which shows that the pathologies are quite numerous at the level of the human knee and the treatment sometimes requires surgery to either repair or implant (implant total knee prosthesis). As we know very well, the success of a total knee implant is highly dependent on the initial stability of the femoral or tibial implant and the integration of femur and tibia bone tissue with these implants in the long term. Due to the optimal distribution of mechanical stresses in the surrounding bone. It is for this reason that the search for reasonable solutions to compensate the damaged knee prosthesis and reduce the stresses in the cortical bone and spongy has become a very important research axis. In this regard, we have proposed three models of prosthesis knee joint from available literature and study the distribution of Von-Mises stresses and strains in the differents composents of knee prosthesis, know the total displacement between the model intact and model artificial of knee, 3D modeling software Solidworks 2016 is used for 3D modeling of knee prosthesis and finite element analysis software ANSYS 16.2 is used for numerical estimation of von-Mises stresses and strains. We find in this study that the maximum stresses and strains of Von Mises at the level of the tibia and tibial bone decrease, that is to say that the cement and the elastomer play a very important role in the absorption of the stresses and their minimization. On the other hand, the four knee prostheses (Model I (Ti6Al4V), Model II (CoCrMo), Model III (316L SS), Model IV (ZrO2)) implanted by elastomer contribute significantly to the reduction of stresses in the patella bone compared to the Intact Model. In general, both models of the knee prosthesis and reinforced by a stress reduction system (cement, elastomer) gave a lower stress level in the tibia and tibial bone of a normal person compared to a healthy model. The results obtained provide a theoretical basis for choosing an appropriate surgical model.
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