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Mechanical response during dynamic loading of layers prepared by cold spray technology
Šprincl, Jan ; Válka, Libor (referee) ; Řehořek, Lukáš (advisor)
Cold spray is a relatively modern technology that falls into the additive category. It is a coating method that doesn´t cause the input material to melt. This brings many advantages, including the minimization of changes to the original structure, the absence of a heat-affected zone, and the possibility of combining different types of materials. This work mainly focuses on the deposition of Ti6Al4V titanium powder, along with other materials to supplement or modify the spray, improve its efficiency, and enhance its mechanical properties. Ballistic tests, three-point bending tests, indentation methods, optical analysis using light and electron microscopy, X-ray diffraction, differential scanning calorimetry, and the influence of thermal treatment on the structure were used to evaluate the properties. Thermal treatment led to the formation of completely new phases in the structure, resulting in a significant increase in the coating's hardness along with a reduction in its porosity. Highly hard phases based on TiC and Ti5Si3 were formed in a tough matrix composed of varying ratios of Ni-Ti and associated elements – V, Al, Si. Finally, proposals for potential future development of this material are described. Preconditions for specific improvements in the methods and procedures used in this work are laid out, with a very promising outlook for the future of this material and its potential implementation in real ballistic protection, typically in the military industry.
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Design of powder preheating for cold spray technology
Kalina, Jan ; Čupera, Jan (referee) ; Řehořek, Lukáš (advisor)
Cold spray is a technology that ranks among the thermal coatings. Its main idea is to prevent both the sprayed and the underlying material from reaching the melting temperature in order to reduce the level of surface oxidation. Cold spray is a relatively young technology that is still being researched. The effect of preheating the sprayed material on the material characteristics of the cold spray is one of the research questions. As part of this work, a device for preheating the powder to temperatures of up to 650 °C is designed in such a way as to minimize interference with the current construction of the Cold Spray workstation at the ÚMVI FSI BUT in Brno. The design is based on significant simplifications of the thermal model of the preheating device and heat losses. In the theoretical part, the reader was introduced to the history of Cold Spray, the effects of various technological parameters of Cold Spray on the resulting spray. Furthermore, the requirements for the preheater device were discussed, several variants of the device design were proposed, and the equations used for the device design were written. In the practical part, the required data for the design of the equipment is obtained for the required materials of the sprayed material, different temperatures, and other input parameters of the Cold Spray injection with the help of equations from the theoretical part. Based on them, the final design of the preheater device is compiled.
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Elastic characteristics of coatings
Olivo, Tomas ; Řehořek, Lukáš (referee) ; Válka, Libor (advisor)
The thesis focuses on the determination of Young's modulus of elasticity in tension of coatings with the inclusion of the effect of porosity using the impulse excitation method (IEM). In the theoretical part, the basics of the impulse excitation method and nanoindentation are discussed. Subsequently, the types of composite materials are presented, followed by a description of the Cold Spray technology used to produce the coatings presented in this work. In the next section, the composite models used to evaluate the measured data are defined. The experimental part is devoted to the description of the preparation of the test specimens, i.e., the substrate-coating system, together with the nanoindentation and pulsed excitation test procedure. Based on these tests, the tensile elastic moduli of the deposited coatings were evaluated using four composite models and compared with the results from the nanoindentation test. The most appropriate of these models was found to be the one based on the rule of mixtures with the inclusion of the nonlinear effect of porosity.
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Utilization of cold spray technology for ballistic applications
Kuník, Adam ; Doubrava, Marek (referee) ; Řehořek, Lukáš (advisor)
The goal of this bachelor's thesis is to get familiar with cold spray technology, as an alternative in the field of both coating application and, among other things, its use for the repair of some parts with complex shapes within additive manufacturing. It then coveres the basic principles of this method, the metal powders used, the characteristics of the device, familiarization with the issue of ballistic protection and terminal ballistics. In the second, experimental part, the quality and mechanical properties (especially the hardness, porosity, and coating thickness) of this layer produced by the above-mentioned method, as part of ballistic protection for light armored vehicles, are evaluated.
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Development of Ti-6Al-4V alloy coatings produced by cold spray technology
Ballayová, Kristýna ; Štěpánek, Roman (referee) ; Řehořek, Lukáš (advisor)
The cold spray method is receiving more and more attention both in research and development and in the industrial sector due to its undeniable advantages over conventional methods. However, the suitability of its application depends on the desired properties of the coating and the nature of the materials used. This work provides insight into cold spray in general and in the context of the spray material used – Ti-6Al-4V. The response to several sets of hot isostatic pressing (HIP) parameters was studied, with attention paid not only to the coating but also to the Al 2618 aluminium alloy substrate. The choice of hot isostatic pressing parameters, especially temperature, was a compromise solution with respect to the temperature resistance of the substrate material and the common values of this process in the processing of the spray material. The results of the practical analyses show that despite the efforts to find HIP parameters satisfying both constraints, the most essential properties of the coating were not improved. On the contrary, the HIP process led to a certain deterioration of the properties of the aluminium alloy substrate. These findings provide information for future process optimization and highlight the need for further research into the combination of these materials and technologies.
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Mechanical properties and their determination in materials prepared by cold deposition
Hamr, Ondřej ; Judas, Jakub (referee) ; Zapletal, Josef (advisor)
The bachelor thesis focuses on conventional mechanical properties and their determination. Additionally, this work contains the methods of determination of mechanical properties using small and miniature test specimens with a focus on tensile and bending tests of miniature size and small punch test. In the conclusion of this work, experiments were carried out, where the mechanical properties of small and miniature dimensions were investigated on the AA 7075 strength alloy, which was applied by kinetic cold deposition. The focus of the experiment on the tensile and bending tests of small specimens followed by the small punch test and the subsequent correlation of the observed results.
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Programming tools for robotic workstations for cold metal deposition
Odehnal, Martin ; Šubrt, Kamil (referee) ; Vetiška, Jan (advisor)
The thesis focuses on the development of software for a robotic workstation designed for the rapid preparation of coating the surface of rotating parts using cold spray metal deposition technology. The cold spray workstation is located in the laboratories of the Institute of Materials Science and Engineering at the Faculty of Mechanical Engineering, Brno University of Technology. The developed application provides support for the institute's staff in experimental activities in this area. The theoretical part of the thesis aims to provide information to the processes associated with virtual commissioning, programming industrial robots, and the basics of cold spray technology. The practical part addresses the specific implementation of the software application and the integration of an external motor to the robotic controller via the PROFINET communication bus.
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Use of modern manufacturing technologies for transmission components
Drapač, Jiří ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
The aim of this bachelor thesis is to evaluate the possibilities of application of alternative production technologies in the company Wikov MGI a. s. for the production of gearbox components. The review part of the thesis deals with additive technologies, which are Selective Laser Melting (SLM), Binder Jetting (BJ), Cold Spray (CS) and Wire Arc Additive Manufacturing (WAAM). For each method, the pre-production preparation, process with printing parameters and post-processing are described. In the next section, each technology is critically evaluated for applicability to gear components. From the results, the most appropriate application of the technology to one selected component is detected. In the practical part, optimization of dimensions and weight is performed by design modification of the selected component. On the basis of economic and technical calculations, a comparison between the current and the proposed manufacturing process is made.
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Design of powder preheating for cold spray technology
Kalina, Jan ; Čupera, Jan (referee) ; Řehořek, Lukáš (advisor)
Cold spray is a technology that ranks among the thermal coatings. Its main idea is to prevent both the sprayed and the underlying material from reaching the melting temperature in order to reduce the level of surface oxidation. Cold spray is a relatively young technology that is still being researched. The effect of preheating the sprayed material on the material characteristics of the cold spray is one of the research questions. As part of this work, a device for preheating the powder to temperatures of up to 650 °C is designed in such a way as to minimize interference with the current construction of the Cold Spray workstation at the ÚMVI FSI BUT in Brno. The design is based on significant simplifications of the thermal model of the preheating device and heat losses. In the theoretical part, the reader was introduced to the history of Cold Spray, the effects of various technological parameters of Cold Spray on the resulting spray. Furthermore, the requirements for the preheater device were discussed, several variants of the device design were proposed, and the equations used for the device design were written. In the practical part, the required data for the design of the equipment is obtained for the required materials of the sprayed material, different temperatures, and other input parameters of the Cold Spray injection with the help of equations from the theoretical part. Based on them, the final design of the preheater device is compiled.
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Optimizing the Properties of the Coatings prepared by the Cold Spray Method using Heat Treatment
Bartošík, Vojtěch ; Šmíd, Miroslav (referee) ; Hutařová, Simona (advisor)
This bachelor's thesis deals with the choice of heat treatment parameters of the metal coating of austenitic unstabilized stainless steel AISI 304L applied by the Cold spray method. With the help of suitable heat treatment, it is possible to adjust the mechanical properties, reduce the porosity and, last but not least, also remove high residual stresses in the material. The theoretical part of the work is devoted to literature research on the topic of Cold spray technology, corrosion and corrosion-resistant steels. The experimental part describes the procedures for measuring samples that have undergone heat treatment. This took place in the temperature range of 500 to 1100 °C, always with an hour's holding time at the temperature, followed by cooling in air. In addition to these samples, the material was also examined in its initial state. Porosity, microhardness and also magnetism were determined. To analyze the structure, photographs were taken on a light and electron scanning microscope. Based on the results, heat treatment with an hourly hold at 700 °C seems to be a good choice, where a significant decrease in porosity, partial recovery of the structure while maintaining high microhardness and also grain fineness was observed.
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