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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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Weldability of hardenable aluminum alloys
Filip, Josef ; Slováček, Marek (referee) ; Kubíček, Jaroslav (advisor)
The thesis deals with the influence of MIG pulsed metal transfer welding on the mechanical properties of the aluminium curable alloy and on the presence of defects in the welded joint. The aluminium alloy EN AW 6082 T6 was chosen for the experiment, i.e. in the state after the artificial ageing. The experimental part first describes the selected base and filler material, the used welding equipment, the choice of welding parameters and then the preparation process of the test samples is described. There were made 6 sets of samples, each of them was welded with a different combination of welding parameters and pulsed welding mode. Subsequently, the work deals with several material destructive tests that were part of the experiment. Tensile tests, hardness measurements and microstructure tests were performed. The results of the tensile tests showed that in all cases the tensile strength was decreased by more than 30% compared to the base material and similar values were achieved. Thus, the theoretical assumption that soluble precipitates occur during the welding of hardened Al alloys, causing a decrease in the mechanical properties in the HAZ, was confirmed. It is evident in the results of hardness measurements, which for all samples reached the lowest values in the HAZ at the same place where fractures occurred in the tensile tests. The macroscopic examinations then showed the presence of micropores in all samples except the set num. 4, which did not develop porosity. In several cases, the presence of unbroken or oxide inclusions was also detected. The results are evaluated at the end of the thesis.
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Determination of anodizing parameters for surface properties of aluminum alloys
Paclík, Eduard ; Vaverka, Ondřej (referee) ; Košťál, David (advisor)
The bachelor's thesis deals with the determination of basic parameters for anodizing aluminum alloys. The introductory passages include an overview of aluminum alloys suitable for anodization, theoretical and practical assumptions of anodic oxidation. The main experimental part discusses the laboratory anodic oxidation of aluminum alloy samples under different parameters of surface roughness, current density, and voltage. Anodically oxidized samples were tested on special UMT tribometer and Contour GT-X profilometer devices for friction coefficient measurement and surface inspection. The measurement results were used to determine the dependence between surface roughness of aluminum alloys and the quality of the anodized layer, the dependence between current density of the anodic process and the quality of the anodized layer, and the dependence between voltage and the quality of the anodized layer. The problem was solved within the possibilities of FSI laboratory conditions. The thesis serves as a basic orientation in this field.
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New Aluminium Alloys in Aircraft Structures
Przeczek, Jan ; Šplíchal, Jan (referee) ; Klement, Josef (advisor)
This bachelor work deals with newly developed wrought aluminium alloys, designed for application in aerospace industry. The task of that work is to compare recent aircraft aluminium alloys with conventional alloys and indicate direction of progress in this field. The comparison is particularly focused on improvement of mechanical and/or technological properties of these alloys.
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CNC pocket milling of aeronautical alloys
Wiecková, Kateřina ; Sedlák, Josef (referee) ; Ohnišťová, Petra (advisor)
The aim of the work is to generate and verify pocket milling technology in aviation alloy 7475-T7351 with respect to machine time, surface and machining productivity. First part of the work is theoretical analysis of cycles of milling of simple and complex pockets. Next part of the work is focused on the desing and optimization of strategy of milling of simple and complex pockets in CAM programs and its experimental verification.
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Influence of degassing parameters on quality of Al castings
Jeřábek, Petr ; Horenský, Jiří (referee) ; Vašťák, Patrik (advisor)
This master’s thesis is focused on optimalization of degassing parameters in the foundry plant and effect of these parameters on mechanical properties of Al-Si alloys. In practical part is used factorial experiment to research effect of degassing parameters on mechanical properties and dichte index. After optimalization the new process is validated by comparing with the previous one. This experiment was taken on AlSi7Mg0,6 alloy in foundry plant MESIT foundry, a.s.
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Inspection of welded joints of loading ramps
Ertl, Roman ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
This master's thesis is focused on problem of welding of loading ramps and inspection of their welded joints. The aim of this thesis is to inspect the welds of loading ramps with regarding to the appearance of defects. The literature review of the research issues of the MIG welding technology and welding of aluminium and its alloys is described in this thesis. There is also described destructive and non-destructive inspection of welds that can be applied to inspection of loading ramps. Theoretical description is followed by an experimental part of the thesis. Experimental part is focused on the three destructive tests (the tensile, the macroscopic and the hardness test) of samples of loading ramps, which are made of EN AW-6005A T6.
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Corrosion resistance of aluminum alloys
Kouba, Jan ; Pacal,, Bohumil (referee) ; Zmrzlý, Martin (advisor)
This diploma thesis deals with cerium-based conversion coatings for aluminium alloys. At first the mechanism of protection of metals by inhibitory substances is described in the theoretical section. The next chapter is devoted to application of lanthanide salts as cathodic corrosion inhibitors. Then the characterization of alloy AA 2024 follows. The main part is dedicated to the growth mechanism of the cerium-based mixed conversion coating on the alloy AA 2024. Finally, the factors affecting the character and the quality of obtained coatings are commented. In the experimental part an influence of the thermal activation together with the activation by a hydrogen peroxide was observed. The created film was characterized using SEM and EDS. The level of corrosion protection was evaluated by the polarization resistance measurement. erized using SEM and EDS. The level of corrosion protection was evaluated by the polarization resistance measurement.
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Surface pre-treatment of structural aluminum alloys for bonded joints
Pikner, Jan ; Doskočil, Leoš (referee) ; Wasserbauer, Jaromír (advisor)
This thesis deals with pre-treatment of surface of aluminium alloys. The theoretical part focuses on the properties of aluminium and its alloys, on methods of surface treatment and the possibilities of quality assessment of pre-treated surface. The experimental part deals with finding of a proper method of pre-treatment. The quality of surface pre-treatment is assessed by observation by SEM with EDS and by single lap shear tests of adhesive joints. According to evaluated results, the optimalised methods are qualitatively and financially compared with the commercial method.
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Optimization of aluminium casting process using numerical simulation
Kolařík, Martin ; Lána, Ivo (referee) ; Krutiš, Vladimír (advisor)
The master’s thesis deals with the analysis of casting technology of the selected aluminium casting. It is a casting of a part of CNC milling machine and it is cast by gravity casting into a permanent mold. The defects which are the cause of a high percentage of nonconforming production were analyzed. Furthermore, the master’s thesis includes a complete analysis of filling and solidification of this casting in the ProCast simulation program. Numerical simulation results are verified and improved. Then the causes of problematic casting defects are proven on several calculated variants. Measures are proposed to minimize the tendency to produce castings with defects leading to nonconforming production.
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