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Structure and mechanical properties biodegradable Mg-3Zn-2Ca alloy processed by ECAP
Havlíček, Štěpán-Adam ; Podrábský, Tomáš (referee) ; Doležal, Pavel (advisor)
Zaměření této bakalářské práce je na mechanické vlastnosti a mikrostrukturu biodegradabilní hořčíkové slitiny Mg-3Zn-2Ca zpracované pomocí uhlového protlačování skrze shodné kanály (ECAP). Každý vzorek se liší počtem protlaku ve směru Bc. Zpracovaná hořčíková slitina ukazuje zlepšení napěťových a deformačních charakteristik, avšak s rostoucím počtem protlaků začínají klesat deformační charakteristiky. Aplikace ECAP metody způsobila v mikrostruktuře zjemnění zrn a ve směru protlačování prodloužení zrn. Ke studiu mikrostruktury bylo využito světelné mikroskopie a studium tahových vlastností bylo provedeno tahovými zkouškami.
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Preparation and properties of bulk material from magnesium powder
Ruttkayová, Veronika ; Pacal, Bohumil (referee) ; Doležal, Pavel (advisor)
Diploma thesis focuses on preparation and characterization of bulk material prepared from pure magnesium powder. The topic includes all the parts of process of bulk material preparation, sintering at hot pressing, diffusion processes and structurally-mechanical properties with respect to final material porosity of the produced material. Thesis solving focuses on study and control of processes during bulk material preparation and description of the processes from physically-chemical point of view of the structure creation and final material properties.
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The corrosion study of part aircraft at the site of spot welds in the salt spray environment
Němčíková, Eva ; Doležal, Pavel (referee) ; Pacal, Bohumil (advisor)
This bachelor’s thesis is focused on the corrosion study of part aircraft at the site of spot welds in the salt spray environment. The panel is made of sheet of aluminium alloy AlCu4Mg1, with surface coated with aluminium of purity 99,5 %, and of square shapes of alloy AlCu4Mg1, without coating. Square shapes are an angle cleat. The thesis deals with corrosion characteristics at the site of spot welds and in the area of contact between them. It deals with character of corrosion, frequency of occurrence and range of corrosive attack. From the data files were detected critical places of construction.
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Optimalization of Temperature for Semi-hot Forming of Roll Bearings
Hrouzková, Andrea ; Klakurková, Lenka (referee) ; Doležal, Pavel (advisor)
This bachelor's thesis solve the problems about optimalization of temperature for semi-hot forming of roll bearings steels. The purpose of this thesis is finding the optimal interval of temperatures, in which 100CrMnSi6-4 bearing steel shows good strain and deformation characteristics after forming. Methods for data evaluation of mechanical properties are the tensile and upsetting tests which were performed on higher temperatures. It was microscoped microstructure changes of the bearing steel 100CrMnSi6-4 during temperature influence and classification with the light microscope.
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Preparation processes and characterization of bulk material from Mg and Zn powders
Hasoňová, Michaela ; Pacal, Bohumil (referee) ; Doležal, Pavel (advisor)
Topic of the diploma thesis is Mg-Zn bulk material preparation process by powder mixtures sintering at hot pressing. Structure, porosity and physically-mechanical properties of prepared bulk materials was evaluated. Obtained results and their interpretation were served as feedback for following optimization of individual processing parameters of bulk materials preparation. Thesis solving focuses on study and control of processes during bulk material preparation and description of the processes from physically-chemical point of view of the structure creation and final material properties.
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Analysis of Iron-Phosphorus Reaction Products Formation During Heat Treatment Processes
Skoumalová, Zuzana ; Jan, Vít (referee) ; Doležal, Pavel (advisor)
During high pressure pulsation tests repeated cracks of CP3. housings occur. High pressure pump CP3 is part of injection system Common Rail. Cracks can be caused by segregation of phosphorous from a washing medium on grain boundaries during subsequent heat treatment process. The present master´s thesis focuses on analysis of phosphorous compounds on specimen surface made from steel 20MnCr5, which were soaked in solutions with different concentration of phosphorous. Master’s thesis is also focused on potencial influence of phosphorous on structure and properties of this material. The first part of the thesis provides a summary of current knowledge in the studied field, experimental results can be found in the second part. The surface analysis XPS, the light microscopy, the scanning electron microscopy equipped by energy dispersive chemical analysis, the glow discharge optical emission spectroscopy, the methods of the phase analysis by means of the X-ray diffraction and impact test were used.
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Project management
Smolíková, Lucie ; Doležal, Pavel (referee) ; Fiala, Alois (advisor)
Project preparation of operating program of competitive advantage education. Create new bachelor honours plan of Metrology and quality assurance testing. Project management. Preparing documents for project formation. Process of working projects. Summary of reguired documents to create projects.
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Fatigue properties of magnesium alloy AZ31 after corrosion degradation
Horynová, Miroslava ; Lukáč, Pavel (referee) ; Doležal, Pavel (advisor)
The present study is focussed on assessment of cyclic deformation response and fatigue behaviour of bare and precorroded AZ31 magnesium alloys. Corrosion degradation was carried out in a salt spray fog (5% solution of sodium chloride) for 480 and 1000 hrs. Microstructure, mechanical properties, low- and high-cycle fatigue behaviour of experimental material in as-cast condition has been evaluated. Furthermore, the corrosion behaviour of material has been investigated. The fatigue tests have been performed using precorroded specimens to assess influence of corrosion degradation on cyclic deformation response and on low- and high-cycle fatigue behaviour. Influence of local corrosion degradation on initiation of fatigue cracks has been studied.
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Technology of manufacture and treatment of medieval arrowhead
Kašpar, Jan ; Stránský, Karel (referee) ; Stránský, Karel (referee) ; Doležal, Pavel (advisor)
This thesis analyses issue of manufacture, typology and use of medieval arrowheads. In theoretical part describe historical evolution of bow and his archaeological discovery in Europe, especially from medieval times. After that is revealed historical evolution of arrowheads and describe their typology. In next chapters are mentioned ways of iron production, mainly in early medieval times and also describe technology of manufacture different types of arrowheads. There is a characterization of medieval arrow, his construction and characteristics. Continuously in this background research are revealing questions of penetration depend on the various types of arrowheads, which are testing on the most known types of armour like chainmail or breast plate. In experimental part of this paper are metallographicaly analyzing archaeological discoveries from the early and late medieval times. Conclusions about their manufacturing, treatment and possibilities of use are built on knowledge about arrowheads structures, hardness and shapes.
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Optimization of Manufacturing and Assembling Technology of the Valve Bolt
Hrouzková, Andrea ; Zapletal, Josef (referee) ; Doležal, Pavel (advisor)
The thesis aimed to study the impact of manufacturing and assembly technology, the valve bolt fitted to diesel high pressure pump CP3 in the Bosch, which has been found to leak. As experimental material was chosen heat treated bolts M16x1,5 made of material 12 050th. Groups of samples were produced in two ranges hardness. Experimental determination of the optimum range of hardness was assessed on the basis of the results of the process of the screw and set the value of plastic deformation of the sealing surfaces of the parts. Experimental section also deals with the analysis of bearing surfaces on the pump and the components, after the screw process. To some extent, is observed as surface treatment
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