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Processing Methods of Fine-grain Materials (ECAP)
Jonák, Martin ; Man, Ondřej (referee) ; Pantělejev, Libor (advisor)
Method of equal-channel angular pressing (ECAP) is very significant SPD method whereby we are able to obtain a bulk material with UFG structure. This research deals with fundamental principles of ECAP method, an influence of the constructional design of a pressing channel and factors related to processing modes on properties of a final structure. Further, this research describes some modifications of a conventional ECAP method and processes based on its principle.
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Assessment of probable causes of corrosion damage of a mould made of cast iron
Sobola, Petr ; Pantělejev, Libor (referee) ; Man, Ondřej (advisor)
Bachelor’s thesis deals with solution of problems on glass moulds, which were exposed to the corrosion medium for up to two days causing their damage. The thesis contains theoretical analysis of the problem, layout for the corrosion experiment and its execution. Based on the experiment a conclusion was pronounced that the extent of damage which was observed was not able to be created by corrosion of initial surface without any previous defect.
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Fatigue endurance of extruded Mg alloy AZ91E
Sobola, Petr ; Štěpánek, Roman (referee) ; Pantělejev, Libor (advisor)
This thesis deals with fatigue behaviour of magnesium alloy AZ91E produced by extrusion. In the frame of this work, basic mechanical characteristics and data from performed fatigue tests were obtained. Further metallographic analysis of microstructure and fractographic analysis of broken specimens after fatigue tests were carried out.
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Fatigue properties of UFG Ti for biomedicine applications
Dobeš, Ondřej ; Pantělejev, Libor (referee) ; Fintová, Stanislava (advisor)
Titanium is thanks to its high corrosion resistance and biocompatibility widely used in medicine. Ti alloys are used due to their superior mechanical properties instead of pure Ti for load carrying components. Ti alloys are often alloyed with elements which are toxic for human body and further increase cost of Ti products. Main focus of current development is to create pure Ti with better mechanical properties. It can be done by reducing grain size by processes based on severe plastic deformation. The aim of this work is to evaluate fatigue properties as well as fatigue crack initiation and propagation mechanism of Ti grade 2 with the ultrafine grained structure. After microstructure analysis, fatigue tests with symmetrical loading were executed. Fracture surfaces of ultrafine grained Ti grade 2 were observed after fatigue tests for identification of failure mechanism. Results were compared with those for course-grained Ti grade 2.
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Prediction of the fracture toughness temperature dependence
Václavík, Martin ; Pantělejev, Libor (referee) ; Válka, Libor (advisor)
The thesis is focused on the prediction of the fracture toughness temperature dependence through a universal curve of fracture toughness (also known as the master curve). To determine the parameters of the universal curve of fracture toughness, values acquired from the measurement results of fracture toughness and tensile tests of structural steel P91 are used. The theoretical part is based on a summary of the relevant information from the field of fracture mechanics and brittle-ductile fracture behavior of steels that are important for the understanding of fracture-strain response of materials depending on load conditions. The experimental part of the thesis contains the results from practical measurements and analyses, which were used for determining the parameters of a universal curve of fracture toughness as well as for the evaluation of fracture behavior and description of the impact of structural parameters on this behavior in case of steel P91.
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Mechanical properties of materials prepared by SLM process
Nopová, Klára ; Štěpánek, Roman (referee) ; Pantělejev, Libor (advisor)
The final thesis determined the properties of alloys formed from mixtures of powders processed by the SLM method. Powders of alloy AlSi12 and EN AW 2618 were fused in the proportion 75 wt. % AlSi12 + 25 wt. % 2618, 50 wt. % AlSi12 + 50 wt. % 2618 and 25 wt. % AlSi12 + 75 wt. % 2618. Metallographic analysis, EBSD analysis and line EDS microanalysis were made on the samples. Tensile test at room temperature and hardness were carried out to determine the mechanical properties. Fractographic analysis was performed after tensile test.
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The application of legal standards in materials engineering
Večeřa, Petr ; Pantělejev, Libor (referee) ; Pavloušková, Zina (advisor)
The thesis describes points where the basic universal prescriptive system of law interferes with the questions of materials engineering. The main part of the thesis concerns legal liabilities, mainly civil liability represented with liability for defects. Basic analysis of chosen topics concerning liability for defects is done, defects are divided into groups as far as both technical and legal point of view is concerned. Consequently, the most common methods, principles and tests used for recognition and assessment of materials characteristics, both destructive and non-destructive, are described. Chapter, which deals with degradation processes follows. Integral part of the thesis are thoughts of possible types of legal liabilities, which could be important for materials engineers, with basic recommendations for contracting, as well as chosen problems connected with judicial proceedings and out of court settling of disputes. Technical standards are described with high attention, because both technical and legal public is not familiar with the legal background of technical normalisation.
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Fatigue properties of AZ61 magnesium alloy
Provazníková, Andrea ; Juliš, Martin (referee) ; Pantělejev, Libor (advisor)
This master’s thesis is dealing with low-fatigue behavior of magnesium alloy AZ61, prepared via squeeze casting method. The main aim of this work was to obtain the basic mechanical properties as well as the low cycle fatigue data. Additional metallographical evaluation of microstructure and fractographical analysis after fatigue tests was made.
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Mechanical properties of the weld of titanium alloy TiAl6V4 prepared by using an electron beam technology
Byrtus, Robin ; Pantělejev, Libor (referee) ; Válka, Libor (advisor)
The aim of the diploma thesis is to evaluate the mechanical properties and fracture behavior of the weld join Ti6Al4V titanium alloy prepared by using an electron beam technology. The theoretical part deals with the welding of titanium alloys with the help of electron beam, the weldability evaluation of titanium alloys, the influence of electron beam welding on the microstructure and the methods of testing of weld joints. Using the experiments, the mechanical properties of the base material and the weld were evaluated and a structural analysis of the weld was performed.
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