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Thickness of sheet and hardness of welded joins
Valášek, Daniel ; IAE, Michal Loskot, IWE, (referee) ; Molliková, Eva (advisor)
Theme of this bachelor’s thesis is to determine the effect of material thickness, laser beam power and the material itself on hardness of the weld joint created by laser welding of construction steels. In addition to description of welding technology, this thesis also includes description of the undertaken experiment and its results which include photographs of microstructure from all weld joint zones and photograph evaluation.
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Filling of Polyurethanes
Bečka, Filip ; Poláček, Petr (referee) ; Kučera, František (advisor)
Bachelor thesis focuses on preparation of filled polyurethanes, determination of tensile properties, hardness and measurement of IR spectra. Theoretical part is devoted to main components of polyurethane systems and the most common inorganic, particulate filler and summarises knowledge about application of mineral fillers into polyurethane matrix. In experimental part was developed method of application of fillers into polyurethane and test specimens were prepared. Dispersion of fillers into polyol and affected workability was investigated. For examination of test specimens 3 methods were used: FTIR spectroscopy, tensile testing and hardness measurement. FTIR spectroscopy was used to investigate conversion of free isocyanate groups an OH groups. Tensile testing proved toughness of material and tensile modulus was determinated. Conformity of strength and stress at break and also conformity of strain at strength and strain at break was found. No yield point was observed for the specimens. Hardness of specimens was measured by the Shore A method.
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Influence of Homogenizing on Mechanical Properties of AZ91 Alloy
Provazníková, Andrea ; Liškutín, Petr (referee) ; Věchet, Stanislav (advisor)
This bachelor thesis includes photos and graphic representations of the influence of heat treatment on the mechanical properties of magnesium alloy AZ91. The structures of the alloy are recorded on the light microscopy pictures as well as photographs taken using a scanning microscope of fracture areas in the material. Results of a Tensile Test determining the strength and plastic properties and measuring of hardness and microhardness of the material are also included.
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Comparison of certified and lowcost material for stereolithography 3D print
Sobota, Matej ; Zatočilová, Aneta (referee) ; Koutecký, Tomáš (advisor)
The aim of the bachelor’s thesis is to define basic quality parameters and compare material impact on quality of printed products. This is a comparison certified material with low-cost material using SLA-DLP method of 3D printing to reduce production costs. The thesis is focused on the comparison of two different materials based on the results of tensile and hardness tests. The effect of the color of photopolymer on material properties is also observed.
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The role of material sciences in solving the problems technical accidents
Tonkovič, Miroslav ; Řičánková, Veronika (referee) ; Klakurková, Lenka (advisor)
Material sciences plays an irreplaceable role in explanation of various technical accidents. The proposed work focuses on examples of sever chosen technical accidents in which the knowledge of materials science was crucial in use and help to solve them. Description of an incident is stated to particular cases as well as results of these investigations, taking in mind the given topis of proposed work. The accidents are always described with necessary theoretical basis connected to each particular issue. Its knowledge was undoubtedly essential in solving the accident. The end of the work is a summary of the most frequent causes of technical accidents.
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Structure and properties of welded joints of steam turbine rotor
Machala, Jan ; Hutařová, Simona (referee) ; Juliš, Martin (advisor)
This thesis deals with the assessment of the structural-mechanical properties of welded joints of steam turbine rotor. Experimental weld material is low alloy steel 30CrMoNiV5-11 in the state after the artificial degradation. The theoretical part of the literary researches the issue, focusing on the weldability of different types of steel used in the energy industry, the metallurgical processes in welding and provides an overview of the most important methods of welding. Great attention is paid to the evaluation of weld quality in accordance with relevant standards and destructive and non-destructive testing of welded joints. In the experimental part of this work was carried out measurements of hardness and microhardness of the weldment by Vickers and evaluation of the microstructure by light microscopy. The obtained values and information about the properties of the material after artificial degradation were compared with previously obtained experimental results in the default state (after annealing).
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Present Trends of Methods for Hardness Measurement
Brzobohatý, Tomáš ; Doležal, Pavel (referee) ; Hutařová, Simona (advisor)
Purpose of this thesis is created view of present methods of hardness measurement and to describe them in more detail. Firstly this thesis deals with representatives of standard and for many years used methods of hardness measurement and hardness evaluation which are used today, too. Secondly this thesis is focused on modern methods, and their successful working experience is question of time.
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