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Evaluation of bearing steel´s microstructural parameters with regards to their mechanical properties and lifetime
Hroš, Michal ; Juliš, Martin (referee) ; Klakurková, Lenka (advisor)
The aim of this bachelor thesis is evaluating the impact of microstructural parameters of bearing materials with an emphasis on evaluation carbidic phase with using protocol SEP 1520. Literary section analyzes the specific groups of materials for the manufacture of rolling bearings, specifically focusing on steel, where is discussed their performance, production, heat treatment, micropurity, microstructure and macroscopic requirements. Work on structure of bearing steel as well as the experimental part of the thesis is focused on a more detailed description carbidic phase materials and the systematic evaluation with regards to type of initial a semifinished product for the manufacture of bearings, the heat treatment, the resulting mechanical properties and especially durability.
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Analysis of degradation processes of the shock absorber rod
Sýkorová, Jitka ; Juliš, Martin (referee) ; Klakurková, Lenka (advisor)
The bachelor thesis deals with the analysis of degradation processes of the rods of the synchronizer generator. The theoretical part deals with the description of the generator, the analysis of the material, the properties of the brass for the production of the absorber rod and the possible parameters influencing its degradation. The experimental part of the thesis analyzes damaged bars of the shock absorber using destructive and non-destructive techniques, suggests non-destructive testing in-field and determines the dependence of electrical properties on the structure.
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Analysis of the structure Hadfield steel depending on the load deformation
Darida, Jiří ; Julišová, Martina (referee) ; Klakurková, Lenka (advisor)
This bachelor´s thesis deals with the analysis of the structure Hadfield steel depending on the load deformation. The first part of the thesis determines summary of basic mechanical and physical properties of Hadfield steel, its chemical composition, the influence of alloying elements on the resulting microstructure, manufacturing, heat treatment, hardening mechanisms and its use in technical applications. Attention is also paid to the various types of work hardening among which include explosive strengthening. The experimental part of the thesis is focused on the analysis of samples Hadfield steel, which were stressed by different loading conditions. Analysis of these samples consists of observations of structural changes and measurement of work hardening using microhardness in surface and sub-surface region of the sample. The final part presents the view into the future and overall evaluation of results.
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The use of surface modifications in recent technical practice
Červinka, Martin ; Čelko, Ladislav (referee) ; Klakurková, Lenka (advisor)
Bachelor's thesis deals with problems of surface treatment materials and their basic division. Work is detail focused on technology of thermal spray coatings. This work summarizes the basic information about the technology thermal spray coatings, their features and an overview of methods for their production. The aim of the project is to create an overview of methods of surface modifications used in recent practice and their application in different branches of industry.
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Corrosive Degradation of Austenitic Steels
Vykoukalová, Tereza ; Juliš, Martin (referee) ; Klakurková, Lenka (advisor)
The main requirement imposed on stainless steel is a high corrosion resistance in aggressive environment. The main aim of the thesis is a numerous group of corrosion resistance stainless steels, i.e. the stainless steel with austenitic matrix. Increased attention is paid to the corrosive attack and corrosion rate of three chosen materials with austenitic matrix in four different corrosive environments (30% solutions of sulphuric acid, nitric acid, acetin acid and sodium chloride). The method of light microscopy was used to study corrosive degradation of different materials.
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Deposition and analysis of AlCrN coatings
Drásalová, Kateřina ; Juliš, Martin (referee) ; Klakurková, Lenka (advisor)
The topic of this thesis is the deposition process and methods of quality assessment of AlCrN surface coatings produced by methods of (i) magnetron sputtering, (ii) magnetron sputtering with arc enhanced glow discharge, and (iii) high power magnetron sputtering with the movable magnetic field. The main focus is placed on categorizing properties of the produced coatings based on the production method (which vary in the ionization level). Qualities of the surface coatings are assessed by adhesion and cohesion parameters testing of coarseness using AFM (Atomic Force Microscopy), depth measuring using a calotest, measuring internal tension using the Bent Strip Method and Instrumented indentation test for hardness.
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Carbon Based Materials
Hrazdíra, Matěj ; Čelko, Ladislav (referee) ; Klakurková, Lenka (advisor)
The proposed bachelor thesis deals with carbon based materials. First of all, an overview of its allotropic modifications including newly discovered forms, conditions of their existence and also their basic properties is shown. Further the extraction of carbon materials is briefly introduced. In the next chapters, forms of carbon are classified and particularly described individually with respect to manufacturing technologies and further applications. Individual chapters are dedicated to synthetic carbon and graphite, carbon fibers and carbon fiber reinforced composites. Manufacturing processes of synthetic carbon and graphite, involving possible precursors, are described in detail together with their use in various engineering applications. The following part is dedicated to carbon fibers, in particular to the manufacturing process based on the precursor used including surface treatment and sizing. Additionally the use of virgin carbon fibers is also described. The last part is focused on carbon fiber reinforced composites. Firstly possible distributions of carbon fibers in a matrix are described. Then the technology of manufacturing, properties and use of single composites according to the matrix material are expounded.
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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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Surface treatment of roll bearings
Kubelka, Milan ; Klakurková, Lenka (referee) ; Švejcar, Jiří (advisor)
The bearings are one of the most widely used construction components enabling mutual movement of parts and at the same time transmission of interacting load. The basic requirements placed on components of roll bearings are particulary increase of contact fatigue resistance, decrease of the friction coefficient between the rolling bodies and bearing rings, increase of hardness and abrasion resistance of functional surfaces, the wear resistance, corrosion protection and finally the electrical and optical properties too. As production of bearings from materials with these attributes would be quite expensive, surface modifications are used for improving the mechanical properties. The main task of this bachelor thesis is description and evaluation of technologies suitable for surface treatment of roll bearings with increased attention to those types of surface treatment which, in cooperation with SVÚM will be studied in more detail in the experimental part of this work (especially polymer coatings, phosphate films and DLC - type coatings). The wear evaluation of different types of coatings was performed with the aid of scanning electron microscopy after the tribological testing.
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