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Structure and fatigue properties of selected titanium alloy
Prudíková, Alena ; Kohout, Jan (referee) ; Věchet, Stanislav (advisor)
Main topic of the thesis was to evaluate fatigue properties of the titanium alloy Ti-A13-V2,5, labelled by ASTM as Grade 9. Most attention was focused on fatigue behaviour of the alloy in the range of high cycle fatigue. Fatigue testing was realised to detect the fatigue properties and consequently to generate the Wöhler curve and the Haigh diagram. In addition to this, tension and bending tests were performed. Metallographic and fractographic analyses of fatigue fracture form part of the overview about material properties, which was accomplished by use of REM. Experimental part of the thesis was backed by the literature research. The first half of it contains a short summary of basic information about the titanium and its alloys, so as some chapters about the history and properties of titanium, the way of its production, classification of titanium alloys and its thermic treatment. The fatigue is thoroughly scrutinised in the second half of the background research. Here can also be found the information about the fatigue process, its stages, the fatigue life and the most significant attributes of the fatigue fracture. The last chapters of the thesis are dedicated to the alloy Ti-A13-V2,5 - being examined in the experimental part - so as to its fatigue properties. The main benefit of this thesis is the completion of the missing information concerning the fatigue behaviour of the alloy, which is – according to the literature research - generally not available.
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Grinding of titanium alloy Ti-6Al-4V ELI
Chalupa, Adam ; Dvořáková, Jana (referee) ; Píška, Miroslav (advisor)
This bachelor thesis is focused on titanium alloys. The first part covers the properties and practical uses of titanium alloys whilst the second part describes the issue of machining titanium alloys. In particular, the specific advantages and disadvantages of grinding titanium alloys. As part of the practical undertaking of this thesis, a titanium alloy Ti-6Al-4V ELI was ground, for which I measured the achieved surface quality and the forces occurring during grinding.
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Surface treatment of aluminum alloys
Petr, Jiří ; Konečný, Tomáš (referee) ; Zmrzlý, Martin (advisor)
The thesis is focused on the surface treatment used for the preparation of aluminium alloys for the adhesive bonding. The theoretical part can be divided into three chapters. The first of them deals with aluminium alloys, the second one speaks about the adhesive bonding. The surface treatment itself, especially the conversion coating issues, is discussed in the last chapter. The experimental part is focused on the optimalization of a two-step titanium and zirconium based conversion coating technology. In the first part, the aluminium alloy is analysed by the glow discharge optical emission spectroscopy. The second part of the experiment deals with the first step of the technology, acidic deoxidation. The objective was to examine the influence of the exposure time on the morphology of the alloy surface and the shear strength of adhesive joints. In the last part of the experiment, the conversion coatings are prepared and characterised by the scanning electron microscopy and energy dispersive spectroscopy.
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Stress-strain analysis of skull implant
Hřičiště, Michal ; Borák, Libor (referee) ; Marcián, Petr (advisor)
Lebeční implantáty se používají jako náhrady částí lebečních kosti, které v důsledku zranění nebo nemoci ztratili svou funkci. Důležitým faktorem, který ovlivňuje funkci celé soustavy implantátu, jsou jeho mechanické projevy. Tato práce stručně shrnuje současné znalosti v oblasti rekonstrukce lebečních defektů a popisuje srovnání různých tvarů stěn implantátu vytvořených z různých materiálů, na základě deformační napěťové analýzy modelu neurocrania s umístěným implantátem, zatíženým nitrolebečním tlakem a vnějším zatížením.
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Thin layers TiO2 prepared by electrochemical way
Janov, Pavel ; Zatloukal, Miroslav (referee) ; Sedlaříková, Marie (advisor)
This work deals with issue of preparation active electrochromic film of titanium dioxide and intercalation properties. By electrodeposition was created active film on glass substrates covered with transparent conductive thin-film In2O3:Sn (ITO). The active films prepared by electrolytic way were compared with active films prepared by vacuum methods. Then has been studied theirs electrode properties in electrolytes containing lithium.
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Forming of titanium alloys
Bednařík, Josef ; Podaný, Kamil (referee) ; Lidmila, Zdeněk (advisor)
The work was focused on the forming of titanium and its alloys in order to verify the ductile properties of titanium alloy VT 3-1. Using the upsetting test performed on the CZR 600 press and processed in the Dewesoft application, the strengthening curves for compaction at temperatures ranging from 25 °C to 800 °C were compiled. Based on the performed experiments, the titanium alloy VT 3-1 can be recommended for forming only at higher temperatures. It is recommended to select 700 °C as the lowest forging temperature limit. The material when being upset at lower temperatures showed poor formability due to the strengthening of the material. The yield strength during upsetting at room temperature was measured to be 1 100,8 MPa. In contrast, at 800 °C it has a value of 321,7 MPa. Hardness was determined before and after the test as an additional measurement. After the test, the measurement was performed on the front of the sample and in section. At 700 °C and 800 °C, the hardness resulted in dynamic recrystallization, which resulted in a decrease in hardness. The highest hardness was recorded in the middle of the sample at all temperatures. This result confirmed the thesis that there is a band of the most intense deformation in the perpendicular and axial direction of the sample.
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Machining of titanium alloys
Kinc, Jiří ; Humár, Anton (referee) ; Píška, Miroslav (advisor)
This thesis describe titanium and titanium alloys from the perspective of charakter, production and use. Thesis gives information about difficulty connected with machining titanium by basic machining methods. Titanium alloy Ti6A14V was turned in practical part. Intention was to measure cutting force and specific cutting force.
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Preparation of Mg-Al-Ti bulk materials via powder metallurgy
Brescher, Roman ; Doskočil, Leoš (referee) ; Březina, Matěj (advisor)
This diploma thesis deals with research and preparation of bulk materials based on the Mg–Al–Ti system. The theoretical part summarizes the basic knowledge about magnesium alloys, focusing mainly on Mg–Al and Mg–Ti systems. Furthermore, basic information on powder metallurgy methods was included here, from the production of powder materials, through their compaction, to heat treatment and spark plasma sintering (SPS). The theoretical part ends with literature review on the current research of the Mg–Al–Ti system. In the experimental part, bulk materials based on the Mg–Al–Ti system was prepared using traditional methods of powder metallurgy, as well as using the SPS method. The microstructure of the material, elemental and phase composition was examined in this thesis. Subsequently, Vickers hardness and flexural strength were measured, and fractographic observation of the fracture surface was performed. It was found that the aluminum was completely dissolved during the heat treatment, but the titanium particles remained almost intact in the material and worked as a particulate reinforcement. Materials prepared by methods of conventional powder metallurgy showed increased porosity compared to materials prepared by the SPS, resulting in lower hardness and flexural strength. The hardness increased with increasing the amount of aluminum and titanium and with the amount of magnesium phase . Fractographic observation of the fracture surface suggests that a diffuse connection between the reinforcement and the matrix may have occurred after the sintering process.
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Multi-material 3D printing of titanium and aluminium alloys
Duchoň, Matěj ; Hutař, Pavel (referee) ; Koutný, Daniel (advisor)
Additive manufacturing of multi-material components is a promising way to produce parts that combine the properties of different materials. The thesis deals with the research, optimization of process parameters and methodology to produce multi-material parts using the SLM method. The aim is to create a mechanically durable interface between two materials based on titanium and aluminium. In order to determine the suitable combination of materials, a single track test was performed, which also established the initial process parameters and the effect of increased preheating temperature on the formation of defects at the material interface. This test provided the basis for the printing of bulk samples whose interfaces were analysed in detail using light microscopy, microhardness testing and EDS. Finally, the mechanical resistance of the interface was verified by tensile testing. According to the results of the single track test, titanium alloy Ti6Al4V in combination with aluminium alloy AlSi10Mg was selected. In further tests, it was found that if the preheating temperature is increased from 200 °C to 300 °C, the number of cracks at the interface is reduced by 31 %. The combination of increased preheating temperature and appropriate process parameters produced a crack-free material interface that exhibited high mechanical durability. The thesis provides a summary overview of the issues related to multi-material metal printing and the causes of individual defects that the interface of two different materials faces. The thesis may serve as a basis for further research on multi-material metal printing.
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