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Relationship between Structure and Properties of cast Ni-alloys
Smékalová, Jana ; Hutařová, Simona (referee) ; Podrábský, Tomáš (advisor)
Nickel superalloys are developed for conditions which request the corrosion resistance, the heat-resisting and the creep-resisting material. They are used for components of air turbine motors and internal combustion turbines. The efficiency of these mechanisms is elevated with increasing combustion temperature so their development is accentuated. This thesis is concerned with a relationship between a structure and properties of nickel superalloys Inconel 713LC and Inconel 738LC in this thesis.
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Influence of AlCr Layer to Fatiague Properties of Nickel Superalloy IN 713LC at the Temperature 800°C
Šulák, Ivo ; Julišová, Martina (referee) ; Podrábský, Tomáš (advisor)
The present diploma thesis is focused on the effect of AlCr layer on the low cycle fatigue behaviour of cast polycrystalline superalloy IN713LC at 800°C. Protective layer is made by chemical vapour deposition followed by heat treatment. Fatigue tests were conducted in strain control mode with constant total strain amplitude and strain rate. The fatigue behaviour is assessed by cyclic hardening/softening curves, cyclic stress-strain curves, Manson-Coffin curves and Basquin curves. Microstructure was observed in as-received state and also after cyclic loading by means of optical microscopy and SEM.
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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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Influence of Explosive Hardening on the Structure and Characteristic of Hadfield Steel in Terms of use in the Railway Transport
Havlíček, Petr ; Podrábský, Tomáš (referee) ; Nesvadba,, Petr (referee) ; Schmidtová,, Eva (referee) ; Stránský, Karel (advisor)
The high alloyed austenitic manganese steel, the Hadfield steel, thanks to its good wear resistance of the work surface and maintaining the high toughness of the internal material in the same time, is successfully applied for casted crossings. The crossings are the most dynamic stressed components in the railway turnouts. Thanks to low surface and sub-surface hardness the occurrence of plastic deformation and the progressive wear of the crossing running surfaces can be found since the initial stages of the crossing operational life. One possibility how to increase the surface and the sub-surface hardness and this way improve the dimensional stability and the crossing lifetime as well is to apply the explosive hardening of the crossing running surfaces. The technology mentioned above means the application of the explosives in the imminent nearness to the running surface of the crossing, when the high pressure wave acting within the extremely short period actuates the plastic deformation of the material structure. The work deals with analysis of influence of explosive hardening on the structure and characteristic of Hadfield steel. The explosive hardened samples have the surface and the sub-surface hardness checked and the microscopic analysis and X – ray diffraction is applied, including the TEM analysis as well carried out by the transmission electronic microscope. The characteristics experimental testing including outcomes from assessment of the contact – fatigue load of the explosive hardened Hadfield steel samples are the part of the work as well. As an experiment final part the outcomes of the long –term validation, the surface hardness and wear of the crossing running surfaces of the explosive hardened crossing already installed into the Czech Republic railway track are introduced as well.
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Automatic barman
Podrabský, Tomáš ; Horna, Jakub (referee) ; Štohl, Radek (advisor)
I was working on a project of the automated bartender, whose construction has already been done. At the beginning I had to acquaint with construction and understand how it should work. I created the software in developmental environment CoDeSys in version 2.3 and later in version 3.5. Both of them allows the program creation, as well as visualization and online monitoring of PLC operation and debugging. PLC communicates via AS-interface. The aim of this project was to create fully functional application for barman. PLC program is structured as a state machine, which is ideal for this application. State machine is written in the developmental environment in language SFC and its individual steps in LD, ST, or FBD. I focused on simplicity and clarity of the program, in which I tried to incorporate as many features as possible. I managed to create a program that is able to tap one of the 4 or mix of any number of drinks. It can be also said that the operator doesn't want a full glass, but fewer doses than the maximum. The main acquisition for me was the fact that I was able to solve the problem independently, using the programmable controller on a real system, which gave me lots of new skills. The result of this work is fully functional automated barman including visualization that shows the status of sensors, the number of doses for individual drinks and allows to control the whole system and check error messages.
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Influence of Al and AlSi Layer to Fatiague Properties of Nickel Superalloy IN 713LC at the Temperature 800°C
Šulák, Ivo ; Juliš, Martin (referee) ; Podrábský, Tomáš (advisor)
Nickel based superalloys are mainly used for high-temperature applications in energetic and aerospace industry. They are exposed to extremely aggressive environment at high temperature with interaction between fatigue and creep processes, oxidation and erosion. Application of protective surface coating is the right way how to increase the lifetime while increasing performance of machine. Theme of this bachelor’s thesis is to investigate the fatigue parameters of superalloy In713LC at 800 °C and the comparison of these parameters between materials with a protective coating based on Al or Al-Si and material without coating.
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