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Obrábění součásti ze slitiny Ni80TiAl
Kudrna, Miloš ; Novák, Zdeněk (oponent) ; Humár, Anton (vedoucí práce)
Diplomová práce se zabývá rozborem technologie obrábění svorníku ze slitiny Ni80TiAl, pro společnost Sanborn a.s. Cílem práce je návrh nové technologie, při použití nového typu nástroje, břitové destičky a řezných podmínek. Výsledkem je zrychlení výroby při hrubovací operaci. Tyto úspory vedou k poklesu nákladů a tedy i ceny výrobku.
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Výroba a vlastnosti žáruvzdorných slitin
Majchrák, Aleš ; Myška, Martin (oponent) ; Záděra, Antonín (vedoucí práce)
Tato bakalářská práce pojednává o žáruvzdorných slitinách, konkrétně o superslitinách a vysoce entropických slitinách. V teoretické části je provedeno rozdělení těchto slitin na základě chemického složení, popis jejich vlastností, struktury a použití. Praktická část se zabývá kobaltovou slitinou UmCo50. Mezi cíle této části patří popis metalurgie dané slitiny, ověření závislosti oduhličení na době vakuování, pozorování mikrostruktury a její zhodnocení.
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Damage mechanisms in nickel-based superalloy René 41 subjected to fatigue
Babinský, Tomáš ; Pippan, Reinhard (oponent) ; Růžička,, Milan (oponent) ; Polák, Jaroslav (vedoucí práce)
The present study deals with the aspects of fatigue damage in a wrought Ni-based superalloy René 41. The material of interest was investigated in two thermodynamical states: solutionised and aged. Uniaxial, fully-reversed low-cycle fatigue tests were conducted at room and elevated (800 °C) temperatures under total strain amplitude control. To study the relevant damage mechanisms and reveal their connection to plastic deformation, a detailed analysis of the cyclic response using a statistical approach was performed, and advanced microscopy techniques were employed, namely scanning and transmission electron microscopy. Interrupted fatigue tests were performed to study the evolution of surface relief and the underlying dislocation structure. After each interruption, the evolution of the microstructure was analysed using electron microscopy techniques. At room temperature, the damage was mostly transgranular, and the cracks initiated predominantly within grains from the roughened surface. Comparing the two investigated material states, the aged material attained higher stresses and exhibited higher lifetimes in service-relevant stress-life relation. Cyclic deformation was found to localize to persistent slip bands since the first cycle, and the majority of slip bands formed very early in the fatigue life. Hence, shearing of the strengthening phase, coherent ’ precipitates, occurred largely only in the first few cycles. Due to the cyclic slip localization, surface roughening emanated in the form of slip steps, extrusions and intrusions. The formation of surface relief was thoroughly discussed with existing models. The exposure to high temperatures led to an environmental attack, due to which an oxide layer formed on the surface. The cracks initiated and propagated along weakened grain boundaries, and the resulting damage was thus intergranular.
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Výroba a vlastnosti žáruvzdorných slitin
Majchrák, Aleš ; Myška, Martin (oponent) ; Záděra, Antonín (vedoucí práce)
Tato bakalářská práce pojednává o žáruvzdorných slitinách, konkrétně o superslitinách a vysoce entropických slitinách. V teoretické části je provedeno rozdělení těchto slitin na základě chemického složení, popis jejich vlastností, struktury a použití. Praktická část se zabývá kobaltovou slitinou UmCo50. Mezi cíle této části patří popis metalurgie dané slitiny, ověření závislosti oduhličení na době vakuování, pozorování mikrostruktury a její zhodnocení.
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Interaction of Creep and High Cycle Fatigue of IN 713LC Superalloy
Horník, V. ; Šmíd, Miroslav ; Hutař, Pavel ; Kunz, Ludvík ; Hrbáček, K.
The study deals with the interaction of creep and high cycle fatigue of cast polycrystalline nickel-based superalloy IN 713LC at high temperatures. Previous works indicated that creep lifetime of superalloy structures was un-affected or even slightly increased in the cases with superimposed vibrations. The reason for this behaviour was not well described up to now. Therefore, set of fatigue tests was conducted at high mean stresses level to observe this phenomenon. The mean stress was kept constant while the stress amplitudes were selected in order to measure wide range of conditions from pure creep to pure fatigue. Fractographic analysis by scanning electron microscopy (SEM) was done with the aim to identify governing damage mechanisms for particular test conditions as a preliminary evaluation of conducted tests.
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IN-SITU HIGH TEMPERATURE LOW CYCLE FATIGUE STUDY OF SURFACE TOPOGRAPHY EVOLUTION IN NICKEL SUPERALLOY
Petrenec, M. ; Polák, Jaroslav ; Šamořil, T. ; Dluhoš, J. ; Obrtlík, Karel
In-situ Low Cycle Fatigue test (LCF) at temperature 635 degrees C have been performed in Scanning Electron Microscope (SEM) equipped with Electron Backscatter Diffraction analysis (EBSD) on a small dog-bone-shaped specimen of cast Inconel 713LC superalloy. The aim of the work was to study early stage fatigue damage at high temperature by the observations of the characteristic surface relief evolution and crystallographic characterization changes by EBSD. The detail of slip bands shape was checked by FIB and AFM microscopes. The LCF test was conducted on GATAN stage with pre tilted position and constant stress amplitude of total cycle number of 20. The relief produced in the first cycle determines the other locations of the localized cyclic slip to the primary slip planes (111). The relief was modified in the next cycles but without forming additionally new slip traces in the primary system. Based on EBSD analysis before and after LCF, the orientation of two grains was changed which caused activation of second slip system. The damage mechanism evolution is closely connected with the cyclic strain localization to the persistent slip bands where the fatigue cracks were initiated.
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Obrábění součásti ze slitiny Ni80TiAl
Kudrna, Miloš ; Novák, Zdeněk (oponent) ; Humár, Anton (vedoucí práce)
Diplomová práce se zabývá rozborem technologie obrábění svorníku ze slitiny Ni80TiAl, pro společnost Sanborn a.s. Cílem práce je návrh nové technologie, při použití nového typu nástroje, břitové destičky a řezných podmínek. Výsledkem je zrychlení výroby při hrubovací operaci. Tyto úspory vedou k poklesu nákladů a tedy i ceny výrobku.
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IN-SITU HIGH TEMPERATURE LOW CYCLE FATIGUE STUDY
Petrenec, M. ; Polák, Jaroslav ; Šamořil, T. ; Dluhoš, J. ; Obrtlík, Karel
In-situ Low Cycle Fatigue test (LCF) at temperature 635 °C have been performed in Scanning Electron Microscope (SEM) equipped with Electron Backscatter Diffraction analysis (EBSD) on a small dog-bone-shaped specimen of cast Inconel 713LC superalloy. The aim of the work was to study early stage fatigue damage at high temperature by the observations of the characteristic surface relief evolution and crystallographic characterization changes by EBSD. The detail of slip bands shape was checked by FIB and AFM microscopes. The LCF test was conducted on GATAN stage with pre tilted position and constant stress amplitude of total cycle number of 20. The relief produced in the first cycle determines the other locations of the localized cyclic slip to the primary slip planes (111). The relief was modified in the next cycles but without forming additionally new slip traces in the primary system. Based on EBSD analysis before and after LCF, the orientation of two grains was changed which caused activation of second slip system. The damage mechanism evolution is closely connected with the cyclic strain localization to the persistent slip bands where the fatigue cracks were initiated.
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