|
|
Analysis of Strain - induced Variations of Phase Composition of the TRIP Steel using EBSD Method
Pešina, Zbyněk ; Pantělejev, Libor (referee) ; Man, Ondřej (advisor)
The diploma thesis deals with phase composition measurement of the TRIP steel, using EBSD method. The steel was delivered as thermo-mechanically treated via two different routes. The phase composition of the steel was examined during gradual plastic deformation in the range 0 to10.99%. One route of thermo-mechanical treatment exhibited good agreement with the literature in terms of measured fraction of the retained austenite (15.6%) as well as its decrease during the deformation (to 8.9% at the maximum imposed strain). The samples of the second route did not show any agreement in either of the parameters spoken.
|
|
|
Processing of Electroceramics from Nanopowders
Kachlík, Martin ; Trunec, Martin (referee) ; Maca, Karel (advisor)
Literature review of processing of bulk EuTiO3 ceramics was performed. Based on experiments performed the experimental conditions of solid-state reaction of Eu2O3 with Ti2O3, resp. TiO2 leading to single phase EuTiO3 were established. Balk EuTiO3 ceramics were prepared by means of cold isostatic pressing and sintering in reduction atmosphere. This ceramics is suitable for further evaluation of electromagnetic properties.
|
|
|
Preparation and properties of nanocomposites based on Zr-Fe
Roupcová, Pavla ; Schneeweiss, Oldřich ; Bezdička, Petr
The spark erosion of the pure Zr and Fe electrodes in hydrogen yielded nanocrystalline powder consisting of the mixture of Zr-rich (Zr3FeH7, ZrO2, and Zr(Fe)) and Fe-rich phases with the mean chemical composition Zr-3.2wt.%Fe. Heat treatment in hydrogen atmosphere at 973K induced phase decomposition and transitions with the final composition of bcc Fe, Zr3Fe, ZrH2 and dominating ZrO2 phases. The result indicates that formation of Fe-rich phase (bcc Fe) embedded in ZrO2 could be possible using an appropriate heat treatment of the as-prepared powder.
|
|
|
Preparation and properties of MgO-Ni(Fe) nanocrystalline composite
Schneeweiss, Oldřich ; Pizúrová, Naděžda ; Jirásková, Yvonna ; Žák, Tomáš ; Bezdička, Petr ; Večerníková, Eva
We have prepared MgO-Ni(Fe) nanocrystalline composites by controlled heat treatment of compacted spark synthesized nanocrystalline powders. Besides particle sizes and their chemical compositions, influence of interaction with surrounding atmosphere and adsorbed gases on phase composition and magnetic properties were investigated. Mössbauer spectroscopy, x-ray diffraction and TEM were used for phase analysis. Thermomagnetic curves and DTA/TG measurements were applied for detection of changes in structure and phase composition during heat treatments. The simultaneous gas analysis using mass spectroscopy by heating yielded information on adsorbed and dissolved gases and their reactions with the nanoparticles.
|
|
| |
guest ::
