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Direct Imaging of Deformation of Metallic Materials by Means of Slow Electrons
Piňos, Jakub ; Kolíbal, Miroslav (referee) ; Kasl, Josef (referee) ; Frank, Luděk (advisor)
Scanning electron microscopy is one of the common tools for the analysis of advanced engineering materials. The development of various techniques allows choosing an appropriate mode of observation to obtain new information about sample structure and properties. The thesis deals with direct imaging of deformation in metal samples by scanning low energy electron microscopy during the in-situ tensile test. Experiments were performed on pure copper samples. Images obtained during the tensile test allow us to observe the effect of deformation in the structure of metal from the first appearance of these effects in structure at deformation intensities about 3-4% up to extreme plastic deformation at the crack tip.
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SMV-2012-15: Examination of microstructure of heat-proof steels by means of the low energy electron microscopy
Mikmeková, Šárka
The CB steel is meant for casted components of turbines – valves and shell. From the COST F and COST FB2 steels, welded rotors are made similarly as from a combination of the F steel and a nickel alloy, which is, however, used for higher temperatures. In order these materials preserve their desired strength for long-time load at high temperatures, slip movement of dislocations should be effectively blocked. In the given materials, this is secured with the help of fine precipitates, which, however, coarse during exploitation and are replaced with particles of different phases that have reduced ability to retard the dislocation movement. By means of the low energy electron microscopy the microstructure of heat-proof metallic materials has been examined, which provided detection and chemical and phase classification of tiny particles of the fine precipitates.
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Prospects of the scanning low energy electron microscopy in materials science
Mikmeková, Šárka ; Hovorka, Miloš ; Konvalina, Ivo ; Müllerová, Ilona ; Frank, Luděk
The use of the scanning low energy electron microscopy (SLEEM) has been slowly making its way into the field of materials science, hampered not by limitations in the technique but rather by the relative scarcity of these instruments in research institutes and laboratories. Various techniques exist which are capable of studying the material microstructure, with the scanning electron microscopy (SEM), (scanning) transmission microscopy ((S)TEM) and focused ion beam (FIB) microscopy being perhaps the most known. A specific way to visualizing the microstructure of materials at high spatial resolution, to achieve a high contrast between grains in polycrystals and very fast data acquisition is to use the cathode lens (CL) mode in SEM. The CL mode in the SEM enables us to detect slow but not only slow, high angle scattered electrons that carry mainly crystallographic contrast based on the electron channeling, mostly in the Mott scattering angular range.
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Superconductive property and microstructure of MgB2/Al composite materials
Matsuda, K. ; Mizutani, M. ; Nishimura, K. ; Kawabata, T. ; Hishinuma, Y. ; Aoyama, S. ; Müllerová, Ilona ; Frank, Luděk ; Ikeno, S.
Scanning low energy electron microscopy (SLEEM) is a useful tool for observation of insulating samples and determination of microstructure on a specimen surface. In the present work, we have applied the SLEEM to examine the microstructure contrast between boride particles and Al matrix.
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Very Low Energy Scanning Electron Microscopy
Hrnčiřík, Petr
Main goal of the work is in-situ comparison of signals in slow and Auger electrons in Scanning Electron Microscope. Construction of experimental device, computer simulations and calculations of properties of the device and interpretation of getting data are parts of the work.
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