The diploma thesis is focused on the determination of the mechanical properties and fracture behaviour of the weld joint X5CrNiCuNb16-4 steel prepared by using electron beam technology. The theoretical part is based on summarization of the relevant information about welding, principle of electron beam welding and testing methods of welded joints. The experimental part of the thesis contains results of practical measurements and analyses, realized for evaluation of the mechanical and structural properties of the base material and weld.

This diploma thesis deals with electrical conductivity of a graphene sample, preparation of a graphene field-effect transistor and his irradiation by electron beam. In the theoretical part of the thesis, we describe electronic properties of graphene, preparation of graphene by CVD and its transfer to Si substrate with SiO_2 layer. Experimental part of this thesis is focused on the preparation of a graphene field-effect transistor for use in UHV conditions. Futher describes electron beam scanning over the transistor and creation of current maps of tranzistor. In the last part, the thesis deals with influence of electron beam on transport properties of graphene layer and doping of graphene layer by electron beam.

This work presents a basic research on the influence of electron beam technology modification on chemical, structural and phases changes of Elektron 21 magnesium alloy. The samples were systematically modified under various parameters of the electron beam and coatings on their respective surfaces were deposited via controlled plasma electrolytic oxidation (PEO) subsequently. The influence of the EB modification on the PEO coating formation was observed. Several samples with remelted fine-grained surface layer were obtained. Having a thickness of 10^1 to 10^3 µm, the average grain sizes in this layer were quantitatively evaluated. The performed EDS analysis revealed in identical chemical composition of the remelted surface layer and the original alloy material, despite the detected sample weight loss upon the EB treatment. XRD analysis revealed an increased content of Mg3(Nd,Gd) intermetallic phase in the remelted area. The PEO coatings were more compact and less porous as compared with their counterpart coatings on the original, unmodified alloy material.The results of the presented work showed, among others, a suitable microstructure and chemical composition of some of the modified samples that could potentially exhibit enhanced corrosion resistance as opposed to the unmodified material. The corrosion testing will be part of a follow-up study. More compact PEO coatings formed on some of the modified surface layers likely represent, too, a more durable variant as compared to the original material.

This thesis deals with surface re-melting by electron beam of thermal sprayed material NiCrBSi by method HVOF. The microstructure, chemical and phase composition, hardness and abrasive wear resistance were evaluated in depending on the electron beam parameters and modes of the electron beam 6-poinst and line. Observed microstructure was better after both methods of re-melting. The splats were not observed, coating porosity decreased and structure was more homogenous. Structure and phase analysis was acquired by light microscopy, scanning electron microscopy, energy dispersive spectroscopy and x-ray diffraction. A small change in hardness between modes of re-melting was observed, but measured hardness was higher than in sample without re-melting. Similar results were observed for abrasion resistance.

Fast deflection is one of the great advantages of an electron beam, making it possible to process a relatively large area at once and also to modify the distribution of the supplied energy. The dissertation deals with surface heat treatment with a focus on the effect of beam deflection on the process. Furthermore, the influence of processing speed and defocusing of the electron beam is studied. The principles of electron beam technology and the summary of surface heat treatment of various materials are presented in the literary part of the thesis. The experimental part is focused on the influence of process parameters on processing in the solid phase, carried out on steel 42CrMo4, and in in the liquid phase, carried out on alloy NiCrBSi. Especially changes in structure, hardness, shape of the processed area and wear resistance are evaluated on processed samples. The results are also evaluated from an energy perspective. Furthermore, an optimum combination of technological parameters is recommended for solid and liquid phase surface heat treatment.

The problematics of weldability of heterogeneous welds of aluminium and titanium alloys produced by electron beam welding is discussed in this work. Homogenous welds of selected alloys were analyzed in the first stage. Welding of these materials relates to formation of intermetallic phases at the interface of base materials due to differences in physical, chemical and metallurgical properties of base materials. One of the prerequisites for producing high quality weld joints is to find optimal process parameters. The influence of selected process parameters to integrity, structure and mechanical properties of heterogeneous Al/Ti joints is evaluated.

This diploma thesis deals with automatic detection and measurement of the electron beam in the images from a transmission electron microscope (TEM). The introduction provides a description of the construction and the main parts of the electron microscope. In the theoretical part, there are summarized modes of illumination from the fluorescent screen. Machine learning, specifically convolution neural network U-Net is used for automatic detection of the electron beam in the image. The measurement of the beam is based on ellipse approximation, which defines the size and dimension of the beam. Neural network learning requires an extensive database of images. For this purpose, the own augmentation approach is proposed, which applies a specific combination of geometric transformations for each mode of illumination. In the conclusion of this thesis, the results are evaluated and summarized. This proposed algorithm achieves 0.815 of the DICE coefficient, which describes an overlap between two sets. The thesis was designed in Python programming language.

Within this work, a set of depositions induced by focused electron beam was prepared. The depositions were prepared in the presence of water vapours from trimethyl(methylcyclopentadienyl)platinum(IV) precursor. The dependence of prepared materials purity on beam accelerating voltage and water vapour pressure was measured. The best platinum content was achieved at (27,2 ± 0,4) at. %, with beam accelerating voltage 5 kV, beam current 1600 pA and water vapour pressure 100 Pa. Due to subsequent long-term exposure to light, air humidity and air oxygen, the platinum content was increased to (39,2 ± 2,1) at. %.

This work deal with problems of investigation materials electron beam. This project is focuses on investigation materials by the help of method environmental scan electron microscopy (ESEM) and describes her patterns. The perfection of ESEM excel above all at studies non - conducting or water containing, often biological samples. These samples not to be in no way prepared or cut – and – dries, in contradistinction to classical scanning electron microscope and thanks is under investigation their native surface structure without desiccation breaking. The general aim is determination of contrast in image acquired by ionization detector.

The present work deals with electron microscopy, electron microscopy primarily environmental. The main task of the work will draft the optimal shape of the differentially pumped chamber, dividing the pressure difference between tube and chamber with sample for a new concept of an electron microscope. By ANSYS Fluent will be analyzed pumping gas. Subsequently, according to the results obtained will be a modified form of the differential Chamber and to achieve the lowest gas pressure on the track of the electron beam.