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Modification of HVOF and cold spray deposited coatings via electron beam technology
Vacek, Petr ; Šiška, Filip (referee) ; Čížek, Jan (advisor)
The aim of this thesis was to modify microstructure and coating-substrate interface of CoNiCrAlY coatings deposited by HVOF and cold spray on Inconel 718 substrates. Electron beam remelting and annealing in a protective atmosphere were used to modify the coatings. Microstructure, chemical and phase composition were analyzed. The effect of beam current, transversal velocity and beam defocus on remelted depth was evaluated. As-sprayed microstructure and chemical composition of coatings were analyzed and compared with remelted samples. The effect of annealing of the as-sprayed and remelted samples was evaluated. Remelted layers exhibited dendritic structure. Chemical composition changed only after remelting of interface and part of a substrate. When only the coating was remelted, chemical composition remained the same. Phases coarsened after the annealing. Chemical composition changed after annealing due to the diffusion.
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Effect of electron beam remeltin on binary mixtures deposited by the cold spray method
Novotný, David ; Řehořek, Lukáš (referee) ; Čupera, Jan (advisor)
This bachelor’s thesis deals with the effect of an electron beam remelting on binary mixtures of Fe-Al and Ni-Al, which were deposited by Cold spray. The Research study is focused on the basic principles of function and usage of the electron beam technology and the Cold spray method. Furthermore, binary systems of Fe-Al and Ni-Al are, along with their binary diagrams, also described in this part. In the Experimental part, the samples were remelted by an electron beam and consequently, the changes in microstucture were examined using electron and optical microscope.
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Unconventional preparation technology of bulk material from Mg
Horálek, Matyáš ; Hasoňová, Michaela (referee) ; Březina, Matěj (advisor)
Topic of the bachelor's thesis is the procedure of preparation and processing of bulk magnesium powder by unconventional technologies. Bulk materials were evaluated from the point of porosity, microstructure and physically-mechanical properties in correlation with changes of parameters during preparation. Furthemore the influence of chosen processing parameters of electron beam was evaluated from structural properties and depth of the affected material. The outcome of this work is focused on study and optimalization of parameters during preparation and processing of bulk material.
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Surface treatment of selected steels using electron beam
Matlák, Jiří ; Jan, Vít (referee) ; Kouřil, Miloslav (advisor)
The aim of diploma thesis was preparation of hardened layer on three chosen types of materials with different alloying components content without surface melt by using electron beam technology. The influence of chosen process parameters was observed on the prepared hardened layers properties and shapes. In the first part of bibliographic search there are described electron beam properties, possibilities of his influencing and control. There is given example of complete set of electron beam are mentioned in the second part of theoretical research.
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Surface melting of graphitic cast iron for hard layer preparation and its optimization
Adam, Ondřej ; Matlák, Jiří (referee) ; Jan, Vít (advisor)
The aim of bachelor thesis is description of microstructures, which were created by surface melting of ductile iron by using electron beam technology. The first part of bibliographic search deals with carbon and its effect on iron. The second part is focused on the general knowledge about cast irons, especially on graphitic cast irons. The last part of bibliographic search deals with electron beam technology. The practical part presents a microstructures, which were created by surface melting. Temperature cycles of the different material areas are described based on microstructures. In the end of bachelor thesis, there are chosen remelted layer with the best parametres and surface melting technology is optimized.
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Electron beam welding of parts made from aluminium alloy
Jirák, David ; Jakoubek, Jaroslav (referee) ; Daněk, Ladislav (advisor)
The topic of this thesis was ordered by Valeo Compressor Humpolec Itd (further referred to as Valeo). It deals with the electron welding of a component made of an aluminium alloy, a piston specifically, which is made for an automobile air-conditioning compressor. The aim of this thesis was to analyze and suggest a way of increasing porosity of the welded area. The data needed for the analysis and the present state of the welded area was provided by Valeo.
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Multiphase Ti-Ni layer on titanium substrate by local alloying
Husťák, Miroslav ; Havlík, Petr (referee) ; Jan, Vít (advisor)
The theory section of this thesis is to describe properties and utilisation of titanium and titanium alloys as well as to deal with various methods of surface treatment and means of alloying a titanium surface layer with nickel. The experimental chapter of this thesis is to describe the creation of a hard surface layer on titanium substrate. In order to achieve a hard surface layer, a layer of nickel was electrodeposited on substrate made of commercially pure ASTM Grade 2 titanium which was subsequently melted with the help of an electron beam. A layer with changed chemical composition and microstructure was created by applying the aforementioned method on the titanium surface. In order to achieve a homogeneous microstructure in the surface layer, several samples with the surface layer were prepared by utilising different parameters of the electron beam. The samples were later tested for their microstructural homogeneity, chemical composition, and hardness.
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Nickel silicides layer by electron beam melting of electro deposited layer
Petr, Jiří ; Pantělejev, Libor (referee) ; Jan, Vít (advisor)
This master’s thesis deals with the possibility of creating a compact nickel-silicide layer on austenitic substrates. The theoretical part describes a variety of surface treatments, silicide division, and basic principles of electron beam. The experimental part contains a description of used experimental methods for evaluation of samples, creation of Ni-Si coating using electroplating, and the parameters of electron beam used for melting the sample coating. The last part is devoted to structural evaluation of the sample coating and its microhardness.
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Surface melting and possible alloying of cast iron with lamellar graphite by electron beam
Abu Khait, Yosef ; Kouřil, Miloslav (referee) ; Pacal, Bohumil (advisor)
In this thesis, the structural and mechanical changes, which took place in flake graphite cast iron after electron beam surface melting and chrome-nickel surface alloying, were studied. Furthermore, the effect of set parameters on properties and depth of the melted and alloyed region is also analyzed. In the experimental part, the analyzed microstructures, micro-hardness and the distribution of elements after melting and alloying, were presented. Structural differences of material regions caused by melting were described based on microstructures. In the end of diploma thesis, the conclusions of using EB technology for surface melting and alloying were discussed.
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