|
|
Stability of dispersoids in aluminium alloys at elevated temperatures.
Králík, Rostislav ; Cieslar, Miroslav (advisor) ; Michalcová, Alena (referee)
Hliníková slitina AA8079 připravena plynulým odléváním mezi válce je běžně používána pro výrobu tenké potravinářské fólie. Vzhledem k použité metodě odlévání a složení slitiny je struktura litého materiálu značně nehomogenní a obsahuje intermetalické fáze, které se shlukují v eutektických koloniích. Litý materiál tak vyžaduje tepelné zpracování před dalšími kroky výroby. Mikrostruktura materiálu po homogenizačních žíháních na různých teplotách je rozdílná, což ovlivňuje další zpracování. Po homogenizaci je materiál válcován což způsobuje snížení tažnosti. Rekrystalizační žíhání je vyžadováno po zválcování na střední tloušťku před finálním válcování, aby byla tažnost obnovena. Chování materiálu během rekrystalizačního žíhání je ovlivněno přítomnými fázemi, jejich velikostí a rozdělením. Byl studován vliv mikrostruktury po homogenizaci na rozdílných teplotách na rekrystalizaci, byla vyhodnocena kinetika rekrystalizace a byly identifikovány dva hlavní mechanismy ovlivňující rekrystalizaci - částicemi stimulovaná nukleace a Zenerův tlak.
|
|
|
Improvement of manufacturing technology of flange
Dvořák, Jakub ; Fiala, Zdeněk (referee) ; Jaroš, Aleš (advisor)
This diploma thesis focuses on improvement of the existing technology of the flange part in cooperation with the company Znojemské strojírny, s r.o. The theoretical part describes the technologies used in machining of the component. Subsequently, cutting materials and aluminum alloys are dealt with. A detailed analysis of the existing technology is performed in the practical part of the thesis followed by rationalization of the production process, which was carried out with respect to time and financial savings. A new technological procedure is developed after the improvement of the current production process. Finally, a technical-economic evaluation of the design improvement process is carried out.
|
|
|
Optimalization of cutting process for machining of aluminium profile on CNC centre
Král, Ondřej ; Fiala, Zdeněk (referee) ; Jaroš, Aleš (advisor)
This master‘s thesis deals with the suggestion of suitable tools for milling aluminum alloys profiles for the construction of aperture fillings and their aplication to a CNC machining center for increasing the efficiency of the cutting process. The first part of the thesis is focused on the description of the company and the workplace of production of aluminum alloys constructions. The following pages contain description of standardized products, which are used to identify the test profile that is part of the experimental verification. Next part of this thesis is characteristic of aluminum alloys and tool materials suitable for their machining. Second part of this work contains an analysis of the current state, suggestion of new cutting tools and their application to the production proces. At the end of this thesis there is the technical-economic evaluation that deals with the time and economic savings of the applied design.
|
|
|
Assessment of weld defects during laser welding with beam wobbling of aluminum alloy
Slíž, Michal ; Šebestová, Hana (referee) ; Mrňa, Libor (advisor)
This bachelor thesis is aimed on assessment of weld defects during laser welding with beam wobbling of aluminum alloy. Theoretical part deals with study of main types of industrial lasers, laser modes and analysis of beam wobbling technique. Further described aluminum alloys, their weldability, weld defects and methods of their evaluation. In the experimental part, sixteen test welds are made on sheet metal from aluminum alloy AlMg3. This is followed by the evaluation of the defects and determination of optimal welding parameters.
|
|
|
Structure and properties of welded joint TiAl6V4 / 6061 made by electron beam technology
Král, Michael ; Jan, Vít (referee) ; Foret, Rudolf (advisor)
Titanium and aluminium alloys are among the most used construct materials due to their physical and mechanical properties except steels. The joining of these alloys can improve properties of whole construction but it is still difficult task. Especially welding of titanium and aluminium alloys is difficult cause formation of undesirable intermetalic phases in the weld. This thesis focuses on influences of electron beam welding parameters especially focusing and deflection of beam and preheating of base material to quality of heterogeneous join of titanium alloy Ti6Al4V and aluminium alloy EN AW-6061 – T651. There is described preparation of welded joins and brazed joins in the thesis, which are evaluated by light microscopy, scanning electron microscopy and EDS analysis of chemical composition. There was evaluated presence and chemical composition of formated intermetalic phases in the welded joins and quality and defects in the brazed joins.
|
|
|
Productive milling of aluminum alloys
Dvořák, Jakub ; Žídek, Jan (referee) ; Jaroš, Aleš (advisor)
This bachelor thesis is focused on milling of aluminum alloys, where the technology of milling is described in the first place, then the cutting materials and aluminum alloys. The main subject of the work was to carry out the experiment. The Experiment was focused on influence of cutting conditions on the final quality of the surface with regard to machine time. The aluminum workpiece was milled at different cutting speeds and various feed per tooth. At the same time the quality of the surface was examened and machine times were calculated. The Experiment showed us, whether it pays to use higher cutting speeds and feed per tooth, keeping the set of limited values of surface roughness with respect to the machine time. The result of the experiment is the following - the increasing feed per tooth deteriorates the quality of machined surface, but machine time is reduced.
|
|
|
Applications of aluminium alloys
Ponka, Ondřej ; Juliš, Martin (referee) ; Němec, Karel (advisor)
This bachelor thesis deals with basic overview of aluminum and its alloys. It deals with properties of primary aluminum, its production and the benefits resulting from the processing of secondary aluminum. The thesis also discusses aluminum alloys as well. It describes the basic alloying elements, their distribution and their specific properties. It also mentions the effects of the heat and surface treatments on the properties of the alloys. Finally, the thesis deals with applicability of aluminum and its alloys in various industries. Briefly describes the issue of specific applications and provides advantages and disadvantages arising from their use.
|
|
|
Welding of bike frames
Kotrík, Marcel ; Daněk, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
In my bachelor thesis I elaborated an overview of suitable materials for the manufacturing of bicycle frames. Most preferred materials for mass production of bicycle frames are cured aluminum alloys. The best method for joining aluminum tubular frame construction is fusion welding at robot lines in a protective atmosphere of inert gas. We measured the hardness of the welded metal, heat affected zone and base material at the weld of the bicycle frame. Values are very similar in all areas, so the whole frame structure was cured. We welded a test weld, using TIG method. Hardness of the test weld is about 24.5 % lower, than hardness of the weld from manufacturer. Hardness of the heat affected zone is even lower. The curing of the whole frame construction is therefore very important. There is a concentration cavity in the cut of the weld from manufacturer and the root of the weld is not welded all over. The same defects are in the cuts of our test welds, there is also porosity in one of the test welds. But the test weld is satisfying, despite the defects.
|
|
|
Optimization of NC program using CAD/CAM software
Paseka, Jan ; Kaderka, Jaroslav (referee) ; Osička, Karel (advisor)
Tendency of this master thesis is a proposal of savings in the process of technological production’s preparation in a manufacturing company. In the first part is elaborated general theoretical study of current components and NC programs. Based on this, and finished analysis was defined optimization’s proposals described in second part. Thanks this complete proposals comes to time and money savings, which are needed for implementation of prototype project into serial production.
|
|
|
Water soluble cores for aluminum alloys and their influence on the surface quality of castings
Blažík, Petr ; Tomek, Ladislav (referee) ; Kaňa, Václav (advisor)
The goal of this thesis is to examine a possible influence of the water soluble cores on the microstructure of commonly used aluminum alloys AlSi7Mg and AlSi10Mg in the lost wax technology. This thesis only deals with the changes of the eutecticum on the contact surface between the metal and the core and its surroundings where interactions can appear between the core based on the alkali salts NaCl and KCl and the alloy modified by sodium or strontium. The experimental part investigates the influence of the alkali salts on the modification additives and the modification of the structure itself.
|
guest ::
