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Microstructure and properties of enhanced twin-roll cast aluminium alloys.
Poková, Michaela ; Cieslar, Miroslav (advisor) ; Karlík, Miroslav (referee) ; Kruml, Tomáš (referee)
Three aluminium alloys from AA3003 series modified by zirconium were pre- pared by twin-roll casting. The role of composition, heat treatment and deforma- tion by cold-rolling or equal channel angular pressing on evolution of microstruc- ture and mechanical properties were studied. High density of α-Al(Mn,Fe)Si pre- cipitates formed during annealing between 300 ◦ C and 500 ◦ C. Coherent Al3Zr particles precipitated during annealing at 450 ◦ C with slow heating rate. Recrys- tallization resistance of deformed alloys was enhanced by either Al3Zr precipitates formed before deformation or by α-Al(Mn,Fe)Si particles nucleating simultane- ously with recrystallization. 1
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Study weld porosity aluminum alloy 5000 series during hybrid welding Laser-TIG
Drápela, Petr ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
This bachelor thesis is aimed on studying weld porosity of aluminium alloys made by laser-TIG technology. Theoretical part deals with welding methods and their parameters, capabilities and usage. Methods are investigated separately then as a unit. At the end of the theoretical part there is summary about welding aluminium alloys and their properties. In experimental part it is made eleven testing welds on sheet metal from aluminium alloy EN AW-5754 H111, thickness 5 mm. After this sizes of welds are measured. From these sizes dependences welding current to input heat Q are made. Final part concerns analysis of welding defects and final evaluation optimum welding parameters.
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Mechanical and microstructural characteristics of materials produced by SLM method
Hradil, David ; Jan, Vít (referee) ; Pantělejev, Libor (advisor)
The master's diploma thesis deals with the mechanical and structural characteristics of aluminium-base alloy 2000 series, produced by selective laser melting (SLM). The experimental part of the thesis deal with selection of SLM processing parameters, influence of scanning strategy and evaluation of mechanical and structural characteristics of fabricated materials. Mechanical characteristics were evaluated based on results of tensile tests and microhardness measurement. Structural characteristics of materials produced by SLM were evaluated using metallographic analysis.
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Heat treatment of aluminum casting alloys
Holátko, Petr ; Roučka, Jaromír (referee) ; Kaňa, Václav (advisor)
This bechelor thesis deals with the description of the heat treatment of aluminium casting alloys and is particularly focused on the frequent heat treatment, which is hardening. The first part describes the properties of aluminium alloys and are further explained the different kinds of heat treatment. The second part describes the experiment, which were cured, two different aluminium alloys. Here, the work focuses on change in hardness before and after hardening.
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Influence of exothermic sleaves on solidification of aluminium alloys
Zajíček, Roman ; Krutiš, Vladimír (referee) ; Roučka, Jaromír (advisor)
The master’s thesis deals with the influence of the exothermic risers on the solidification of aluminum alloys. The work is divided into three parts. The first theoretical part describes the differences of properties of cast aluminum alloys compared to other based metals, especially iron alloys. It also describes the methodology of designing risers, composition of exothermic mixtures and finally gives an overview on the simulation programs on the market, their application in foundry practice and briefly explains how to define the material in the simulation program ProCAST. The second part describes the experimental measurement of the solidification time of aluminum alloy AlSi7Mg0,3 in the sand form with exothermic riser. The final section describes the simulation of experimental measurements. Further with help of simulation software it is tried to find the general principles that have an influence on feed module rate of exothermic riser.
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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.
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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.
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Welding of aluminum alloys using high-power semiconductor laser
Mikeš, David ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
Thesis deals with the optimization of process parameters during laser welding of aluminum alloys 5000 series. The theoretical part describes the types of lasers and their applications in industry, further discusses the properties of aluminum alloys, laser welding theory and principles of monitoring and diagnostics of laser process. In the experimental part the samples were welded using a semiconductor laser. For those samples were evaluated mechanical properties, welded defects and structure depending on the process parameters. Using the photodetector was observed stability of laser process by sensing the plasma plume. The link between stability and the formation of structural defects in the weld joint was observed from the measurement results.
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Controled crystallisation of aluminium alloys castings poured in shell moulds
Mašková, Lenka ; Střítecký, František (referee) ; Roučka, Jaromír (advisor)
The aim of this thesis is to verify a possibility of controlling the crystallisation of aluminium alloys poured in shell moulds in order to achieve directional solidification. For this purpose, new cooling plant has been designed and fabricated. Several sample castings were produced under different initial conditions. Based on the evaluation of measured temperatures, a numerical simulation of heat transfer was created using the ProCAST software. Finally, the sample castings were sectioned into specimens that were, subsequently, metallographically polished and the evaluation of their structure with respect to the amount and types of defects was performed.
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