National Repository of Grey Literature 13 records found  previous11 - 13  jump to record: Search took 0.01 seconds. 
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.
High temperature alloying of high power semiconductor devices
Straškraba, Vojtěch ; Szendiuch, Ivan (referee) ; ABB, Vladimír Andrš, (advisor)
The thesis deals with study of high-temperature alloying process of power semiconductor devices. Mechanical durability and loss heat extraction is achieved via contacting silicon devices on molybdenum electrode in vacuum alloying furnace. Properties of alloy contact determine electrical, geometrical and mechanical parameters of device and are related with durability of device under heavy load during operation in various industrial machines or transport vehicles. Process parameters are evaluated in terms of input materials and their preparation along with temperature ramp profile and conditions in vacuum furnace. Test samples are analyzed to assess their electrical and geometrical parameters and selected samples underwent element analysis of alloy contact. Optimal process parameters are estimated according to analysis of experiments.
Optimization of die casting technology of a thin-walled casting
Míšek, Jakub ; Přecechtěl, Petr (referee) ; Cupák, Petr (advisor)
The aim of this work is to suggest changes of technological process, which will reduce amount of casting defects in cast made by high pressure method. The cast is casting by Alfred Engelmann CZ, spol. s.r.o. from aluminum alloy EN AB - AlSi12 (Fe). Current technology was analyzed and also was made detailed description of the high-pressure casting technology, including a description of materials and machines. To determine the causes of defects and their effects were done casting experimental test series. The results of this experiment showed that the set of casting parameter has a significant influence on the quality of the casting. It was also shown that the preparation of the melt affects the porosity of the casting. At the end was suggested changes of technological process.

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