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Unconventional methods of welding of wrought magnesium alloys
Klimčáková, Kateřina ; Mrňa, Libor (referee) ; Doležal, Pavel (advisor)
Master's thesis deals with consideration possibility of conventional and unconvetional welding methods of wrought magnesium alloys. Methods of Friction Stir Welding, Pulsed Nd:YAG laser and Continuous Fiber laser was used to join magnesium alloy sheets AZ31, AZ61, ZE10 and ZE41. For studying influence of processing parameters on microstructure and mechanical properties were used methods of light microscopy, scanning electron microscopy, tensile tests and microhardness measurements. The results of tensile tests show that from the point of view of keeping ultimate tensile strength is the best methods for welding magnesium alloys Friction Stir Welding. Compared with Nd:YAG laser, fiber laser give better properties of welds. From comparing microstructure and mechanical properties . It wasn't found publications about Friction Stir Welding of magnesium ZE alloys or about FSW sheets with thickness only 0,8 mm and 1,6 mm.
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Research and development of surface modifications of bearing steels by means of ion nitridation
Klimčáková, Kateřina ; Klakurková, Lenka (referee) ; Doležal, Pavel (advisor)
Basic requirements placed on rolling bearing components include the high fatigue limit, the wear resistance and the corrosion resistance. As full production of bearings from materials with these attributes would be quite expensive, surface modifications are used to improve mechanical characteristics. This thesis deals with application of layers to the bearing steel by means of ion nitridation. It studies effects of input conditions of the ion nitridation and of the surface condition on tribological characteristics of the bearing steel with the above mentioned finishing. The study employed the interaction light microscopy, the scanning electron microscopy equipped by energy dispersive chemical microanalysis, the hardness measurement by Vickers, the glow discharge optical emission spectroscopy, and methods of the phase analysis by means of the X-ray diffraction were used.
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Unconventional methods of welding of wrought magnesium alloys
Klimčáková, Kateřina ; Mrňa, Libor (referee) ; Doležal, Pavel (advisor)
Master's thesis deals with consideration possibility of conventional and unconvetional welding methods of wrought magnesium alloys. Methods of Friction Stir Welding, Pulsed Nd:YAG laser and Continuous Fiber laser was used to join magnesium alloy sheets AZ31, AZ61, ZE10 and ZE41. For studying influence of processing parameters on microstructure and mechanical properties were used methods of light microscopy, scanning electron microscopy, tensile tests and microhardness measurements. The results of tensile tests show that from the point of view of keeping ultimate tensile strength is the best methods for welding magnesium alloys Friction Stir Welding. Compared with Nd:YAG laser, fiber laser give better properties of welds. From comparing microstructure and mechanical properties . It wasn't found publications about Friction Stir Welding of magnesium ZE alloys or about FSW sheets with thickness only 0,8 mm and 1,6 mm.
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Research and development of surface modifications of bearing steels by means of ion nitridation
Klimčáková, Kateřina ; Klakurková, Lenka (referee) ; Doležal, Pavel (advisor)
Basic requirements placed on rolling bearing components include the high fatigue limit, the wear resistance and the corrosion resistance. As full production of bearings from materials with these attributes would be quite expensive, surface modifications are used to improve mechanical characteristics. This thesis deals with application of layers to the bearing steel by means of ion nitridation. It studies effects of input conditions of the ion nitridation and of the surface condition on tribological characteristics of the bearing steel with the above mentioned finishing. The study employed the interaction light microscopy, the scanning electron microscopy equipped by energy dispersive chemical microanalysis, the hardness measurement by Vickers, the glow discharge optical emission spectroscopy, and methods of the phase analysis by means of the X-ray diffraction were used.
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