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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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Evaluation of electrochemical properties of wrought Mg-Al-Zn type magnesium alloys
Slouková, Karolína ; Hadzima, Branislav (referee) ; Tkacz, Jakub (advisor)
The aim of this master’s thesis is electrochemical characteristics evaluation of magnesium alloys. The theoretical part describes the properties of magnesium and its alloys and their corrosion characteristics. In the experimental part are presented results of corrosion resistance measurement of two types of wrought magnesium alloys. It was AZ31 and AZ61 magnesium alloys, which were measured in Hank’s solutions with addition of ions Ca2+ and Mg2+ (SBF+) and without addition of the ions (SBF). The solution temperature during the measurement was 37 ± 1 °C. The experiments were used electrochemical impedance spectroscopy (EIS) and potentiodynamic tests using linear polarization (LP). EIS measurements were done in times of 5 minutes, 1, 2, 4, 8, 12, 24, 48, 72, 96 and 168 hours. Potentiodynamic tests were only short-term and they started after 5 minutes of stabilization. Both methods were used for measuring the electrochemical characteristics of polished and ground surface of the samples. The most important measurement results were polarization resistance, corrosion potential and corrosion current density. The electrochemical measurements are used to estimate the chemical composition influence and alloy’s structure of the corrosion resistance.
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Element analysis of magnesium alloys using laser induced breakdown spectrometry
Veis, Samuel ; Fintová, Stanislava (referee) ; Doležal, Pavel (advisor)
Bachelor‘s thesis is aimed at assessing the possibilities of trace elements detection in magnesium alloys using laser induced breakdown spectroscopy with a focus on rare earth elements. Base materials were wrought magnesium alloy sheet ZE10 with thickness of 1,6 mm and ZE41 with thickness of 2 mm produced using Direct Chill casting method. Qualitative and quantitative ways of LIBS spectra evaluation were described in the work. Qualitative analysis confirmed the presence of La, Ce, Nd and Pr in ZE41, and La with Ce in ZE10. These informations confirm results of EDS analysis. For a demonstration, quantitative analysis of ZE10 was made, which confirmed the possibility of using LIBS for detection of REE in Mg alloys.
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Evaluation of electrochemical properties of wrought Mg-Al-Zn type magnesium alloys
Slouková, Karolína ; Hadzima, Branislav (referee) ; Tkacz, Jakub (advisor)
The aim of this master’s thesis is electrochemical characteristics evaluation of magnesium alloys. The theoretical part describes the properties of magnesium and its alloys and their corrosion characteristics. In the experimental part are presented results of corrosion resistance measurement of two types of wrought magnesium alloys. It was AZ31 and AZ61 magnesium alloys, which were measured in Hank’s solutions with addition of ions Ca2+ and Mg2+ (SBF+) and without addition of the ions (SBF). The solution temperature during the measurement was 37 ± 1 °C. The experiments were used electrochemical impedance spectroscopy (EIS) and potentiodynamic tests using linear polarization (LP). EIS measurements were done in times of 5 minutes, 1, 2, 4, 8, 12, 24, 48, 72, 96 and 168 hours. Potentiodynamic tests were only short-term and they started after 5 minutes of stabilization. Both methods were used for measuring the electrochemical characteristics of polished and ground surface of the samples. The most important measurement results were polarization resistance, corrosion potential and corrosion current density. The electrochemical measurements are used to estimate the chemical composition influence and alloy’s structure of the corrosion resistance.
|
|
|
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.
|
|
|
Element analysis of magnesium alloys using laser induced breakdown spectrometry
Veis, Samuel ; Fintová, Stanislava (referee) ; Doležal, Pavel (advisor)
Bachelor‘s thesis is aimed at assessing the possibilities of trace elements detection in magnesium alloys using laser induced breakdown spectroscopy with a focus on rare earth elements. Base materials were wrought magnesium alloy sheet ZE10 with thickness of 1,6 mm and ZE41 with thickness of 2 mm produced using Direct Chill casting method. Qualitative and quantitative ways of LIBS spectra evaluation were described in the work. Qualitative analysis confirmed the presence of La, Ce, Nd and Pr in ZE41, and La with Ce in ZE10. These informations confirm results of EDS analysis. For a demonstration, quantitative analysis of ZE10 was made, which confirmed the possibility of using LIBS for detection of REE in Mg alloys.
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