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Influence of fabrication and alloying on magnesium alloys
Jakl, Tomáš ; Remešová, Michaela (referee) ; Horynová, Miroslava (advisor)
This bachelor thesis compares mechanical properties of magnesium alloys in dependence on their composition and fabrication. The first part deals with a pure magnesium and its properties. The second part contains information about alloying elements and an overview of the fabrication methods. The third part consists of different magnesium alloys. The thesis contains photographs of microstructures, a review of mechanical properties and their comparison.
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Structure and mechanical properties of magnesium materials prepared by SPS
Pleskalová, Kateřina ; Hutařová, Simona (referee) ; Doležal, Pavel (advisor)
This diploma thesis deals with the processing of the magnesium-based powder materials with the addition of zinc by the spark plasma sintering. The aim of this thesis is to evaluate influence of sintering parameters and zinc content on the microstructure and mechanical properties of the material. First part of the thesis is literary research which is divided into two main chapters. The first chapter describes magnesium-based materials and mentions their use as biomaterials. The second chapter discusses powder metallurgy, specifically magnesium powders and spark plasma sintering. In the experimental part the powders were sintered at temperatures 300 °C and 400 °C and an analysis was performed using optical microscope, scanning electron microscope, then also EDS analysis and hardness, microhardness and three-point bending tests were performed. An increase in hardness was observed with increasing zinc content and with increasing sintering temperature. The flexural strength was higher for materials sintered at a temperature of 400 ° C.
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Electrochemical corrosion characteristics of Mg-Zn systems prepared by powder metallurgy
Kotek, Jakub ; Hadzima, Branislav (referee) ; Fintová, Stanislava (advisor)
The diploma thesis deals with evaluation of electrochemical corrosion characteristics of Mg-Zn systems prepared by powder metallurgy in SBF solution. The main aim of the thesis is to analyze the influence of chemical composition, achieved structure and parameters of the process of production of Mg-Zn systems on their electrochemical corrosion characteristics. The basic electrochemical properties of the prepared materials will be evaluated by electrochemical impedance spectroscopy. In order to clarify the mechanism of corrosion of materials, the immersion tests will be used, accompanied by metallographic observations.
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Effect of glucose on the corrosion behaviour of AZ31 magnesium alloy in saline solution
Faltýnková, Denisa ; Hasoňová, Michaela (referee) ; Doskočil, Leoš (advisor)
This bachelor thesis deals with the influence of glucose concentration on corrosion behaviour of magnesium alloy AZ31 in saline solution. The theoretical part briefly summarises the use of magnesium and its alloys in biomedical applications and offers insight into the current state of knowledge of the effect of glucose on corrosion of these materials. In the experimental part, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to evaluate the electrochemical behaviour of AZ31 alloy in saline solution with varying concentrations of glucose. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterise post-corrosion surface of the alloy. The corrosion environment was analysed by measurement of conductivity, pH, inductively coupled plasma atomic emission spectroscopy (ICP-OES) and liquid chromatography with conductivity detector. Results showed that glucose, depending on concentration, impairs corrosion resistance of AZ31 alloy in 0.9% NaCl. Three organic acids were identified in the corrosion environment, of which gluconic acid is the most abundant.
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Structure and properties of Hydroxyapatite-Magnesium composites produced by the means of current assisted infiltration sintering
Casas Luna, Mariano ; Obrtlík,, Karel (referee) ; Georgarakis, Konstantinos (referee) ; Čelko, Ladislav (advisor)
Hořčík a kompozity fosforečnanu vápenatého jsou slibnými materiály pro biodegradabilní a nosné implantáty určené pro regeneraci kostí. Předložená práce je zaměřena na návrh, zpracování a charakterizaci vnitřně propojených kompozitů hořčíku s fosforečnanem vápenatým (Mg/CaP). Fosforečnany vápenaté jako jsou hydroxyapatit (HA), kalcium-deficitní hydroxyapatit (CDHA) a fosforečnan vápenatý (TCP) byly syntetizovány a použity pro výrobu skafoldů s kontrolovanou porozitou pomocí metody robocastingu. Byly připraveny porézní předlisky s ortogonální mřížkou a s vnitřními makropóry o velikosti ~500 µm, které byly následně slinovány za teploty 1100 °C po dobu 5 hodin. Vnitřně propojené Mg/CaP kompozity byly připraveny infiltrací čistého hořčíku a hořčíkových slitin obsahujících malá množství vápníku nebo zinku, například 0,2 hm.% vápníku a 1 hm.% zinku do porézních keramických skafoldů. Infiltrace byla provedena pomocí námi vyvinuté a nově popsané metody známé jako “Proudem asistovaná slinovací infiltrace” (z angl. Current Assisted Metal Infiltration (CAMI)). CAMI metoda umožňuje do 15 minut infiltrovat porézní keramický předlisek roztaveným kovem. Pulzujícím elektrickým proudem bylo dosaženo rychlého tavení a následného tuhnutí Mg/CaP kompozitů. Fyzikálně-chemické vlastnosti finálních vnitřně propojených kompozitů byly stanoveny pomocí rastrovací elektronové mikroskopie, počítačové mikro-tomografie, rentgenové difrakční analýzy a optické mikroskopie za účelem stanovení fázové distribuce a interakce mezi materiály. Kromě toho byla u připravených kompozitů hodnocena jejich mechanická pevnost v tlaku, degradační rychlost pomocí různých metod a biokompatibilita spolu s pokusem o uvedení těchto typů materiálů jako potenciálních degradabilních biomateriálů určených pro výrobu desek a/nebo šroubů pro ortopedické aplikace.
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Preparation processes of Mg and Ca based powder materials
Jakůbek, Zdeněk ; Březina, Matěj (referee) ; Hasoňová, Michaela (advisor)
Bachelor thesis is focused on preparation of Mg-Ca material prepared from magnesium powder and calcium particles by hot pressing. Materials were characterized by microstructure and physically-mechanical properties. The influence of pressing temperature and the influence of calcium content was evaluated from final material properties. Obtained results serve to optimize these parametres.
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Interactions of metal ions with humic substances
Obručová, Kateřina ; Smilková, Marcela (referee) ; Klučáková, Martina (advisor)
This bachelor thesis is focused on humic substances, especially fulvic and humic acids. It deals with their genesis and subsequent extraction from nature materials. There are described not only physical and chemicals properties, structure of humic and fulvic acid, but also their reactivity. There is also described the method od isothermal titration calorimetry, which was subsequently used to study of interaction fulvic acid with selected metal ions (Cu2+, Ca2+, Mg2+). From the resulting titration data were determined values of reaction enthalpy, which was then compared with model complexes. From the resulting graphs, it was possible to determine when the reaction reached its maximum, the state when all the binding sites were full. Heat values were determined for this condition.
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Unconventional preparation technology of bulk material from Mg
Horálek, Matyáš ; Hasoňová, Michaela (referee) ; Březina, Matěj (advisor)
Topic of the bachelor's thesis is the procedure of preparation and processing of bulk magnesium powder by unconventional technologies. Bulk materials were evaluated from the point of porosity, microstructure and physically-mechanical properties in correlation with changes of parameters during preparation. Furthemore the influence of chosen processing parameters of electron beam was evaluated from structural properties and depth of the affected material. The outcome of this work is focused on study and optimalization of parameters during preparation and processing of bulk material.
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