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Mg-hydroxyapatite composite materials prepared by powder metallurgy
Řičánek, Adam ; Doskočil, Leoš (referee) ; Buchtík, Martin (advisor)
This bachelor thesis focuses on the preparation of magnesium-hydroxyapatite composite by powder metallurgy methods. The theoretical part of bachelor thesis deals with magnesium, magnesium alloys and magnesium materials. Furthermore, the theoretical part of the bachelor thesis deals with the basics of powder metallurgy, processing of materials prepared by powder metallurgy and metal matrix composites. In the experimental part of the bachelor thesis, two series of composites were made with different quantities of hydroxyapatite. Composites were made by mixing Mg with filler and by mixing and milling Mg with filler. Both series of composites were characterised by investigation of microstructure and element composition, hardness, compressive strength and corrosion resistance. Composites of mixed and milled series showed a highly homogenous structure. Hardness, compressive strength and corrosion resistance increased with increasing amounts of hydroxyapatite. Composites of mixed series showed heterogeneous structures. Hardness did not increase with increasing amount of hydroxyapatite. Corrosion resistance slightly increased with increasing amount of filler. Compression strength decreased with the increasing amount of filler due to lower cohesion and incompactness of the structure.
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Utilization of immiscible alloys for the SERS substrates
Klimšová, Zuzana ; Čupera, Jan (referee) ; Adam, Ondřej (advisor)
Surface-enhanced Raman spectroscopy (SERS) is an analytical method that enables the sensitive detection of biological molecules by enhancing the Raman signal on nanoporous metal substrates. This bachelor's thesis focuses on the preparation of immiscible alloys, specifically Cu75Ag25, using powder metallurgy and its application for SERS. The aim was to develop a fine-grained, two-phase microstructure suitable for SERS analysis. The process included mechanical alloying and isostatic pressing, followed by heat treatment to achieve the optimal microstructure. The results show that mechanical alloying and subsequent heat treatment create a fine two-phase microstructure suitable for further research as SERS substrates. The thesis also explores the possibility of preparing SERS substrates by casting and describes the structure of such prepared samples. The casting was conducted in a vacuum induction furnace, ensuring high material purity. Comparative studies between samples prepared by casting and powder metallurgy revealed differences in the resulting microstructures. The results indicate that powder metallurgy provides finer structures suitable for SERS applications, while cast samples exhibit coarser microstructures. Differential scanning calorimetry (DSC) was used to analyze the thermal properties of the samples, contributing to a better understanding of the kinetics of phase transformations. This thesis provides a comprehensive view of various methods for preparing SERS substrates and their impact on the resulting microstructures.
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Preparation processes and characterization of bulk material from Mg and Zn powders
Hasoňová, Michaela ; Pacal, Bohumil (referee) ; Doležal, Pavel (advisor)
Topic of the diploma thesis is Mg-Zn bulk material preparation process by powder mixtures sintering at hot pressing. Structure, porosity and physically-mechanical properties of prepared bulk materials was evaluated. Obtained results and their interpretation were served as feedback for following optimization of individual processing parameters of bulk materials preparation. Thesis solving focuses on study and control of processes during bulk material preparation and description of the processes from physically-chemical point of view of the structure creation and final material properties.
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Cemented carbides and theirs effective use
Salajka, Jaroslav ; Sedlák, Josef (referee) ; Humár, Anton (advisor)
The aim of this thesis is a complex processing of obtained technical findings in the area of cutting materials, especially the evaluation and comparison of work possibilities recommended by prime world manufacturers for effective usage and application of coated and uncoated cemented carbides. Characteristics of cemented carbides in terms of production, marking method, physical and mechanical properties and application. Comparison of cemented carbides in the range of production of the most significant world tool and cutting material producers. Cutting efficiency evaluation of the tool. Recommended areas and operating conditions for effective usage of cemented carbides and their technical economic evaluation.
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In-situ Synthesised Intermetallic Compounds in Powder Materials
Hanusová, Petra ; Novák, Pavel (referee) ; Skotnicová, Kateřina (referee) ; Dlouhý, Ivo (advisor)
The mechanical treatment of solids is one of the most common and widely used operations. The volume of solids subjected to chemical treatment is very large too. Therefore, combining these two ways into one seems to be a logical solution. This method is called the mechanochemical processing of materials. Processing materials in this way has many advantages. On the one hand, this processing is economically as well as technologically feasible. Even the materials that not react together in conventional way can be prepare in this way. The mechanochemistry/mechanochemical synthesis utilizes the mechanical energy to activate chemical reactions and structural changes. The aluminothermic reduction reactions induced by the high – energy ball milling are gaining importance because of the potential applications like the synthesis of microcrystalline and nanocrystalline in – situ metal matrix composites. The mechanical activation of the chemical reactions by high energy ball milling often changes the reaction mechanism and produces metastable materials. Changes of reaction mechanisms during mechanical alloying on four different systems were studied. The system was based on this composition: Al - B2O3 - X (X = C, Ti, Nb, Cr). The possibility of another in – situ reactions during spark plasma sintering process (SPS) was also investigated. All systems were mechanically alloyed under the same conditions. After alloying, on each system scanning electron microscopy was performed and qualitative and quantitative analysis was performed using X-ray diffraction. The indentation hardness and the indentation modulus of elasticity were evaluated using nanoindentation. All analyzes were performed after mechanical alloying as well as SPS and the results were compared to each other. Based on the results, a change of reaction mechanisms was proposed for all systems. It has been found that metal matrix composites are formed and, when chromium is used, hybrid composite material reinforced with intermetallic phase and aluminum borate has been developed.
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In-situ Synthesised Intermetallic Compounds in Powder Materials
Hanusová, Petra ; Novák, Pavel (referee) ; Skotnicová, Kateřina (referee) ; Dlouhý, Ivo (advisor)
The mechanical treatment of solids is one of the most common and widely used operations. The volume of solids subjected to chemical treatment is very large too. Therefore, combining these two ways into one seems to be a logical solution. This method is called the mechanochemical processing of materials. Processing materials in this way has many advantages. On the one hand, this processing is economically as well as technologically feasible. Even the materials that not react together in conventional way can be prepare in this way. The mechanochemistry/mechanochemical synthesis utilizes the mechanical energy to activate chemical reactions and structural changes. The aluminothermic reduction reactions induced by the high – energy ball milling are gaining importance because of the potential applications like the synthesis of microcrystalline and nanocrystalline in – situ metal matrix composites. The mechanical activation of the chemical reactions by high energy ball milling often changes the reaction mechanism and produces metastable materials. Changes of reaction mechanisms during mechanical alloying on four different systems were studied. The system was based on this composition: Al - B2O3 - X (X = C, Ti, Nb, Cr). The possibility of another in – situ reactions during spark plasma sintering process (SPS) was also investigated. All systems were mechanically alloyed under the same conditions. After alloying, on each system scanning electron microscopy was performed and qualitative and quantitative analysis was performed using X-ray diffraction. The indentation hardness and the indentation modulus of elasticity were evaluated using nanoindentation. All analyzes were performed after mechanical alloying as well as SPS and the results were compared to each other. Based on the results, a change of reaction mechanisms was proposed for all systems. It has been found that metal matrix composites are formed and, when chromium is used, hybrid composite material reinforced with intermetallic phase and aluminum borate has been developed.
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Preparation processes and characterization of bulk material from Mg and Zn powders
Hasoňová, Michaela ; Pacal, Bohumil (referee) ; Doležal, Pavel (advisor)
Topic of the diploma thesis is Mg-Zn bulk material preparation process by powder mixtures sintering at hot pressing. Structure, porosity and physically-mechanical properties of prepared bulk materials was evaluated. Obtained results and their interpretation were served as feedback for following optimization of individual processing parameters of bulk materials preparation. Thesis solving focuses on study and control of processes during bulk material preparation and description of the processes from physically-chemical point of view of the structure creation and final material properties.
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Cemented carbides and theirs effective use
Salajka, Jaroslav ; Sedlák, Josef (referee) ; Humár, Anton (advisor)
The aim of this thesis is a complex processing of obtained technical findings in the area of cutting materials, especially the evaluation and comparison of work possibilities recommended by prime world manufacturers for effective usage and application of coated and uncoated cemented carbides. Characteristics of cemented carbides in terms of production, marking method, physical and mechanical properties and application. Comparison of cemented carbides in the range of production of the most significant world tool and cutting material producers. Cutting efficiency evaluation of the tool. Recommended areas and operating conditions for effective usage of cemented carbides and their technical economic evaluation.
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