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Press quenching of HEMA sword blades
Achberger, Šimon ; Řehořek, Lukáš (oponent) ; Kouřil, Miloslav (vedoucí práce)
Martensitic transformation during quenching is inherently related to creation of residual stresses within the quenched part, which lead to quenching-induced distortion. There are multible approaches to reducing quenching-induced distortion. Among the more effective is utilising cold die quenching. Construction of a cold die quench press for quenching thin, flat parts is relatively simple, but scarcely used due to high investment costs and the difficulty of determining thermal contact conductance between quench press dies and quenched part. An example of a part whose manufacture is complicated because of quenching-induced distortion is a sword blade. The experimental part of this thesis examines quenching samples of a steel used for making sword blades, 42CrMo4, using two different quench press die constructions. Analysis of said samples shows that proposed quenching method is comparable or superior to quenching via conventional quenchants. Proposed quenching method lowers quenching-induced distortion and has minimal recurring costs connected to using liquid quenchants and the method is therefore viable for quenching sword blades.
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Antibacterial properties of bioceramic materials
Achberger, Šimon ; Částková, Klára (oponent) ; Salamon, David (vedoucí práce)
Implant surgery carries a risk of infection caused by bacterial contamination of the implant surface. An effective way to inhibit proliferation of bacteria is via antibacterial surfaces, however, their usage is medically and technologically difficult. Previous research shows that cicada wing topography exhibits unique bactericidal properties. In this thesis, various topographies were fabricated using heat treatment under hydrothermal conditions. The goal was to produce a surface covered by high aspect ratio structures with 60–215 nm width and 200–300 nm length. A relative density of 85%, 12 hrs long heat treatment and solution pH 4 and 5,6 had a positive effect on formation of thin surface structures. Quantity of morphological changes was proportional to -tricalcium phosphate content.
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Antibacterial properties of bioceramic materials
Achberger, Šimon ; Částková, Klára (oponent) ; Salamon, David (vedoucí práce)
Implant surgery carries a risk of infection caused by bacterial contamination of the implant surface. An effective way to inhibit proliferation of bacteria is via antibacterial surfaces, however, their usage is medically and technologically difficult. Previous research shows that cicada wing topography exhibits unique bactericidal properties. In this thesis, various topographies were fabricated using heat treatment under hydrothermal conditions. The goal was to produce a surface covered by high aspect ratio structures with 60–215 nm width and 200–300 nm length. A relative density of 85%, 12 hrs long heat treatment and solution pH 4 and 5,6 had a positive effect on formation of thin surface structures. Quantity of morphological changes was proportional to -tricalcium phosphate content.
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