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Processing of magnesium alloys using selective laser melting
Kaščák, Pavol ; Paloušek, David (referee) ; Suchý, Jan (advisor)
The processing of magnesium-based materials with Selective laser melting technology is due to its high reactivity in the initial stages of development. This bachelor thesis deals with the elucidation of impacts of individual process parameters in processing of magnesium alloys on the resulting material porosity. The aim is to develop initial experiments for the shift in the processing of magnesium alloys by additive technologies. The theoretical part contains an insight into the SLM technology and an overview of the current state of knowledge of processing of magnesium alloys by this technology. By the analysis of the theoretical part, the main volume test of this thesis has been designed. The selected material for this test was the biodegradable magnesium alloy WE43. According to the author's knowledge, no research has been published on this alloy so far. Based on the results of the experiment, the dependencies of the individual process parameters were made on the resulting relative density of the samples. At the end, the outputs were compared with the literature.
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Impact loading of lattice structures produced by Selective Laser Melting technology from magnesium alloy WE43
Foltán, Tomáš ; Červinek, Ondřej (referee) ; Jaroš, Jan (advisor)
Strut-based lattice structures manufactured with magnesium alloy WE43, due to their high strength-to-weight ratio, seem like an ideal solution for biomedical and aerospace industries. Previous research has focused mainly on the behaviour of these structures under quasi-static stress conditions. Dynamic stressing of these structures has not been deeply researched. Therefore, this work deals with impact testing of strut-based lattice structures manufactured by SLM. Low-velocity impact tests were performed on a set of cell topologies with different strut diameters. Absorbed energy, stress-strain curve, and deformation mechanism of each sample were studied. Clear effect of cell topology on the amount of absorbed energy was observed, where structures of similar relative densities displayed considerably different values. Highest specific absorbed energy was achieved with the FCCZ cell. In comparison with other materials (e.g., steel) magnesium proved to be far less efficient. This was most probably caused by its brittle fracture failure mode. Conducted tests give insight into mechanical behaviour of magnesium alloy structures under dynamic compression and their ability to absorb energy. Collected data may prove useful for biomedical applications e.g., in designing bone implants.
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Surface roughness of lattice structures produced by SLM technology
Bóssi, Adam ; Malý, Martin (referee) ; Jaroš, Jan (advisor)
Selective laser melting (SLM) is an additive manufacturing technique (AM), that allows production of complex geometries that can be found in lattice structures. Processing of magnesium-based materials with this technology is difficult because of their high reactivity. This bachelor’s thesis clarifies the effects of processing parameters (laser power and laser scan speed) on surface roughness of lattice structures. The theoretical part of this thesis deals with the issue of magnesium alloys and manufacturing of lattice structures. The practical part of this thesis contains the design of the experiment and evaluation of the given experiment. Based on the results of the experiment, the dependencies of process parameters were made on surface roughness and incline angle of struts. The main takeaway of this thesis for the reader is in familiarization with the issue of process parameters and their effect on surface roughness in lattice structures.
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Preclinical research of degradation of metallic osteosynthetic alloys in vivo on animal biomodels
Machoň Levorová, Jitka ; Foltán, René (advisor) ; Hauer, Lukáš (referee) ; Hirjak, Dušan (referee)
The dissertation is dealing with the option of using biodegradable metal alloys such as osteosynthetic material in maxillofacial surgery, The hypothesis presupposes that Zn-1,6Mg and WE43 alloys are from the viewpoint of the degradation period and biological interactions suitable for fixation of facial skeleton. The theoretical part of the work evaluates current trends in the use of biodegradable metal alloys. It monitors the development of material for osteosynthesis in maxillofacial surgery emphasizing the biological reactions of material and undesirable qualities including their clinical impact. The experiment part of the work is divided in two successive stages. The first stage used the rat biomodel to implant Zn-1,6Mg and WE43 alloys. The aim was to compare the duration of degradation and to receive the reaction of the ambient tissue. The animals were euthanized in regular intervals. They were scanned ex vivo by means of cone-beam tomography to find the degradation period of each alloy. Histopathological examination was performed to receive the reaction of the ambient bone tissue. The conclusion evaluates WE43 alloy is more suitable for osteosynthesis in the facial skeleton according to the results of the first stage. The second stage used the rabbit biomodel for implantation of WE43 and titanium as a...
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Effect of substantial grain refinement on microstructure and mechanical properties of precipitation hardenable magnesium alloys.
Hofman, Daniel ; Minárik, Peter (advisor) ; Janeček, Miloš (referee)
Properties of magnesium alloy WE43 and the effect of substantial grain refinement by ECAP were studied. The compressive strength test revealed a significant increase of yield strength after ECAP, resulting in yield strength of over 400 MPa after 8 ECAP passes. The material remained surprisingly ductile in both compression and tension. Thermal stability of the material was investigated via Vickers hardness test. The ultrafine-grained structure shows good thermal stability up to 300 řC, where the precipitates start to dissolve and grain size starts to increase, resulting in sharp fall of hardness. Annealing of the initial state showed best results for 210 řC where the precipitation hardening led to an increase in hardness up to ∼101 HV.
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Effect of substantial grain refinement on microstructure and mechanical properties of precipitation hardenable magnesium alloys.
Hofman, Daniel ; Minárik, Peter (advisor) ; Janeček, Miloš (referee)
Properties of magnesium alloy WE43 and the effect of substantial grain refinement by ECAP were studied. The compressive strength test revealed a significant increase of yield strength after ECAP, resulting in yield strength of over 400 MPa after 8 ECAP passes. The material remained surprisingly ductile in both compression and tension. Thermal stability of the material was investigated via Vickers hardness test. The ultrafine-grained structure shows good thermal stability up to 300 řC, where the precipitates start to dissolve and grain size starts to increase, resulting in sharp fall of hardness. Annealing of the initial state showed best results for 210 řC where the precipitation hardening led to an increase in hardness up to ∼101 HV.
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Processing of magnesium alloys using selective laser melting
Kaščák, Pavol ; Paloušek, David (referee) ; Suchý, Jan (advisor)
The processing of magnesium-based materials with Selective laser melting technology is due to its high reactivity in the initial stages of development. This bachelor thesis deals with the elucidation of impacts of individual process parameters in processing of magnesium alloys on the resulting material porosity. The aim is to develop initial experiments for the shift in the processing of magnesium alloys by additive technologies. The theoretical part contains an insight into the SLM technology and an overview of the current state of knowledge of processing of magnesium alloys by this technology. By the analysis of the theoretical part, the main volume test of this thesis has been designed. The selected material for this test was the biodegradable magnesium alloy WE43. According to the author's knowledge, no research has been published on this alloy so far. Based on the results of the experiment, the dependencies of the individual process parameters were made on the resulting relative density of the samples. At the end, the outputs were compared with the literature.
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