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The Use of the Aluminium Alloy in the Bicycle Industry
Hudec, Jiří ; Liškutín, Petr (referee) ; Liškutín, Petr (referee) ; Němec, Karel (advisor)
Bachelor's thesis deals with the aluminum alloys in the cycling industry. It contains information on the properties of aluminum and its alloys and the distribution of aluminum alloys according to certain criteria. It is discussed in more detail in the work of most alloys in the cycling industry - Al-Cu-Mg, Al-Mg-Si, Al-Mg-Zn and Al-Zn-Mg-Cu with examples, for which components are suitable alloys. Everything is accompanied by images in the enclosure at the end of work.
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Properties and the Use of Metal Foams
Křivánek, Robin ; Liškutín, Petr (referee) ; Němec, Karel (advisor)
In this thesis are summarized the findings of metal foams, with prevailing constraints on aluminum foam, because in them hides the greatest potential. The first part is described the production of porous materials, especially the way of floam production by thermal decomposition of floaming agent and melt gas injection. There are also written stress tests to gain a deeper knowledge of their properties, but also the latest exploring methods of foams, such as using a radioscopiy and CT scanner from which then creates a voxel model of foam. They are summarized here the basic ways of processing. Finally we must mention the possibility of using these materials with a focus on commercially produced foams Alporas® and Duocel®. Mass using foams mainly prevents high production costs and in some cases difficult reproducibility of properties.
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Influence of Homogenizing on Mechanical Properties of AZ91 Alloy
Provazníková, Andrea ; Liškutín, Petr (referee) ; Věchet, Stanislav (advisor)
This bachelor thesis includes photos and graphic representations of the influence of heat treatment on the mechanical properties of magnesium alloy AZ91. The structures of the alloy are recorded on the light microscopy pictures as well as photographs taken using a scanning microscope of fracture areas in the material. Results of a Tensile Test determining the strength and plastic properties and measuring of hardness and microhardness of the material are also included.
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Influence of Structure Directionality on Fatigue Properties of Formed Al Alloy.
Jíša, David ; Mazal, Pavel (referee) ; Liškutín, Petr (advisor)
The main goal of this diploma thesis is the examination of the influence of structure directionality on fatigue properties of formed aluminium alloy 6082/T6. The main attention is focused on the study of the influence of structure directionality on kinetics of short fatigue cracks growth. The measurement of short fatigue cracks growth was performed on cylindrical samples. The samples were made in two different directions; one parallel with the forming direction and second perpendicular to the forming direction. Servo hydraulic machine MTS 880 was used for the cyclic loading. The samples were cycled at two different constant stress amplitudes. Cyclic loading was systematically interrupted in order to measure the length of short cracks by a light microscope. Tensile tests, measuring of cycling hardening-softening curves, observation of microstructure, observation of surface relief, measuring of microhardness and fractographical analysis of fracture surfaces were used for further examination of the influence of the structure directionality. Some of these measured characteristics did not show any influence of the structure directionality (microhardness, fatigue life curve, Young modulus). In other cases is this influence measurable, however insignificant (yield stress, ultimate stress, cyclic hardening-softening curves and kinetics of short fatigue cracks growth). It can be summarised that the material, though the directionality of its microstructure is apparent, shows relatively isotropic mechanical behaviour.
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Tensile and Fatigue Testing of Thin Fibres and Foils
Štěrbáček, Jaroslav ; Liškutín, Petr (referee) ; Kruml, Tomáš (advisor)
A testing system MTS Tytron 250 with an original construction was bought at the Institute of Physics of Materials, AVCR v.v.i. The main aim of this diploma thesis was to obtain experiences with the controlling of the system and with its advantages and limitations. The tensile tests were performed on Al fibres with diameters of 125 micrometer, 180 micrometer a 500 micrometer, nylon fibres of 250 micrometer and 500 micrometer and tensile and cyclic tests on Al foil of 77 micrometer in thickness. It was found that the machine is suitable for testing of either subtle specimens with low loading forces or specimens with low stiffness as e.g. polymers or very long metallic or ceramic fibres. On the other side, the Tytrom system is not able to perform tests on specimens with a high stiffness and high loading forces. Material parameters were determined with a high reproducibility. Advantages and limitations of several types of subtle specimen's fixation into the grips were studied too.
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High cycle fatigue of Ti6Al4V titanium alloy
Bártková, Denisa ; Liškutín, Petr (referee) ; Věchet, Stanislav (advisor)
The main goal of this master's thesis is an analysis of high-cycle fatigue of titanium alloy Ti- 6Al- 4V. In the first section of a theoretical part of the thesis, there are summarized current facts about production, properties and aplications of titanium alloys. The second section pursues fatigue behaviour of material. An experimental part consists of metallographic analysis, evaluation of tension and bending tests and mainly analysis of high-cycle fatigue behavior for different assymetry ratios.
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Low cycle fatigue of EN-AW 7075 aluminium alloy
Bártková, Denisa ; Liškutín, Petr (referee) ; Věchet, Stanislav (advisor)
The main goal of this bachelor thesis is analysis of low-cycle fatigue of wrought alluminium alloy EN-AW 7075. In theoretical part of thesis, current facts about alluminium alloys and fatigue behaviour of material are summarized. Practical part contains evaluation of tension tests and analysis of experiments in low-cycle fatigue region. In additional, the microstructure of an alloy was observed.
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