This thesis deals with measurement of hardness and microhardness in relation to structure of homogeneous and heterogeneous materials. In the introduction basic theoretical background is commented, i.e. definitions, terminology, principles of measuring techniques for estimation of hardness, microhardness, tensile strength, compressive strength and bending strength. Follows a brief review of present research results focused on use of described principles in materials engineering. Then the experimental equipment and sample preparation is described. The crucial part of the thesis is summary of achieved results of original measurement and discussion of their relations to each other. Finally, the groundbreaking estimation is described, showing the correlation of chemical composition gradient and mechanical properties in interfacial zone of geopolymeric material.

This thesis is concerned to the study of behaviour of fibre composites with ceramics matrix. The composite consists of pyrolysed polysiloxane matrix reinforced by ceramic fibre Nextel 720. Main aim of this work is optimisation of fibre matrix interface through the selection of suitable precursor of the matrix with respect to temperature stability, sufficient strength and reasonable fracture toughness. Samples of matrices were exposed to the long term heat treatment in the range 1100 – 1500 °C. The mechanical properties as hardness and indentation elastic modulus were determined after heat treatment. Selected precursors of matrices were used for composite fabrication. Elastic modulus and fracture toughness at room and elevated temperatures were studied. Discussion is dedicated to the description of changes in mechanical properties with respect to chemical processes taking place during high temperature exposition. Further, reasons of fracture behaviour of composite materials are discussed, and finally, gained knowledge and outlined possibilities of subsequent development are summarised.

Heat treatment influences structure and characteristics of treatmented material. Good heat treatment of steels for bearings ensures hardness of matrix 60 - 65 HRC, whereas structure has be formed by tempered fine needle-shaped martensite with definite part of residual austenite. Carbides should be evenly dispersed, they mustn´t create carbide network and carbide lines. Quality of steels for bearings is also influenced by volume and morphology of inclusions in the matrix. In this diploma thesis various conditions of heat treatment were to be set up with the aim of choose the optimal ones. These ensures perfect martensite transformation and full hardening of all component. Quenching from 760 °C – 770 °C was quite unsatisfactory. At this temperature resulting structure was ferritic-perlitic, because martensite transformation did not pass. Too long hold on hardening temperature also had unfavourable influence on resulting structure and characteristics. In this case, structure was created by very coarse needle-shaped martensite. Coarsening of martensite needle locally exceeded maximum allowed level. In the structure there was also possible to watch partly soluted globular carbides. Optimal heat treatment is quenching from 850 °C – 870 °C followed by tempering at 220 °C. Resulting structure quite agree with above-mentioned needs. This heat treatment can be recommended for technical practise.

Microstructure and mechanical properties of AZ61 magnesium alloy in cast condition and after solution annealing were compared. The compare of mechanical properties of alloy, their hardness and microanalysis of occurring phases are included in this work. For compare has been used a light microscopy, tensile test, hardness measurements and scanning electron microscopy.

Diploma thesis is divided into two parts. The first part is focused on theoretical description of coating methods, on currently used coatings, their properties and it is also focused on description of methods, which are used for analyzing each property. The second part focuses on testing of coatings and analyzing of the values obtained from experiments. The aim of this thesis is then to compare the properties of the tested coatings.

The high alloyed austenitic manganese steel, the Hadfield steel, thanks to its good wear resistance of the work surface and maintaining the high toughness of the internal material in the same time, is successfully applied for casted crossings. The crossings are the most dynamic stressed components in the railway turnouts. Thanks to low surface and sub-surface hardness the occurrence of plastic deformation and the progressive wear of the crossing running surfaces can be found since the initial stages of the crossing operational life. One possibility how to increase the surface and the sub-surface hardness and this way improve the dimensional stability and the crossing lifetime as well is to apply the explosive hardening of the crossing running surfaces. The technology mentioned above means the application of the explosives in the imminent nearness to the running surface of the crossing, when the high pressure wave acting within the extremely short period actuates the plastic deformation of the material structure. The work deals with analysis of influence of explosive hardening on the structure and characteristic of Hadfield steel. The explosive hardened samples have the surface and the sub-surface hardness checked and the microscopic analysis and X – ray diffraction is applied, including the TEM analysis as well carried out by the transmission electronic microscope. The characteristics experimental testing including outcomes from assessment of the contact – fatigue load of the explosive hardened Hadfield steel samples are the part of the work as well. As an experiment final part the outcomes of the long –term validation, the surface hardness and wear of the crossing running surfaces of the explosive hardened crossing already installed into the Czech Republic railway track are introduced as well.

This thesis deals with the properties of ledeburitic chrome-vanadium tool steel after heat treatment. Theoretical part contains charakterization of ledeburitic steels, the posibility of manufacturing and heat treatment. There are also briefly describes the principles of the test methods, which were used. The practical part is focused on describing the results of 12 sample groups, with different heat treatment. The results are compared in the final discussion.

The aim of this thesis is to summarize the knowledge gained in the field of grinding medium-hard and hard materials. Work has focused on examining the grindability of the material using available laboratory mill. The part of the work is subsequent optimization of the grinding process on the device and evaluation of the results.

The doctoral thesis is divided into two parts - Thermal analysis in physics education on high school and Material research of Al-Zn-Mg(-Cu-Sc-Zr) alloys. Within the first part, the areas of crystallization and/or melting of selected foods were determined using differential scanning calorimetry. A practical lesson for high school physics has been created and tested. The study text focused mainly on differential scanning calorimetry and its use was made. In the second part of the doctoral thesis, there was analysed thermal evolution of the phase transformation in the Al- Zn-Mg(-Cu) alloys with Sc and Zr addition. The effect of (cold and hot) deformation on the decomposition sequences was studied. The hardening effect after annealing above 300 řC in the Sc and Zr alloys is caused by the precipitation of the secondary Al3Sc,Zr) particles. These particles were observed by transmission electron microscopy after annealing up to 360 řC in all studied AlZnMg(Cu)ScZr alloys. In the AlZnMgCu alloy the partial recrystallization was observed after annealing at 350 řC/10 hours and after annealing at 450 řC/10 hours the grain size was 50-200 m (depending on the treatment of the alloy). The addition of Sc, Zr in the AlZnMgCuScZr stabilizes grains and there is no recrystallization in the AlZnMgCuScZr alloy at temperature...

The aim of this work is to get the best detailed knowledge about hardness distribution in first 60 mm below the surface of backing roll. To this end, a method for obtaining multi-dimensional polynomial regression was developed and then a computer program for its processing was written.Way of finding suitable regression surfaces and their subsequent interpretation, is a pivotal part of this work.