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Nickel coatings and their properties
Buchtík, Martin ; Tkacz, Jakub (referee) ; Zmrzlý, Martin (advisor)
The aim of the bachelor’s thesis was summary of existing knowledge concerning to electroless deposition of nickel coatings and their properties. In the theoretical part there are two chapters. In the first chapter present knowledge of chemical nickel plating is described in details. It also discuss mechanisms of this type of coating and individual components of nickel plating bath. In the second chapter there is summarized knowledge of composite coatings deposition and description of their mechanical properties. The experimental part deals with deposition of composite coatings on steel substrates and heat treatment of Ni-P coatings. Dependence of microhardness on temperature of heat treatment was studied and then there is also described dependence of microhardness on duration of heat treatment. Deposited coatings, their morphology and composition were studied using scanning electron microscope and EDS analysis. The values of microhardness of both types of coatings were measured and compared using microhardness tester.
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Fatigue behaviour of nickel-based superalloy IN738LC with AlSi coating at 800°C
Hlavnička, Radek ; Juliš, Martin (referee) ; Hutařová, Simona (advisor)
This work deals with influence of applied protective AlSi layer on low cycle fatigue behaviour of substrate from nickel base superalloy Inconel 738 LC. Protective layer is made by thermal spraying, plasma spraying followed by heat treatment. The emphasis is especially concentrated to the microstructure evaluation of the protect layer and basic material, in addition, measurement of layer thickness and the microhardness in as sprayed conditions and after heat treatment. The fatigue behaviour is assessed by fracture area observation and fatigue cracks evaluation after low cycle fatigue tests carried out at 800 °C.
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Structure and properties of welded joints of steam turbine rotor
Machala, Jan ; Hutařová, Simona (referee) ; Juliš, Martin (advisor)
This thesis deals with the assessment of the structural-mechanical properties of welded joints of steam turbine rotor. Experimental weld material is low alloy steel 30CrMoNiV5-11 in the state after the artificial degradation. The theoretical part of the literary researches the issue, focusing on the weldability of different types of steel used in the energy industry, the metallurgical processes in welding and provides an overview of the most important methods of welding. Great attention is paid to the evaluation of weld quality in accordance with relevant standards and destructive and non-destructive testing of welded joints. In the experimental part of this work was carried out measurements of hardness and microhardness of the weldment by Vickers and evaluation of the microstructure by light microscopy. The obtained values and information about the properties of the material after artificial degradation were compared with previously obtained experimental results in the default state (after annealing).
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Weldability of steels for steam turbine parts
Jech, David ; Hutařová, Simona (referee) ; Juliš, Martin (advisor)
The aim of contemporary standard welding technologies is to create compact welds with high value of solidity and toughness in laboratorial and operational conditions. This welding technology is asserted in new creep - resisting steels on basis of steel CrMoV and CrMoNiV, which have high value of solidity and creep - resistance. The thesis deals with problems connected with the weldability of steels for steam turbine rotors and it´s aim is to interpret the structural and mechanical features of the weld joint for material combinations under consideration. For the assessment of weld joint features has been used measuring of micro hardness and hardness according to Vickers, microstructure was observed by methods of light microscopy.
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Present Trends of Methods for Hardness Measurement
Brzobohatý, Tomáš ; Doležal, Pavel (referee) ; Hutařová, Simona (advisor)
Purpose of this thesis is created view of present methods of hardness measurement and to describe them in more detail. Firstly this thesis deals with representatives of standard and for many years used methods of hardness measurement and hardness evaluation which are used today, too. Secondly this thesis is focused on modern methods, and their successful working experience is question of time.
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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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Kvalita svarových spojů
Pénz, Attila
The thesis may be divided into two parts, the theoretical and practical part. In the theoretical part of my thesis describe the permanent connection in engineering includes soldering, gluing, riveting and welding and further describe the building-up and weldability tests as part of the technological tests. In the practical part of my thesis describe what and how I was doing. How I progressed in the production of individual samples and testing. We can find there a description of the tensile test, graphical display each tensile test, measured and calculated values and evaluation of tests. Further describe the detection of microstructure and microhardness. Each photo of microstructure I worked to the table and commented what can we see on them. At microhardness we can read about the gist and execution of the test. Obtained values I compiled to the chart and commented. According to the hardness can recognize a structural component and phases. In conclusion is a summary of the measured values and evaluation.
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