|
|
Influence of Process Parameters and Heat Treatment on the Structure and Properties of Cold Spray Method
Lindner, Patrik ; Řehořek, Lukáš (referee) ; Hutařová, Simona (advisor)
The bachelor thesis is a research of the state of knowledge focused on Cold spray technology and process parameters affecting the properties of coating, such as pressure, temperature, nozzle speed, sequence of individual layers, size of powder and others. This technology uses the kinetic energy of the impact of particles on the substrate. The main advantage of this method is possibility of forming a coating of large thicknesses (in millimeters) without oxides, with relatively low porosity and favourable mechanical properties. Aim of this work is to get acquainted with the Cold spray technology and the influence of process parameters on the quality of the spray. The influence of process parameters on properties is also demonstrated by own experimental results.
|
|
|
Optimizing the Properties of the Coatings prepared by the Cold Spray Method using Heat Treatment
Bartošík, Vojtěch ; Šmíd, Miroslav (referee) ; Hutařová, Simona (advisor)
This bachelor's thesis deals with the choice of heat treatment parameters of the metal coating of austenitic unstabilized stainless steel AISI 304L applied by the Cold spray method. With the help of suitable heat treatment, it is possible to adjust the mechanical properties, reduce the porosity and, last but not least, also remove high residual stresses in the material. The theoretical part of the work is devoted to literature research on the topic of Cold spray technology, corrosion and corrosion-resistant steels. The experimental part describes the procedures for measuring samples that have undergone heat treatment. This took place in the temperature range of 500 to 1100 °C, always with an hour's holding time at the temperature, followed by cooling in air. In addition to these samples, the material was also examined in its initial state. Porosity, microhardness and also magnetism were determined. To analyze the structure, photographs were taken on a light and electron scanning microscope. Based on the results, heat treatment with an hourly hold at 700 °C seems to be a good choice, where a significant decrease in porosity, partial recovery of the structure while maintaining high microhardness and also grain fineness was observed.
|
|
|
Fatigue Crack Growth Retardation Techniques for the Integral Airframe Structure
Jetela, Václav ; Růžička, Milan (referee) ; Petrásek, Miloslav (referee) ; Klement, Josef (advisor)
Při zavádění integrální letecké konstrukce vyvstal problém s rychlým růstem únavové trhliny v této konstrukci. Jednou z možností, jak zpomalit růst trhliny a zvýšit životnost konstrukce, je aplikace tzv. zastavovače trhliny. Tato disertační práce porovnává aditivně vyráběné a lepené zastavovače trhlin z hlediska životnosti, rychlosti šíření trhliny a delaminace. V případě lepených zastavovačů trhlin; doposud nebyla věnována pozornost zastavovačům z nerezové oceli. Nerezová ocel se jeví jako vhodný kandidát z důvodu koeficientu tepelné roztažnosti blízkého hliníkové slitině, vysoké tahové pevnosti a vysokého modulu pružnosti v tahu. S ohledem na aditivně vyráběné zastavovače trhlin, žádná pozornost nebyla věnována zastavovačům trhlin z materiálů odlišných od podkladové konstrukce. Za účelem doplnění současného stavu poznání byly vybrány tyto aditivní technologie: studená kinetizace a ultrazvuková konsolidace. Metodou studené kinetizace byly deponovány zastavovače z nerezové oceli a titanové slitiny. Metodou ultrazvukové konsolidace byly navařeny zastavovače z nerezové oceli. V experimentální části práce byl pozorován růst únavové trhliny v podkladové konstrukci. Delaminace zastavovače byla monitorována metodou pulzní termografie s následnou rekonstrukcí termografického signálu. Lepené zastavovače trhlin z nerezové oceli se prokázaly jako vhodná alternativa k zastavovačům s uhlíkovými vlákny. Nerezové zastavovače výrazně snížily rychlost šíření únavové trhliny, čímž značně prodloužily životnost vzorku. Bohužel, všechny zastavovače připravené metodou studené kinetizace urychlily růst únavové trhliny, čímž došlo k předčasnému selhání vzorku. Ultrazvukově konsolidované zastavovače s dvěma vrstvami oceli byly nejefektivnější z hlediska zvýšení životnosti. Tato práce navíc prokázala, že pro detekci delaminace v ultrazvukově konsolidovaném laminátu je možné použít metodu pulzní termografie.
|
|
|
Evaluation of cold kinetic deposition technology (Cold Spray)
Buček, Tomáš ; Zimáková, Jana (referee) ; Binar, Tomáš (advisor)
Cold spray or Cold gas dynamic spraying is actually new process for coating application. Origin of Colds technology spray is thermal spray. Cold spray technology has some advantages therefor any other common thermal technology. Cold spray technology has unique properties mainly due to low deposition temperatures and the physical principle of layer growth. Master’s thesis has focused on the possibility of use for corrosion protection. Accelerated corrosion tests were performed in a condensation chamber with samples of aluminium substrate and low pressure cold sprayed copper layer. The formation of corrosion was evaluated by acoustic emission and metallographic analysis. The anti-corrosion properties of copper have been considered in practical design, as have the unique antibacterial and virus inactivating properties.
|
|
|
The use of surface modification for enhancing mechanical properties of SLM bulk materials
Barinka, Michal ; Řehořek, Lukáš (referee) ; Jan, Vít (advisor)
This diploma thesis deals with the surface modification of 3D printed metallic materials. The research part presents the most used methods of additive manufacturing and their process parameters influencing the quality of printed components. Defects arising during these processes and the techniques used to eliminate them are also described. In the experimental part of the work, the optimization of electrochemical polishing parameters was performed. The aim was to modify the rough surface of the components and thus prevent the formation of defects on the surface. The mechanical properties were investigated by means of three-point bending under static and dynamic loading. Fractographic analysis was performed on the quarry surfaces.
|
|
| |
|
|
Digital commissioning of robotized workplace for cold spraying of rotating parts
Šimůnek, Petr ; Bražina, Jakub (referee) ; Vetiška, Jan (advisor)
This work deals with the virtual and later real commissioning of the workplace for cold spraying of rotating parts, which is located in the laboratories of the Institute of Materials Science and Engineering, Faculty of Mechanical Engineering, Brno University of Technology. The workplace put into operation in this way serves the employees of the mentioned institute for experimental activities in the field of cold spraying. The theoretical part of the thesis describes all the essentials associated with virtual commissioning and the theory of cold spray. The practical part then deals with the creation of a robotic program, including the user interface, which is used to control the workplace. Part of this diploma thesis is also the realization of the connection between the external motor driver and the robot controller via the PROFINET communication bus.
|
|
|
Virtual commissioning of robotized workplace for cold spraying
Miklis, Peter ; Holub, Michal (referee) ; Vetiška, Jan (advisor)
The diploma thesis deals with the virtual commissioning of robotized workplace for cold spraying. The theoretical part of the thesis contains an overview of the current state of knowledge in the field of virtual commissioning, the theory of crating HMI user environments, deals principles of the Rapid programming language as a tool for controlling industrial robots and analysis of robotic workplace components. The practical part defines the structure of the proposed user program and user environment, which are created using software tools Robotstudio and Screenmaker. The last part discusses in detail the steps during the implementation of the created program together with the HMI into commission, which is associated with the testing of functionalities on a real device for cold spraying. The diploma thesis also includes a user manual created for operating an industrial robot.
|
|
|
Determination of mechanical characteristics of coatings using impulse excitation technique
Valášek, Daniel ; Řehořek, Lukáš (referee) ; Válka, Libor (advisor)
This diploma thesis deals with the determination of the Young’s modulus of coatings using the impulse excitation technique (IET). The theoretical part of the thesis describes Cold and Thermal Spray technology, theoretical foundations of the impulse excitation technique and models of composite materials. The experimental part of the thesis deals with the determination of the tensile modulus of copper coating created by Cold Spray technology. The impulse excitation technique has been used to measure fifteen samples with coating thickness ranging approximately from 0,4 to 2 mm. Results from this measurement were evaluated using five composite models to establish the Young’s modulus of the applied coating. The best results were achieved by using the composite model based on rule of mixtures (ROM).
|
|
|
Possibilities of using cold gas dynamic spray (Cold Spray) in military applications
Dvořáček, Jan ; Štěpánek, Roman (referee) ; Řehořek, Lukáš (advisor)
This work aims to acquaint with thermal spray method called Cold spray. This method is used for repair of expensive and badly replaceable components, which are mainly used in aerospace and military branch of industry. These repairs cause economic savings, higher accuracy and quality than other thermal spray methods. There is a possibility to use Cold spray for ballistic armor production. It is possible that ballistic protection would have higher ballistic efficiency, durability and coherence. The second part of the work handle with the evaluation of the interface of a metal-ceramic two-layer ballistic protection system made by the cold spray method. The evaluation was performed in the form of light and electron microscopy.
|
guest ::
