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Processing of Inconel 939 alloy using laser powder bed fusion at elevated temperatures
Hertl, David ; Dočekalová, Kateřina (referee) ; Malý, Martin (advisor)
The thesis deals with the problem of Inconel 939 alloy processing by SLM technology using base plate preheating. The main objective of the work is to verify the effect of base plate preheating on residual stresses. The problem was solved by two approaches: process simulation, and subsequent experimental verification. The process simulation with preheating temperature of 400 °C achieved the highest agreement with the experiment with a deviation of 4.1 %. Based on the experiment, a suitable base plate preheating temperature of 100 °C was determined to reduce the deformation and residual stresses. By processing Inconel 939 using preheating temperatures of 100 °C and 400 °C, static mechanical properties comparable to those of the standard components processed by SLM technology from Inconel 939 after the heat treatment were achieved. These results offer the potential for significant reductions in overall production time and costs associated with manufacturing Inconel 939.
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Workability study 3D metal printing as technology for prototype plastic parts manufacturing
Kovář, Tomáš ; Herčík, Tomáš (referee) ; Sigmund, Marian (advisor)
This bachelor thesis is focused on the feasibility of metallic 3D printing. The 90MnCrV8 tool steel die is time consuming and expensive to manufacture by conventional methods. When considering the use of a die for a maximum of 50 pieces of moldings, it is possible to choose a material other than tool steel. From the offered possibilities of metal 3D printing, 2 suitable methods were selected, namely SLM and WAAM, where the WAAM method appears to be cheaper. Available materials for steel replacement 90MnCrV8 are metal wire G4Si1 for WAAM method and stainless steel X2CrNiMo17-12-2 for the SLM method. After listing all the options and evaluations, it can be seen that the feasibility of metallic 3D printing as a replacement for conventional tool production is possible.
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The influence of heat treatment on magnetic properties of additive manufactured stainless steel components
Schäffer, Matúš ; Hutař, Pavel (referee) ; Paloušek, David (advisor)
The aim of this master thesis is selection of heat treatment for additive manufactured multimaterial components composed of 1.4404 and 1.4542 stainless steels regarding their magnetic and mechanical properties. Individual materials were studied after fabrication and also after the same heat treatments. The chosen process consists of solution annealing and subsequent precipitation hardening. A significantly higher value of maximum relative permeability and lower of coercive field of 1.4542 steel were achieved. At the same time, the relative permeability of 1.4404 was not considerably influenced. A decrease in Rp0,2 of 1.4404, but an increase in Rm and Rp0,2 values of 1.4542 steel were observed. Elongation at break A increased in the case of both alloys. The experiments proved that multimaterial components composed of these stainless steels can be successfully manufactured by SLM technology. It is therefore possible to design and manufacture stainless steel components of magnetic circuits and adjust their magnetic and mechanical properties by heat treatment.
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Determination of Material Properties of Specimens Produced by Metallic 3D Printing
Zakl, Alexandr ; Peterková, Eva (referee) ; Řiháček, Jan (advisor)
This bachelor's thesis deals with mechanical properties and current status of 3D printing of metal parts, especially by DMLS/SLM method. Research part is dedicated to various technologies and suppliers in the field of 3D printing with emphasis on printing metal methods. Main purpose of this thesis is to connect the worlds of 3D printing and 3D optical measuring of deformation, so the part of research segment is dedicated to optical measuring and leading innovative company GOM. One of the leading product of this company is ARAMIS and in the context of this thesis it was present during the experiment as a instrument for measuring and inspecting material characteristics, and is present in research part where is mentioned a principle on which this device is working (digital image correlation) as is the device itsself. In the experimental part of this thesis, samples were printed on DMLS printer from company XactMetal, which were then submitted to a tensile test. Measurement was done using DIC based device ARAMIS and inspected for basic material properties in same named program.
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Stainless steels for cryogenic applications processed by 3D printing
Grygar, Filip ; Hutař, Pavel (referee) ; Koutný, Daniel (advisor)
This thesis deals with properties of austenitic stainless steel 304L processed by SLM technology and tested at room and cryogenics temperatures. Result is description of mechanical properties and microstructure. First step was to develop processing parameters to achieve porosity of prints fell below 0,01 %. Following tensile test showed higher yield and ultimate tensile strength than conventionally fabricated parts, even at temperature -80 °C, but at cost of reduced ductility. Due to deformation and low temperature austenite transformed into martensite. This transformation also occurred in Charpy toughness test, that resulted in ductile to brittle behaviour.
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Analysis of thermal behavior focused on additive manufacturing of lattice structures from AlSi10Mg
Nosek, Jakub ; Dočekalová, Kateřina (referee) ; Paloušek, David (advisor)
Using Additive manufacturing it is possible to manufacture complicated components, that cannot be manufactured using conventional methods. The typical example is the lattice structure. Fabrication of these structures is complicated, and it is different from the fabrication of bulk parts. Using numerical simulation which can reflect process parameters it is possible to analyze the thermal behaviour of vertical and inclined struts fabrication. Results show that the diameter of struts influences weld track width. This influence is caused by preheating the powder material by previous scanning paths. The final geometry of inclined struts is made in more scanning layers. In this work influence of the start and endpoint of trajectory is described.
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Influencing the surface roughness of materials created by the SLM technique and the influence of roughness on macroscopic properties
Rotter, Marek ; Havlík, Petr (referee) ; Jan, Vít (advisor)
Theses resumes the principle of SLM method and submits the most used materials for this technology and its properties. The main issue is influencing the surface roughness of these materials, when the electro-chemical polishing in the concentrated sulfuric acid was used with five difference options. It was observed, that the roughness is caused by two factors, fused nonmelted grains of metal powder and layered structure. Polishing at 8 V, 0,5 A and after 40 min was the best results, when the smooth wave surface was achieved. The Ra parameter descended from initial 5,0 m to 3,9 m after this polishing. One of the factors, which causes the high roughness, was eliminated.
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The development of multimaterial 3D printing of metal parts by SLM technology
Pliska, Jan ; Dočekalová, Kateřina (referee) ; Koutný, Daniel (advisor)
This thesis deals with research and optimization of process parameters and methodology of production of multimaterial parts manufactured by SLM. This work investigates iron-based and copper-based materials. The aim of the work is to create a good-quality horizontal and vertical multimaterial interface. In the case of the horizontal interface, the optimal process parameters for the processing of selected materials, their subsequent optimization for a goodquality horizontal interface and verification of mechanical properties were experimentally determined. For the vertical interface, it was necessary to design a production methodology and further optimize the process parameters. Finally, some mechanical properties of the interface were determined. However, research of the vertical interface has been a scientific task with some degree of uncertainty, and as this area has not yet been fully explored, it has proved to be a more complex problem than previously thought. It was therefore not possible to completely clarify it in the given time and with the available means. This work provides a detailed description of the mechanisms of creating both types of interfaces and their properties and can serve as a basis for further study of multimaterial 3D printing of metals based on iron and copper.
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Lattice Topology Optimization in ANSYS software
Černák, Martin ; Vaverka, Ondřej (referee) ; Vrána, Radek (advisor)
ANSYS is one of the first commercially available software which allows to make topology optimization of lattice structures. In this bachelor’s thesis optimization workflow, calibration of numerical model, validation of numerical results and revelation of influence of basic parameters involved in computation – cell type, minimum and maximum relative density, cell size and used discretization, are showed. Optimised part was compared by means of FEM and homogenization with available experimental data. Subsequently, influence of basic parameters was evaluated. It was shown that optimized structure is stiffer than benchmark and influence of basic parameters for mechanical response and computational complexity was introduced. Simultaneously, it was shown that homogenization overestimated mechanical response. The findings of bachelor’s thesis validate computational model in program ANSYS and can be used for more effective making of optimization models.
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The use of small punch tests for materials with a higher level of structural inhomogeneity
Gordiak, Michal ; Řehořek, Lukáš (referee) ; Válka, Libor (advisor)
Master's thesis deals with evaluating applicability of correlation relationships between material characteristics determined by Small Punch Test and standard tensile test for material AlSi7Mg0,6 manufactured by casting and technology SLM. Results of Small Punch Tests are correlated with yield strength, tensile strength, elongation, and Young's modulus of elasticity. For each material characteristic various correlation methods are compared, while for each method corresponding coefficients are determined. Consequently, the applicability of individual methods is evaluated by substituting coefficients determined by various studies. Primarily analyzed are correlation methods for which future normalization is expected. The results of master's thesis show that structural inhomogeneity caused by SLM process does not result in high inaccuracies in determining material characteristics. Larger impact on material characteristics has high porosity, which was identified in cast material and led to significant deviations in evaluating tensile strength and elongation.
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