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Structure and properties of welded joint TiAl6V4 / 6061 made by electron beam technology
Král, Michael ; Jan, Vít (referee) ; Foret, Rudolf (advisor)
Titanium and aluminium alloys are among the most used construct materials due to their physical and mechanical properties except steels. The joining of these alloys can improve properties of whole construction but it is still difficult task. Especially welding of titanium and aluminium alloys is difficult cause formation of undesirable intermetalic phases in the weld. This thesis focuses on influences of electron beam welding parameters especially focusing and deflection of beam and preheating of base material to quality of heterogeneous join of titanium alloy Ti6Al4V and aluminium alloy EN AW-6061 – T651. There is described preparation of welded joins and brazed joins in the thesis, which are evaluated by light microscopy, scanning electron microscopy and EDS analysis of chemical composition. There was evaluated presence and chemical composition of formated intermetalic phases in the welded joins and quality and defects in the brazed joins.
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ELECTRON BEAM WELDING OF HETEROGENEOUS WELDS OF Ti/Al ALLOYS
Havlík, Petr ; Dřímal, Daniel (referee) ; Schwarz,, Drahomír (referee) ; Foret, Rudolf (advisor)
The problematics of weldability of heterogeneous welds of aluminium and titanium alloys produced by electron beam welding is discussed in this work. Homogenous welds of selected alloys were analyzed in the first stage. Welding of these materials relates to formation of intermetallic phases at the interface of base materials due to differences in physical, chemical and metallurgical properties of base materials. One of the prerequisites for producing high quality weld joints is to find optimal process parameters. The influence of selected process parameters to integrity, structure and mechanical properties of heterogeneous Al/Ti joints is evaluated.
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Heat and mechanical resistance of zinc coating
Horák, Karel ; Dzimko, Marián (referee) ; Černý, Michal (advisor)
The work is aimed at studying the thermal degradation of the protective zinc coating. Its large part deals with the structure of the various stages of transition and their arrangement, the main emphasis is on analysis of brittle intermetallic phases, which arise due to increased temperature. Conclusion of the work is trying to clear itself causes degradation of this protective layer.
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Manufacturing, use and properties of duplex austenitic-ferritic steels
Klapetek, Václav ; Blažík, Petr (referee) ; Myška, Martin (advisor)
This bachelor thesis focuses on stainless duplex austenitic-feritic steels. The first chapter is focused on mechanical and technological properties, microstructure and chemical proposition with its impact on corrosion resistance, following the introduction to the issue. Intermetallic phases and their effect on properties are also described. Second chapter deals with their usage in several industry spheres, such as petrochemical industry, paper-producing, transport and storage of chemicals etc.
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Precipitation of Intermetallic Phases in Austenitic-Ferritic Duplex Steels
Myška, Martin ; Foret, Rudolf (referee) ; Čech, Jan (referee) ; Záděra, Antonín (advisor)
This PhD thesis addresses the issue of precipitation of intermetallic phases in cast duplex stainless steel according to the ASTM A890 Gr4A standard. The aim of the thesis was to determine the amount of precipitated intermetallic phases depending on the temperature and holding time during isothermal annealing and under anisothermal conditions during cooling of the material in the temperature range from 1000 to 600 °C. The partial aim of the work was to determine the relationship between the amount of precipitated intermetallic phases and the mechanical properties of cast steel ASTM A890 Gr4A. As part of the work, the description and prediction of the kinetics of precipitation of intermetallic phases using the Johnson-Mehl-Avrami equation were verified. The relationship between the amount of precipitated intermetallic phases and the failure character of the material was determined by fractographic evaluation. The critical cooling rate of the casting was determined to ensure the minimum toughness of the steel that is desirable to reduce the risk of cracking during cooling of duplex stainless steel castings.
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ELECTRON BEAM WELDING OF HETEROGENEOUS WELDS OF Ti/Al ALLOYS
Havlík, Petr ; Dřímal, Daniel (referee) ; Schwarz,, Drahomír (referee) ; Foret, Rudolf (advisor)
The problematics of weldability of heterogeneous welds of aluminium and titanium alloys produced by electron beam welding is discussed in this work. Homogenous welds of selected alloys were analyzed in the first stage. Welding of these materials relates to formation of intermetallic phases at the interface of base materials due to differences in physical, chemical and metallurgical properties of base materials. One of the prerequisites for producing high quality weld joints is to find optimal process parameters. The influence of selected process parameters to integrity, structure and mechanical properties of heterogeneous Al/Ti joints is evaluated.
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Manufacturing, use and properties of duplex austenitic-ferritic steels
Klapetek, Václav ; Blažík, Petr (referee) ; Myška, Martin (advisor)
This bachelor thesis focuses on stainless duplex austenitic-feritic steels. The first chapter is focused on mechanical and technological properties, microstructure and chemical proposition with its impact on corrosion resistance, following the introduction to the issue. Intermetallic phases and their effect on properties are also described. Second chapter deals with their usage in several industry spheres, such as petrochemical industry, paper-producing, transport and storage of chemicals etc.
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Structure and properties of welded joint TiAl6V4 / 6061 made by electron beam technology
Král, Michael ; Jan, Vít (referee) ; Foret, Rudolf (advisor)
Titanium and aluminium alloys are among the most used construct materials due to their physical and mechanical properties except steels. The joining of these alloys can improve properties of whole construction but it is still difficult task. Especially welding of titanium and aluminium alloys is difficult cause formation of undesirable intermetalic phases in the weld. This thesis focuses on influences of electron beam welding parameters especially focusing and deflection of beam and preheating of base material to quality of heterogeneous join of titanium alloy Ti6Al4V and aluminium alloy EN AW-6061 – T651. There is described preparation of welded joins and brazed joins in the thesis, which are evaluated by light microscopy, scanning electron microscopy and EDS analysis of chemical composition. There was evaluated presence and chemical composition of formated intermetalic phases in the welded joins and quality and defects in the brazed joins.
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|
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Heat and mechanical resistance of zinc coating
Horák, Karel ; Dzimko, Marián (referee) ; Černý, Michal (advisor)
The work is aimed at studying the thermal degradation of the protective zinc coating. Its large part deals with the structure of the various stages of transition and their arrangement, the main emphasis is on analysis of brittle intermetallic phases, which arise due to increased temperature. Conclusion of the work is trying to clear itself causes degradation of this protective layer.
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Influence of annealing conditions on Mossbauer spectroscopy parameters of Fe-Zn intermetallic phases
Zmrzlý, Martin ; Schneeweiss, Oldřich ; Houbaert, Y. ; Fiala, J.
The phase composition of galvannealed zinc coatings strongly depends on used annealing conditions. According to equilibrium binary phase diagram of iron and zinc, it is possible to find four intermetallic phases. They arise due to diffusion of zinc and have some certain limits of stability. After dipping into molten zinc the steel sheet proceeds to annealing furnace. Since this is the diffusion controlled and thermodynamically determined process, the composition of coating differs with temperature and time of annealing. Also within the phases themselves there are small but important differences of space arrangement of unit cells, what is clearly observable at Mossbauer spectra parameters ů isomer shifts, quadrupole splittings and relative areas of peaks.
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