National Repository of Grey Literature 9 records found  Search took 0.00 seconds. 
Evaluation of mechanical characteristics of shape memory alloys under cyclic loading in torsion
German, Roman ; Štěpánek, Roman (referee) ; Horníková, Jana (advisor)
The main aim of this thesis is to process the results of fatigue tests of wires of a NiTi shape memory alloy subjected to symmetric cyclic torsion. The first part of this work is dedicated to literature research about NiTi alloys, their response to cyclic loading and the specific features of torsion loading. The second part contains a review of the influence of heat treatment and strain amplitude on the ability to dissipate mechanical energy, changes in mechanical properties and fatigue life of the tested material.
Microscopic characterisation of pores in intermetallic materials prepared from bi metallic powder mixtures
Nepovím, Petr ; Kachlík, Martin (referee) ; Jan, Vít (advisor)
The work deals with assessment of metallic foams manufactured from coldspray deposits of binary metallic mixtures. The compacts were heat treated and subsequently analysed by means of electron microscopy. Phase composition was analysed using X-ray diffraction after oxidation annealing step. The oxidized compounds were tested for catalytical activity on methane oxidation process. Best results were achieved using FeAl compound.
DSC evaluation of homogenity of Ni-Ti alloys ingots
Kuběnová, Monika ; Zemčík, Ladislav (referee) ; Dlouhý, Antonín (advisor)
Alloy NiTi with nearequiatomic composition of nickel and titan belongs to a group of metal materials with a shape memory effect (Shape memory alloys). NiTi alloys are a guite attractive materials not only as practical shape memory alloys with hight strenght and ductility but also as those exhibiting unique physical properties. The production of these matrerials is complying with chemical composition. Final charakteristics of alloy are influenced by these bounderies and also by mechanical-heat treatment. This work deal with DSC evaluation of homogenity of ingot structure of NiTi alloy containing 50,8 at.% Ni. The alloy was melted in Y2O3 cricible. In the end the results of DSC method are compared to the microstructure of alloy obtained by SEM and TEM methods.
Memory Materials
Josiek, Robert ; Šesták, Petr (referee) ; Molliková, Eva (advisor)
Currently, shape memory materials are very popular, especially intermetallic compounds NiTi. This alloy is very stable and corrosion resistant, but its production is very difficult because of the high reactivity of titanium. Shape memory effect in this material is dependent on many parameters, such as chemical composition or heat treatment. This bachelor’s thesis explains one-way and two-way memory effect. Another one phenomenon associated with the martensitic transformation, superelasticity, is mentioned, too. The applications of these materials are described in separate chapter of this bachelor’s thesis.
Processing of NiTi alloy by SLM technology
Lukačovič, Samuel ; Dočekalová, Kateřina (referee) ; Koutný, Daniel (advisor)
This thesis deals with development of process parameters suitable for processing nickel titanium alloy, also known as nitinol, using technology Selective laser melting. The main goal of this thesis is development of process parameters capable of producing dense and thin wall parts. Minor goals are description of effect of process parameters on chemical composition, thermomechanical and mechanical properties of printed parts. By analyzing the experiments carried out on single tracks, dense parts and thin walls, the optimal combination of process parameters was able to be determined. Using this combination, it was possible to produce non-porous dense and thin wall parts, which exhibit superelasticity under load. The effects of process parameters on nickel evaporation and transition temperatures were described using analyses of thermal response and chemical composition.
Microscopic characterisation of pores in intermetallic materials prepared from bi metallic powder mixtures
Nepovím, Petr ; Kachlík, Martin (referee) ; Jan, Vít (advisor)
The work deals with assessment of metallic foams manufactured from coldspray deposits of binary metallic mixtures. The compacts were heat treated and subsequently analysed by means of electron microscopy. Phase composition was analysed using X-ray diffraction after oxidation annealing step. The oxidized compounds were tested for catalytical activity on methane oxidation process. Best results were achieved using FeAl compound.
Evaluation of mechanical characteristics of shape memory alloys under cyclic loading in torsion
German, Roman ; Štěpánek, Roman (referee) ; Horníková, Jana (advisor)
The main aim of this thesis is to process the results of fatigue tests of wires of a NiTi shape memory alloy subjected to symmetric cyclic torsion. The first part of this work is dedicated to literature research about NiTi alloys, their response to cyclic loading and the specific features of torsion loading. The second part contains a review of the influence of heat treatment and strain amplitude on the ability to dissipate mechanical energy, changes in mechanical properties and fatigue life of the tested material.
DSC evaluation of homogenity of Ni-Ti alloys ingots
Kuběnová, Monika ; Zemčík, Ladislav (referee) ; Dlouhý, Antonín (advisor)
Alloy NiTi with nearequiatomic composition of nickel and titan belongs to a group of metal materials with a shape memory effect (Shape memory alloys). NiTi alloys are a guite attractive materials not only as practical shape memory alloys with hight strenght and ductility but also as those exhibiting unique physical properties. The production of these matrerials is complying with chemical composition. Final charakteristics of alloy are influenced by these bounderies and also by mechanical-heat treatment. This work deal with DSC evaluation of homogenity of ingot structure of NiTi alloy containing 50,8 at.% Ni. The alloy was melted in Y2O3 cricible. In the end the results of DSC method are compared to the microstructure of alloy obtained by SEM and TEM methods.
Memory Materials
Josiek, Robert ; Šesták, Petr (referee) ; Molliková, Eva (advisor)
Currently, shape memory materials are very popular, especially intermetallic compounds NiTi. This alloy is very stable and corrosion resistant, but its production is very difficult because of the high reactivity of titanium. Shape memory effect in this material is dependent on many parameters, such as chemical composition or heat treatment. This bachelor’s thesis explains one-way and two-way memory effect. Another one phenomenon associated with the martensitic transformation, superelasticity, is mentioned, too. The applications of these materials are described in separate chapter of this bachelor’s thesis.

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