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Magnetic shape memory alloys - ab initio approach
Heczko, Martin ; Šesták, Petr (referee) ; Zelený, Martin (advisor)
This Bachelor’s thesis is focused on theoretical study of magnetic shape memory alloys based on Ni2MnGa using ab initio calculations of electronic structure within the projector augmented wave method. In particular, the effect of increasing concertation of manganese instead of gallium was studied on total-energy and magnetic moment profiles along the tetragonal deformation path between austenite phase with cubic L21 structure and phase of nonmodulated martensite. Further, the effect of manganese atoms distribution within the gallium sublattice was studied as well as changes of this distribution under applied tetragonal deformation. At last but not at least, the elastic constants for austenitic and martensitic structures of studied alloys were calculated. The results show that the non-modulated martensite stabilized with increasing concentration of manganese, because its total energy decreased. The energetic barrier between austenitic and martensitic structures also decreased, which means the metastable austenite will change to unstable.
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Computer modeling of twin-boundaries in shape memory alloys
Heczko, Martin ; Pokluda, Jaroslav (referee) ; Zelený, Martin (advisor)
This Master‘s thesis is focused on theoretical study of twinning in magnetic shape memory alloys based on Ni2MnGa using ab initio calculations of electronic structure within the projector augmented wave method. In particular, the effect of increasing concentration of manganese at the expense of gallium was studied on total energy and stress profiles along different deformation paths in the (10-1)[101] shear system of non-modulated martensite. Further, this work deals with the effect of the concentration of manganese on the energy of planar fault caused by presence of partial dislocation due to motion of twin boundary. The results show that the shear modulus in studied shear system increases with the increasing concentration of manganese as well as energy barrier and deformation characteristics along shear deformation paths increases, which makes the shear more difficult in Mn-rich alloys. Increasing concentration of manganese also leads to rising the planar fault energy. All these effects can be responsible for lower mobility of twin boundaries in alloys with higher concentration of manganese.
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Detached house Hluchová
Heczko, Martin ; Komínková, Kateřina (referee) ; Petříček, Tomáš (advisor)
The subject of this thesis is the process of building technical part of the project documentation for the realization of a new family house in Nydek, parcel number 1150/4. The building is located in the sparsely built-up area. The building is situated on a gentle sloping ground. The building is designed as a three-level. The main residential part consists of a two-storey object with a gable roof with a slope of 12%. Mezzanine is made up by garage and foyer. Mezzanine is roofed by a flat roof. Entry to the building is from the north-east side, relaxing terraces are conceived on the southwest side. The main living area is divided to social part as first overground floor and reclined part as first overground floor. House has got a partial basement. Connection with public communications will be provided by a paved surface. Ground plan dimensions of the building are 18.14 x 16.44 m. Vertical load-bearing masonry is made of molded bricks Porotherm 30 P+D and formwork molded bricks BT 30 suffused by concrete. Partition walls are made of molded bricks Porotherm 14 P+D and Porothem 11,5 P+D. The ceiling are made of the systém called Porothem. The building will be based on the foundation strips. Foundation ratios are simple.
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Cold spray technology as a tool for repairing of worn parts
Hevessy, Zoltán ; Heczko, Martin (referee) ; Doubrava, Marek (advisor)
Cold spray (CS), also known as cold dynamic gas spraying, is a state-of-the-art process from the thermal spray family, characterized by a combination of low temperature and high velocity of the particles, which makes coatings of sufficient quality for applications in many industries where other processes cannot be used, including repairs of civil and military aircraft and helicopters. The bachelor thesis presents a detailed description of this process, the influence of its parameters on the quality of the coatings, examples of repairs and evaluation of the mechanical and corrosion properties of the repaired parts.
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Computer modeling of twin-boundaries in shape memory alloys
Heczko, Martin ; Pokluda, Jaroslav (referee) ; Zelený, Martin (advisor)
This Master‘s thesis is focused on theoretical study of twinning in magnetic shape memory alloys based on Ni2MnGa using ab initio calculations of electronic structure within the projector augmented wave method. In particular, the effect of increasing concentration of manganese at the expense of gallium was studied on total energy and stress profiles along different deformation paths in the (10-1)[101] shear system of non-modulated martensite. Further, this work deals with the effect of the concentration of manganese on the energy of planar fault caused by presence of partial dislocation due to motion of twin boundary. The results show that the shear modulus in studied shear system increases with the increasing concentration of manganese as well as energy barrier and deformation characteristics along shear deformation paths increases, which makes the shear more difficult in Mn-rich alloys. Increasing concentration of manganese also leads to rising the planar fault energy. All these effects can be responsible for lower mobility of twin boundaries in alloys with higher concentration of manganese.
|
|
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Magnetic shape memory alloys - ab initio approach
Heczko, Martin ; Šesták, Petr (referee) ; Zelený, Martin (advisor)
This Bachelor’s thesis is focused on theoretical study of magnetic shape memory alloys based on Ni2MnGa using ab initio calculations of electronic structure within the projector augmented wave method. In particular, the effect of increasing concertation of manganese instead of gallium was studied on total-energy and magnetic moment profiles along the tetragonal deformation path between austenite phase with cubic L21 structure and phase of nonmodulated martensite. Further, the effect of manganese atoms distribution within the gallium sublattice was studied as well as changes of this distribution under applied tetragonal deformation. At last but not at least, the elastic constants for austenitic and martensitic structures of studied alloys were calculated. The results show that the non-modulated martensite stabilized with increasing concentration of manganese, because its total energy decreased. The energetic barrier between austenitic and martensitic structures also decreased, which means the metastable austenite will change to unstable.
|
|
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Detached house Hluchová
Heczko, Martin ; Komínková, Kateřina (referee) ; Petříček, Tomáš (advisor)
The subject of this thesis is the process of building technical part of the project documentation for the realization of a new family house in Nydek, parcel number 1150/4. The building is located in the sparsely built-up area. The building is situated on a gentle sloping ground. The building is designed as a three-level. The main residential part consists of a two-storey object with a gable roof with a slope of 12%. Mezzanine is made up by garage and foyer. Mezzanine is roofed by a flat roof. Entry to the building is from the north-east side, relaxing terraces are conceived on the southwest side. The main living area is divided to social part as first overground floor and reclined part as first overground floor. House has got a partial basement. Connection with public communications will be provided by a paved surface. Ground plan dimensions of the building are 18.14 x 16.44 m. Vertical load-bearing masonry is made of molded bricks Porotherm 30 P+D and formwork molded bricks BT 30 suffused by concrete. Partition walls are made of molded bricks Porotherm 14 P+D and Porothem 11,5 P+D. The ceiling are made of the systém called Porothem. The building will be based on the foundation strips. Foundation ratios are simple.
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