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5 Acta Physica Polonica A

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Structure and Properties of NiTi Shape Memory Alloy after Cold Rolling in Martensitic State

100%

Świec P. , Zubko M. , Lekston Z. , Stróż D.

nr 4

1081-1084

Due to unique features, like shape memory effects and superelasticity, NiTi alloys with nearly equiatomic composition are used in various branches of industry. Application of severe plastic deformation can drastically change properties of the materials. In the present paper the Ni_{50.4}Ti_{49.6} alloy after cold rolling in the martensitic state and further annealed is studied. Phase transformations were studied using X-ray diffraction and differential scanning calorimetry measurements. Microstructure was examined using transmission electron microscopy and electron backscattering diffraction methods. Mechanical properties of obtained alloys has been studied using Vickers microhardness tests. Based on the performed measurements it can be seen that in studied alloys two steps B2 ↔ R ↔ B19' phase transitions occurred. Performed plastic deformation influences course of phase transitions and phases composition. Due to the reduction of grain size microhardness of the studied material is increasing with increase of deformation degree.

NiTi Shape Memory Marformed Alloy Studied by Electron Beam Precession TEM Orientation Mapping Method

100%

Świec P. , Zubko M. , Lekston Z. , Stróż D.

Acta Physica Polonica A

2017

tom 131

nr 5

1307-1310

Severe plastic deformation by cold-rolling in martensitic state was applied to Ni_{50.4}Ti_{49.6} shape memory alloy. Received materials with 17, 20, 25, and 35% deformation were further annealed at 450°C for 15 min. After such treatment hardness of this alloy increased significantly reaching 365 HV0.5 for highest deformation degree. Calorimetric studies revealed two-stage and two-step character of martensitic transformation occurring in all specimens. Nanocrystalline structure with average grain size 53, 34, 28, and 24 nm was obtained. In material with 35% of deformation amorphous regions containing a nuclei of B2 parental phase with average size of 5 nm were observed. To determine the crystallographic orientation of observed nanograins and for better phase analysis, electron beam precession transmission electron microscopy orientation mapping was performed.

Precession Electron Diffraction Studies of SrₓBa_{1-x}Nb₂O₆ and CaₓBa_{1-x}Nb₂O₆ Single Crystals

88%

Wspaniała-Rak J. , Zubko M. , Stróż D. , Rak J. , Dec J.

nr 4

830-832

Crystal structures of two single crystals SrₓBa_{1-x}Nb₂O₆ and CaₓBa_{1-x}Nb₂O₆ have been reinvestigated using automated electron diffraction tomography method with beam precession. 3D reciprocal space has been reconstructed based on recorded tilt series. For both samples the crystal structure was refined and the tetragonal symmetry with space group P4bm was confirmed. The three dimensional reciprocal space allowed to observe and to study satellite reflections in both materials.

Electrochemical Formation of Second Generation TiO₂ Nanotubes on Ti13Nb13Zr Alloy for Biomedical Applications

88%

Stróż A. , Dercz G. , Chmiela B. , Stróż D. , Łosiewicz B.

nr 4

1079-1080

The aim of this study was to obtain the second generation TiO₂ nanotubes on the Ti13Nb13Zr alloy. Anodic oxidation of the alloy under study was carried out in 1 M (NH₄)₂SO₄ electrolyte under voltage-time conditions of 20 V for 120 min. The morphological parameters of the obtained nanotubes of second generation such as the length (L), internal (D_{i}) and outer (D_{o}) diameter of nanotube were determined. It was found that the anodic oxidation of the Ti13Nb13Zr alloy conducted under proposed conditions allowed to obtain the single-walled nanotubes of the following geometrical parameters: the internal diameter 61 nm, outer diameter 103 nm, and the length 3.9 μm. The total surface area of the single-walled nanotubes was equal to 4.1 μm², and the specific surface area per cm² (A_{s}) was estimated to be 15.6 cm²/cm². Formation mechanism, structure and optimal morphological parameters of the obtained single-walled nanotubes on the Ti13Nb13Zr alloy have been discussed in detail.

Properties of Sonochemically Prepared CuIn_{x}Ga_{1-x}S_{2} and CuIn_{x}Ga_{1-x}Se_{2}

63%

Jesionek M. , Nowak M. , Szperlich P. , Kępińska M. , Mistewicz K. , Toroń B. , Stróż D. , Szala J. , Rzychoń T.

nr 5

1107-1109

Nanoparticles of chalcopyrites copper indium gallium sulfide (CuIn_{x}Ga_{1-x}S_{2} or CIGS) and copper indium gallium selenide (CuIn_{x}Ga_{1-x}Se_{2} or CIGSe) were fabricated sonochemically. They were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, high resolution transmission electron microscopy, selected area electron diffraction, and diffuse reflectance spectroscopy. The electrical and photoelectrical properties of the fabricated nanomaterials were investigated.