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In this work Ni-rich NiTi alloy subjected to 35 % cold-rolling in the martensitic state followed by annealing at 450 °C for 15 min has been studied by transmission electron microscopy observations. It has been found that the material after thermo-mechanical treatment has a non-uniform nanostructure with canal-like shaped amorphous areas containing crystallites of R and B19′ phases. Zones surrounding these regions contain grains elongated in different directions in different areas. They are identified to be a mixture of B2 parent, R rhombohedral and B19′ martensitic phases. Selected area electron diffraction as well as transmission electron microscope orientation maps taken from these zones exhibit differences in their crystallographic orientations. It is proposed that the amorphous areas form along grain boundaries during severe plastic deformation.

The paper presents results of structural studies of hot extruded NiTi shape memory alloy that is in the B2 phase at room temperature. Texture of the alloy was determined from the X-ray diffraction measurements. It was found that in result of 60 % sample reduction (at a cross-section of a bar formed by hot extrusion) weak axial texture - type <110>B2 was formed. The volume of the grains oriented in this way was approx. 20 %. Basing on metallographic observations it was also found that the size of the grains formed as a result of the thermomechanical treatment was uniform with the average area of 1700 μm2. This information is significant from the point of view of functional properties. Hot extruded alloy revealed presence of the reversible martensitic transformation. Its characteristic temperatures were slight higher than in as-cast alloy. Moreover, the extruded NiTi alloy showed 100 % of the shape recovery.

Shape memory effects, the course and characteristic temperatures of phase transitions and mechanical properties and surface properties of NiTi alloys strongly depend on the chemical composition, the production process used and the plastic working and thermomechanical treatment as well as surface treatment. The test alloy was obtained by vacuum metallurgy by melting the components in a graphite crucible and casting into a graphite ingot mould. In order to obtain the rods in the process of hot plastic working, hot forging was applied using a smith hammer and rotary hot forging on a swaging machine. The resulting rods were subjected to an appropriate heat treatment and thermo mechanical treatment to obtain, at room temperature, a parent phase structure B2.The paper presents the results of the research of NiTi rods after hot rotary forging. The phase composition of the samples of the tested alloy after different heat treatments were determined by X-ray powder diffraction technique. It was found that at room temperature, depending upon the processing the samples had a structure parent phase with a small amount of martensite. The courses of phase transitions and the changes of the temperature characteristic were determined on the basis of the recorded DSC curves. It was found that the test rate after aging in the temperature range of 400-500 °C transitions take place involving the rhombohedral R phase. The temperature ranges of shape recovery of samples after various heat treatments were determined by recording the recovery of the shape during heating, in tests performed according to the standard ASTM 2082-06.

Ni-rich alloy (50.8at.%Ni) was plastically deformed by compression combined with reversion oscillating torsion. The compression rate was 0.05 mm/s and the torsion frequency and angle were 1,5Hz and ±3°. After the deformation process the specimens were annealed at 350°C/1h (623K/1h) and 400°C/1h (673K/1h). Their structure and transformation characteristic were studied with the use of TEM, X-ray phase analysis and DSC measurements. TEM observation of specimens after annealing at 350°C/1h (623K/1h) indicate presence of highly deformed B2 phase. In the specimen annealed at 400°C/1h (673K/1h) additionally Ni4Ti3 precipitates and the R-phase in the B2 matrix was found. DSC measurements show that the transformation sequence changes for the deformed and then annealed samples from single step B2  B19’ transformation to the B2  R  B19’ on cooling. Also increase of R-phase transformation temperature TR with the decrease of annealing temperature was observed.

In the present study the series of the Ni46.2Co5.0Mn36.1In12.6, Ni48.7Co5.2Mn34.4In11.6 and Ni45.6Co4.8Mn36.4In13.2 alloys (at. %) were studied. The influence of the indium addition on structure and phase transitions was studied. All alloys were annealed at 900°C for 24 hours and then slowly cooled in the furnace. After annealing all of the studied alloys showed the macrostructure of radially oriented columnar grains, which lied in the direction perpendicular to the casting axis. For the alloy containing about 13 at. % of indium the monoclinic 14M modulated martensite was stated at room temperature. Apart from the modulated martensite in a1_133 alloy the gamma phase was also observed. For alloy with higher indium content the mixture of cubic L21 parent phase and cubic gamma phase was identified. All studied alloys showed one-step martensitic transformation.

Two Ni-based (Ni-Mn-Ga and Ni-Mn-Co-In) ferromagnetic nonstoichiometric shape memory alloys were studied in order to determine the influence of hot extrusion process on macro, microstructure and texture of the studied alloys. The microstructure of the alloys in the as cast state and after extrusion was analyzed by electron backscatter diffraction technique. Typical microstructure of the as cast alloys consisted of radially oriented columnar grains elongated perpendicularly to the casting axis. For the alloys Ni-Mn-Ga and Ni-Mn-Co-In alloys the 10M and 14M modulated martensite were observed, respectively. After extrusion Ni-Mn-Ga samples revealed high density of fibre texture parallel to the extrusion axis. In spite of applying different extrusion parameters it was not possible to avoid cracks and overcome the brittleness of the Ni-Mn-Co-In alloys.

Crystal structure of two spinel single crystals CdCr2Se4 and ZnCr2-xVxSe4 have been reinvestigated using automated electron diffraction tomography method with beam precession. 3D reciprocal space have been reconstructed base on recorded tilt series. For both samples crystal structure was refined and the cubic symmetry with space group Fd-3m was confirmed. No additional electron potential has been located beside occupied atom sites.

Nickel-based single-crystal superalloys are widely used for production of high pressure turbine blades. The studied blades were obtained in an ALD Vacuum Technologies furnace by the Bridgman technique. Crystallization process was carried out with drawing rates of 3 mm/min and 5 mm/min. The dendrite microstructure based on the γ/γ’ phases and their defects was characterized using X-Ray topography, Laue diffraction, transmission electron microscopy. The defect structure samples were examined with the positron annihilation lifetime spectroscopy. It was found that crystal orientation, lattice parameter of γ’ phase and concentration of defects are correlated. The defect concentration increases in some areas which was the result of deviation of the primary dendrite arm from crystallization direction . Only one type of point defects was detected.

The aim of this paper is to obtain an experimental characterization of glucose-carburized substrates of α-Fe. The carburization process was achieved under vacuum condition using glucose as a carburizing medium. The process was carried out at several temperatures keeping the duration constant at 2h. The samples were treated at 4000C, 6500C and 9000C. The microstructure of the as produced coatings was observed by Scanning Electron Microscopy (SEM) and the formed phases were analyzed by X-Ray Diffraction (XRD). To investigate the corrosion properties of the carburized iron specimens, electrochemical tests were conducted. The samples were exposed to a solution of 3.5% wt. NaCl electrolyte, under quiescent conditions at room temperature and open to the air. The corroded samples were observed with use of Optical Microscopy in order to evaluate the corrosion effect on their surfaces. Carburization of iron samples at temperatures up to 6500C resulted in a shift of the polarization curves to lower current densities. Smaller corrosion rates were measured indicating higher corrosion resistance for these specimens.

The results presented here concern two NiTi alloys (near-equiatomic NiTi and Ni-rich alloy) subjected to plastic deformation by compression combined with reversion oscillating torsion. The maximal strain obtained was εc = 6.20. Finally the alloys were annealed at the temperature range 300 – 500oC for 1 hour. The structure of the as-prepared alloys was studied with the use of temperature X-ray diffraction and TEM observations. Also the DSC and bend and free recovery ASTM tests were carried out. It was found that the structure consists of a mixture of highly deformed B2 parent phase and B19’ martensite. The TEM studies revealed some amorphous areas in the most strained region of the samples. Annealing at lower temperatures caused formation of nanocrystalline structure that grew to the microcrystalline and finally well-defined polygonized structure in annealed at 500oC specimens. Multi-stage transformation was observed in the annealed at lower temperatures samples.

In present paper two ribbons of the Ni44Co6Mn36In14 (at.%) were prepared under different melt-spinning technique conditions. Microstructure of the ribbons was studied by scanning electron microscopy (SEM). Depending on the liquid ejection overpressure two types of ribbons microstructures were observed. Ribbon T1 for which ejection overpressure was 1.5 bar showed typical melt-spun ribbon microstructure consisting of a top layer of small equi-axial grains and columnar grains below. For T2 ribbon (ejection overpressure 0.2 bar) only a small fraction of the columnar grains were observed. Structure analysis of the ribbons performed by XRD showed that at room temperature both ribbons have B2 parent phase superstructure. No gamma phase precipitates were observed. In order to determine the orientation of the grains the EBSD technique was applied.

Ferromagnetic shape memory alloys (FSMA) are relatively new smart materials group. Recently, new FSMA from NiMnX (X=Sb, Sn, In, Co+In) systems are considered as alternative to the well known NiMnGa alloys. Four alloys of the following compositions: Ni43Mn35Co4In18, Ni41Mn35Co4In20, Ni42Mn35Co5In18, Ni40Mn35Co5In20 were studied in order to determine microstructure, phase composition and martensitic transformation temperatures versus their chemical composition. Structure of the alloys was studied by optical and transmission electron microscopy (TEM). All of the studied alloys showed macrostructure consisting of radially oriented columnar grains in the direction perpendicular to the casting axis. The structure of the phases occurred in the studied alloys depended on the cobalt and indium content. For the alloys containing 20 at. % of In at room temperature only L21 parent phase was observed whereas for those containing 18 at. % of In either single phase 14M modulated martensite or mixture of 14M martensite and L21 parent phase were seen. DSC measurements showed in studied alloys single-state martensitic transformation. Decrease In content of 2 at.% caused about 80oC fall of martensitic transformation temperatures. Curie temperature Tc increases of 20oC with 1 at% rise of the cobalt content.

In this paper a specific method of severe plastic deformation (SPD) applied to the NiTi shape memory alloy and the obtained structure and the alloy properties are presented. Cold rolling combined with transverse movement of the rolls was the method. The maximal strain obtained was εc ≈ 10.20 for the relatively large specimens. Then the alloy was annealed in order to obtain samples of a given grain size. In the paper the structure of the alloy annealed at 350oC was studied with the use of TEM equipped with Nanomegas attachment ASTAR allowing determination of the orientation of grains in nanoareas.

Thermomechanical treatment was applied to a binary NiTi alloy in order to improve its functional properties by forming nanocrystalline structure of the alloy. The alloy deformation was obtained by cold rolling combined with transverse movement of the rolls. This technique allowed us to obtain high strain (c ≈ 6) for the relatively large specimens. Subsequently, the samples were annealed in the temperature range 300 -500oC in order to form a nano-, submicro –and/or microcrystalline structure. The evolution of the structure and associated changes of the transformation sequences and functional properties were studied with the use of TEM, X-ray phase analysis, DSC and bend and free recovery ASTM tests. A mixed amorphous/crystalline structure was obtained after severe deformation, the martensitic transformation was completely suppressed in the sample. Annealing at lower temperatures caused formation of nanocrystalline structure that grew to the microcrystalline and finally well-defined polygonized structure in annealed at 500oC specimens.

The results presented here concern the NiTi alloy subjected to plastic deformation by compression combined with reversion oscillating torsion. The compression rate was 0.05 mm/s and the torsion frequency and angle were 1Hz and ± 3o, respectively. The maximal strain obtained was c = 6.20. The structure of the deformed samples was studied with the use of X-ray phase analysis and TEM observations. It was found that the structure consists of a mixture of highly deformed B2 parent phase and B19’ martensite. The strain distribution after the applied plastic deformation was not uniform, the highest strain region was in the middle of the cylinder sample. In these regions small amount of the Ni2Ti phase was indentified. The TEM studies revealed some amorphous areas in the most strained region of the samples.

The effect of plastic deformation by drawing and rolling in the martensite state and final annealing on the structure, grain size, martensitic transformations and shape memory properties of TiNiCo wires is described in the paper. The wires were cold worked by 30 and 40% and then annealed at the temperature range 300-600oC. The structure, phase composition and transformation behaviour of samples after processing and annealing were studied using transmission electron microscopy (TEM), X-ray diffraction (XRD) method and differential scanning calorimetry (DSC) technique. The marformed and annealed at 400 and 450oC wires exhibited a very good superelastic behaviour. The obtained wires were used for production of the shape memory staples with the recovery temperatures close to the human body temperature and as well as for small superelastic staples for fixation of mandible bone fractures.

This paper presents a brand new hybrid material on the nanometric scale: the antimony sulfoiodide (SbSI) within carbon nanotubes (CNTs). It was prepared in CNTs ultrasonically by using elemental antimony (Sb), sulfur (S) and iodide (I) in the presence of methanol under ultrasonic irradiation (34 kHz, 2.6 W/cm2). The sonochemical process was leaded for 3 hours at 323 K. The antimony sulfoiodide (SbSI) consisted in multiwalled carbon nanotubes (CNTs) were characterized high-resolution transmission electron microscopy (HRTEM). These investigations exhibit that the SbSI filling the CNTs has single-crystal structure in nature and in the form of multiwalled carbon nanotubes. The SbSI grown in CNTs are very promising materials for further investigations as well as for some industrial and medical applications.

The Ni-Mn-Ga alloys extruded at high temperature with a relatively large reduction rate were the subject of the studies. The microscopic observations of the transient zone in the extruded rods revealed rotation of the columnar grains in the ingot along the rod axis - giving the preferred <001> orientations. Comparison of the texture, magnetization and magneto-crystalline anisotropy constant for samples cut out from the columnar grain zone and these cut from the extruded rods was carried out for two alloys which differ in chemical composition and Ms temperature. Both alloys have the 5M martensitic structure at room temperature. The samples cut out of the ingot and the extruded rods have shown the axial <001> orientation, similar magnetization curves and magnetocrystalline anisotropy constant Ku = 1.5-1.6 J/m3•105.