Number of found documents: 437
Published from to

The effect of the heat treatment at 450°C on distribution of residual stresses of modified Cr-Mo steel welds
Mráz, L.; Hervoches, Charles; Mikula, Pavol; Kotora, J.
2020 - English
The effect of low-temperature long-term heat treatment on distribution of residual stresses on the modified chromium-molybdenum steel of the type 7 CrMoVTiB10-10 and known as the T24 steel which was studied by using neutron diffraction method, is presented. Keywords: neutron diffraction; stress analysis Available at various institutes of the ASCR
The effect of the heat treatment at 450°C on distribution of residual stresses of modified Cr-Mo steel welds

The effect of low-temperature long-term heat treatment on distribution of residual stresses on the modified chromium-molybdenum steel of the type 7 CrMoVTiB10-10 and known as the T24 steel which was ...

Mráz, L.; Hervoches, Charles; Mikula, Pavol; Kotora, J.
Ústav jaderné fyziky, 2020

On a possible High-Resolution Residual Strain/Stress Measurements by Three Axis Neutron Diffractometer
Mikula, Pavol; Šaroun, Jan; Rogante, M.
2020 - English
The new unconventional high-resolution neutron diffraction three axis set-up for strain/stress measurements of rather large bulk polycrystalline samples is presented. Keywords: neutron diffraction; 3 axis neutron diffractometer Available at various institutes of the ASCR
On a possible High-Resolution Residual Strain/Stress Measurements by Three Axis Neutron Diffractometer

The new unconventional high-resolution neutron diffraction three axis set-up for strain/stress measurements of rather large bulk polycrystalline samples is presented.

Mikula, Pavol; Šaroun, Jan; Rogante, M.
Ústav jaderné fyziky, 2020

Laser-generated nanoparticles to change physical properties of solids, liquids and gases
Torrisi, Alfio; Cutroneo, Mariapompea; Ceccio, Giovanni; Cannavó, Antonino; Horák, Pavel; Torrisi, L.; Vacík, Jiří
2019 - English
Synthesis of nanoparticles was possible employing a Nd: YAG pulsed laser at fundamental harmonic. The production of nanoparticles in water depends mainly on the laser parameters (pulse duration, energy, wavelength), the irradiation conditions (focal spot, repetition rate, irradiation time) and the medium where the ablation occurs (solid target, water, solution concentration). The nanoparticles can be introduced in solids, liquids or gases to change many physical characteristics. The optical properties of polymers and solutions, the wetting ability of liquids, the electron density of laser-generated plasma, represent some examples that can be controlled by the concentration of metallic nanoparticles (Au, Ag, Ti, Cu). Some bio-medical applications will be presented and discussed. Keywords: bio-medical applications; laser; nanoparticles Available at various institutes of the ASCR
Laser-generated nanoparticles to change physical properties of solids, liquids and gases

Synthesis of nanoparticles was possible employing a Nd: YAG pulsed laser at fundamental harmonic. The production of nanoparticles in water depends mainly on the laser parameters (pulse duration, ...

Torrisi, Alfio; Cutroneo, Mariapompea; Ceccio, Giovanni; Cannavó, Antonino; Horák, Pavel; Torrisi, L.; Vacík, Jiří
Ústav jaderné fyziky, 2019

On a possible use of neutron three axis diffractometer for studies of elastic and plastic deformation of polycrystalline materials
Mikula, Pavol; Ryukhtin, Vasyl; Rogante, M.
2019 - English
Feasibility of using a high-resolution three axis neutron diffractometer performance for elastic and plastic deformation studies of metallic polycrystalline samples is presented. The method consists of unconventional set up employing bent perfect crystal (BPC) monochromator and analyzer with a polycrystalline sample in between. After the realization of focusing conditions in real and momentum space at the neutron wavelength of 0.162 nm, a high angular resolution up to FWHM(d/d)=2x10-3 was achieved on the standard Fe(110) sample (2 mm diameter) which then opened the possibility for the measurements of small lattice parameter changes of samples. The feasibility of the instrument for macro-and microstrain as well as grain size studies is demonstrated on the polycrystalline samples of low carbon shear deformed steel wires and the NiTi plates subjected to heat treatment. Keywords: instrumentation; neutron diffraction; strain measurements Available at various institutes of the ASCR
On a possible use of neutron three axis diffractometer for studies of elastic and plastic deformation of polycrystalline materials

Feasibility of using a high-resolution three axis neutron diffractometer performance for elastic and plastic deformation studies of metallic polycrystalline samples is presented. The method consists ...

Mikula, Pavol; Ryukhtin, Vasyl; Rogante, M.
Ústav jaderné fyziky, 2019

Residual stresses of laser-welded pressure vessel steel determined by X-ray and neutron diffraction
Trojan, K.; Vlk, A.; Čapek, J.; Hervoches, Charles; Ganev, N.
2019 - English
To gain insight into the quality of the laser weld, information about the residual stress state across the weld is very useful. In this contribution, the residual stress profiles for lowalloy carbon steel plates of P355NL1 grade, which were laser welded from both sides, are presented. To separate the effects of the production of plates from the welding process, the samples were annealed for stress relieving. Using X-ray and neutron diffraction, the surface and bulk RS profiles were obtained. From the obtained data, first, the difference in the character of the longitudinal (parallel to the weld axis) and the transversal component of the RS tensor can be seen. The longitudinal component has a tensile character with a maximum value approximately 500 MPa. Values and character of the transversal component vary strongly with depth and distance from the weld axis. Keywords: nondestructive examination; ferromagnetic materials; residual stresses Available at various institutes of the ASCR
Residual stresses of laser-welded pressure vessel steel determined by X-ray and neutron diffraction

To gain insight into the quality of the laser weld, information about the residual stress state across the weld is very useful. In this contribution, the residual stress profiles for lowalloy carbon ...

Trojan, K.; Vlk, A.; Čapek, J.; Hervoches, Charles; Ganev, N.
Ústav jaderné fyziky, 2019

Study of lithium encapsulation in porous membrane using ion and neutron beams
Ceccio, Giovanni; Cannavó, Antonino; Horák, Pavel; Torrisi, Alfio; Tomandl, Ivo; Hnatowicz, Vladimír; Vacík, Jiří
2019 - English
Ion track-etched membranes are porous systems obtained by etching of the latent ion tracks using a suitable etchant solution. In this work, control of the pores' spatial profiles and dimensions in PET polymers was achieved by varying etching temperature and etching time. For determination of the pores' shape, Ion Transmission Spectroscopy technique was employed. In this method, alterations of the energy loss spectra of the transmitted ions reflect alterations in the material density of the porous foils, as well as alterations of their thickness. Simulation code, developed by the team, allowed the tomographic study of the ion track 3D geometry and its evolution during chemical etching. From the doping of porous membranes with lithium-based solution and its analysis by Thermal Neutron Depth Profiling method, the ability of porous PET membranes to encapsulate nano-sized material was also inspected. The study is important for various applications, e.g., for catalysis, active agents, biosensors, etc. Keywords: doping; etching; ion transmission spectroscopy; thermal neutron depth profiling Available at various institutes of the ASCR
Study of lithium encapsulation in porous membrane using ion and neutron beams

Ion track-etched membranes are porous systems obtained by etching of the latent ion tracks using a suitable etchant solution. In this work, control of the pores' spatial profiles and dimensions in PET ...

Ceccio, Giovanni; Cannavó, Antonino; Horák, Pavel; Torrisi, Alfio; Tomandl, Ivo; Hnatowicz, Vladimír; Vacík, Jiří
Ústav jaderné fyziky, 2019

Instrumentation for study of nanomaterials in NPI REZ (New laboratory for material study in Nuclear Physics Institute in REZ)
Bejšovec, Václav; Cannavó, Antonino; Ceccio, Giovanni; Hnatowicz, Vladimír; Horák, Pavel; Lavrentiev, Vasyl; Macková, Anna; Tomandl, Ivo; Torrisi, Alfio; Vacík, Jiří
2019 - English
Nano-sized materials become irreplaceable component of a number of devices for every aspect of human life. The development of new materials and deepening of the current knowledge require a set of specialized techniques-deposition methods for preparation/modification of the materials and analytical tools for proper understanding of their properties. A thoroughly equipped research centers become the requirement for the advance and development not only in nano-sized field. The Center of Accelerators and Nuclear Analytical Methods (CANAM) in the Nuclear Physics Institute (NPI) comprises a unique set of techniques for the synthesis or modification of nanostructured materials and systems, and their characterization using ion beam, neutron beam and microscopy imaging techniques. The methods are used for investigation of a broad range of nano-sized materials and structures based on metal oxides, nitrides, carbides, carbon-based materials (polymers, fullerenes, graphenes, etc.) and nano-laminate composites (MAX phases). These materials can be prepared at NPI using ion beam sputtering, physical vapor deposition and molecular beam epitaxy. Based on the deposition method and parameters, the samples can be tuned to possess specific properties, e.g., composition, thickness (nm-μm), surface roughness, optical and electrical properties, etc. Various nuclear analytical methods are applied for the sample characterization. RBS, RBS-channeling, PIXE, PIGE, micro-beam analyses and Transmission Spectroscopy are accomplished at the Tandetron 4130MC accelerator, and additionally the Neutron Depth Profiling (NDP) and Prompt Gamma Neutron Activation (PGNA) analyses are performed at an external neutron beam from the LVR-15 research reactor. The multimode AFM facility provides further surface related information, magnetic/electrical properties with nano-metric precision, nano-indentation, etc. Keywords: AFM; ion beam analysis; LEIF Available at various institutes of the ASCR
Instrumentation for study of nanomaterials in NPI REZ (New laboratory for material study in Nuclear Physics Institute in REZ)

Nano-sized materials become irreplaceable component of a number of devices for every aspect of human life. The development of new materials and deepening of the current knowledge require a set of ...

Bejšovec, Václav; Cannavó, Antonino; Ceccio, Giovanni; Hnatowicz, Vladimír; Horák, Pavel; Lavrentiev, Vasyl; Macková, Anna; Tomandl, Ivo; Torrisi, Alfio; Vacík, Jiří
Ústav jaderné fyziky, 2019

Mechanical properties of WN43 magnesium alloy prepared by spark plasma sintering
Knapek, Michal; Minárik, P.; Greš, A.; Zemková, M.; Cinert, Jakub; Král, R.
2019 - English
The spark plasma sintering (SPS) method was used to prepare bulk materials form WN43 magnesium alloy atomized powder. Compression tests were carried out in order to investigate the effect of different sintering regimes (10 min at 400, 450, or 500 degrees C) on the mechanical properties of the material. Furthermore, complementary in-situ acoustic emission (AE) recording was employed to reveal the dynamics of deformation processes during compression. It was shown that by increasing the sintering temperature, the ultimate compressive strength and ductility were significantly improved. The AE data and microstructure observations suggest that pronounced twin nucleation takes place around the yield point whereas twin growth and dislocation activity are the dominant deformation mechanisms in the later stages of deformation. Keywords: spark plasma sintering; magnesium; deformation; twinning; acoustic emission Available at various institutes of the ASCR
Mechanical properties of WN43 magnesium alloy prepared by spark plasma sintering

The spark plasma sintering (SPS) method was used to prepare bulk materials form WN43 magnesium alloy atomized powder. Compression tests were carried out in order to investigate the effect of different ...

Knapek, Michal; Minárik, P.; Greš, A.; Zemková, M.; Cinert, Jakub; Král, R.
Ústav jaderné fyziky, 2019

Neutron investigation of Nitinol stents and massive samples before and after PIRAC coating
Rogante, M.; Buhagiar, J.; Cassar, G.; Debono, M.; Lebedev, V.; Mikula, Pavol; Ryukhtin, Vasyl
2019 - English
Nitinol, a thermoelastic Ni-Ti Shape Memory Alloy (SMA) with approximately 50 at. % Ti, is adopted in a wide range of medical equipment and devices used in interventional radiology, orthopaedics, neurology and cardiology, in particular as a smart material for stents. In this work, NiTi real stents and massive samples before and after different Powder Immersion Reaction Assisted Coating (PIRAC) treatments have been investigated by using two neutron techniques: (1) Small and Ultra-Small Angle Neutron Scattering (SANS, USANS) for nano- and micro-scale characterization, obtaining information on structure and the effects due to the coating treatment, and (2) High-Resolution Neutron Diffraction (HRND), evaluating the macrostrain components resulting from angular shifts of diffraction peaks and the micro-strains in the plastically deformation region by means of profile-broadening analysis. The obtained results contribute: improving knowledge of defects and other key features of the materials complementary to those achieved by using traditional examination techniques. helping to better understand the functional characteristics of Nitinol parts and predict the material's mechanical behaviour. Keywords: high-resolution neutron diffraction; nanostructure; Nitinol; SANS Available at various institutes of the ASCR
Neutron investigation of Nitinol stents and massive samples before and after PIRAC coating

Nitinol, a thermoelastic Ni-Ti Shape Memory Alloy (SMA) with approximately 50 at. % Ti, is adopted in a wide range of medical equipment and devices used in interventional radiology, orthopaedics, ...

Rogante, M.; Buhagiar, J.; Cassar, G.; Debono, M.; Lebedev, V.; Mikula, Pavol; Ryukhtin, Vasyl
Ústav jaderné fyziky, 2019

Investigation of deformation mechanisms in textured magnesium alloy
Dittrich, J.; Čapek, J.; Knapek, Michal; Minárik, P.
2019 - English
Advanced in-situ and ex-situ methods were used to reveal active deformation mechanisms during deformation of magnesium alloy with a strong texture. Three sets of samples were prepared from the rolled sheet of commercial AZ31 alloy with respect to its strong basal texture - normal direction (ND), rolling direction (RD) and 45 degrees between RD and ND, and were deformed in both compression and tension. The signal of acoustic emission (AE) was measured concurrently during the deformation. Electron backscattered diffraction (EBSD) was used to study the microstructure after the selected stages of the deformation. It is shown that the extension twinning played an important role during the plastic deformation in the samples having favorably oriented basal texture component, whereas in the unfavorably oriented samples, the role of twinning was marginal. Pronounced activation of twinning only in some samples caused a considerable variation in the deformation behavior and AE response. A consistent link between the energy and amplitudes of the AE signal and the microstructure changes investigated by EBSD was established. Keywords: magnesium; deformation; twinning; acoustic emission; EBSD Available at various institutes of the ASCR
Investigation of deformation mechanisms in textured magnesium alloy

Advanced in-situ and ex-situ methods were used to reveal active deformation mechanisms during deformation of magnesium alloy with a strong texture. Three sets of samples were prepared from the rolled ...

Dittrich, J.; Čapek, J.; Knapek, Michal; Minárik, P.
Ústav jaderné fyziky, 2019

About project

NRGL provides central access to information on grey literature produced in the Czech Republic in the fields of science, research and education. You can find more information about grey literature and NRGL at service web

Send your suggestions and comments to nusl@techlib.cz

Provider

http://www.techlib.cz

Facebook

Other bases