Tabela A z publikacjami w czasopismach wyróżnionych w Journal Citation Reports (JCR) 
Tabela B z publikacjami w czasopismach zagranicznych i krajowych, wyróżnionych na liście MNSzW
Publikacje konferencyjne indeksowane w bazie Web of Science Core Collection
Inne publikacje w pozostałych czasopismach i wydawnictwach konferencyjnych
Afiliacja IPPT PAN

1.Ryś M., Forest S., Petryk H., A micromorphic crystal plasticity model with the gradient-enhanced incremental hardening law, International Journal of Plasticity, ISSN: 0749-6419, DOI: 10.1016/j.ijplas.2019.102655, Vol.128, pp.102655-1-21, 2020
Ryś M., Forest S., Petryk H., A micromorphic crystal plasticity model with the gradient-enhanced incremental hardening law, International Journal of Plasticity, ISSN: 0749-6419, DOI: 10.1016/j.ijplas.2019.102655, Vol.128, pp.102655-1-21, 2020

Abstract:
A model of crystal plasticity is developed in which the effects of plastic flow non-uniformity are described through the full dislocation density tensor. The micromorphic approach is used in which the dislocation density tensor is represented by the curl of an independent constitutive variable called microdeformation. The microdeformation tensor is enforced by an energetic penalty term to be close to the actual plastic distortion tensor. The curl of microdeformation tensor enters the constitutive model in two independent but complementary ways. First, it is an argument of the free energy density function, which describes the kinematic-type hardening in cyclic non-uniform deformation. Second, its rate influences the rates of critical resolved shear stresses, which corresponds to additional isotropic hardening caused by incompatibility of the plastic flow rate. The latter effect, missing in the standard slip-system hardening rule, is described in a simple manner that does not require any extra parameter in comparison to the non-gradient theory. In the proposed model there are two independent internal length scales whose interplay is examined by means of 1D and 2D numerical examples of plastic shearing of a single crystal.

Keywords:
gradient theory, crystal plasticity, dissipation, length scale, cyclic deformation, numerical regularization

(200p.)
2.Majewski M., Hołobut P., Kursa M., Kowalczyk-Gajewska K., Packing and size effects in elastic-plastic particulate composites: micromechanical modelling and numerical verification, International Journal of Engineering Science, ISSN: 0020-7225, DOI: 10.1016/j.ijengsci.2020.103271, Vol.151, pp.103271-1-18, 2020
Majewski M., Hołobut P., Kursa M., Kowalczyk-Gajewska K., Packing and size effects in elastic-plastic particulate composites: micromechanical modelling and numerical verification, International Journal of Engineering Science, ISSN: 0020-7225, DOI: 10.1016/j.ijengsci.2020.103271, Vol.151, pp.103271-1-18, 2020

Abstract:
The issue of applicability of the Morphologically Representative Pattern (MRP) approach to elastic-plastic composites is addressed. The extension to the regime of non-linear material behaviour is performed by employing the concept of incremental linearization of the material response in two basic variants: tangent and secant. The obtained predictions are evaluated through comparison with the outcomes of numerical analyses. Finite Element simulations are carried out using periodic unit cells with cubic arrangements of spherical particles and representative volume elements (RVE) with 50 randomly placed inclusions. In addition to the analysis of the packing effect in two-phase composites, the size effect is also studied by assuming an interphase between the matrix and inclusions. It is concluded that the MRP approach can be used as an effective predictive alternative to computational homogenization, not only in the case of linear elasticity but also in the case of elastic-plastic composites.

Keywords:
particulate composites, elastoplasticity, micromechanics, size effect, packing effect, morphologically representative pattern

(200p.)
3.Jarząbek D.M., Milczarek M., Nosewicz S., Bazarnik P., Schift H., Size effects of hardness and strain rate sensitivity in amorphous silicon measured by nanoindentation, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-020-05648-w, Vol.51, No.4, pp.1625-1633, 2020
Jarząbek D.M., Milczarek M., Nosewicz S., Bazarnik P., Schift H., Size effects of hardness and strain rate sensitivity in amorphous silicon measured by nanoindentation, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-020-05648-w, Vol.51, No.4, pp.1625-1633, 2020

Abstract:
In this work, dynamic mechanical properties of amorphous silicon and scale effects were investigated by the means of nanoindentation. An amorphous silicon sample was prepared by plasma-enhanced chemical vapor deposition (PECVD). Next, two sets of the samples were investigated: as-deposited and annealed in 500 °C for 1 hour. A three-sided pyramidal diamond Berkovich's indenter was used for the nanoindentation tests. In order to determine the strain rate sensitivity (SRS), indentations with different loading rates were performed: 0.1, 1, 10, 100 mN/min. Size effects were studied by application of maximum indentation loads in the range from 1 up to 5 mN (penetrating up to approximately one-third of the amorphous layer). The value of hardness was determined by the Oliver-Pharr method. An increase of hardness with decrease of the indentation depth was observed for both samples. Furthermore, the significant dependence of hardness on the strain rate has been reported. Finally, for the annealed samples at low strain rates a characteristic "elbow" during unloading was observed on the force-indentation depth curves. It could be attributed to the transformation of (β-Sn)-Si to the PI (pressure-induced) a-Si end phase.

(200p.)
4.Węglewski W., Pitchai P., Bochenek K., Bolzon G., Konetschnik R., Sartory B., Ebner R., Kiener D., Basista M., Experimental and numerical investigation of the deformation and fracture mode of microcantilever beams made of Cr(Re)/Al2O3 metal–matrix composite, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-020-05687-3, Vol.51, No.5, pp.2377-2390, 2020
Węglewski W., Pitchai P., Bochenek K., Bolzon G., Konetschnik R., Sartory B., Ebner R., Kiener D., Basista M., Experimental and numerical investigation of the deformation and fracture mode of microcantilever beams made of Cr(Re)/Al2O3 metal–matrix composite, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-020-05687-3, Vol.51, No.5, pp.2377-2390, 2020

Abstract:
This work presents a combined experimental and computational study of the deformation and fracture of microcantilever specimens made of chromium(rhenium)-alumina metal–matrix composite (MMC), with a particular focus on the failure properties of the metal–ceramic interfaces. The obtained experimental results show that the bending strength of microcantilevers containing alumina particles in critical cross-sections near specimen's fixed end is considerably higher than that of unreinforced chromium(rhenium) samples. Brittle cracking along chromium–alumina interfaces is the dominant fracture mode of the composite microcantilevers. The interface characteristics are determined in an indirect way by numerical simulations of the experiment with account of the actual specimen microstructure from the scanning electron microscope (SEM) images. A parametric study demonstrates that the overall material response may be reproduced by different sets of model parameters, whereas the actual failure mode permits to discriminate among the possible alternatives. Using this approach, the in situ values of the chromium–alumina interface cohesive strength and the fracture energy are estimated.

(200p.)
5.Alvi S., Jarząbek D.M., Kohan M.G., Hedman D., Jenczyk P., Natile M.M., Vomiero A., Akhtar F., Synthesis and mechanical characterization of a CuMoTaWV high-entropy film by magnetron sputtering, ACS Applied Materials and Interfaces, ISSN: 1944-8244, DOI: 10.1021/acsami.0c02156, Vol.12, No.18, pp.21070-21079, 2020
Alvi S., Jarząbek D.M., Kohan M.G., Hedman D., Jenczyk P., Natile M.M., Vomiero A., Akhtar F., Synthesis and mechanical characterization of a CuMoTaWV high-entropy film by magnetron sputtering, ACS Applied Materials and Interfaces, ISSN: 1944-8244, DOI: 10.1021/acsami.0c02156, Vol.12, No.18, pp.21070-21079, 2020

Abstract:
Development of high-entropy alloy (HEA) films is a promising and cost-effective way to incorporate these materials of superior properties in harsh environments. In this work, a refractory high-entropy alloy (RHEA) film of equimolar CuMoTaWV was deposited on silicon and 304 stainless-steel substrates using DC-magnetron sputtering. A sputtering target was developed by partial sintering of an equimolar powder mixture of Cu, Mo, Ta, W, and V using spark plasma sintering. The target was used to sputter a nanocrystalline RHEA film with a thickness of ~900 nm and an average grain size of 18 nm. X-ray diffraction of the film revealed a body-centered cubic solid solution with preferred orientation in the (110) directional plane. The nanocrystalline nature of the RHEA film resulted in a hardness of 19 ± 2.3 GPa and an elastic modulus of 259 ± 19.2 GPa. A high compressive strength of 10 ± 0.8 GPa was obtained in nanopillar compression due to solid solution hardening and grain boundary strengthening. The adhesion between the RHEA film and 304 stainless-steel substrates was increased on annealing. For the wear test against the E52100 alloy steel (Grade 25, 700-880 HV) at 1 N load, the RHEA film showed an average coefficient of friction (COF) and wear rate of 0.25 (RT) and 1.5 (300 °C), and 6.4 × 10^–6 mm^3/N m (RT) and 2.5 × 10^–5 mm^3/N m (300 °C), respectively. The COF was found to be 2 times lower at RT and wear rate 10^2 times lower at RT and 300 °C than those of 304 stainless steel. This study may lead to the processing of high-entropy alloy films for large-scale industrial applications.

Keywords:
high-entropy alloys, magnetron sputtering, spark plasma sintering, mechanical properties, wear

(200p.)
6.Lengiewicz J., Souza M., Lahmar M.A., Courbon C., Dalmas D., Stupkiewicz S., Scheibert J., Finite deformations govern the anisotropic shear-induced area reduction of soft elastic contacts, JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS, ISSN: 0022-5096, DOI: 10.1016/j.jmps.2020.104056, Vol.143, pp.104056-1-19, 2020
Lengiewicz J., Souza M., Lahmar M.A., Courbon C., Dalmas D., Stupkiewicz S., Scheibert J., Finite deformations govern the anisotropic shear-induced area reduction of soft elastic contacts, JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS, ISSN: 0022-5096, DOI: 10.1016/j.jmps.2020.104056, Vol.143, pp.104056-1-19, 2020

Abstract:
Solid contacts involving soft materials are important in mechanical engineering or biomechanics. Experimentally, such contacts have been shown to shrink significantly under shear, an effect which is usually explained using adhesion models. Here we show that quantitative agreement with recent high-load experiments can be obtained, with no adjustable parameter, using a non-adhesive model, provided that finite deformations are taken into account. Analysis of the model uncovers the basic mechanisms underlying anisotropic shear-induced area reduction, local contact lifting being the dominant one. We confirm experimentally the relevance of all those mechanisms, by tracking the shear-induced evolution of tracers inserted close to the surface of a smooth elastomer sphere in contact with a smooth glass plate. Our results suggest that finite deformations are an alternative to adhesion, when interpreting a variety of sheared contact experiments involving soft materials.

Keywords:
contact mechanics, friction, contact area, elastomer, full-field measurement

(140p.)
7.Bochenek K., Węglewski W., Morgiel J., Maj M., Basista M., Enhancement of fracture toughness of hot-pressed NiAl-Re material by aluminum oxide addition, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2020.139670, Vol.790, pp.139670-1-6, 2020
Bochenek K., Węglewski W., Morgiel J., Maj M., Basista M., Enhancement of fracture toughness of hot-pressed NiAl-Re material by aluminum oxide addition, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2020.139670, Vol.790, pp.139670-1-6, 2020

Abstract:
In the search for a remedy to increase the fracture toughness of NiAl, the effect of rhenium and aluminum oxide addition is explored. Using a powder metallurgy processing route an optimum composition of NiAl-Re-Al2O3 material is found which manifests KIC over two times higher than as-received NiAl sintered under the same conditions.

Keywords:
fracture behavior, stress/strain measurements, intermetallics, composites, powder metallurgy, grains and interfaces

(140p.)
8.Maj M., Nowak M., Musiał S., Płociński T., Experimental analysis of material, lattice and plastic rotation during deformation of aluminium multicrystal, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2020.139725, Vol.790, pp.139725-1-5, 2020
Maj M., Nowak M., Musiał S., Płociński T., Experimental analysis of material, lattice and plastic rotation during deformation of aluminium multicrystal, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2020.139725, Vol.790, pp.139725-1-5, 2020

Abstract:
This paper focuses on the experimental determination of the distribution of material, lattice and plastic rotation during deformation of crystalline aggregate. The proposed methodology uses standard electron backscattering diffraction technique combined with 3D digital image correlation data. The presented approach is used for analysis of rotations during deformation of aluminium multicrystal.

Keywords:
image analysis, electron backscattering diffraction, plastic deformation, misorientation, plastic rotation

(140p.)
9.Szymczyk M., Nowak M., Sumelka W., Plastic strain localization in an extreme dynamic tension test of steel sheet in the framework of fractional viscoplasticity, Thin-Walled Structures, ISSN: 0263-8231, DOI: 10.1016/j.tws.2019.106522, Vol.149, pp.106522-1-11, 2020
Szymczyk M., Nowak M., Sumelka W., Plastic strain localization in an extreme dynamic tension test of steel sheet in the framework of fractional viscoplasticity, Thin-Walled Structures, ISSN: 0263-8231, DOI: 10.1016/j.tws.2019.106522, Vol.149, pp.106522-1-11, 2020

Abstract:
The paper considers the plastic strain localization phenomenon in the framework of the fractional viscoplasticity. As an illustrative example, full spatial modelling of a tension test under extreme dynamic conditions is presented. The modelling assumes adiabatic conditions including isotropic work hardening-softening effects induced by plastic strains, temperature and damage (scalar). Special attention is paid to additional, compared to the classical Perzyna viscoplasticity, model parameters resulting from application of fractional calculus in the evolution law for plastic strains. It is shown that the proposed formulation allows for high flexibility of modelling of the localization zone with a limited number of model parameters.

Keywords:
fractional viscoplasticity, strain localization, extreme dynamics

(140p.)
10.Golasiński K.M., Pieczyska E.A., Maj M., Staszczak M., Świec P., Furuta T., Kuramoto S., Investigation of strain rate sensitivity of gum metal under tension using digital image correlation, ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1007/s43452-020-00055-9, Vol.20, No.2, pp.53-1-14, 2020
Golasiński K.M., Pieczyska E.A., Maj M., Staszczak M., Świec P., Furuta T., Kuramoto S., Investigation of strain rate sensitivity of gum metal under tension using digital image correlation, ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1007/s43452-020-00055-9, Vol.20, No.2, pp.53-1-14, 2020

Abstract:
Mechanical behavior of a multifunctional titanium alloy Gum Metal was investigated by conducting tensile tests at various strain rates and applying digital image correlation (DIC) technique. Stress–strain curves confirmed low Young's modulus and high strength of the alloy. The determined values of yield strength had a tendency to increase, whereas the elongation to the specimen rupture tended to decrease with increasing strain rate. True stress versus strain curves were analyzed using selected lengths of virtual extensometer (VE) placed in the strain localization area. When the initial length of the VE was the same as the gauge length, work hardening was observed macroscopically at lower strain rates, and a softening was seen at higher strain rates. However, the softening effect was not observed at the shorter VE lengths. Evolution of the Hencky strain and rate of deformation tensor component fields were analyzed for various strain rates at selected stages of Gum Metal loading. The DIC analysis demonstrated that for lower strain rates the deformation is macroscopically uniform up to the higher average Hencky strains, whereas for higher strain rates the strain localization occurs at the lower average Hencky strains of the deformation process and takes place in the smaller area. It was also found that for all strain rates applied, the maximal values of Hencky strain immediately before rupture of Gum Metal samples were similar for each of the applied strain rates, and the maximal local values of deformation rate were two orders higher when compared to applied average strain rate values.

Keywords:
titanium alloy, gum metal, strain rate sensitivity, strain localization, digital image correlation, full-field deformation analysis

(140p.)
11.Magliulo M., Lengiewicz J., Zilian A., Beex L.A.A., Non-localised contact between beams with circular and elliptical cross-sections, COMPUTATIONAL MECHANICS, ISSN: 0178-7675, DOI: 10.1007/s00466-020-01817-1, Vol.65, No.5, pp.1247-1266, 2020
Magliulo M., Lengiewicz J., Zilian A., Beex L.A.A., Non-localised contact between beams with circular and elliptical cross-sections, COMPUTATIONAL MECHANICS, ISSN: 0178-7675, DOI: 10.1007/s00466-020-01817-1, Vol.65, No.5, pp.1247-1266, 2020

Abstract:
The key novelty of this contribution is a dedicated technique to efficiently determine the distance (gap) function between parallel or almost parallel beams with circular and elliptical cross-sections. The technique consists of parametrizing the surfaces of the two beams in contact, fixing a point on the centroid line of one of the beams and searching for a constrained minimum distance between the surfaces (two variants are investigated). The resulting unilateral (frictionless) contact condition is then enforced with the Penalty method, which introduces compliance to the, otherwise rigid, beams' cross-sections. Two contact integration schemes are considered: the conventional slave-master approach (which is biased as the contact virtual work is only integrated over the slave surface) and the so-called two-half-pass approach (which is unbiased as the contact virtual work is integrated over the two contacting surfaces). Details of the finite element formulation, which is suitably implemented using Automatic Differentiation techniques, are presented. A set of numerical experiments shows the overall performance of the framework and allows a quantitative comparison of the investigated variants.

Keywords:
beams, contact, circular and elliptical cross-sections, rigid cross-sections, single-pass algorithm, two-half-pass algorithm

(100p.)
12.Ustrzycka A., Skoczeń B., Nowak M., Kurpaska Ł., Wyszkowska E., Jagielski J., Elastic–plastic-damage model of nano-indentation of the ion-irradiated 6061 aluminium alloy, INTERNATIONAL JOURNAL OF DAMAGE MECHANICS, ISSN: 1056-7895, DOI: 10.1177/1056789520906209, pp.1-35, 2020
Ustrzycka A., Skoczeń B., Nowak M., Kurpaska Ł., Wyszkowska E., Jagielski J., Elastic–plastic-damage model of nano-indentation of the ion-irradiated 6061 aluminium alloy, INTERNATIONAL JOURNAL OF DAMAGE MECHANICS, ISSN: 1056-7895, DOI: 10.1177/1056789520906209, pp.1-35, 2020

Abstract:
The paper presents experimental and numerical characterization of damage evolution for ion-irradiated materials subjected to plastic deformation during nano-indentation. Ion irradiation technique belongs to the methods where creation of radiation-induced defects is controlled with a high accuracy (including both, concentration and depth distribution control), and allows to obtain materials having a wide range of damage level, usually expressed in terms of displacements per atom (dpa) scale. Ion affected layers are usually thin, typically less than 1 micrometer thick. Such a low thickness requires to use nano-indentation technique to measure the mechanical properties of the irradiated layers. The He or Ar ion penetration depth reaches approximately 150 nm, which is sufficient to perform several loading-partial-unloading cycles at increasing forces. Damage evolution is reflected by the force-displacement diagram, that is backed by the stress–strain relation including damage. In this work the following approach is applied: dpa is obtained from physics (irradiation mechanisms), afterwards, the radiation-induced damage is defined in the framework of continuum damage mechanics to solve the problem of further evolution of damage fields under mechanical loads. The nature of radiation-induced damage is close to porosity because of formation of clusters of vacancies. The new mathematical relation between radiation damage (dpa) and porosity parameter is proposed. Deformation process experienced by the ion irradiated materials during the nano-indentation test is then numerically simulated by using extended Gurson–Tvergaard– Needleman (GTN) model, that accounts for the damage effects. The corresponding numerical results are validated by means of the experimental measurements. It turns out, that the GTN model quite successfully reflects closure of voids, and increase of material density during the nano-indentation.

Keywords:
radiation-induced damage, evolution of vacancy clusters, nano-indentation test, ion irradiation, radiation hardening

(100p.)
13.Krajewski M., Liou S.C., Chiou W.A., Tokarczyk M., Małolepszy A., Płocińska M., Witecka A., Lewińska S., Ślawska-Waniewska A., Amorphous FexCo1–x wire-like nanostructures manufactured through surfactant-free magnetic-field-induced synthesis, Crystal Growth and Design, ISSN: 1528-7483, DOI: 10.1021/acs.cgd.0c00070, Vol.20, No.5, pp.3208-3216, 2020
Krajewski M., Liou S.C., Chiou W.A., Tokarczyk M., Małolepszy A., Płocińska M., Witecka A., Lewińska S., Ślawska-Waniewska A., Amorphous FexCo1–x wire-like nanostructures manufactured through surfactant-free magnetic-field-induced synthesis, Crystal Growth and Design, ISSN: 1528-7483, DOI: 10.1021/acs.cgd.0c00070, Vol.20, No.5, pp.3208-3216, 2020

Abstract:
So far, it has been proven that the magnetic-field-induced (MFI) synthesis is a process which mainly leads to the formation of magnetic metallic one-dimensional nanostructures. Taking advantage of this method, the new procedures which allow manufacture of the magnetic bimetallic iron–cobalt wire-like nanochains with Fe0.75 Co0.25, Fe0.50 Co0.50, and Fe0.25 Co0.75 compositions are demonstrated in this work. They were produced through a simple one-step magnetic-field-induced (MFI) chemical co-reduction of three different mixtures containing a proper amount of Fe2+ and Co2+ ions with aqueous sodium borohydride solution as the reducing agent. The synthesis process was carried out at room temperature without the use of templates, surfactants, complexing agents, and organic solvents. The morphological and structural studies indicated that all as-prepared materials were amorphous, and they were composed of nanoparticles aligned in almost straight chains. Moreover, they revealed the core–shell structures with bimetallic alloy cores containing desired iron-to-cobalt ratios and very thin oxide shells. Furthermore, the obtained nanostructures behaved as ferromagnetic materials. Their magnetic properties were correlated with their structural properties and chemical compositions. It was observed that their saturation magnetization decreased significantly with increasing content of cobalt in the chains, whereas the variation of their coercivity was less pronounced.

(100p.)
14.Jarząbek D.M., Harvey C., Levintant-Zayonts N., Wojciechowski T., Gniadek M., Krajewski M., Pathak S., Enhancement of mechanical properties of vertically aligned carbon nanotube arrays due to N+ ion irradiation, NANOTECHNOLOGY, ISSN: 0957-4484, DOI: 10.1088/1361-6528/ab8665, Vol.31, No.28, pp.285703-1-9, 2020
Jarząbek D.M., Harvey C., Levintant-Zayonts N., Wojciechowski T., Gniadek M., Krajewski M., Pathak S., Enhancement of mechanical properties of vertically aligned carbon nanotube arrays due to N+ ion irradiation, NANOTECHNOLOGY, ISSN: 0957-4484, DOI: 10.1088/1361-6528/ab8665, Vol.31, No.28, pp.285703-1-9, 2020

Abstract:
In this work we apply N+ ion irradiation on vertically aligned carbon nanotube (VACNT) arrays in order to increase the number of connections and joints in the CNT network. The ions energy was 50 keV and fluence 5 × 10^17 ions cm^−2. The film was 160 μm thick. SEM images revealed the ion irradiation altered the carbon bonding and created a sponge-like, brittle structure at the surface of the film, with the ion irradiation damage region extending ~4 μm in depth. TEM images showed the brittle structure consists of amorphous carbon forming between nanotubes. The significant enhancement of mechanical properties of the irradiated sample studied by the cyclic nanoindentation with a flat punch indenter was observed. Irradiation on the VACNT film made the structure stiffer, resulted in a higher percentage recovery, and reduced the energy dissipation under compression. The results are encouraging for further studies which will lead to create a class of materials - ion-irradiated VACNT films - which after further research may find application in storage or harvesting energy at the micro/nanoscale.

Keywords:
vertically aligned carbon nanotubes, ion irradiation, nanoindentation

(100p.)
15.Lee B.Y., Chu C.T., Krajewski M., Michalska M., Lin J.Y., Temperature-controlled synthesis of spinel lithium nickel manganese oxide cathode materials for lithium-ion batteries, CERAMICS INTERNATIONAL, ISSN: 0272-8842, DOI: 10.1016/j.ceramint.2020.05.124, Vol.46, No.13, pp.20856-20864, 2020
Lee B.Y., Chu C.T., Krajewski M., Michalska M., Lin J.Y., Temperature-controlled synthesis of spinel lithium nickel manganese oxide cathode materials for lithium-ion batteries, CERAMICS INTERNATIONAL, ISSN: 0272-8842, DOI: 10.1016/j.ceramint.2020.05.124, Vol.46, No.13, pp.20856-20864, 2020

Abstract:
In this work, we successfully synthesized series of LiNi0.5Mn1.5O4 (LNMO) cathode materials with spinel structure by using a facile sol-gel method and then calcined at various temperature ranging from 600 to 1000 °C. The application of different calcination temperatures significantly influenced the surface morphology, stoichiometry and crystalline nature of the as-synthesized LNMO material. According to the results of physical characterizations, the LNMO materials calcined at various temperatures mainly revealed the stoichiometric disordered Fd-3m structure with a small amount of well-ordered P4332 phase. The structural analysis also exhibited that the control of the calcination temperature contributed to the higher crystalline nature. Moreover, the morphological investigations indicated that the increasing calcination temperatures caused the formation of large micron-sized LNMO material. In turn, the electrochemical evaluations revealed the impact of the calcination temperatures on enhancing the electrochemical performances of the LNMO electrode materials up to 900 °C. The LNMO electrode calcined at 900 °C exhibited an impressive initial discharge specific capacity of ca. 142 mAh g^−1 between 3.5 and 4.9 V vs. Li/Li+, and remarkably improved capacity retention of 97% over 50 cycles. Those excellent electrochemical properties were associated with the presence of the dominant Fd-3m phase over the P4332 phase. Additionally, the results of the corrosion and dissolution tests which were performed for all calcined LNMO materials in order to estimate the amount of manganese and nickel ions leached from them, proved that the micro-sized LNMO calcined at 900 °C was the most stable.

Keywords:
spinel LiNi0.5Mn1.5O4, sol-gel synthesis, calcination temperature, cathode material, lithium-ion batteries

(100p.)
16.Mościcki T., Psiuk R., Słomińska H., Levintant-Zayonts N., Garbiec D., Pisarek M., Bazarnik P., Nosewicz S., Chrzanowska-Giżyńska J., Influence of overstoichiometric boron and titanium addition on the properties of RF magnetron sputtered tungsten borides, SURFACE AND COATINGS TECHNOLOGY, ISSN: 0257-8972, DOI: 10.1016/j.surfcoat.2020.125689, Vol.390, pp.125689-1-12, 2020
Mościcki T., Psiuk R., Słomińska H., Levintant-Zayonts N., Garbiec D., Pisarek M., Bazarnik P., Nosewicz S., Chrzanowska-Giżyńska J., Influence of overstoichiometric boron and titanium addition on the properties of RF magnetron sputtered tungsten borides, SURFACE AND COATINGS TECHNOLOGY, ISSN: 0257-8972, DOI: 10.1016/j.surfcoat.2020.125689, Vol.390, pp.125689-1-12, 2020

Abstract:
In this work, (W,Ti)B2 films with different stoichiometric ratio Ti/W deposited on silicon and 304 stainless steel by radio frequency magnetron sputtering are presented. The coatings were deposited from plasma spark sintered targets obtained from the mixture of pure boron, tungsten and titanium powders. It is shown that during plasma spark sintering process using overstoichiometric boron and a low content of titanium change the WB2 to WB4 phase with almost no secondary phases. Subsequently, the impact of titanium content on the films properties is investigated systematically, including the chemical and phase composition, crystalline structure, surface and cross-section morphology. Simultaneously, nano-indentation test and ball-on-disk tribometery are performed to analyse the hardness and tribological properties of the films. It is shown that deposited films with titanium content of 3.6 and 5.5 at.% are formed in the zone T of the Thornton's Structural Zone Model. In opposite to α-WB2 magnetron sputtered coatings they are more flexible and hard nanocomposite coatings. The results show that the addition of titanium is apparently changing the film structure from nanocrystalline columnar to amorphous, very dense and compact structure with the addition of TiB2 phase. That films are simultaneously hard (H > 37.5 GPa), have high hardness to effective Young's modulus ratio values (H/E* > 0.1) and elastic recovery (We > 60%) appropriate for tough and resistant to cracking materials. The presented (W,Ti)B2 films exhibit also tribological and corrosion properties better than unalloyed coatings.

Keywords:
superhard films, ternary tungsten borides, RF magnetron sputtering, wear resistance, corrosion

(100p.)
17.Muszalski J., Sankowska I., Kucharski S., Nanoindentation of GaAs/AlAs distributed bragg reflector grown on GaAs substrate, Materials Science in Semiconductor Processing, ISSN: 1369-8001, DOI: 10.1016/j.mssp.2020.104912, Vol.109, pp.104912-1-8, 2020
Muszalski J., Sankowska I., Kucharski S., Nanoindentation of GaAs/AlAs distributed bragg reflector grown on GaAs substrate, Materials Science in Semiconductor Processing, ISSN: 1369-8001, DOI: 10.1016/j.mssp.2020.104912, Vol.109, pp.104912-1-8, 2020

Abstract:
Nanoindentation was used to investigate the mechanical parameters of GaAs/AlAs Distributed Bragg Reflectors. Such heterostructures are commonly employed in surface-emitting optoelectronic devices as LED or lasers. The investigation was carried for fully pseudomorphic AlAs/GaAs heterostructures and compared with bulk GaAs. The nanoindentation tests with sharp (Vickers) and spherical tip were conducted, and pop-in events were observed. We show that below pop-in load, the response of both materials is similar i.e., elastic parameters of the heterostructure and GaAs are practically the same. However, the pop-in events take place at higher loads for heterostructures than for GaAs. This in turn indicates that the heterostructure has a higher resistance to damage. For both materials, the pop-in load depends on loading rate. The possible mechanisms of pop-in are discussed. In the elastic-plastic stage (after pop-in), the heterostructure exhibits lower stiffness and lower hardness than GaAs does. The surface cracks that are generated in the heterostructure during the indentation test continue to grow even when the load is removed.

(70p.)
18.Krajewski M., Tokarczyk M., Stefaniuk T., Słomińska H., Małolepszy A., Kowalski G., Lewińska S., Ślawska-Waniewska A., Magnetic-field-induced synthesis of amorphous iron-nickel wire-like nanostructures, MATERIALS CHEMISTRY AND PHYSICS, ISSN: 0254-0584, DOI: 10.1016/j.matchemphys.2020.122812, Vol.246, pp.122812-1-7, 2020
Krajewski M., Tokarczyk M., Stefaniuk T., Słomińska H., Małolepszy A., Kowalski G., Lewińska S., Ślawska-Waniewska A., Magnetic-field-induced synthesis of amorphous iron-nickel wire-like nanostructures, MATERIALS CHEMISTRY AND PHYSICS, ISSN: 0254-0584, DOI: 10.1016/j.matchemphys.2020.122812, Vol.246, pp.122812-1-7, 2020

Abstract:
Manufacturing process of wire-like binary or ternary metal nanoalloys applying the magnetic-field-induced (MFI) synthesis is still a challenging task. Hence, this work demonstrates for the first time how to produce the iron-nickel wire-like nanostruc-tures with Fe0.75Ni0.25, Fe0.5Ni0.5 and Fe0.25Ni0.75 compositions. In a contrary to the previously reported synthesis of the Fe-Ni wire-like nanomaterials, this process has been carried out at room temperature without employment of templates, surfactants, organic solvents, and other chemical additives. The as-prepared samples exhibit specific structures with the amorphous bimetallic alloy cores covered by thin amorphous oxide shells. Moreover, they are composed of nanoparticles which are aligned in nearly linear chains. The Fe-Ni samples are ferromagnetic materials. Their coercivity values and saturation magnetizations depend on chemical compositions and dimensions of the investigated chains. The highest saturation magnetization and the lowest coercivity is found for the material with the lowest content of nickel and vice versa.

Keywords:
amorphous materials, Fe–Ni chains, magnetic-field-induced synthesis, magnetic materials, wire-like nanostructure

(70p.)
19.Krajewski M., Tokarczyk M., Witecka A., Lewińska S., Ślawska-Waniewska A., Płocińska M., Towards magnetic bimetallic wire-like nanostructures ‒ magnetic field as growth parameter, ACTA PHYSICA POLONICA A, ISSN: 0587-4246, DOI: 10.12693/APhysPolA.137.59, Vol.137, No.1, pp.59-61, 2020
Krajewski M., Tokarczyk M., Witecka A., Lewińska S., Ślawska-Waniewska A., Płocińska M., Towards magnetic bimetallic wire-like nanostructures ‒ magnetic field as growth parameter, ACTA PHYSICA POLONICA A, ISSN: 0587-4246, DOI: 10.12693/APhysPolA.137.59, Vol.137, No.1, pp.59-61, 2020

Abstract:
The magnetically-assisted growth of the amorphous bimetallic iron–nickel wire-like nanostructures is presented in this work. The applied process is based on a simple reduction reaction of aqueous solutions containing Fe2+ and Ni2+ ions with NaBH4 in the presence of an external magnetic field of about 0.05 T. The morphology, chemical composition, and magnetic properties of as-prepared Fe–Ni nanostructures have been determined by means of scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffractometry, and vibrating sample magnetometry. The obtained experimental data indicate that the as-prepared samples exhibit quite complex architectures i.e., they comprise of nanoparticles aligned in almost straight lines. In addition, they reveal the typical core-shell structures where the amorphous bimetallic alloy cores are covered by thin amorphous oxide shells. In turn, the magnetic measurements show that the Fe–Ni wire-like nanostructures behave as typical ferromagnetic nanomaterials and their magnetic parameters like saturation magnetizations and coercivities are strictly dependent on their sizes and chemical compositions.

Keywords:
amorphous materials, bimetallic nanostructures, magnetic-field-induced synthesis, magneticmaterials, wire-like nanostructures

(40p.)
20.Pęcherski R.B., Rusinek A., Frąś T., Nowak M., Nowak Z., Energy-based yield condition for orthotropic materials exhibiting asymmetry of elastic range, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.24425/amm.2020.132819, Vol.65, No.2, pp.771-778, 2020
Pęcherski R.B., Rusinek A., Frąś T., Nowak M., Nowak Z., Energy-based yield condition for orthotropic materials exhibiting asymmetry of elastic range, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.24425/amm.2020.132819, Vol.65, No.2, pp.771-778, 2020

Abstract:
The aim of the paper is to formulate physically well founded yield condition for initially anisotropic solids revealing the asymmetry of elastic range. The initial anisotropy occurs in material primarily due to thermo-mechanical pre-processing and plastic deformation during the manufacturing processes. Therefore, materials in the "as-received" state become usually anisotropic. After short account of the known limit criteria for anisotropic solids and discussion of mathematical preliminaries the energy-based criterion for orthotropic materials was formulated and confronted with experimental data and numerical predictions of other theories. Finally, possible simplifications are discussed and certain model of isotropic material with yield condition accounting for a correction of shear strength due to initial anisotropy is presented. The experimental verification is provided and the comparison with existing approach based on the transformed-tensor method is discussed.

Keywords:
energy-based yield condition, orthotropic solids, initial anisotropy, strength differential effect, numerical simulation

(40p.)