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.Ranachowski Z., Ranachowski P., Dębowski T., Brodecki A., Kopeć M., Roskosz M., Fryczowski K., Szymków M., Krawczyk E., Schabowicz K., Mechanical and non-destructive testing of plasterboards subjected to a hydration process, Materials, ISSN: 1996-1944, DOI: 10.3390/ma13102405, Vol.13, No.10, pp.2405-1-18, 2020
Ranachowski Z., Ranachowski P., Dębowski T., Brodecki A., Kopeć M., Roskosz M., Fryczowski K., Szymków M., Krawczyk E., Schabowicz K., Mechanical and non-destructive testing of plasterboards subjected to a hydration process, Materials, ISSN: 1996-1944, DOI: 10.3390/ma13102405, Vol.13, No.10, pp.2405-1-18, 2020

Abstract:
The aim of this study was to investigate the effect of plasterboards' humidity absorption on their performance. Specimens' hydration procedure consisted of consecutive immersing in water and subsequent drying at room temperature. Such a procedure was performed to increase the content of moisture within the material volume. The microstructural observations of five different plasterboard types were performed through optical and scanning electron microscopy. The deterioration of their properties was evaluated by using a three-point bending test and a subsequent ultrasonic (ultrasound testing (UT)) longitudinal wave velocity measurement. Depending on the material porosity, a loss of UT wave velocity from 6% to 35% and a considerable decrease in material strength from 70% to 80% were observed. Four types of approximated formulae were proposed to describe the dependence of UT wave velocity on board moisture content. It was found that the proposed UT method could be successfully used for the on-site monitoring of plasterboards' hydration processes.

Keywords:
plasterboards, moisture content, hydration processes, mechanical properties, ultrasound measurements

(140p.)
2.Kopeć M., Jóźwiak S., Kowalewski Z.L., A novel microstructural evolution model for growth of ultra-fine Al2O3 oxides from SiO2 silica ceramic decomposition during self-propagated high-temperature synthesis, Materials, ISSN: 1996-1944, DOI: 10.3390/ma13122821, Vol.13, No.12, pp.2821-1-11, 2020
Kopeć M., Jóźwiak S., Kowalewski Z.L., A novel microstructural evolution model for growth of ultra-fine Al2O3 oxides from SiO2 silica ceramic decomposition during self-propagated high-temperature synthesis, Materials, ISSN: 1996-1944, DOI: 10.3390/ma13122821, Vol.13, No.12, pp.2821-1-11, 2020

Abstract:
In this paper, experimental verification of the microstructural evolution model during sintering of aluminum, iron and particulate mullite ceramic powders using self-propagated high-temperature synthesis (SHS) was performed. The powder mixture with 20% wt. content of reinforcing ceramic was investigated throughout this research. The mixed powders were cold pressed and sintered in a vacuum at 1030 °C. The SHS reaction between sintered feed powders resulted in a rapid temperature increase from the heat generated. The temperature increase led to the melting of an aluminum-based metallic liquid. The metallic liquid infiltrated the porous SiO2 ceramics. Silicon atoms were transited into the intermetallic iron-aluminum matrix. Subsequently, a ternary matrix from the Fe-Al-Si system was formed, and synthesis of the oxygen and aluminum occurred. Synthesis of both these elements resulted in formation of new, fine Al2O3 precipitates in the volume of matrix. The proposed microstructural evolution model for growth of ultra-fine Al2O3 oxides from SiO2 silica ceramic decomposition during SHS was successfully verified through scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS) analysis and X-ray diffraction (XRD).

Keywords:
intermetallics, powder methods, electron microscopy, X-ray analysis

(140p.)
3.Maździarz M., Mościcki T., New zirconium diboride polymorphs—first-principles calculations, Materials, ISSN: 1996-1944, DOI: 10.3390/ma13133022, Vol.13, No.13, pp.3022-1-13, 2020
Maździarz M., Mościcki T., New zirconium diboride polymorphs—first-principles calculations, Materials, ISSN: 1996-1944, DOI: 10.3390/ma13133022, Vol.13, No.13, pp.3022-1-13, 2020

Abstract:
Two new hypothetical zirconium diboride (ZrB 2) polymorphs: (hP6-P6 3 /mmc-space group, no. 194) and (oP6-Pmmn-space group, no. 59), were thoroughly studied under the first-principles density functional theory calculations from the structural, mechanical and thermodynamic properties point of view. The proposed phases are thermodynamically stable (negative formation enthalpy). Studies of mechanical properties indicate that new polymorphs are less hard than the known phase (hP3-P6/mmm-space group, no. 191) and are not brittle. Analysis of phonon band structure and density of states (DOS) also show that the phonon modes have positive frequencies everywhere and the new ZrB 2 phases are not only mechanically but also dynamically stable. The estimated acoustic Debye temperature, ΘD, for the two new proposed ZrB 2 phases is about 760 K. The thermodynamic properties such as internal energy, free energy, entropy and constant-volume specific heat are also presented.

Keywords:
zirconium diboride, ab initio calculations, mechanical properties, elastic properties, phonons

(140p.)
4.Wang K., Kopeć M., Chang S., Qu B., Liu J., Politis D.J., Wang L., Liu G., Enhanced formability and forming efficiency for two-phase titanium alloys by fast light alloys stamping technology (FAST), Materials & Design, ISSN: 0264-1275, DOI: 10.1016/j.matdes.2020.108948, pp.1-25, 2020
Wang K., Kopeć M., Chang S., Qu B., Liu J., Politis D.J., Wang L., Liu G., Enhanced formability and forming efficiency for two-phase titanium alloys by fast light alloys stamping technology (FAST), Materials & Design, ISSN: 0264-1275, DOI: 10.1016/j.matdes.2020.108948, pp.1-25, 2020

Abstract:
During hot stamping of titanium alloys, insufficient forming temperatures result in limited material formability, whereas temperatures approaching the β phase transus also result in reduced formability due to phase transformation, grain coarsening and oxidation during the long-time heating. To solve this problem, Fast light Alloys Stamping Technology (FAST) is proposed in this paper, where fast heating is employed. Effects of heating parameters on the formability and post-form strength were studied by tensile tests. Forming of a wing stiffener was performed to validate this new process. Results show that microstructure of TC4 alloy after fast heating was in nonequilibrium state, which could enhance ductility significantly compared with the equilibrium state. When TC4 alloy was first heated to 950 °C with heating rate of 100 °C/s and then cooled to 700 °C, the elongation at 700 °C was more than 3 times that of a slow heating rate with soaking. Nano-scaled martensite with high dislocation density transformed from β phase was observed under fast heating condition. A complex shaped wing stiffener was successfully formed from TC4 titanium alloy in less than 70 s including heating, transfer and forming, and the post-form strength was almost the same with the initial blank.

Keywords:
titanium alloys, fast heating, hot stamping, formability, post-form strength

(140p.)
5.Tabin J., Skoczeń B., Bielski J., Discontinuous plastic flow in superconducting multifilament composites, INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, ISSN: 0020-7683, DOI: 10.1016/j.ijsolstr.2020.05.033, Vol.202, pp.12-27, 2020
Tabin J., Skoczeń B., Bielski J., Discontinuous plastic flow in superconducting multifilament composites, INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, ISSN: 0020-7683, DOI: 10.1016/j.ijsolstr.2020.05.033, Vol.202, pp.12-27, 2020

Abstract:
Modern superconducting intermetallic materials (e.g. NbTi, Nb3Sn) are used to build conductors composed of a matrix and the superconductor strands. One of the most popular materials for matrix is copper, because of its excellent physical and mechanical properties at extremely low temperatures. Ductile OFE copper stabilizes, on one hand, the mechanical response of brittle superconductor strands and, on the other hand, takes over the electrical charge in case of quench (resistive transition). Thus, the composite structure of modern conductors used to build the coils of superconducting magnets is fully justified. Such a composite structure results in common deformation of the matrix and the strands when winding the coils and during the operation, when the coils are subjected to the prestress and to the Lorentz forces at extremely low temperatures (liquid or superfluid helium). When the loads are large enough, the copper-superconductor strands composite is subjected to inelastic deformation, including moderately large plastic strains. It is known, that copper and superconductor strands exhibit the so-called discontinuous plastic flow (DPF) at extremely low temperatures, that results in abrupt drops of stress against strain of different amplitude and frequency. In order to describe correctly the behaviour of composite superconductors at extremely low temperatures, a constitutive model of DPF has been developed and applied to both components: matrix and strands. The results of numerical analysis are compared with the experiments, carried out in dedicated cryostat containing liquid helium and the relevant instruments.

Keywords:
superconductor, plastic deformation, cryogenic temperatures, constitutive model

(140p.)
6.Liu X., Kopeć M., Fakir O., Qu H., Wang Y., Wang L., Li Z., Characterisation of the interfacial heat transfer coefficient in hot stamping of titanium alloys, International Communications in Heat and Mass Transfer, ISSN: 0735-1933, DOI: 10.1016/j.icheatmasstransfer.2020.104535, Vol.113, pp.104535-1-14, 2020
Liu X., Kopeć M., Fakir O., Qu H., Wang Y., Wang L., Li Z., Characterisation of the interfacial heat transfer coefficient in hot stamping of titanium alloys, International Communications in Heat and Mass Transfer, ISSN: 0735-1933, DOI: 10.1016/j.icheatmasstransfer.2020.104535, Vol.113, pp.104535-1-14, 2020

Abstract:
The interfacial heat transfer coefficient (IHTC) for titanium alloys is an important parameter in non-isothermal hot stamping processes to determine the temperature field as well as temperature-dependent material behaviours that consequently affect the post-form properties of the formed components. However, the IHTC for titanium alloys in hot stamping processes has seldom been studied before. In the present research, the effects of contact pressure, lubricant, surface roughness, tooling material and initial blank temperature on the IHTC for the titanium alloy Ti-6Al-4V were studied and modelled to characterise the IHTC values under various hot stamping conditions as well as identify the functional mechanisms affecting the IHTC. Furthermore, the results of hot stamping of Ti-6Al4V wing stiffener components were used to verify the simulation results of the temperature field of the formed component with an error of less than 5%.

Keywords:
interfacial heat transfer coefficient (IHTC), Ti-6Al-4V, hot stamping, experimental validation

(140p.)
7.Jóźwiak-Niedźwiedzka D., Antolik A., Dziedzic K., Gméling K., Bogusz K., Laboratory investigations on fine aggregates used for concrete pavements due to the risk of ASR, Road Materials and Pavement Design, ISSN: 1468-0629, DOI: 10.1080/14680629.2020.1796767, pp.1-13, 2020
Jóźwiak-Niedźwiedzka D., Antolik A., Dziedzic K., Gméling K., Bogusz K., Laboratory investigations on fine aggregates used for concrete pavements due to the risk of ASR, Road Materials and Pavement Design, ISSN: 1468-0629, DOI: 10.1080/14680629.2020.1796767, pp.1-13, 2020

Abstract:
The assessment of the aggregate suitability for concrete pavements applies mainly to coarse aggregate. However, even fine aggregate can significantly affect the long-term durability of concrete when it is susceptible to alkali-silica reaction (ASR). The sustainable use of available fine aggregates for the production of concrete, while reducing the effects of ASR, requires special preventive measures. The paper proposed different procedures to determine the chemical composition of aggregate and the related ASR risk. The study covers various properties of natural fine aggregates from glacial deposits. The experiments included determination of chemical composition by prompt gamma activation analysis (PGAA), quantitative mineralogical characterisation on thin sections using digital image procedure (DIP) and expansion measurements in mortar bar test (MBT). The strong correlation of sand origin and its susceptibility to ASR was observed. Content of micro- and cryptocrystalline quartz in siliceous sand was found to have a crucial effect on its performance in AMBT.

Keywords:
fine aggregate, alkali-silica reaction, mineral composition, prompt gamma activation analysis, digital image procedure, glacial deposit

(140p.)
8.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.)
9.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.)
10.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.)
11.Jarosik P., Klimonda Z., Lewandowski M., Byra M., Breast lesion classification based on ultrasonic radio-frequency signals using convolutional neural networks, Biocybernetics and Biomedical Engineering, ISSN: 0208-5216, DOI: 10.1016/j.bbe.2020.04.002, Vol.40, No.3, pp.977-986, 2020
Jarosik P., Klimonda Z., Lewandowski M., Byra M., Breast lesion classification based on ultrasonic radio-frequency signals using convolutional neural networks, Biocybernetics and Biomedical Engineering, ISSN: 0208-5216, DOI: 10.1016/j.bbe.2020.04.002, Vol.40, No.3, pp.977-986, 2020

Abstract:
We propose a novel approach to breast mass classification based on deep learning models that utilize raw radio-frequency (RF) ultrasound (US) signals. US images, typically displayed by US scanners and used to develop computer-aided diagnosis systems, are reconstructed using raw RF data. However, information related to physical properties of tissues present in RF signals is partially lost due to the irreversible compression necessary to make raw data readable to the human eye. To utilize the information present in raw US data, we develop deep learning models that can automatically process small 2D patches of RF signals and their amplitude samples. We compare our approach with classification method based on the Nakagami parameter, a widely used quantitative US technique utilizing RF data amplitude samples. Our better performing deep learning model, trained using RF signals and their envelope samples, achieved good classification performance, with the area under the receiver attaining operating characteristic curve (AUC) and balanced accuracy of 0.772 and 0.710, respectively. The proposed method significantly outperformed the Nakagami parameter-based classifier, which achieved AUC and accuracy of 0.64 and 0.611, respectively. The developed deep learning models were used to generate parametric maps illustrating the level of mass malignancy. Our study presents the feasibility of using RF data for the development of deep learning breast mass classification models.

Keywords:
breast lesion classification, convolutional neural networks, deep learning, radio-frequency signals, ultrasound imaging

(100p.)
12.Yakymechko Y., Lutsyuk I., Jaskulski R., Dulnik J., Kropyvnytska T., The effect of vibro-activation time on the properties of highly active calcium hydroxide, Buildings, ISSN: 2075-5309, DOI: 10.3390/buildings10060111, Vol.10, No.6, pp.111-1-8, 2020
Yakymechko Y., Lutsyuk I., Jaskulski R., Dulnik J., Kropyvnytska T., The effect of vibro-activation time on the properties of highly active calcium hydroxide, Buildings, ISSN: 2075-5309, DOI: 10.3390/buildings10060111, Vol.10, No.6, pp.111-1-8, 2020

Abstract:
The results of studying the effect of the vibration processing time on the size of calcium hydroxide particles are given. The physicochemical processes affecting the size and morphology of calcium hydroxide particles have been studied. A stage-by-stage mechanism of the process of the carbonation of lime, depending on its specific surface, is established. The results show that the optimal period for the vibration treatment of lime to obtain the most active material is 20 min. A longer period of vibration results in the merging of particles into larger agglomerates.

Keywords:
lime, portlandite, vibration treatment, carbonation, crystallization

(70p.)
13.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.)
14.Dziedzic K., Dąbrowski M., Antolik A., Glinicki A., Characteristics of concrete mix air-entrainment applying the sequential pressure method / Charakterystyka napowietrzenia mieszanki betonowej metodą sekwencyjno-cioenieniową, Roads and Bridges - Drogi i Mosty, ISSN: 1643-1618, DOI: 10.7409/rabdim.020.007, Vol.19, No.2, pp.107-118, 2020
Dziedzic K., Dąbrowski M., Antolik A., Glinicki A., Characteristics of concrete mix air-entrainment applying the sequential pressure method / Charakterystyka napowietrzenia mieszanki betonowej metodą sekwencyjno-cioenieniową, Roads and Bridges - Drogi i Mosty, ISSN: 1643-1618, DOI: 10.7409/rabdim.020.007, Vol.19, No.2, pp.107-118, 2020

Abstract:
The purpose of introducing air into the concrete mix is to increase the freeze-thaw and scaling resistance of hardened concrete. The utility of the sequential pressure method (Super Air Meter - SAM) for assessment of the air entrainment quality was verified by comparing the results obtained with this method with the results of the air-void analysis of hardened concrete. The results of the tests carried out on mixes designed and produced at a laboratory and the mixes produced on an industrial scale during expressway construction are considered. Furthermore, the relationships between the SAM number and the micro air-void content A300 in hardened concrete and the freeze-thaw and de-icing salt resistance are analysed as part of this research. A clear co-relation between the SAM number, a parameter that characterises the air-entrainment of the concrete mix, and the microvoid content has been demonstrated.
Napowietrzenie mieszanki betonowej stosuje się w celu podwyższenia mrozoodporności betonu i jego odporności na złuszczenia powierzchniowe. Przeprowadzono badania możliwości charakteryzowania jakości napowietrzenia mieszanki betonowej za pomocą pomiarów metodą sekwencyjno-ciśnieniową, oceniając zgodność jej wyników z wynikami pomiaru charakterystyki porów w betonie stwardniałym. Przedstawiono wyniki badań mieszanek zaprojektowanych i wykonanych w laboratorium, jak i mieszanek wykonanych przemysłowo na budowie drogi ekspresowej. Analizowano relację tzw. liczby SAM mieszanki betonowej w odniesieniu do zawartości mikroporów A300 w stwardniałym betonie oraz odporności na cykliczne działanie mrozu w obecności soli odladzających. Wykazano wyraźną korelację między parametrem charakteryzującym napowietrzenie mieszanki betonowej (liczba SAM) a zawartością mikroporów w betonie stwardniałym.

Keywords:
air-entrainment, air-void parameters, concrete, freeze-thaw resistance, microvoid content, sequential pressure method, surface scaling / beton, charakterystyka porów, metoda sekwencyjno-cioenieniowa, mrozoodporność, napowietrzenie, zawartość mikroporów, złuszczenia powierzchniowe

(40p.)
15.Makowska K., Kowalewski Z.L., Variation of Barkhausen noise, magnetic and crystal structure of ferromagnetic medium-carbon steel after different loading processes, PHYSICS OF METALS AND METALLOGRAPHY, ISSN: 0031-918X, DOI: 10.1134/S0031918X20020118, Vol.121, No.2, pp.115-122, 2020
Makowska K., Kowalewski Z.L., Variation of Barkhausen noise, magnetic and crystal structure of ferromagnetic medium-carbon steel after different loading processes, PHYSICS OF METALS AND METALLOGRAPHY, ISSN: 0031-918X, DOI: 10.1134/S0031918X20020118, Vol.121, No.2, pp.115-122, 2020

Abstract:
The article presents variations of rms Barkhausen noise envelopes in the medium-carbon steel used in automotive and power industry. The material was subjected to different loading processes: monotonic loading at room temperature, and constant loading at elevated temperature. The first one enforced a plastic deformation, whereas the second one a creep. The changes of Barkhausen signal were analysed using microstructural observations including X-ray measurements. In the second part of the paper, the magnetic structure and pinning effect were illustrated by means of the Lorentz microscopy.

Keywords:
Barkhausen noise, magnetic structure, plastic deformation, creep, dislocation density

(40p.)
16.Fantilli A.P., Jóźwiak-Niedźwiedzka D., Influence of Portland cement alkalinity on wool reinforced mortar, Proceedings of the Institution of Civil Engineers - Construction Materials, ISSN: 1747-650X, DOI: 10.1680/jcoma.20.00003, pp.1-10, 2020
Fantilli A.P., Jóźwiak-Niedźwiedzka D., Influence of Portland cement alkalinity on wool reinforced mortar, Proceedings of the Institution of Civil Engineers - Construction Materials, ISSN: 1747-650X, DOI: 10.1680/jcoma.20.00003, pp.1-10, 2020

Abstract:
Natural wool is a good insulating material, both thermal and acoustic. Nevertheless, with the increase in demand for the use of waste materials, other applications, such as the use of wool as a fibre-reinforcement in mortars and concretes, have been found. Unfortunately, wool, like other natural organic materials, dissolve in alkaline environment and, consequently, the performances of the reinforcement cannot be guaranteed for a long time. To solve the above issue, three series of reinforced mortar beams, with various contents of alkalis in cement, are investigated herein. The chemical compatibility, and the effects of alkalinity on the mechanical performances, are investigated by testing the beams in three point bending and, subsequently, by analysing the microstructure of the mortars through a scanning electron microscope equipped with energy dispersive X-ray spectroscopy. The results reveal that the lower the alkalinity of the cement paste, the better the resistance of wool fibres in cementitious matrix, which guarantees larger post-cracking residual stresses in the wool reinforced mortars.

Keywords:
fibre-reinforcement, fracture & fracture mechanics, microstructure, waste valorisation

(40p.)
17.Papliński P., Wańkowicz J., Śmietanka H., Ranachowski P., Ranachowski Z., Kúdela Jr S., Aleksiejuk M., Comparative studies on degradation of varistors subjected to operation in surge arresters and surge arrester counters, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.24425/amm.2020.131739, Vol.65, No.1, pp.367-374, 2020
Papliński P., Wańkowicz J., Śmietanka H., Ranachowski P., Ranachowski Z., Kúdela Jr S., Aleksiejuk M., Comparative studies on degradation of varistors subjected to operation in surge arresters and surge arrester counters, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.24425/amm.2020.131739, Vol.65, No.1, pp.367-374, 2020

Abstract:
The paper presents results of investigation of microstructure and micro-hardness for material of ZnO varistors applied to 110 kV surge arrester and surge arrester counter. The research combined two pairs of varistors, each consisted of one varistor subjected before to operation, while the other one was brand new unit and constituted a reference. All varistors were made of the same material by the reputable manufacture. The tests revealed a different degree of the material degradation for varistors subjected before to operation. This also refers to different degradation mechanism observed for the material of these varistors, if typical effects of degradation of aged ZnO varistors were considered as a reference. Physical state of spinel in the microstructure had a significant impact on the material degradation, however a considerable loosening of the microstructure associated with bismuth oxide was observed too. It was surprising, since the precipitates of the bismuth oxide phase most often showed very good binding to the ZnO matrix and high resistance to associated electrical, thermal and mechanical effects. The degradation effects in the ZnO matrix proved to be limited only.

Keywords:
surge arrester, surge arrester counter, MO varistors, microstructure of ceramics, ceramic material degradation

(40p.)
18.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.)
19.Ranachowski Z., Ranachowski P., Brodecki A., Kopeć M., Kúdela Jr S., Quasi-static and dynamic testing of carbon fiber reinforced magnesium composites, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.24425/amm.2020.132836, Vol.65, No.2, pp.893-899, 2020
Ranachowski Z., Ranachowski P., Brodecki A., Kopeć M., Kúdela Jr S., Quasi-static and dynamic testing of carbon fiber reinforced magnesium composites, ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.24425/amm.2020.132836, Vol.65, No.2, pp.893-899, 2020

Abstract:
Two types of composites, consisting of pure magnesium matrix reinforced with two commercially used carbon fibers, were systematically studied in this paper. The composites fabricated by the pressure infiltration method, were subjected to quasistatic and dynamic compression tests. Morphology of fiber strands was observed using scanning electron microscope (SEM). The application of carbon fibre reinforcement led to the stiffening of tested materials, resulting in the limitation of the possible compression to approx. 2.5%. The performed tests revealed the remarkable difference in compression strength of investigated compositions. The cause of that effect was that GRANOC fiber reinforced composite exhibited insufficient bond quality between the brittle fibers and the ductile matrix. T300 reinforced composite presented good connection between reinforcement and matrix resulting in increased mechanical properties. Investigated composites demonstrated higher mechanical strength during deformation at high strain rates. Microscopic observations also proved that the latter fibers with regular shape and dense packaging within the filaments are proper reinforcement when designing the lightweight composite material.

Keywords:
Mg matrix composite, compressive properties, carbon fiber, Split-Hopkinson pressure bar

(40p.)
20.Chmielak W.S., Paczkowski R., Papliński P., Piątek Z., Ranachowski P., Ranachowski Z., Śmietanka H., Ocena jakości mikrostruktury warystora poprzez pomiar wyższych harmonicznych w prądzie, PRZEGLĄD ELEKTROTECHNICZNY, ISSN: 0033-2097, DOI: 10.15199/48.2020.01.10, Vol.96, No.1, pp.39-43, 2020
Chmielak W.S., Paczkowski R., Papliński P., Piątek Z., Ranachowski P., Ranachowski Z., Śmietanka H., Ocena jakości mikrostruktury warystora poprzez pomiar wyższych harmonicznych w prądzie, PRZEGLĄD ELEKTROTECHNICZNY, ISSN: 0033-2097, DOI: 10.15199/48.2020.01.10, Vol.96, No.1, pp.39-43, 2020

Abstract:
Celem prezentowanej pracy było znalezienie zależności pomiędzy parametrami mikrostruktury warystorów, a prądem płynącym przez ogranicznik przepięć dla różnych poziomów napięcia. Badania zostały wykonane na losowo wybranej populacji beziskiernikowych ograniczników przepięć w osłonach polimerowych, przeznaczonych do pracy w sieci średniego napięcia. Wykonano pomiary przebiegów referencyjnych dla badanej populacji ograniczników. Przyjęto jako kryterium oceny udział wyższych harmonicznych w przebiegu prądu. Praca stanowi wstęp do szerszego zakresu badań, prowadzonych w ramach wspólnych działań laboratoriów Instytutu Energetyki i Instytutu Podstawowych Problemów Techniki PAN.

Keywords:
beziskiernikowy ogranicznik przepięć, warystor ZnO, mikrostruktura ceramiki, analiza FFT

(20p.)
21.Kúdela Jr S., Bajana O., Orovčík L., Ranachowski P., Ranachowski Z., Alloying effect of Li and Y on the strengthening of Mg/T300 composites, KOVOVE MATERIALY-METALLIC MATERIALS, ISSN: 0023-432X, DOI: 10.4149/km_2020_3_151, Vol.58, No.3, pp.151-159, 2020
Kúdela Jr S., Bajana O., Orovčík L., Ranachowski P., Ranachowski Z., Alloying effect of Li and Y on the strengthening of Mg/T300 composites, KOVOVE MATERIALY-METALLIC MATERIALS, ISSN: 0023-432X, DOI: 10.4149/km_2020_3_151, Vol.58, No.3, pp.151-159, 2020

Abstract:
Composite materials based on MgLi and MgY matrices reinforced with unidirectional T300 carbon fibres (45 vol.%) have been prepared by gas pressure infiltration technique. Nominal Li and Y alloying of Mg matrix were 0.5, 2, and 4 wt.% Li and 7, 13, and 20 wt.% Y, respectively. Back-scattered electron (BSE) observations and electron dispersive X-ray (EDX) analysis have revealed that penetration of lithium and formation of lithium carbide Li2C2 inside carbon fibres took place. Bending tests have shown that low Li alloying of Mg matrix (0.5 and 2 wt.% Li) has a favourable effect on the strength of MgLi/T300 composites. Higher Li content (4 wt.% Li) brings a much lower composite strengthening presumably due to degradation of carbon fibres with Li2C2. A negative effect of high yttrium alloying on the strength of MgY/T300 composites is explained by poor adherence of YC2 interfacial layer to carbon fibres.

Keywords:
magnesium matrix, magnesium composites, magnesium-lithium matrix, magnesium-lithium composites, magnesium-yttrium matrix, magnesium-yttrium composites, lithium carbide, yttrium carbide, reactive wetting

(20p.)