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The aim of this work was to investigate the possibility of doping copper sulfide Cu2S with selected fifth-group elements, potentially having a positive effect on the thermoelectric properties of the resulting materials. For the selected model structures, theoretical calculations and an analysis of the electronic structure and changes in the enthalpy of formation due to doping were performed using the WIEN2k package employing the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) method within density functional theory (DFT) formalism. Polycrystalline materials with the nominal composition of Cu32S15X1 (X = P, As, Sb, Bi) were synthesized in quartz ampoules, then sintered using the spark plasma sintering (SPS) technique and "SPS melting" method. The chemical and phase compositions of the obtained sinters were studied by X-Ray diffraction (XRD) and scanning electron microscopy (SEM). Additionally, investigations of thermoelectric properties, i.e., electrical conductivity, Seebeck coefficient and thermal conductivity in the temperature range 300–920 K, were performed. The results of this study indicate that only phosphorus is successfully incorporated into the Cu₂S structure. [ABSTRACT FROM AUTHOR]

In this work, the electrocaloric effect (ECE) and electrocaloric strength (ΔT/E) were measured and thermal and dielectric studies were performed on Pb-modified BaTiO3 (BPT). The saturated hysteresis loops and normal ferroelectric behavior of the ferroelectric ceramics allow the utilization of the indirect method to estimate the electrocaloric properties. The electrocaloric measurements were performed under high (18 kV/cm) versus low (8 kV/cm) electric field conditions. These conditions were chosen to notice and then eliminate an artificial negative electrocaloric effect in the tested ceramics. At the same time, relatively high values of positive electrocaloric temperature change ΔT ( ~   2.19   K ) and electrocaloric strength ΔT/E ( ~ 0.27–0.11 K · cm/kV) were obtained. [ABSTRACT FROM AUTHOR]

K0.5Na0.5NbO3:xEu sol–gel powders and bulk samples were synthesized by means of a modified sol–gel method. Two types of samples were obtained via sintering at two temperatures. X-ray diffraction revealed the presence of the perovskite phase in materials obtained at both temperatures. Eu3+ emission and excitation studies were conducted to determine its luminescence response. For K0.5Na0.5NbO3:xEu sinters, the excitation spectra included narrow peaks in the VIS range due to the 5D0–7F1 and 5D0–7F2 relaxation processes. These transitions were indicative of the presence of Eu3+ at sites of low symmetry. Dielectric studies indicated that Eu2O3 affected the observed phase transitions. The influence of sintering temperature on structure and physicochemical properties was discussed. [ABSTRACT FROM AUTHOR]

This research explores the welding process of a high-entropy CrMnFeCoNi alloy with iron, unraveling the intricate chemical compositions that materialize in distinct regions of the weld joint. A mid-wave infrared thermal camera was deployed to monitor the cooling sequences during welding. A thorough analysis of the metallographic sample from the weld joint, along with measurements taken using a nano-hardness indenter, provided insights into the hardness and Young's modulus. The element distribution across the weld joint was assessed using a scanning electron microscope equipped with an EDS spectrometer. Advanced techniques such as X-ray diffraction and Mössbauer spectroscopy underscored the prevalence of the martensitic phase within the weld joint, accompanied by the presence of bcc (iron) and fcc phases. In contrast, Young's modulus in the base metal areas displayed typical values for a high-entropy alloy (202 GPa) and iron (204 GPa). The weld joint material displayed substantial chemical heterogeneity, leading to noticeable concentration gradients of individual elements. The higher hardness noted in the weld (up to 420 HV), when compared to the base metal regions (up to 290 HV for CrMnFeCoNi alloy and approximately 150 HV for iron), can be ascribed to the dominance of the martensitic phase. These findings provide valuable insights for scenarios involving diverse welded joints containing high-entropy alloys, contributing to our understanding of materials engineering. [ABSTRACT FROM AUTHOR]

This work presents the microstructure and properties of two‐phase amorphous melt‐spun alloys ejected from the crucible with partition between liquids. The microstructure was studied by scanning electron microscopy and transmission electron microscopy and the phase composition was studied by X‐ray diffraction. The thermal stability of the alloys was determined using differential scanning calorimetry. The microstructure study proves that the composite alloys are heterogeneous because of the existence of the two amorphous phases obtained due to the use of a partition between the liquids. This microstructure correlates with complex thermal characteristics not found in homogeneous alloys of the same nominal composition. The layered structure of these composites influences the formation of fractures during tensile tests. LAY DESCRIPTION: The aim of this investigation is to present the special features and properties of the glassy two‐component melt‐spun alloys in comparison to the melt‐spun alloys ejected from single‐chamber crucible. The studies of the composite microstructure were performed using transmission electron microscopy and scanning electron microscopy. The alloys also were heated to elevated temperatures and their characteristics were studied by means of differential scanning calorimetry. The phase composition of the alloys was investigated using X‐ray diffraction. The results of the microstructure examination show that these alloys are heterogeneous due to the production method. The special feature of the alloys is that they essentially inherit the transformations possible to occur in the precursor alloys after amorphisation of the these precursors. Results of thermal analysis also confirm the occurrence of transformations of the regions from the transition zones of the intermediate compositions between the two main constituents A and B. These transformations are found to be similar to the transformations identified in the amorphous alloys of the averaged compositions, that is, the homogeneous chemical compositions that are possible for obtaining, when alloys A and B are molten together to form a single liquid phase before ejection into a spinning cylinder. Unique feature of these composite alloys is lamellar morphology. This microstructure consists mainly of the stripes/layers of precursor alloys A and B that are inserted into each chamber of the two‐chamber crucibles. After ejection of the alloys into the surface of the spinning cooper wheel, they form the microstructure of the layered morphology. This band‐like morphology affects formation of the ductile fracture. Actually, this relationship is confirmed by observation of the fracture surfaces of the composite samples. The scanning electron microscopy observations with mappings of the chemical composition performed for all of the composite ribbons show that their microstructure consists of the layers of differentiated chemical compositions parallel to the surface of the ribbon. The arrangement of vein‐like pattern of the fractures coincides with the boundaries between the regions of the differentiated chemical compositions. [ABSTRACT FROM AUTHOR]

In this paper, physicochemical properties of pure Y2O3 and samarium (Sm)-doped Y2O3 transparent ceramics obtained via arc plasma melting are presented. Yttria powder with a selected molar fraction of Sm was first synthesized by a solid-state reaction method. High transparent yttria ceramics were obtained by arc plasma melting from both the pure and Sm oxide-doped powders. The morphological, chemical and physical properties were investigated by X-ray diffraction and scanning electron microscopy. The optical band gap was calculated from the absorption spectra so as to understand the electronic band structure of the studied materials. Samples indicate a series of luminescence bands in the visible region after excitation by laser light in the range from 210 to 250 nm. Magneto-optical measurements were carried out in the 300–800 nm range at room temperature. It can be seen that a maximum Verdet constant ca. 24.81 deg/T cm was observed for 405 nm and this value decreases with increasing wavelength. The potential usefulness of the polycrystalline material dedicated to optics devices is presented. [ABSTRACT FROM AUTHOR]

The aim of the article is to present the role of a father in a child upbringing in the early school age. The paper consists of theoretical and research parts. The first part describes father’s role as an educator in child’s life, the influence of the father’s values on child’s upbringing, the father’s authority and reasons for father’s absence in child’s life. The second part presents analysis of the research results. Seven children of early school aged have participated in the study. The methods used in the study were observation, interviews with supervising teacher and document analysis. The subject of the study was the relationship of the father with the early school-age child. The influence of the father’s participation in the child’s upbringing on the child’s self-esteem and perception of reality was being examined. The effect of father’s absence on the child’s behavior and self-esteem was being analyzed. The study showed a relationship between father’s participation in child upbringing and high or inflated self-esteem and the child’s positive attitude towards reality. The relationship between father’s absence and lowered self-esteem of the subjects was presented. [ABSTRACT FROM AUTHOR]

There is a problem in obtaining a suitable impact strength of the padding weld after cladding with a martensitic filler metal. Too low annealing temperature below 580°C and the excessive annealing temperature above 650°C do not provide adequate impact strength of the padding weld. A heat treatment technology for mixed joints has been developed based on the results of the microscopic observations, X-ray diffraction measurements and transmission electron microscope examination. The problem was identified and a special technology of heat treatment for the dissimilar joint was elaborated. This technology provides a high impact resistance of the padding weld and an appropriate properties of the base material. [ABSTRACT FROM AUTHOR]

The paper presents the results of the investigation of microstructure of the welded X5CrNiCuNb16-4 (17-4PH) steel after solution treatment and aging at 620°C for different periods. The microstructure and the phase composition of the steel was investigated using light microscopy (LM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM) and the X-ray diffraction (XRD). Hardness was measured for samples aged at different times. Density distributions of Cu precipitates were established. The investigation has shown that the microstructure of the X5CrNiCuNb16-4 steel welds after aging at 620 ° C consists of tempered martensite, fine Cu precipitates and austenite. It was observed that the size of the Cu precipitates increases with increasing the aging time, what affects the decrease of hardness. Simultaneously, the quantity of reversed austenite increases with increase of aging time. It was revealed that enrichment of the austenite in Ni, Cu and C affects the increase of Ms, but this factor does not determine the stability of austenite. [ABSTRACT FROM AUTHOR]

In this work, a mid infrared thermography was used to study thermal behavior of solid oxide fuel cell (SOFC) with a circular shape and a diameter of 90 mm. The emissivity of the anodic surface of the fuel cell was determined to be from 0.95 to 0.46 in the temperature range 550-1200 K and the profile and temperature distribution of the anodic surface of the unloaded cell was given. The surface temperature of the cell was determined during operation and the polarity changes from open circuit voltage (OCV) to 0.0 V. It was found that the cell self-heating effect decreases with increasing temperature of the cell. [ABSTRACT FROM AUTHOR]

The aim of this work was to investigate the possibility of obtaining an amorphous/crystalline composite starting from Ni-Si- B-based powder grade 1559-40 and silver powder. The alloy was produced using arc melting of 95% wt. Ni-Si-B-based powder (1559-40) and 5% wt. Ag powder. Ingot was re-melted on a copper plate and observed while cooling using a mid-wave infra-red camera. The alloy was then melt-spun in a helium atmosphere. The microstructure of the ingot as well as the melt-spun ribbon was studied using light microscopy and scanning electron microscopy with energy dispersive spectrometry. Phase identification was performed by means of X-ray diffraction. The observations confirmed an amorphous/crystalline microstructure of the ribbon where the predominant constituent of the microstructure was an amorphous phase enriched with Ni, Si, and B, while the minor constituent was an Ag-rich crystalline phase distributed in a film along the melt-spinning direction. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Metallurgy & Materials is the property of Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this work was to investigate the microstructure and mechanical properties of the two-component melt-spun (TCMS) alloy produced from Ni40Fe40B20 and Ni70Cu10P20 melts. The Ni40Fe40B20, Ni70Cu10P20, Ni55Fe20Cu5P10B10 alloys were arc-melted. Then the alloys were melt-spun in the two different ways i.e.: by casting from a single-chamber crucible and from the two-chamber crucible. All of the above mentioned alloys were processed in the first way and the Ni40Fe40B20 and Ni70Cu10P20 were simultaneously cast on the copper roller from the two-chamber crucible. The microstructure of the alloy was studied using transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS) and light microscopy. The mechanical properties were investigated using tensile testing and nanoindentation. The two-component melt-spun (TCMS) amorphous Ni55Fe20Cu5P10B10 alloy present hardness, tensile strength and Young modulus on the significantly higher level than for a single phase amorphous Ni55Fe20Cu5P10B10 alloy and slightly below the corresponding values for the Ni40Fe40B20. [ABSTRACT FROM AUTHOR]

The aim of this study was to reveal the influence of the heat treatment after welding of 17-7PH (X7CrNiAl17-7) steel on the microstructure evolution and the texture of the welds. Microstructure investigation carried out by light microscopy and transmission electron microscopy showed that the austenite and δferrite coexist in as-welded condition. Annealing at the temperature range between 400 °C and 620 °C after welding causes small changes in the microstructure and the hardness of the welds increases. Heat treatment at 760 °C for 1 h resulted in the partial destabilization of the austenite. Aging after destabilization leads to tempering of the martensite: first the hardness increases and then decreases. The maximum hardness is observed when the ageing temperature reaches 510 °C. XRD studies confirmed the presence of the two phases: δ ferrite and austenite. Annealing at 400 °C/1 h and 550 °C/1 h results in changes of the intensities for individual peaks derived from austenite and ferrite. The calculated ratios of peak intensity were compared with the intensities of the reference sample. The differences in intensities suggested strong texture of the material. [ABSTRACT FROM AUTHOR]

The article presents the results of Transvarestraint test of a modern precipitation hardened steel X10CrNiCuNb18-9-3 with copper. For comparison, the results of tests of conventional steel without the addition of copper X5CrNi18-10 are presented. The total length of all cracks and the maximum length of cracks were measured. The study of microstructure (LM, SEM) showed that the austenitic stainless steel X10CrNiCuNb18-9-3 is very prone to hot cracking. After performing the Transvarestraint tests three types of cracks were observed: solidification cracks occurring during crystallization, liquation cracks due to segregation in the heat affected zone (HAZ) and surface cracks. Niobium carbonitrides dispersed in the bands of segregation are the reason of high susceptibility to liquation cracking. Segregation of copper occurring during solidification causes of surface cracking. A combined effect of copper and stresses contributes to formation of hot microcracks. These microcracks propagate to a depth of 20-30 μm. [ABSTRACT FROM AUTHOR]

Positron annihilation studies of aluminium alloys with nanodispersions of insoluble elements, i.e., In, Sn, Pb and Au were reported. The alloys were obtained using a rapid solidification process. For all alloys, except that with Au, the average diameter of nanoparticles in aluminium matrix was 100 nm, and variance of the size distribution was above 50 nm. Positron annihilation studies reveal the presence of monovacancies or divacancies, which were located at the interface between nanoparticles and the matrix. In the as-cast reference pure aluminium sample as well as the aluminium and gold alloy dislocations were identified as well. The isothermal annealing of the obtained alloys and measurement of the annihilation characteristic, i.e., S-parameter, allow us to determine the activation energy of grain boundary migration, which for the alloys was higher by the factor of four than for the reference sample. The measurements of friction parameters for the alloys confirmed the results reported by the other authors that, the friction coefficient was lower by the factor of about two and the specific wear rate was by the factor of about fifty higher than the reference sample. The present study confirmed the attractive positron affinity of the nanoparticles of In, Sn, Pb and Au compared to aluminium matrix. [ABSTRACT FROM AUTHOR]

The aim of this work was to investigate the features of microstructure, phase composition, mechanical properties, and thermal stability of the two-component melt-spun Ni55Fe20Cu5P10B10 alloy. The development of the microstructure after heating to elevated temperatures was studied using scanning electron microscope and in situ high temperature X-ray diffraction. The high-temperature behavior of the two-component melt-spun Ni55Fe20Cu5P10B10 alloy and Ni40Fe40B20, Ni70Cu10P20, and Ni55Fe20Cu5P10B10 alloys melt-spun from single-chamber crucible was investigated using differential scanning calorymetry at different heating rates and by dynamic mechanical thermal analysis. The results show that band-like microstructure of the composite alloy is stable even at 800 K, although coarsening of bands forming the microstructure of the ribbons is observed above 550 K. Plastic deformation is observed in the composite previously heated to temperatures of 600–650 K. The properties of the composite alloy are generally different than the properties obtained for the melt-spun alloy of the same average nominal composition produced traditionally. Additionally, the mechanical and the thermal properties in this composite are inherited from the amorphous state of alloys that are precursors for two-component melt spinning (TCMS) processing. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Metallurgy & Materials is the property of Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper reviews the results of investigations on how post-weld heat treatment (PWHT) influences the hardness and microstructures of welded joints in stainless steel X3Cr-NiMo 13-4. It is known that welding leads to high segregation of components in the solidification process, which has an influence on phase transitions in PWHT. The investigated steel has a very narrow PWHT range, about 600-620°C, which provides optimum levels of hardness and toughness. Excessive annealing temperature leads to decreased toughness, which in turn causes exceeding of the Ac1 temperature in the segregation range, which then leads to increased 'fresh' martensite content. [ABSTRACT FROM AUTHOR]

The article presents a study on the role of hydrogen in weld cracking processes. It mentions that hydrogen's effect on steel properties causes chevron cracking, welded joint cracking, and fish-eye cracking. Reasons for creation mechanism in non-alloy and low-alloy steels include the presence of low-alloy phases and high strain in high temperatures. Moreover, hydrogen emissions creates a gas layer between crystallines during the solidification process.

This paper shows the results of welding tests used so far on high-temperature creep resistant steels and new bainitic and martensitic steels. The positive results of this research allowed the elaboration of a welding procedure specification that was ultimately approved by TUV. This then allowed the SEFAKO Company to attempt welding of the latest generation boiler steels for use under heavy conditions. [ABSTRACT FROM AUTHOR]

The work presents the microstructure characterization of the new (Fe, Ni)–Cu–(P, Si, B) melt-spun glass forming alloys investigated by means of transmission electron microscope. The results are compared with the data obtained by other complementary methods such as XRD and Mössbauer spectroscopy. The phases occurring during the crystallization of the glassy matrix are identified and characterized in terms of a long-range order and a short-range order. The thermal stability of the alloy is characterized by differential scanning calorimetry. The study describes the mechanical and magnetic properties of the new alloys at room temperature as well as characteristics resulting from heating the as-cast melt-spun alloy at elevated temperatures. The changes of the properties of the alloy at elevated temperatures are correlated with the microstructural changes. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the cracking of welded joints at elevated temperatures. The precipitation of sigma phase, an iron-chromium intermetallic compound, in steel structures is described. It is inferred that the presence of intermetallic compound in welded joints reduces the ductility and impact-resistance properties.

The aim of this work was to obtain dense Cu2S superionic thermoelectric materials, homogeneous in terms of phase and chemical composition, using a very fast and cheap induction-melting technique. The chemical composition was investigated via scanning electron microscopy (SEM) combined with an energy-dispersive spectroscopy (EDS) method, and the phase composition was established by X-ray diffraction (XRD). The thermoelectric figure of merit ZT was determined on the basis of thermoelectric transport properties, i.e., Seebeck coefficient, electrical and thermal conductivity in the temperature range of 300–923 K. The obtained values of the ZT parameter are comparable with those obtained using the induction hot pressing (IHP) technique and about 30–45% higher in the temperature range of 773–923 K in comparison with Cu2S samples densified with the spark plasma sintering (SPS) technique. [ABSTRACT FROM AUTHOR]

The paper presents research results of the influence of heat input into high carbon rail steel during cutting processes on microstructure transformation and cracking. The massive block of steel prepared for rail rolling processes was cut and examined by nondestructive magnetic testing and destructive testing by microscopic examination and hardness measurements. The results show unfavorable microstructure changes where pearlite and transformed ledeburite were obtained. The effects of the presence of such microstructures are high hardness near to cutting surfaces (above 800 HV) and microcracks which grow into low hardness block cores during rolling and rail shaping. [ABSTRACT FROM AUTHOR]

In the article the author presents the problem of real-time demonstrative robot control with the use of computer. It includes information on up-to-date knowledge on digital control of actuators being the key components of e.g. robots and description of up-to-date status of technology within the scope of design and production support with the use of computer. The paper includes the examples of using a robot in teaching. [ABSTRACT FROM AUTHOR]