Thermodynamic description of the Fe-B-C system in its iron-rich corner is developed in the context of a new Fe-B-X (X = Cr, Ni, Mn, Si, Ti, V, C) database. The thermodynamic parameters of the binary sub-systems, Fe-B, Fe-C and B-C, are taken from earlier assessments modifying the B-C description. The parameters of the Fe-B-C system are optimized in this study using experimental thermodynamic and phase equilibrium data from the literature. Liquid, beta-rhombo-B and graphite phases are described using the substitutional solution model, while the ferrite (bcc), the austenite (fcc), the cementite (M3C) and the M23C6 phases are described with the sublattice model and the borides, Fe2B, FeB and B4C, are treated as stoichiometric phases. A good correlation was obtained between the calculated and the experimental thermodynamic and phase equilibrium data. The description is recommended to be used at the composition region of wt% C + wt% B < 15 and at temperatures below 2700oC.

The Nb-Si based in-situ composite was produced by resistive sintering (RS) technique. In order to identify present phases, X-ray diffraction (XRD) analysis was used on the composite. XRD analysis revealed that the composite was composed of Nb solid solution (Nbss) and α-Nb5Si3 phases. The microstructure of the composite was characterized by using a scanning electron microscope (SEM). The energy-dispersive spectroscopy (EDS) was performed for the micro-analysis of the chemical species. SEM-EDS analyses show that the microstructure of composite consists of Nbss, Nb5Si3 and small volume fraction of Ti-rich Nbss phases. The micro hardness of constituent phases of the composite was found to be as 593±19 and 1408±33 Hv0.1, respectively and its relative density was % 98.54.

The paper presents the effect of deformation temperature on the mechanical stability of retained austenite in a multiphase TRIP steel. Series of static tensile tests were carried out in the temperature range –20 to 140°C in order to simulate the temperatures occurring during stamping process of automotive steel sheets and conditions of their exploitation. Samples deformed at 20°C and 60°C showed the best combination of strength and ductility. It was related to the gradual transformation of retained austenite into martensite. Obtained results revealed that the intensity of TRIP effect is significantly related to the deformation temperature. The amount of retained austenite, which transformed into martensite during plastic deformation decreases as the deformation temperature increases. It was also found that the stability of retained austenite depends on its morphology. The obtained results showed the relationship between deformation temperature and the stability of retained austenite. The chemical composition and microstructure of multiphase steels dedicated to the automotive industry should be designed for providing the maximum TRIP effect at the specific deformation temperatures.

The paper presents the results of the electrodeposition of nickel composite coatings reinforced with the nano size SiC ceramic particles. The type and size of the ceramic particles or organic additives used play a important role during electrodeposition processes. A Watts type galvanic bath with various organic additives was used. These additives were: 2-sulfobenzoic acid imide, dioctyl sulfosuccinate sodium salt (DSS), sodium dodecyl sulfate, tris (hydroxymethyl) aminomethane and hexamethyldisilizane. The nickel composite coating was electrodeposited on a 2xxx aluminum alloy series substrate (EN-AW 2017) with zinc interlayer. The work concerns the determination of the impact of the change in the zeta potential of SiC nanoceramic particles used on properties of composite coatings (wear resistance, corrosion, etc.). The paper characterized the composite nickel coatings on aluminum alloy using SEM techniques, wear resistance tests by TABER method and coating adhesion to the substrate using the “scratch test” method. The corrosion resistance of coatings was also tested using electrochemical methods. The research allowed to determine the effect of SiC nanoceramic particle size on the value of the zeta potential in the model KCl solution.

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.

In this work, gel-casting of foams method was used to produce ZrO2 porous ceramics. The obtained foams with total porosity of 89.5 vol% were composed of approximately spherical cells having the mean diameter of 537 ± 153 μm interconnected by circular cell windows having the mean diameter of 152 ± 82 μm. Next, the ZrO2 foams were coated with fluorapatite (FA) and hydroxyapatite (HA) layers by slurry infiltration. The intermediate fluorapatite (FA) layer was introduced to prevent the chemical reactions between ZrO2 and HA at high temperatures during sintering process. The ZrO2 samples containing only HA coatings, were also tested, for comparison. The obtained ceramic biomaterials were subjected to in vitro tests in the simulated body fluid (SBF) solution. The results show that the ZrO2 foams with FA/HA layers possessed better bioactivity than the foams with the HA/HA coating.

Crystal structure and phase composition of stainless steel substrates (AISI 304 type) was studied and it was found that they adopted the cubic symmetry. The calculated elementary cell parameter for the mayor Fe-Ni phase (weight fraction 99%) was a = 3.593 Å, whereas the mean grain size was <D> = 2932 Å. Morphology of the stainless steel substrate surface was studied with profilometry. Mechanical properties of the stainless steel substrates and stainless steel substrates coated with ceramic layer of barium strontium titanate were studied with microhardness tester. For measurements performed according to the Vickers method the average microhardness was found HV = 189 or HV = 186 for the “in-line” and “mapping” measurement pattern, respectively. The sol-gel method was used to coat the surface of the stainless steel substrate with a thin ceramic layer of the chemical composition Ba0.6Sr0.4TiO3. It was found that the stainless steel substrate covered with sol-gel deposited ceramic coating exhibited the average hardness within the range HV = 217 up to HV = 235 for loading force F = 98 mN and F = 0.98 N, respectively. The Knopp method was also used and it was found that the stainless steel substrate with Ba0.6Sr0.4TiO3 coating exhibited hardness HK = 386.

It has been shown that the precipitation of bismuth orthovanadate from a fly ash leachate is a promising method of vanadium recovery. BiVO4 obtained after appropriate heat treatment can be sold as a pigment. The yield of recovery of solubilised vanadium is equal to 68% and the precipitate is free from nickel impurity. The precipitate is insoluble in the solutions with pH ≥ 3. In more acidic media the solubility of precipitate increases with the decreasing pH. The solubility of the precipitate increases also with the increasing concentration of chloride ions.

The paper describes modification to Fm3–m (space group no. 225) lattice of aluminium based α-solid solution observed in Zn-Al alloys required to properly correlate quantitative data from X-ray diffraction analysis with results obtained from quantitative scanning electron microscopy image analysis and those predicted from Zn-Al binary phase diagram. Results suggests that 14 at.% of Zn as a solute atom should be introduced in crystal lattice of aluminium to obtain correct estimation of phase quantities determined by quantitative X-ray diffraction analysis. It was shown that this modification holds for Cu mould cast as well as annealed and water-cooled samples of Zn-3wt.%. Al and Zn-5wt.% Al.

Production processes of hot forging most often look similar [1-3]. Forging in several operations, usually in three or four. Most often the first operation is upsetting or flattening (sometimes rolling). The last operation is finishing forging. This applies to the production of steel forgings for the automotive, agricultural and other similar industries. Typical production proceeds as follows: the forgings are cleaned (shot-blasted) and then heat treatment is performed. It can be normalization, hardening and tempering, etc. After the heat treatment, forgings are checked and subjected to strength and microscopic tests, hardness tests, impact tests. The type of tests depends on the recipient. The process described in the work takes place in three operations. The heat treatment used so far is hardening and tempering. An attempt was made to change the heat treatment technology for a selected product made of 42CrMo4 steel (1.7225) (4140). An isothermal annealing test was carried out at different temperatures and for different times. The possibility of using heat from the forging process in heat treatment processes for the described product has been confirmed.

This paper presents the results of obtaining and investigations of Pb1–xBax(Zr1–yTiy)1–zSnzO3 (PBZTS) ceramics with constant x = 0.03 and y = 0.02, and variable z = 0, 0.04, 0.06 and 0.08 (abbreviations of the samples were following PBZTS0, PBZTS4, PBZTS6, PBZTS8, respectively). The investigated compositions are close to rhombohedral-orthorhombic morphotropic phase boundary. The ceramic samples have been obtained by conventional ceramic technology from simple oxides PbO, ZrO2, TiO2, SnO2 and barium carbonate BaCO3. The ceramic powders, after calcination, have been pressed into discs and sintered using free sintering (FS) method. For samples obtained in such a way, the dielectric properties at various frequencies and electrical conductivity have been investigated. The increase of Sn content orders the microstructure of ceramics, and as a result the improvement of the dielectric properties of ceramic samples can be obtained.

The present research is focused on the characterization of the composites from Al2O3-Cu-Ni system. Two methods of ceramic-metal composite forming were applied: uniaxial powder pressing and Pulse Plasma Sintering (PPS). To obtain the samples the powder mixtures containing 85 vol.% of Al2O3 and 15 vol.% of metal powders were used. Influence of the sintering process on microstructure and mechanical properties of the two series of the composites was analyzed in detail. The selected physical properties of samples were characterized by Archimedes immersion method. Vickers hardness and the fracture toughness of the composites was determined as well. The microstructure of the composites was characterized by XRD, SEM, EDX. Fractography investigation was carried out as well. Independently on composite production method Al2O3, Cu, Ni, and CuNi phases were revealed. Fractography investigation results revealed different character of fracture in dependence of fabrication method. Pulse Plasma Sintered samples were characterized by higher crack resistance and higher Vickers hardness in comparison to the specimens manufactured by uniaxial pressing.

Polycrystalline samples BaTiO3 and the solid solutions Ba0.9Sr0.1TiO3, Ba0.9Sr0.1Ti0.9Sn0.1O3, Ba0.9Sr0.1Ti0.8Sn0.2O3 were obtained by means of a mechanochemical treatment based on the high-energy ball milling technique and next a high temperature solid state reaction method. The influence of synthesis condition on microstructural, dielectric and ferroelectric properties of obtained solid solutions were investigated. The structure and morphology of the investigated samples were characterized by an X-ray diffraction (XRD) and scanning electron microscopy (SEM). The characterization of electrical properties of the ceramics within the temperature range from –130°C to 250°C were performed by means of a dielectric spectroscopy method at the frequency ranging from 0.1 Hz to 10 MHz. The diffusion of the paraelectric – ferroelectric phase transition and dielectric relaxation for ceramic samples are described.

In the paper the multiferroic (ferroelectric-ferromagnetic) composites based on ferroelectromagnetic/ferroelectric (BaFe1/2Nb1/2O3 (BFN)) powder and ferrite powder (zinc-nickel ferrite) were obtained by two technological methods. In the composite samples the ratio of the ferroelectromagnetic/ferroelectric powder to the magnetic powder was equal to 90:10. The ceramic powders were synthesized by the classical technological method using powder calcination/solid state synthesis, while densification of the composite powders (sintering) was carried by two different methods: (i) Free Sintering method (FS), and (ii) Spark Plasma Sintering (SPS).

At the work, a comparison of measurement results for composite samples obtained by two sintering methods was made. The studies included the following analysis: DTA, XRD, SEM, DC electrical conductivity, electric permittivity and magnetic properties. The result of measurements presented in the work revealed that the ceramic composite obtained by two different technological sintering method (classical technology – Free Sintering method and Spark Plasma Sintering technique) can be promising lead-free materials for functional applications, for example in sensors for magnetic and electric field.

Bismuth niobate (BiNbO4) ceramics were fabricated by mixed oxide method and sintered by presureless sintering method. BiNbO4 ceramics doped with V2O5 additive in amount 0.125 wt%, 0.250 wt% and 1 wt% of was sintered at T = 910°C whereas BiNbO4 ceramics doped with 2 wt% of CuO additive was sintered at T = 890°C and T = 910°C. It was found that V2O5 additive improved morphology of the ceramic samples. However, the chemical composition of BiNbO4 ceramics in relation to bismuth oxide and niobium oxide manifested a tendency of lack of Bi2O3 component. Absorption bands for the BiNbO4 compound were identified. FTIR band positions associated with NbO6 octahedra suggested that the crystal structure changes after V2O5 incorporation.

Goal of the present research was to apply a solid state reaction route to fabricate bismuth layer-structured multiferroic ceramics described with the formula Bi5FeTi3O15 and reveal the influence of processing conditions on its crystal structure and phase composition. Simple oxide powders Bi2O3, TiO2 and Fe2O3 were used to fabricate Aurivillius-type bismuth layer-structured ferroelectrics. Pressureless sintering in ambient air was employed and the sintering temperature was TS = 900°C, TS = 1000°C and TS = 1040°C. The phase composition as well as crystal structure of ceramics sintered at various processing conditions was examined with powder X-ray diffraction method at room temperature. The Rietveld refinement method was applied for analysis of X-ray diffraction data. It was found that ceramics adopted orthorhombic structure Cmc21. The unit cell parameters of bismuth layer-structured multiferroic ceramics increased slightly with an increase in sintering temperature.

This paper presents the results of experimental studies and numerical simulations of the ratcheting for the PA6 aluminum. In the initial determination of the material hardening parameters, the samples were subjected to the symmetrical strain-controlled cyclic tension-compression test. The experimental stress-strain curve was compared with the numerical one obtained for non-linear Frederick-Armstrong and Voce models. For better fitting of both curves, the optimization procedure based on the least-square method and the fuzzy logic was applied. After establishing the hardening parameters, numerical simulations of the ratcheting were made. The boundary value problem was solved by means of discrete analysis. The data (force and displacement) obtained in numerical computations were used to control the ratchetting experiment. The results of experiments and numerical calculations were compared. Good convergence proves the reliability of the determination of material hardening data.

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.

Thin films of crystallized LaCoO3 were grown on Si substrate by Pulsed Laser Deposition at different temperatures (750°C, 850°C and 1000°C). The structural characterization of the LaCoO3 thin films was done by combining several techniques: Scanning Electron Microscopy (SEM), Atomic Force Microscope (AFM), Transmission Electron Microscopy (TEM) and Grazing Incidence X-Ray Diffraction (GIXRD). The thin films crystallized in the expected rhombohedral phase whatever the deposition temperature, with an increase of crystallite size from 70 nm at 750°C to 100 nm at 1000°C, and an average thickness of the thin films of less than 200 nm. At 850°C and 1000°C, the thin films are crack-free, and with a lower number of droplets than the film deposited at 750°C. The grains of LaCoO3 film deposited at 850°C are columnar, with a triangular termination. At 1000°C, an intermediate layer of La2Si2O7 was observed, indicating diffusion of Si into the deposited film.

Traditional press and sinter processes have gained in the last decades more and more importance in the manufacturing of high volume and precise mechanical components especially in the field of iron based powders. In recent years, the reductions of processing times and temperatures were spotted as critical targets to increase productivity and reduce energy consumption. Electric current assisted sintering (ECAS) technologies have always been seen as an alternative to traditional furnace based sintering techniques and have been the target of different researches with the specific purpose of reducing both operational times and costs. The aim of the present study is to investigate the effect of an innovative process called Electro Sinter Forging (ESF) applied to CuSn15 powders. Thanks to a very short processing time (less than 1 second to densify loose powders), this process is able to retain a very small grain size, thus enhancing mechanical properties of the processed materials. Furthermore, to the authors knowledge, cold – rolled electro – sinter – forged alloys has never been investigated before. First of all, bars were electro – sinter – forged and subsequently characterized in the as sinter – forged condition. The observation of microstructure evidenced an extremely fine microstructure and a reduced degree of porosity. Afterwards, bars were cold rolled after different reduction ratios; macrostructural integrity of the rolled bars was assessed before evaluating the effects of cold rolling on the sinter – forged microstructure.

In the present time, advanced high strength steel (AHSS) has secured a dominant place in the automobile sector due to its high strength and good toughness along with the reduced weight of car body which results in increased fuel efficiency, controlled emission of greenhouse gases and increased passengers’ safety. In the present study, four new advanced high strength steels (AHSS) have been developed using three different processing routes, i.e., thermomechanical controlled processing (TMCP), quenching treatment (QT), and quenching & tempering (Q&T) processes, respectively. The current steels have achieved a better combination of the high level of strength with reasonable ductility in case of TMCP as compared to the other processing conditions. The achievable ultrahigh strength is primarily attributed to mixed microstructure comprising lower bainite and lath martensite as well as grain refinement and precipitation hardening.

In this paper the development and method of production of modern, Ni-free sintered structural steels containing Cr, Mn and Mo, enabling the production of structural sintered steels in industrial conditions, using safe, with low H2-content, sintering atmospheres is presented. For this purpose, the analysis of microstructure and mechanical properties of these sintered structural steels produced in different processing conditions and also the connections between the microstructure of sintered material and its mechanical properties, was presented. Following the investigations, the appropriate chemical composition of sintered Ni-free steels with properties which are comparable or even better than those of sintered structural steels containing rich and carcinogenic nickel was choosen. Additionally, in the paper the properties of electrolitically coated carbon steels were presented, as the beginning of investigation for improving the mechanical properties of alloyed, structural sintered steels.

Multiferroic six-layer Aurivillius type Bi7Fe3Ti3O21 ceramics was obtained by conventional mixed oxides method. The final sintering process was taken in several different sintering times, which determined changes in properties of discussed ceramic material. The structure and dielectric properties of the material are reported. In order to examine the technological conditions on the crystal structure, XRD analysis was carried out. The microstructure, as well as the quantitative and qualitative analysis of the chemical composition were investigated by scanning electron microscope with an energy dispersion spectrometer. The main purpose of the paper is to present the effect of sintering time on the microstructure, crystallographic structure and dielectric properties of Bi7Fe3Ti3O21 ceramics.

A mechanistic exposure experiment was performed on the commercially available and welded Ni-Cr-Mo-Fe alloy samples used in the piping materials of the coal gasification pilot plant. Thermodynamic Ellingham-Pourbaix stability diagrams were constructed to provide insight into the mechanism of the observed corrosion behavior. The thermodynamic inference on the corrosion mechanism was supplemented with the morphological, compositional and microstructural analyses of the exposed samples using scanning electron microscopy, X-ray diffraction and energy-dispersive X-ray spectroscopy analyses. X-ray diffraction result revealed stable corrosion products of NiO, MoNi4 and Cr4.6MoNi2.1 after accumulated total exposure duration of 139 h to the corrosive atmosphere. Scanning electron microscopy and energy-dispersive X-ray spectroscopy positively identified formation of rather continuous and adherent pre-oxidation corrosion products although extensively peeled-off oxides were finally observed as corrosion scales on the post-exposure alloy samples, which were attributed to the chlorination/oxidation into thin (spalled) oxides.