Archives of Metallurgy and Materials

Uniaxial tensile tests were performed on porcine skin to investigate the tensile stress-strain constitutive characteristic at quasistatic deformations using uniaxial tensile tests. Experimental results were then used to determine the parameters of the various constitutive model types for rubber, including the Mooney-Rivlin, Yeoh, Ogden, and others. The Prony series viscoelastic model was also calibrated based on the stress relaxation test. To investigate the calibrated constitutive equations (visco-hyperelastic), the falling impact test was conducted. From the viewpoint of the maximum impact load, the error was approximately 15.87%. Overall, the Ogden model predicted the experimental measurements most reasonably. The calibrated constitutive model is expected to be of practical use in describing the mechanical properties of porcine skin.

Residual stress has a great influence on the metal, but it is difficult to measure at small area using a general method. Residual stress calculations using the Vickers indentation can solve this problem. In this paper, a numerical simulation has been made for the residual stress measurement method of metal material deformed by high-speed impact. Then, the stress-strain curve at the high-speed deformation was confirmed through actual experiments, and the residual stresses generated thereafter were calculated by the Vickers indenter method. A Vickers indentation analysis under the same conditions was performed at the position where a residual stress of about 169.39 MPa was generated. Experiments were carried out and high speed impact was applied to the specimen to generate residual stress. The obtained results indicate that it is possible to identify residual stresses in various metals with various shapes through Vickers indentation measurements, and to use them for process and quality control.

A liquid crystal display (LCD) recycling process is needed to increase its efficiency by recovering the resources in addition to metals and plastics. This study investigates the pre-treatment process for recycling LCD glass. Recycling pre-treatment includes dismantling the LCD from the waste product, crushing the glass, and separating the glass particles from the impurities. Scanning electron microscopy confirmed that the oscillation milling process is more effective in maintaining uniform powder shape and size as compared to the cut milling process. The glass particles crushed by the oscillating mill, optimized at 1500 rpm, had a uniformly distributed particle size of less than 10 µm. These small particles were separated from the organic impurities, achieving a 98% pure powder that can be used as recycled raw materials. The proposed pre-treatment process for recycling LCD glass will enhance the ability to use waste glass as a valuable resource in the manufacturing of future displays.

In this study, BaFe12-2xCoxTixO19 (X : 0 to 2.0, 0.2) powders were synthesized by sol-gel process. TG-DTA, XRD, SEM, VSM, and Network analyzer were measured in order to influence easy magnetization axis change on the wave absorption frequency range change. The easy magnetization axis change of the annealed powder at 900°C and 1200°C was confirmed by the coercive force decreased 4,800 and 3,870 Oe to 260 and 269 Oe, respectively, at the substitution ratio of 0.8 and 1.0. And it was confirmed that the change of the easy magnetization axis affected the change of the wave absorption frequency. The wave absorption frequency of substituted Barium Ferrite was less than 10 GHz range after the easy magnetization axis of Barium ferrite changed to a-b plan direction. It was confirmed the BaFe12-2xCoxTixO19(x = 0.8 to 1.6) was synthesized by the sol-gel process and it was annealed at 900°C and 1200°C, which could be used as a wave absorber in the X-band region of 10 GHz less.

Poppet valves made from high-frequency heat-treated SUH3 steel have insufficient durability, and scratches appear on the valve face in prolonged use. It is necessary to develop surface treatment technology with excellent durability to prevent the deterioration of engine performance. Therefore, a surface treatment technology with higher abrasion resistance than existing processes was developed by direct metal deposition to the face where the cylinder and valve are closed. In this study, heat pretreatment and deposition tests were performed on three materials to find suitable powders. In the performance evaluation, the hardness, friction coefficient, and wear rate were measured. Direct metal deposition using Inconel 738 and Stellite 6 powders without heat pretreatment were experimentally verified to have excellent durability.

Considering the advantages of hollow fiber supported liquid membrane (HFSLM), it has been applied for extraction of Co(II) with a motivation to extract cobalt from various waste resources. Extraction efficiency and transport behavior of Co(II) through HFSLM containing Cyanex 272 diluted in kerosene were investigated. Experiments were performed as a function of aqueous feed solution velocity (1000 mL/min) for both feed and strip, pH of feed solution in the range of 4.00-6.75, the carrier concentration of 25-1000 mol/m3, and acid concentration in strip solution of 1-500 mol/m3on. The mass transfer rate or flux JCo(II), which is a function of metal concentration, volume of solution, and membrane area were analyzed. The optimum condition for extraction of Co(II) was pH of 6.00, Cyanex 272 concentration of 500 mol/m3 and H2SO4 concentration of 100 mol/m3.

In this study, agar-based nanocomposite films containing ultra-porous silica aerogel particles were fabricated by gel casting using an aqueous agar/silica aerogel slurry. The silica aerogel particles did not show significant agglomeration and were homogeneously distributed in the agar matrix. Transmission electron microscopy observations demonstrated that the silica aerogel particles had a mesoporous microstructure and their pores were not incorporated into the agar polymer molecules. The thermal conductivities of the agar and agar/5 wt.% silica aerogel nanocomposite films were 0.36 and 0.20 W·m–1·K–1, respectively. The transmittance of the agar films did not decrease upon the addition of silica aerogel particles into them. This can be attributed to the anti-reflection effect of silica aerogel particles.

Trace elements Co, Cr were added to investigate their influence on the microstructure and physical properties of Al-Si extruded alloy. The Co, Cr elements were randomly distributed in the matrix, forms intermetallic phase and their existence were confirmed by XRD, EDS and SEM analysis. With addition of trace elements, the microstructure was modified, Si particle size was reduced and the growth rate of β-(Al5FeSi) phase limited. Compared to parent alloy, hardness and tensile strength were enhanced while the linear coefficient of thermal expansion (CTE) was significantly reduced by 42.4% and 16.05% with Co and Cr addition respectively. It is considered that the low CTE occurs with addition of Co was due to the formation of intermetallic compound having low coefficient of thermal expansion. The results suggested that Co acts as an effective element in improving the mechanical properties of Al-Si alloy.

The effects of carbon content on the austenite stability and strain-induced transformation of nanocrystalline Fe-11% Ni alloys were investigated using X-ray analysis and mechanical tests. The nanocrystalline FeNiC alloy samples were rapidly fabricated using spark plasma sintering because of the extremely short densification time, which not only helped attain the theoretical density value but also prevented grain growth. The increased austenite stability resulted from nanosized crystallites in the sintered alloys. Increasing compressive deformation increased the volume fraction of strain-induced martensite from austenite decomposition. The kinetics of the strain-induced martensite formation were evaluated using an empirical equation considering the austenite stability factor. As the carbon content increased, the austenite stability was enhanced, contributing to not only a higher volume fraction of austenite after sintering, but also to the suppression of its strain-induced martensite transformation.

The grain boundary wetting phase transition in an industrial EZ33A cast alloy is studied. 12% of the grain boundaries are completely wetted at the temperature slightly higher than the eutectic transformation temperature (530°C). The fraction of wetted grain boundaries increases with temperature, reaches a maximum of 85% at 570°C, and does not change further until the alloy melts. In the as-cast state, the alloy has low ductile properties at the ambient temperature. The microstructure in the as-cast state corresponds to the wetting state at about 560°C, which indicates that the cooling rate in casting is almost equal to that in quenching. The volume and the surface fraction of the second phase and the hardness measured at the least wetted state of samples point to its good machinability. The wetting data are used to suggest a sequence of heat treatment and machining for processing EZ33A alloy parts.

Microstructures and mechanical properties of as-cast Al-6.5Mg-1.5Zn-0.5Fe alloys newly alloy-designed for the parts of automobile were investigated in detail. The aluminum (Al) sheets of 4 mm thickness, 30 mm width and 100 mm length were reduced to a thickness of 1mm by multi-pass rolling at ambient temperature and subsequently annealed for 1h at 200~500°C. The as-cast Al sheet was deformed without a formation of so large cracks even at huge rolling reduction of 75%. The recrystallization begun to occur at 250°C, it finished at 350°C. The as-rolled material showed tensile strength of 430 MPa and tensile elongation of 4.7%, however the specimen after annealing at 500°C showed the strength of 305 MPa and the elongation of 32%. The fraction of high angle grain boundaries above 15 degree increased greatly after annealing at high temperatures. These characteristics of the specimens after annealing were discussed in detail.

The present study, aims to investigate the effect of minor Zr and Nb alloying on soft magnetic and electrical properties of Fe86(ZrxNb1-x)7B6Cu1 (x = 1, 0.75, 0.5, 0.25) alloys. The investigated alloys were prepared through the melt spinning process. Within the examined compositional range (Nb up to 5.25at%, respectively), the soft magnetic properties and electrical resistivity of the alloys continuously increase with increasing Nb content. However increasing the Nb content further decreases such properties. We could confirm the influence of ratio of Zr and Nb on grain growth and crystallization fraction during crystallization by using the soft magnetic properties and electrical properties.

439L stainless steel composites blended with fifteen micron SiC particles were prepared by uniaxial pressing of raw powders at 100 MPa and conventional sintering at 1350oC for 2 h. Based on the results of X-ray diffraction analysis, dissolution of SiC particles were apparent. The 5 vol% SiC specimen demonstrated maximal densification (91.5%) among prepared specimens ­(0-10 vol% SiC); the relative density was higher than the specimens in the literature (80-84%) prepared by a similar process but at a higher forming pressure (700 MPa). The stress-strain curve and yield strength were also maximal at the 5 vol% of SiC, indicating that densification is the most important parameter determining the mechanical property. The added SiC particles in this study did not serve as the reinforcement phase for the 439L steel matrix but as a liquid-phase-sintering agent for facilitating densification, which eventually improved the mechanical property of the sintered product.

In this study, we investigated the bonding mechanism of surface-treated steel with an Al-Si alloy in order to produce steel-aluminum (STL-Al) hybrid composite materials by cast-bonding. The results showed that there are differences in the phase and properties of the hybrid composite materials bonded specimens depending on the surface treatment of the steel sheet used, and that the bonding conditions can be controlled further by detailed conditions of the surface treatment. Based on the interfacial bonding strengths measured here, the galvanized surface treatment induced metallurgical bonding to form a reaction layer on the bonding surface and was determined to be the most effective surface treatment.

Cu-Ni composite nanoparticles were successfully synthesized by electrical explosion of wire (EEW) method. Cu-Ni alloy and twisted wires with various Ni contents were used as the feeding material for a 3 kV charging voltage EEW machine in an ethanol ambient chamber. The phase structure and magnetic properties of the as-fabricated samples were studied. It was established that the prepared powders after drying have a spherical form with the particle size is under 100 nm. XRD analysis indicated that the nanopowders consisted of binary Cu-Ni phases. Only pure phases of the intermetallic compound Cu-Ni (Cu0.81Ni0.19 and Cu3.8Ni) were observed in the XRD patterns of the samples. The synthesized intermetallic Cu-Ni alloy nanopowders reveal magnetic behaviors, however, the lower Ni content samples exhibited paramagnetic behaviors, meanwhile, the higher Ni content samples exposed ferromagnetic properties.

In this study, molten salt electrorefining was used to recover indium metal from In-Sn crude metal sourced from indium tin oxide (ITO) scrap. The electrolyte used was a mixture of eutectic LiF-KF salt and InF3 initiator, melted and operated at 700°C. Voltammetric analysis was performed to optimize InF3 content in the electrolyte, and cyclic voltammetry (CV) was used to determine the redox potentials of In metal and the electrolyte. The optimum initiator concentration was 7 wt% of InF3, at which the diffusion coefficients were saturated. The reduction potential was controlled by applying constant current densities of 5, 10, and 15 mA/cm2 using chronopotentiometry (CP) techniques. In metal from the In-Sn crude melt was deposited on the cathode surface and was collected in an alumina crucible.

Effects of various friction stir processing (FSP) variables on the microstructural evolution and microhardness of the AZ31 magnesium alloy were investigated. The processing variables include rotational and travelling speed of the tool, kind of second phase (i.e., diamond, Al2O3, and ZrO2) and groove depth (i.e., volume fraction of second phase). Grain size, distribution of second phase particle, grain texture, and microhardness were analyzed as a function of the FSP process variables. The FSPed AZ31 composites fabricated with a high heat input condition showed the better dispersion of particle without macro defect. For all composite specimens, the grain size decreased and the microhardness increased regardless of the grooved depth compared with that of the FSPed AZ31 without strengthening particle, respectively. For the AZ31/diamond composite having a grain size of about 1 μm, microhardness (i.e., about 108 Hv) was about two times higher than that of the matrix alloy (i.e., about 52 Hv). The effect of second phase particle on retardation of grain growth and resulting hardness increase was discussed.

For the reliable applications of silver nanowires, AgNW, which is used as a conductive transparent film in electronic devices, the isothermal degradation behaviors of AgNW films with and without overcoating were investigated. Accelerated isothermal degradation was performed as a function of temperature, time, and atmosphere. Electrical resistance and optical transmittance were measured and correlated with the microstructural damages, such as formation of oxide particles and fragmentations of AgNW, which were quantitatively determined from the scanning electron micrographs. The overcoating retarded the formation of oxide particles and subsequent fragmentations as well as resulting degradation in electrical resistance without affecting the optical transmittance.

Usually porous metals are known as relatively excellent characteristic such as large surface area, light, lower heat capacity, high toughness and permeability for exhaust gas filter, hydrogen reformer catalyst support. The Ni alloys have high corrosion resistance, heat resistance and chemical stability for high temperature applications. In this study, the Ni-based porous metals have been developed with Hastelloy powder by gas atomization and water atomization in order to find the effects of powder shape on porous metal. Each Hastelloy powder is pressed on disk shape of 2 mm thickness with 12 tons using uniaxial press machine. The specimens are sintered at various temperatures in high vacuum condition. The pore properties were evaluated using Porometer and microstructures were observed with SEM.

In this study, ODS ferritic stainless steels were fabricated using a commercial alloy powder, and their microstructures and mechanical properties were studied to develop the advanced structural materials for high temperature service applications. Mechanical alloying and uniaxial hot pressing processes were employed to produce the ODS ferritic stainless steels. It was revealed that oxide particles in the ODS stainless steels were composed of Y-Si-O, Y-Ti-Si-O, and Y-Hf-Si-O complex oxides were observed depending on minor alloying elements, Ti and Hf. The ODS ferritic stainless steel with a Hf addition presented ultra-fine grains with uniform distributions of fine complex oxide particles which located in grains and on the grain boundaries. These favorable microstructures led to superior tensile properties than commercial stainless steel and ODS ferritic steel with Ti addition at elevated temperature.

In this paper the effect of soldering technique and thermal shock test were investigated on SAC 305 solder joints, produced by two different solder method. The solder joints were subjected to different cycle numbers up to 5000 thermal shock tests with two different thermal profiles of –30/+110°C and –40/+125°C. Microstructural properties of the tested joints were examined with the focus on intermetallic layer thickness and crack formation/propagation. Thickness of the scallop shaped Cu6Sn5 intermetallic layer was increased with increasing cycle number for both THRS and multiwave joints, but the thickening was more effective for the THRS joints. Cracks typically formed at the solder alloy/ PTH barrel and the solder alloy/pin interfaces and propagated along grain boundaries and precipitations of intermetallic compound.

Al-CuO is a thermite material exhibiting the exothermic reaction only when aluminum melts. For wide spread of its application, the reaction temperature needs to be reduced in addition to the enhancement of total reaction energy. In the present study, a thermite nanocomposite with a large contact area between Al and CuO was fabricated in order to lower the exothermic reaction temperature and to improve the reactivity. A cryomilling process was performed to achieve the nanostructure, and the effect of composition on the microstructure and its reactivity was studied in detail. The microstructure was characterized using SEM and XRD, and the thermal property was analyzed using DSC. The results show that as the molar ratio between Al and CuO varies, the fraction of uniform nanocomposite structure was changed affecting the exothermic reaction characteristics.

Electron beam melting(EBM) is a useful technique to obtain high-purity metal ingots. It is also used for melting refractory metals such as tantalum, which require melting techniques employing a high-energy heat source. Drawing is a method which is used to convert the ingot into a wire shape. The required thickness of the wire is achieved by drawing the ingot from a drawing die with a hole of similar size. This process is used to achieve high purity tantalum springs, which are an essential component of lithography lamp in semiconductor manufacturing process. Moreover, high-purity tantalum is used in other applications such as sputtering targets for semiconductors. Studies related to recycling of tantalum from these components have not been carried out until now. The recycling of tantalum is vital for environmental and economic reasons. In order to obtain high-purity tantalum ingot, in this study impurities contained in the scrap were removed by electron beam melting after pre-treatment using aqua regia. The purity of the ingot was then analyzed to be more than 4N5 (99.995%). Subsequently, drawing was performed using the rod melted by electron beam melting. Owing to continuous drawing, the diameter of the tantalum wire decreased to 0.5 mm from 9 mm. The hardness and oxygen concentration of the tantalum ingot were 149 Hv and less than 300 ppm, respectively, whereas the hardness of the tantalum wire was 232.12 Hv. In conclusion, 4N5 grade tantalum wire was successfully fabricated from tantalum scrap by EBM and drawing techniques. Furthermore, procedure to successfully recycle Tantalum from scraps was established.

Ultra-precision testing is a very important procedure to secure the reliability of the products as well as for the technology development in the areas of semiconductor and display. Accordingly, companies manufacturing equipment for testing of semiconductor and display have been continuously executing researches for the improvement of the performances of test sockets used in test equipment.

Through this study, characteristics of the materials in accordance with the mechanical and electrical properties of Ni-30wt%Co alloy and newly developed Cu-2wt%Be alloy were analyzed in order to select the probe pin material of the socket, which is a key component used in the semiconductor testing equipment. In addition, finite element interpretation was executed by using Ansys Workbench 14.0 to comparatively analyze the finite element interpretation results and experimental results. Experiment was executed for the mechanical properties including tensile strength, elasticity modulus, specific heat, thermal expansion coefficient and Contact Force, for electrical properties, experiment on surface resistance, specific resistance and electrical conductivity was executed to measure the properties. It was confirmed that the results of finite element interpretation and experiment displayed similar trend and it is deemed that the Contact Force value was superior for Be-Co alloy.

Through this study, it was confirmed that the newly developed Be-Co alloy is more appropriate as probe pin material used as the core component of test socket used in the semiconductor testing equipment than the existing Ni-Co alloy.

The effects of different types of process control agents (PCA) on the microstructure evolution of Ni-based oxide dispersion-strengthened superalloy have been investigated. Alloy synthesis was performed on elemental powders having a nominal composition of Ni-15Cr-4.5Al-4W-2.5Ti-2Mo-2Ta-0.15Zr-1.1Y2O3 in wt % using high energy ball milling for 5 h. The prepared powders are consolidated by spark plasma sintering at 1000oC. Results indicated that the powder ball-milled with ethanol as PCA showed large particle size, low carbon content and homogeneous distribution of elemental powders compared with the powder by stearic acid. The sintered alloy prepared by ethanol as PCA exhibited a homogeneous microstructure with fine precipitates at the grain boundaries. The microstructural characteristics have been discussed on the basis of function of the PCA.

U-10wt.%Zr metallic fuel slugs containing rare-earth (RE: a rare-earth alloy comprising 53% Nd, 25% Ce, 16% Pr and 6% La) elements for a sodium-cooled fast reactor were fabricated by modified injection casting as an alternative method. The distribution, size and composition of the RE inclusions in the metallic fuel slugs were investigated according to the content of the RE inclusions. There were no observed casting defects, such as shrunk pipes, micro-shrinkage or hot tears formed during solidification, in the metallic fuel slugs fabricated by modified injection casting. Scanning electron micrographs and energy-dispersive X-ray spectroscopy (SEM-EDS) showed that the Zr and RE inclusions were uniformly distributed in the matrix and the composition of the RE inclusions was similar to that of a charged RE element. The content and the size of the RE inclusions increased slightly according to the charge content of the RE elements. RE inclusions in U-Zr alloys will have a positive effect on fuel performance due to their micro-size and high degree of distribution.

This study was carried out to evaluate the aspect of microstructure and mechanical property development on additive manufactured pure Ti at elevated heat-input. For this work, pure Ti powder (commercial purity, grade 1) was selected, and selective laser melting was conducted from 0.5 to 1.4 J/mm. As a result, increase in heat-input led to the significant grain growth form 4 μm to 12 μm, accompanying with the change of grain shape, correctly widmanstätten structured grains. In addition, Vickers microhardness was notably increased from 228 Hv to 358 Hv in accordance with elevated heat-input, which was attributed to the increased concentration of oxygen and nitrogen mainly occurred during selected laser melting process.

In this study, the effect of electroless Pd-P plating on the bonding strength of the Bi-Te thermoelectric elements was investigated. The bonding strength was approximately doubled by electroless Pd-P plating. Brittle Sn-Te intermetallic compounds were formed on the bonding interface of the thermoelectric elements without electroless Pd-P plating, and the fracture of the bond originated from these intermetallic compounds. A Pd-Sn solder reaction layer with a thickness of approximately 20 µm was formed under the Pd-P plating layer in the case of the electroless Pd-P plating, and prevented the diffusion of Bi and Te. In addition, the fracture did not occur on the bonding interface but in the thermoelectric elements for the electroless Pd-P plating because the bonding strength of the Pd-Sn reaction layer was higher than the shear strength of the thermoelectric elements.

The aim of the work was to obtain thin bismuth oxide films containing, at room temperature, the Bi1,5Er0,5O3 phase. This phase corresponds to the structure of the high-temperature δ-Bi2O3 phase, in pure bismuth oxide, characterized by the highest ionic conductivity of all known solid state ionic conductors. The high-temperature δ-Bi2O3 phase with the face centered cubic structure, in pure bismuth oxide, occurs only at temperature above 730°C.

Stabilization of the δ-Bi2O3 phase at room temperature was achieved by an addition of the erbium together with the employment of the Pulsed Laser Deposition (PLD) technique. The influence of an amount of Er alloying and the film thickness on surface morphology, microstructure, phase composition of thin films were investigated. The velocity of deposition of thin layers of bismuth stabilized with erbium in the PLD process using the Nd: YAG laser was about 0.5 nm/s.

The investigation results of erbium doped bismuth oxide thin films deposited onto (0001) oriented Al2O3 monocrystalline substrate are presented.

Thin films of uniform thickness, without cracks, and porosity were obtained. All deposited thin films (regardless of the film thickness or erbia (Er2O3) content) exhibited a columnar structure. In films stabilized with erbium, up to approx. 250 nm thickness, the columns have a diameter at the base from 25 to 75 nm. The columns densely and tightly fill the entire volume of the films. With increasing of the film thickness increases, porosity also significantly increases. In thin layers containing from 20 to 30 mole % Er2O3 the main identified phase at room temperature is Bi1.5Er0.5O3. It is similar to the defective fluorite-type structure, and belongs to the Fm-3m space group. This phase corresponds to the structure of the high-temperature δ-Bi2O3 phase in pure bismuth oxide.

The paper presents the results of research on the modification of the face geometry of the refill friction stir spot welding tool sleeve for welding thin aluminum sheets with an Alclad and an oxide anode coating. The analysis of the impact of such modification on the process perform (tool motion parameters, temperature) and microstructure as well as mechanical strength of the lap joints were analyzed. The tests were carried out using aluminum alloy 2024-T3 sheets with thickness 1.27 mm. For comparative purposes, joints were also made using plates without an Alclad and without anodized coating with using unmodified tool and modified tools with developed 3 variants of face geometry. The samples with the joint were subjected to metallographic and strength tests. It has been shown that the use of modified geometry has a decisive influence on the performance of the process and the effect of softening and mixing of materials in the zone of point connection.

Magnetic properties of Fe nanowire arrays (NWs) electrodeposited in anodic alumina membranes have been studied. The influence of nanowire geometry (length, pore diameter) and an external magnetic field applied during electrodeposition process on the magnetic properties of nanowire arrays was investigated. With the use of the X-ray diffraction analysis the structure of iron wires was determined. The iron wires have the regular Body Centered Cubic structure. Magnetic measurements show that shape anisotropy aligns the preferential magnetization axis along the wire axis. It was found that the application of an external magnetic field in a parallel direction to the sample surface induces magnetic anisotropy with an easy axis of magnetization following the nanowire axis. The dependence of the height of Fe wires on the electrodeposition time was determined.

Multilayered materials give a range of possibilities with regard to control of their properties through selection of layers’ materials, their thickness and the layout of layers. This research is focused on examining the behaviour of three-layer material with perforated sheet as the inner layer during the stretching and drawing process. Four remove tests were carried out: Erichsen, Engelhardt-Gross, Fukui and cup drawing test. Mechanical properties and weld quality were also determined. Sheets with four perforations were used: Po2s3, Po2s4, Po2s10 and Po2s30, which corresponds to the open area values of 34.9%, 19.6%, 3.1% and 0.35%.

The effect of plastic deformation process on the dissolution rate of biocompatible Mg alloys was investigated. Two biocompatible MgLi1Ca0,2Zn1 and MgLi1Ca1Zn1 alloys were selected for the study. The alloys were deformed on a 100T press at a temperature of 350°C by conventional extrusion and by the equal channel angular extrusion process (ECAE). The grain size analysis showed a high degree of the grain refinement from approximately 110 mm in the initial state to 2.8 mm after the 3rd pass of the ECAE process. Compared to as-cast state, the degree of strengthening has increased after plastic forming. The results of biodegradation tests have shown a significant increase in corrosion rate after both conventional extrusion and ECAE, although after subsequent ECAE passes, this rate was observed to slightly decrease in the MgLi1Ca1Zn1 alloy. Based on the results of macro- and microstructure examinations, the corrosion progress in samples after the extrusion process was described.

In the work results of research on electrodischarge machining (EDM) of titanium alloy Ti10V2Fe3Al with (α + β) structure were presented. Preliminary heat treatment of samples allows to obtain different morphology and volume fraction of the α phase. The main goal of research was to assessment of the material microstructure impact on EDM technological factors (ie. material removal rate, tool wear) and morphology of technological surface layer. Electrodischarge machining is alternative and increasingly used method of titanium alloys machining. Research allowed to indicate the possibilities and limitations of use EDM in this area. It is especially important in the aspect of parts produced for aircraft industry and related requirements for the technological surface layer quality.

The aim of the paper is the residual stress analysis of AlSi10Mg material fabricated by selective laser melting (SLM). The SLM technique allows to product of complex geometries based on three-dimensional model, in which stiffness and porosity can be precisely designed for specific uses. As the studied material, there were chosen solid samples built in two different directions: parallel (P-L) and perpendicular (P-R) to the tested surface and cellular lattice built in perpendicular direction, as well. In the paper, for the complex characterization of obtained materials, the phase analysis, residual stress and texture studies were performed. The classical non-destructive sin2ψ method was used to measure the residual stress measurements.

The final products, both solid sample and cellular lattice, have a homogeneous phase composition and consist of solid solution Al(Si) (Fm-3m) type, Si (Fd-3m) and Mg2Si (Pnma). The obtained values of the crystallite size are in a range of 1000 Å for Al(Si), 130-180 Å for Si phase. For Mg2Si phase, the crystallite sizes depend on sintering process, they are 800 Å for solid samples and 107 Å for cellular lattice. The residual stress results have the compressive character and they are in a range from –5 to –15 MPa.

Mixture of nickel and titanium powders were milled in planetary mill under argon atmosphere for 100 hours at room temperature. Every 10 hours the structure, morphology and chemical composition was studied by X-ray diffraction method (XRD), scanning electron microscope (SEM) as well as electron transmission microscope (TEM). Analysis revealed that elongation of milling time caused alloying of the elements. After 100 hours of milling the powders was in nanocrystalline and an amorphous state. Also extending of milling time affected the crystal size and microstrains of the alloying elements as well as the newly formed alloy. Crystallization of amorphous alloys proceeds above 600°C. In consequence, the alloy (at room temperature) consisted of mixture of the B2 parent phase and a small amount of the B19' martensite. Dependently on the milling time and followed crystallization the NiTi alloy can be received in a form of the powder with average crystallite size from 1,5 up to 4 nm.

Powdered polyaniline (PANI) was synthesised chemically with different doping anions namely hydrochloric acid, sulphuric acid and para-toluenesulfonic acid (pTSA). Two-step synthetic procedure was utilised at low temperature. The highest reaction efficiency was found for chlorine-doped PANI. Structural characterization with FTIR revealed the vibration bands characteristic to formation of the emeraldine salt. The surface morphology of doped PANIs was studied by SEM images which showed near globular shape and porous structures with different size of the aggregated particles. They were smaller for Cl–- or pTS–-doped PANI while for SO42– the size was markedly larger. The XRD patterns revealed that there are ordered regions especially for pTS– doped PANI, while the highest conductivity value was recorded for Cl– doped one followed by organic pTS– doped and SO42– doped one.

The main purpose of this study was to identify the mineral composition of soil sample taken from the upper layer of topsoil. High absorption of chemical substance is a characteristic for humus-organic layer of topsoil. The source of those substance could be a pollutant emitted to the atmosphere by human activity. The research area includes Upper Silesia region, which is the most industrial region of Poland. In the present study, the phase composition of the top soil separates were analyzed by using X-ray diffraction and Mössbauer spectroscopy. X-ray diffraction analysis revealed the presence of seven mineral phases in the material magnetic separated by lower current (quartz, illite, kaolinite, Fe3+ oxides, hematite, magnetite and pyrite). In case of higher current were identified four phases (quartz, muscovite, kaolinite and K0.94 Na0.06(AlSi3O8)). Mössbauer spectroscopy was used for an extensive analysis of iron-containing phases (pyrrhotite, magnetite, aluminosilicate oxides with Fe3+ and kaolinite/Fe2+ silicate).

The aim of the paper is to study the effect of zinc addition on the corrosion behavior of Ca65–xMg17.5Zn17.5+x (x = 0, 2.5, 5 at.%) alloys in simulated physiological fluids at 37°C. The electrochemical measurements allowed to determine a corrosion potential, which showed a positive shift from –1.60 V for Ca65Mg17.5Zn17.5 alloy to –1.58 V for Ca60Mg17.5Zn22.5 alloy, adequately. The more significant decrease of hydrogen evolution was noticed for Ca60Mg17.5Zn22.5 alloy (22.4 ml/cm2) than for Ca62.5Mg17.5Zn20 and Ca65Mg17.5Zn17.5 samples (29.9 ml/cm2 and 46.4 ml/cm2), consequently. The corrosion products after immersion tests in Ringer’s solution during 1 h were identified by X-ray diffraction and X-ray photoelectron spectroscopy as calcium, magnesium oxides, carbonates, hydroxides and calcium hydrate.

Due to the wide range of various sheet metal grades and the need to verify the material properties, there are numerous methods to determine the material formability. One of them, that allows quick determination of sheet metal formability, is the Erichsen cupping test described in the ISO 20482: 2003 standard. In the presented work, the results of formability assessment for DC04 deep drawing sheet metal were obtained by means of the traditionally carried out Erichsen cupping test and compared with the results obtained by using two advanced methods based on vision analysis. Application of these methods allows extending the traditional scope of analysis during Erichsen cupping test by determination of the necking and strain localization before fracture. The proposed methods were compared in order to dedicate appropriate solution for the industrial application and laboratory tests respectively, where the simplicity and reliability are the mean aspects need to be considered when applied to the Erichsen cupping test.

The broad range applications of Ultra-Fine Grained metals is substantially limited by the lack of a welding method that allows them to be joined without losing the strong refinement of structure. From this point of view, the solid state welding processes are privileged. Friction welding tests were carried out on UFG 316L stainless steel. A joining process at high temperature activates the recrystallization, therefore the friction welding parameters were selected according to the criterion of the lowest degree of weakness due to recrystallization in the heat affected zone. In order to characterize the structure of basic material and selected areas of the obtained joint, were performed SEM, TEM and metallographic examinations in terms of hardness and range of softening of the material and tensile test. Despite the short time and relatively low welding temperature, results of the test by scanning electron microscopy and transmission electron microscopy confirmed the loss of the primary ultrafine structure in the Heat Affected Zone of welded joint.

Fuzzy logic determination of the material hardening parameters based on the Heyer’s method was applied in this research. As the fuzzy input variables, the length of two measuring bases and the maximum force registered in the Heyer’s test were used. Firstly, the numerical experiment (the simulation of the fuzzification of the input data) with the assumed disturbance of input variables was performed. Next, on the basis of experimental investigations (eleven samples made from the same material), the membership functions associated with the input data were created. After that, the fuzzy analysis was examined. Fuzzy material hardening constants obtained by means of the α-level optimization and the extension principle methods were compared. Discrete values of the hardening data are found in the defuzzification process, by application of the mass center method.

The paper presents the results of the experimental tests of Mg/Al bimetallic bars rolling process in classic and multi-radial modified round-oval-round passes. The bimetallic bar consist of magnesium core, grade AZ31 and aluminium outer layer, grade 1050A. The stocks were round bars with diameter 22.5 mm with an aluminium layer share of 28%. As a result of rolling in four passes, bars of a diameter of about 17 mm were obtained. A bimetallic feedstock was manufactured using an explosive welding method. The use of the designed arrangement of multi-radial modified stretching passes resulted in obtaining Mg/Al bimetallic bars with an uniform distribution of the cladding layer over the bar perimeter and high quality of shear strength between individual layers compared to Mg/Al bars obtained in the classic passes.

The article discusses the development of an approximation model of selected plastic and mechanical properties obtained from compression tests of model materials used in physical modeling. The use of physical modeling with the use of soft model materials such as a synthetic wax branch with various modifiers is a popular tool used as an alternative or verification of numerical modeling of bulk metal forming processes. In order to develop an algorithm to facilitate the choice of material model to simulate the behavior of real-metallic materials used in industrial production processes the induction of decision trees was used. First of all, the Statistica program was used for data mining, which made it possible to determine / find the relationship between the percentage of particular constituents of the model material (base material and modifiers) and yield strength, critical and maximum strain, and provide the opportunity to indicate the most important variables determining the shape of the stress – strain curve. Next, using the induction of decision trees, an approximation model was developed, which allowed to create an algorithm facilitating the selection of individual modifying components. The last stage of the research was verification of the correctness of the developed algorithm. The obtained research results indicate the possibility of using decision tree induction to approximate selected properties of modeling materials simulating the behavior of real materials, thus eliminating the need for costly and time-consuming experiments carried out on metallic material.

In the paper the results of experimental research of the process of flow forming of cylindrical drawpieces were presented. The drawpieces were made of the 3.1 mm thick AMS 5596 sheet by drawing process. Tests were performed on two-roller metal spinning machine of a vertical axis Leifeld SFC 800 V500.

The main purpose of this research was to determine the relationship between relative thickness reduction and the mechanical properties of tested material. Knowledge of these dependencies is especially useful in designing machines’ components manufactured by flow forming, in the selection of parameters of realization of this technological process as well. Mechanical properties were determined on the basis of uniaxial tensile of the micro samples obtained from the drawpieces: (I) after cold flow forming, (II) after cold flow forming and in-process heat treatment. Obtained results were shown graphically in the diagrams and their analysis was carried out. In addition, the microstructure of the sheet material tested after drawing and flow forming is presented.

Snap-fit connections have been used for many years in various fields of technology and everyday objects. They often have complex shapes, which is allowed by the processing technology of the polymers from which they are made, but they are not designed to carry loads. Changing the material to a metal or fiber composite allows these types of joints to be used as replacements for rivets or screws, but there are problems with the closing technique – an increase in closing force due to the large Young’s modulus of these materials relative to polymers without reinforcement. One of the methods to solve this problem may be the use of a thermo-bimetallic effect consisting in heating both or one of the connection parts to the appropriate temperature. This kind of treatment results in deflection of the beam of the clip (Fig. 1), followed by assembly with zero force or less in relation to the case without heating.

The paper presents the results of numerical simulations for the connection in which the beam of the clip consisted of two materials: (1) a fiber composite designed to carry loads, (2) thin metal layer tied with the composite and designed to create a thermo-bimetallic effect. In the case of this solution, the main parameter is the difference in coefficients of linear thermal expansion of both materials.

The paper presents results for two cases of connection work: closing and opening. The calculations were carried out in the Abaqus/Standard solver using thermal-displacement steps.

The melt cleaning is an important aspect in the production of high-quality aluminum castings. Specifically inclusions within the melt and an excessively high hydrogen content lead to defects and undesired porosity in the castings. Although it is possible to reduce the amount of hydrogen and oxidic inclusions by purge gas treatment and the use of melting salts, it is impossible to remove oxides (bifilms) created during filling of gating system. Paper deals with the effects of melt quality and the placement of a filter in the filling system on Al-7%Si-Mg alloy mechanical properties. Three different filters were used: (a) rectangular ceramic pressed filter with 3 mm thickness (b) cubical pressed ceramic filter with thickness 10 mm (c) cubical pressed ceramic filter with thickness 22 mm. The results showed that the highest tensile strength values were obtained from the filter with thickness of 22 mm. Numerical simulation analysis of the filling process showed that velocity reduction by filter is the major phenomenon affecting the mechanical properties. Another evaluated aspect during experiments was capability of filters to retain old bifilms. For this purpose multiply remelted alloy was prepared and analyzed. Results showed that filter efficiency increases with decreasing melt quality as a result of possibility to retain “old” bifilms better than small and thin “new” bifilms.

The impact of small addition of zirconium in hypoeutectic commercial AlSi10MgCu alloys on their mechanical properties (hardness) in as cast and thermally treated conditions was investigated. Small addition of zirconium does not change significantly the as cast and heat-treated microstructure of investigated alloys except to reduce the SDAS and grain size of primary α-aluminium phases. Addition of zirconium up to 0.14 wt. percentage increases the hardness of investigated alloys in as cast conditions. The increase in the hardness of samples after various solid solution times can correlate very well with the formation of small needle like coherent Al3Zr particles.

Materials based on cast irons are often used for protection against wear. One of the methods of creating protective surface with cast iron structures is hardfacing. The application of hardfacing with self shielded flux cored wire with high carbon content is one of the economical ways often used to protect machinery parts exposed to both abrasion and erosion. The wear resistance of hardfacings depends on their chemical composition, structure obtained after hardfacing, parameters of depositing process and specific conditions of wear. As the base material in the investigation the steel grade S235JR was used. The wear behavior mechanism of hardfacings made with one type of self shielded flux cored wire and different process parameters were evaluated in this paper. Structures obtained in deposition process were different in hardness, amount of carbides and resistance to wear with two investigated impingement angles. The erosion tests showed that impingement angle 30° gives lower erosion rate than angle 60°.

The main goal of the article is to identify artificially created defects like lack of fusion and incomplete penetration in butt weld joint using non-destructive volumetric methods. These defects are the most serious defects in welds of steel constructions from the safety point of view. For identification, an ultrasonic phased array technique and a conventional X-ray using digital imaging were used. The theoretical part of the article describes the current state of the given issue and provides basic theoretical knowledge about ultrasonic and X-ray welding tests. In the experimental part, the procedure and results of testing butt weld joint are described by both non-destructive methods. The butt weld joint was made from steel S420MC. Each indication obtained by the ultrasonic and x-ray technique is supplemented by the macrostructure of the weld taken from the indication position. The results of the experimental work mentioned in the article point to the possibility and reliability of the identification of melting defects by selected nondestructive methods in terms of their character and orientation.

The article presents tests results of metalforming of magnesium alloy AZ61. Materials for tests were ingots sized  40×90 mm from magnesium alloy marked with symbol AZ61. Before the shaping process the ingots underwent heat treatment. As a result of conduction of the deformation processes there were rods achieved with diameter of 8 mm. There were axisymmetrical compression tests conducted on the samples taken from rods in temperature range from RT to 350ºC in order to determine the plasticity and formability of the alloy AZ61. Static tensile test was conducted in room temperature (RT), in 300ºC and in 350ºC. With the use of light and electron microscopy techniques the changes which occurred in the microstructure of AZ61alloy in initial condition and after plastic deformation (classic extrusion, KoBo method extrusion) were described. The deformation of alloy AZ61 using the KoBo method contributes to an increase in strength and plastic properties. The effect of superplastic flow was found at a temperature of 350ºC, where a 300% increase in plastic properties – elongation value was obtained. The analysis of the microstructure showed a significant grain size reduction in the microstructure of alloy AZ61 after deformation by the KoBo method and after an axisymmetric compression test, where grains of an average diameter of d = 13 µm were obtained.

In the paper an analysis of the influence of two parameters on the die wear, i.e. the shape of the die and the backpull with the specified force values has been presented. The conical and curve-profile tools have been selected to determine an influence of the die geometry on its wear, and the backpull force has been tested with the use of conical dies. The research was conducted for the drawing of copper wire by sintered carbide die with a mesh diameter of 3 mm. A fixed draw value of 30% relative gap loss was assumed. The axisymmetric numerical model of the drawing process was built and modeled in the MARC/Mentat commercial program for nonlinear and contact issues. As a result of the tests, wear of the dies according to their shape was determined. In addition, for the conical die the drawing force and the force of the metal pressure on the die using different values of the force of the contraction were calculated, as well as wear of the conical die according to the value of the applied backpull force. It has been shown that in the case of the arc die, the distribution of pressure and stress is more uniform over the entire length of the contact zone compared to the conical die. The highest stress gradients occurred in the area of the transition of the crushing part into the drawing part of the die, which caused that the use of the conical die in this area was more than twice as large as the arc die. In addition, on the example of a conical die, it was shown to what extent the depth of its wear decreases with an increase of the test pull force in the range (0-400) of Newtons.

The mechanical properties of the commercial synthetic surgical threads (i.e., monofilament MonosynR and polyfilament PolysorbTM) and threads made of pure zinc and selected magnesium alloys were compared. Tensile and relaxation tests of fine fibers/wires without and with a surgical knot were performed on a Zwick 250 tensile machine and on the specially constructed tensile machine dedicated for ultra-thin samples. An about 50% decrease in the maximum tensile load was registered for both synthetic and Mg-based threads due to the presence of a surgical knot while only an about 10% decrease was documented for the zinc threads.

The present article describes selected aspects of investment casting technology for manufacturing of open-cell aluminium. The main focus is, among others, on the precursor thickening. Two groups of total 30 samples were produced, basing on open-cell polyurethane foam used as the precursor. Each of the two sample groups was thickened with a different type of suspension consisting of carbonaceous substances and organic binders. The influence of the coating mixture type was compared, leading to conclusions regarding the desired composition and fluidity of the suspensions. Both sample groups of the obtained open-cell aluminium had stochastic cell distributions, the average pore diameter was 5.2 mm and the PPI index was 8. The apparent densities were respectively: 0.485 g/cm3 and 0.312 g/cm3, which reflected the impact of the precursor coating. Additionally, samples from both groups differed in quality.

The article presents the results of investigation of ultra-strength nanostructured bainitic steel Fe-0.6%C-1.9%Mn-1.8%Si-1.3%Cr-0.7%Mo (in wt. %) subjected to shear and uniaxial compression under high strain rate loading. Steel of microstructure consisted of carbide-free bainite and carbon enriched retained austenite presents a perfect balance of mechanical properties especially strength to toughness ratio. Two retained austenite morphologies exist which controlled ductility of the steel: film between bainite laths and separated blocks. It is well established that the strain induced transformation of carbon enriched retained austenite to martensite takes place during deformation. Shear localisation has been found to be an important and often dominant deformation and fracture mode in high-strength steels at high strain rate. Deformation tests were carried out using Gleeble simulator and Split Hopkinson Pressure Bar. Shear and compression strength were determined and toughness and crack resistance were assessed. Susceptibility of nanostructured bainitic steel to the formation of adiabatic shear bands (ASBs) and conditions of the bands formation were analysed. The results suggest that the main mechanism of hardening and failure at the dynamic shearing is local retained austenite transformation to high-carbon martensite which preceded ASBs formation. In the area of strain localization retained austenite transformed to fresh martensite and then steel capability to deformation and strengthening decreases.

The computational intelligence tool has major contribution to analyse the properties of materials without much experimentation. The B4C particles are used to improve the quality of the strength of materials. With respect to the percentage of these particles used in the micro and nano, composites may fix the mechanical properties. The different combinations of input parameters determine the characteristics of raw materials. The load, content of B4C particles with 0%, 2%, 4%, 6%, 8% and 10% will determine the wear behaviour like CoF, wear rate etc. The properties of materials like stress, strain, % of elongation and impact energy are studied. The temperature based CoF and wear rate is analysed. The temperature may vary between 30°C, 100°C and 200°C. In addition, the CoF and wear rate of materials are predicted with respect to load, weight % of B4C and nano hexagonal boron nitride %. The intelligent tools like Neural Networks (BPNN, RBNN, FL and Decision tree) are applied to analyse these characteristics of micro / nano composites with the inclusion of B4C particles and nano hBN % without physically conducting the experiments in the Lab. The material properties will be classified with respect to the range of input parameters using the computational model.

In this study, we present a new method for obtaining the parameters of the Johnson-Mehl-Avrami-Kolmogorov equation for dynamic recrystallization grain size. The method consists of finite-element analysis and optimization techniques. An optimization tool iteratively minimizes the error between experimental values and corresponding finite-element solutions. Isothermal backward extrusion of the AA6060 aluminum alloy was used to acquire the main parameters of the equation for predicting DRX grain size. We compared grain sizes predicted using optimized and reference parameters with experimental values from the literature and found better agreement when the optimized parameters were applied.

The objective of this study was to investigate the dependence of the room temperature tensile properties on the volume fraction of discontinuous precipitates (DPs) in a cast AZ91 magnesium alloy. In order to obtain various volume fractions of DPs, the solution-treated alloy was aged at 428 K for up to 48 h. The volume fraction of DPs increased from 0% to 72% with an increase in the aging time up to 24 h; for aging times longer than 24 h, discontinuous precipitation was substantially inhibited owing to the occurrence of significant continuous precipitation within the α-(Mg) grains. YS and UTS of the alloy increased with the volume fraction of DPs, whereas the elongation showed a reverse trend. A relatively rapid change in the tensile properties with increasing volume fraction of DPs up to ~40% was noted, which would be due to the reduction of the effective α grain size in response to the formation of DPs along the grain boundaries.

The publication presents a novel concept of the process of plastic forming of variable longitudinal-section cylindrical products, being the subject of Patent Application P.427426 [1]. Additionally, these products are provided with a connection stub pipe. The plastic forming method proposed in the article combines many advantages and utilitarian benefits associated with the manufacturing technology itself, as well as with its further implementation. Using stock in the form of normalized bar commonly available in the metal product market as a finished product obviously reduces the process costs involved with stock preparation, i.e. casting, rolling, machining, etc. It also results in obtaining a much smaller surface area of stock contact with the tool and, as a consequence, a smaller surface of stock friction against the tool, which contributes to a reduction of force needed for the plastic forming of the product. The smaller contact surface area and the shorter time of stock contact with the cooler tool cause, above all, less intensive heat exchange and stock chilling. This has a significant effect on the plasticity of the cast material and, as a consequence, the plastic forming force. The proposed method enables also manufacturing cylinders with either a closed or open stub pipe with a regulated length and a varying section. In addition, unlike the method known from Polish Patent Specification PL 212062 [2], the proposed method does not require using a multi-tool press. The upper punch is furnished with a flange, whose job is to start the stock extruding sleeve at the next process stage.

In the current study, the hot deformation of medium carbon V-Ti micro-alloyed steel was surveyed in the temperature range of 950 to 1150°C and strain rate range of 0.001 to 1 s–1 after preheating up to 1200°C with a compression test. In all cases of hot deformation, dynamic recrystallization took place. The influence of strain rate and deformation temperature on flow stress was analyzed. An increase in the strain rate and decrease in the deformation temperature postponed the dynamic recrystallization and increased the flow stress. The material constants of micro-alloyed steel were calculated based on the constitutive equations and Zener-Hollomon parameters. The activation energy of hot deformation was determined to be 458.75 kJ/mol, which is higher than austenite lattice self-diffusion activation energy. To study the influence of precipitation on dynamic recrystallization, the stress relaxation test was carried out in a temperature range of 950 to 1150°C after preheating up to 1200°C. The results showed no a stress drop while representing the interaction of particles with dynamic recrystallization.