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To perform quality assessments of both metal alloys and many other engineering materials, measurements of the volume fractions of phases or microstructure components are utilized. For this purpose, quantitative analysis of the evaluated components' distribution on metallographic specimens is often employed. Phases or components of the microstructure are identified based on the variation in signal received in the band of light seen. Problems with the correct identification of measurement results in this spectral band can be caused by the inhomogeneity of the etching when the alloy components are segregated. Additional uncertainty arises when the analyzed image pixel contains a boundary between grains of different phases. This article attempts to use the results of local chemical composition measurements as a source signal for quantitative evaluation of phase composition. For this purpose, quantitative maps of elemental concentration distributions, obtained with a Tescan Mira GMU high-resolution scanning electron microscope in QuantMap mode, were used as input data for the phase composition evaluation of an EN AC 46000 alloy sample. The X-ray microanalysis signal generation area may contain grains of more than one phase. Therefore, evaluation of the phase fractions in areas of individual measurements were calculated by looking for the minimum of the objective function, calculated as the sum of the squares of the deviations of the results of measurements of the concentration of individual elements from the weighted average values of solubilities of these elements in the phases. [ABSTRACT FROM AUTHOR]

Bimetallic composites have a wide range of application prospects in various industries. Different bonding temperatures, as one of the influencing factors, directly affect the bonding effectiveness as well as the performance and application of the materials. Using metallurgical bonding techniques ensures a strong bond at the interface of bimetallic materials, resulting in high-quality composite pipe billets. This paper describes an Incoloy825/P110 steel bimetal composite material made by the solid–liquid composite method. By utilizing ProCAST 14.5 software for simulation and deriving theoretical formulas, an initial range of temperatures for bimetallic preparation has been tentatively determined. And this temperature range will be utilized for on-site experiments to prepare bimetallic samples. After the preparation process is completed, samples will be selected. The influence of the external mold temperature on the interface bonding of Incoloy825/P110 steel solid–liquid composite material is studied using an ultra-depth three-dimensional morphology microscope and a scanning electron microscope. Through research, the optimal preheating temperature range for the solid–liquid composite outer mold of Incoloy825/P110 bimetallic composite material has been determined. The casting temperature of the inner mold has a significant impact on the interface bonding of this bimetal composite material. As the casting temperature of the inner mold increases, the interface thickness gradually increases. At lower temperatures, the interface thickness is lower and the bonding is poorer. At higher temperatures, melting may occur, leading to coarse grains at the interface. When the temperatures of the inner and outer molds are within a certain range, a new phase appears at the interface. Indeed, it increases the strength of the interface bonding. Due to co-melting of the bimetal near the interface, element migration occurs, resulting in increased Ni and Cr content at the interface and enhanced corrosion resistance. [ABSTRACT FROM AUTHOR]

Manganese slag (MS) containing a certain amount of active hydration substances may be used as a kind of cementitious material. In the present study, we measured the mass, the relative dynamic modulus of elasticity (RDME), and the flexural and compressive strengths of MS high-performance concrete (MS-HPC) with added basalt fibers exposed to NaCl freeze–thaw cycles (N-FCs), NaCl dry–wet alternations (N-DAs), and Na2SO4 dry–wet alternations (NS-DAs). Scanning electron microscope energy-dispersive spectrometer (SEM-EDS) spectra, thermogravimetric analysis (TG) curves, and X-ray diffraction spectroscopy (XRD) curves were obtained. The mass ratio of MS ranged from 0% to 40%. The volume ratio of basalt fibers varied from 0% to 2%. We found that, as a result of salt action, the mass loss rate (MLR) exhibited linear functions which were inversely correlated with the mass ratio of MS and the volume ratio of basalt fibers. After salt action, MLR increased by rates of 0~56.3%, but this increase was attenuated by the addition of MS and basalt fibers. Corresponding increases in RDME exhibited a linear function which was positively correlated with MS mass ratios in a range of 0~55.1%. The addition of MS and basalt fibers also led to decreased attenuation of mechanical strength, while the addition of MS led to increased levels of flocculent hydration products and the elements Mn, Mg, and Fe. CaClOH and CaSO4 crystals were observed in XRD curves after N-DA and NS-DA actions, respectively. Finally, the addition of MS resulted in increased variation in TG values. However, the opposite result was obtained when dry–wet actions were exerted. [ABSTRACT FROM AUTHOR]

In the present work, we studied the impact of excess Na addition on the structure of the standard NASICON ion conductor along with Na ion transport mechanisms. In this sense, NASICON ceramic membranes (NZSP) were prepared by a simple chemical synthesis method, the solid state reaction (SSR), using an excess of 5% Na (Na3.15Zr2Si2PO12) and an excess of 10% Na (Na3.3Zr2Si2PO12), in order to improve the conduction properties of the ceramic membrane. The characterization of the NZSP nanoparticles was performed by measuring the particle size by dynamic light scattering (DLS), the morphology of the NASICON samples pre-sintered at 1100 °C was analyzed by the SEM method (scanning electron microscope), and X-ray diffraction (XRD) analysis was used to investigate the crystal structure of samples, while the surface area was measured using the BET technique. The electrical properties (i.e., ionic conductivity) were evaluated by impedance spectroscopic methods at room temperature (RT). Following the experiments for NASICON membranes without Na excess, with 5% Na excess, and with 10% Na excess synthesized at different pressing forces and sintering temperatures, it was found that membranes with a 10% Na excess, sintered at 1175 °C for 10 h, presented a good ionic conductivity (4.72 × 10−4 S/cm). [ABSTRACT FROM AUTHOR]

Type II inorganic clathrates consist of cage-like structures with open frameworks, and they are considered promising materials due to their unique properties. However, the difficulty of synthesizing phase-pure and continuous films has hindered their application in practical devices. In this report, we demonstrate the synthesis of type II SiGe clathrate films through the thermal decomposition of a Na-deposited amorphous SiGe film on a sapphire substrate in a high vacuum. The as-prepared films of type II SiGe clathrates showed uniform growth and were evaluated for their structural and optical properties. Morphological studies conducted using a scanning electron microscope showed the presence of cracks on the film surface. [ABSTRACT FROM AUTHOR]

The application of organic coatings is a common way of protecting metal substrates against corrosion. To dry the coating faster, catalytic infrared radiation (IR) can be applied. This paper aims to assess the differences in the physical, chemical, and corrosion properties of primer coatings dried with catalytic infrared radiation, compared to the same coatings dried under atmospheric conditions. Corrosion properties were characterized using humidity and a salt spray chamber, as well as electrochemical impedance spectroscopy (EIS), preceded by open circuit potential (OCP) measurement. Pencil hardness, cross-cut, and pull-off adhesion tests were used to compare the properties of examined primers before and after testing in the corrosion acceleration chambers. The microstructure and distribution of chemical composition were studied by scanning electron microscope (SEM) with energy-dispersive X-ray spectroscopy (EDX) together with Fourier-transform infrared spectroscopy (FTIR). Phase transitions in the coating were determined by differential scanning calorimeter (DSC). Infrared-dried primers achieved a higher curing degree. Therefore, their mechanical and corrosion properties are superior when compared to the same coatings dried under atmospheric conditions. [ABSTRACT FROM AUTHOR]

This in vitro study aimed to assess the presence of microgaps at the implant–abutment interface in monolithic zirconia partial implant-supported fixed prostheses on transepithelial abutments versus Ti-base abutments. Methods: Sixty conical connection dental implants were divided into two groups (n = 30). The control group consisted of three-unit bridge monolithic zirconia connected to two implants by a transepithelial abutment. The test group consisted of monolithic zirconia three-unit restoration connected to two implants directly by a titanium base (Ti-base) abutment. The sample was subjected to thermocycling (10,000 cycles at 5 °C to 55 °C, dwelling time 50 s) and chewing simulation (300,000 cycles, under 200 N at frequencies of 2 Hz, at a 30° angle). The microgap was evaluated at six points (mesiobuccal, buccal, distobuccal, mesiolingual, lingual, and distolingual) of each implant–abutment interface by using a scanning electron microscope (SEM). The data were analyzed using the Mann–Whitney U tests (p > 0.05). Results: The SEM analysis showed a smaller microgap at the implant–abutment interface in the control group (0.270 μm) than in the test group (3.902 μm). Statistically significant differences were observed between both groups (p < 0.05). Conclusions: The use or not of transepithelial abutments affects the microgap size. The transepithelial abutments group presented lower microgap values at the interface with the implant than the Ti-base group in monolithic zirconia partial implant-supported fixed prostheses. However, both groups had microgap values within the clinically acceptable range. [ABSTRACT FROM AUTHOR]

CoCrNi alloys exhibit excellent strength and ductility. In this work, the CoCrNiV multi-principal alloy with single-phase fine grained (FG) structure was prepared by rolling and heat treatment. The characteristics of deformation microstructures and mechanical properties were systematically investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). The results indicate that the CoCrNiV alloy successfully attains a yield strength of 1060 MPa while maintaining a uniform elongation of 24.1%. The enhanced strength originates from FG structure and severe lattice distortion induced by V addition. Meanwhile, the exceptional ductility arises from the stable strain-hardening ability facilitated by dislocations and stacking faults. The deformation mechanisms and the optimization strategies for attaining both strength and ductility are thoroughly discussed. [ABSTRACT FROM AUTHOR]

Improving the vacuum degree inside the vacuum device is vital to the performance and lifespan of the vacuum device. The influence of the Ti and ZrCoCe barrier layers on the performance of ZrCoCe getter films, including sorption performance, anti-vibration performance, and binding force between the ZrCoCe getter film and the Ge substrate were investigated. In this study, the Ti and ZrCoCe barrier layers were deposited between the ZrCoCe getter films and Ge substrates. The microtopographies of barrier layers and the ZrCoCe getter film were analyzed using scanning electron microscopes. The sorption performance was evaluated using the constant-pressure method. The surface roughness of the barrier layers and the getter films was analyzed via atomic force microscopy. The binding force was measured using a nanoscratch tester. The anti-vibration performance was examined using a vibration test bench. The characterization results revealed that the Ti barrier layer significantly improved the sorption performance of the ZrCoCe getter film. When the barrier material was changed from ZrCoCe to Ti, the initial sorption speed of the ZrCoCe getter film increased from 141 to 176 cm3·s−1·cm−2, and the sorption quantity increased from 223 to 289 Pa·cm3·cm−2 in 2 h. The binding force between the Ge substrate and the ZrCoCe getter film with the Ti barrier layer was 171 mN, whereas that with the ZrCoCe barrier layer was 154 mN. The results showed that the Ti barrier layer significantly enhanced the sorption performance and binding force between the ZrCoCe getter film and the Ge substrate, which improved the internal vacuum level and the stability of the microelectromechanical system vacuum devices. [ABSTRACT FROM AUTHOR]

This study investigated the stress–strain behavior and microstructural changes of Fe-Mn-Si-C twin-induced plasticity (TWIP) steel cylindrical components at different depths of deep drawing and after deep drawing deformation at various positions. The finite element simulation yielded a limiting drawing coefficient of 0.451. Microstructure and texture were observed using a scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). The research revealed that the extent of grain deformation and structural defects gradually increased with increasing drawing depth. According to the orientation distribution function (ODF) plot, at the flange fillet, the predominant texture was Copper (Cu){112}<111> orientation; at the cylinder wall, the main textures were Copper Twin (CuT) and Goss (G) orientations; at the rounded bottom corner of the cylinder, the primary texture was τ-fiber (<110>//TD), with its strength increasing with deeper drawing. [ABSTRACT FROM AUTHOR]

Cu additions notably strengthen Al-Mg-Si and Al-Si-Mg alloys due to the dense precipitation of quaternary nano precipitates during ageing. However, the chemical evolution and mechanical behaviors of the quaternary micro-scale Q constituent phase occurring in cast and homogenized states have rarely been studied. Meanwhile, there exists a type of AlCuMgSi cluster in the cast state, which has been regarded as Q particles. The accurate identification of phase constituents is the basis for the future design of alloys with better performance. In our work, this type of cluster was revealed to consist of α-Al, θ-Al2Cu, Q, and Si phases through micro-to-atomic scale studies using scanning and transmission electron microscopes. The skeleton of the dendrite was θ phase. The second phases in the dendritic eutectic cluster dissolved quickly during a 4 h homogenization at 550 °C. The Q phase was found to effectively absorb the Fe impurities during casting and homogenization. As a result, the formation of other harmful Fe-rich intermetallics was suppressed. These Q constituent particles were observed to break into separate pieces in an intermediately brittle manner when compressed in situ in a scanning electron microscope. These findings provide insights into the thermodynamic modeling of the Al-Mg-Si-Cu system and alloy design. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the effect of adding rhenium to Cu-Ni-Si alloys on the mechanical properties and electrical conductivity of these alloys. The scientific objective was to analyze the effect of Re addition on the microstructure of heat- and cold-treated CuNi2Si1 alloys. Transmission electron microscopy (TEM, STEM) and scanning electron microscopy (EDS, WDS) were used to examine the microstructure. Orientation mapping was also performed using a scanning electron microscope (SEM) equipped with a backscattered electron diffraction (EBSD) system. In addition, hardness at low load and conductivity were tested. The obtained results showed that modifying the chemical composition of Re (0.6 wt%) inhibits the recrystallization process in the CuNi2Si1 alloy, which was cold deformed and then subjected to recrystallization annealing. [ABSTRACT FROM AUTHOR]

A systematic study was conducted to investigate the distinct mechanisms involved in the formation of the inner surfaces of cylindrical and parallelepipedic-shaped structures. The surface roughness, flatness, and sinking distance were used as key indices to measure the quality of overhanging surfaces, while the surface flatness and roughness were used to evaluate the quality of the side and bottom surfaces of the inner hole. The inner surface morphology was observed using a scanning electron microscope and a white light interferometer. The test results show that the quality of the overhanging surface had a significant impact on the quality of the parallelepipedic-shaped inner hole. In contrast, the cylindrical-shaped inner hole had a shorter but more uniformly distributed overhanging surface, resulting in a different behavior of the overhanging and side surface quality. An improved model of the overhanging surface was established by combining all of the above results and comparing them with the traditional Euler Bernoulli beam model. The factors affecting the quality of the overhanging surface were analyzed, and measures for improving the quality of the overhanging surface during the SLM manufacturing process were proposed. [ABSTRACT FROM AUTHOR]

Cold forging is suitable for manufacturing thin-walled tubes; however, a poorly planned forging process results in serious quality problems. This paper aims to determine an appropriate cold forging process for thin-walled A286 superalloy tube with ideal forming quality. We analyzed the effects of the two forging processes with reverse forging sequences on forming defects and hardness distribution in the thin-walled tubes via finite element simulation. The methods of optical microscope, micro-hardness, scanning electron microscope, and electron-backscattered diffraction were used to validate the tube forming quality. The simulation results revealed that the Type-I process was an appropriate forging process for meeting the quality requirements. For the Type-I process, an underfilling defect was observed at the bottom of the rod section of the tube. The stress concentration in the head section was lower than that in the Type-II process, potentially reducing the probability of crack initiation. Compared to the rod section, the head section may exhibit higher hardness magnitudes due to the greater strain distribution. The experimental results confirmed the feasibility of the Type-I process. The increased hardness in the head section may be primarily attributed to the more intense plastic deformation applied to the material in this section by the Type-I process. [ABSTRACT FROM AUTHOR]

The hot cracking behaviors of Mg-5Zn-xEr (x = 0.83, 1.25, 2.5, 5 wt.%) alloys are investigated by optimized hot cracking experimental apparatus, optical microscope, and scanning electron microscope, such as contraction behaviors, feeding behaviors, and permeability characteristics. It is found that the solid phase fraction at hot crack initiation and within the freezing range both increased with increasing Er contents up to 2.5 wt.% and then decreased at 5 wt.% Er content. The Mg-5Zn-5Er alloy exhibits the lowest solid phase fraction (87.4%) and a reduced freezing range (74.2 °C), which leads to more effective liquid feeding in the latter stages of solidification. Combined with the grain size, the permeability of the mushy zone, and fracture morphology, the overall permeability is optimal in the Mg-5Zn-5Er alloy, which is beneficial for feeding the cavities and micro-pores. Meanwhile, a large amount of W phase precipitated by the eutectic reaction (L→α-Mg + W phase), which facilitates healing of the incurred cracking. Conversely, the Mg-5Zn-2.5Er alloy shows inferior feeding ability due to the lowest solid phase fraction (98.3%), wide freezing range (199.5 °C), and lowest permeability. Therefore, the Mg-5Zn-2.5Er alloy exhibits maximal hot cracking susceptibility, and the Mg-5Zn-5Er alloy exhibits minimal hot cracking susceptibility. This work provides guidance for improving the hot cracking resistance of cast Mg-Zn-Er alloy and enables an understanding of the hot cracking behaviors of Mg-Zn-RE alloys. [ABSTRACT FROM AUTHOR]

Due to the unique functional properties of shape memory alloys (SMAs) and current scientific interest in Cu-containing biomaterials, a continuously cast Cu-Al-Ni alloy in the form of rods has been investigated as a potential candidate for biomedical application. Additionally, the fact that Cu- complexes have an antitumour effect served as a cornerstone to develop more efficient drugs based on trace element complexes. In line with that, our study aimed to analyse the basic properties of the Cu-Al-Ni alloy, along with its anticancer properties. The detailed chemical analysis of the Cu-Al-Ni alloy was performed using XRF and SEM/EDX analyses. Furthermore, a microstructural and structure investigation was carried out, combined with hardness measurements using the static Vickers method. Observations have shown that the Cu-Al-Ni microstructure is homogeneous, with the presence of typical martensitic laths. XRD analysis confirmed the presence of two phases, β′ (monoclinic) and γ′ (orthorhombic). The viability of osteosarcoma cells in contact with the Cu-Al-Ni alloy was evaluated using epifluorescence microscopy, while their morphology and attachment pattern were observed and analysed using a high-resolution SEM microscope. Biocompatibility testing showed that the Cu-Al-Ni alloy exerted a considerable antineoplastic effect. [ABSTRACT FROM AUTHOR]

This paper presents the possibilities of applying atomic force microscopy (AFM) techniques to the study of the wear of prosthetic biomaterials. In the conducted research, a zirconium oxide sphere was used as a test piece for mashing, which was moved over the surface of selected biomaterials: polyether ether ketone (PEEK) and dental gold alloy (Degulor M). The process was carried out with constant load force in an artificial saliva environment (Mucinox). An atomic force microscope with an active piezoresistive lever was used to measure wear at the nanoscale. The advantage of the proposed technology is the high resolution of observation (less than 0.5 nm) in the three-dimensional (3D) measurements in a working area of 50 × 50 × 10 µm. The results of nano wear measurements in two measurement setups are presented: zirconia sphere (Degulor M and zirconia sphere) and PEEK were examined. The wear analysis was carried out using appropriate software. Achieved results present a tendency coincident with the macroscopic parameters of materials. [ABSTRACT FROM AUTHOR]

Different collagen barrier membranes come in various sources and crosslinking that may affect barrier function and tissue integration. This study investigated barrier function and tissue integration of the three different collagen membranes (Jason®: porcine pericardium, GENOSS: bovine tendon, and BioMend® Extend: cross-linked bovine tendon) with human gingival fibroblasts. The barrier function and tissue integration properties were determined under confocal microscopy. Morphological characteristics were observed using scanning electron microscopy. Our results showed that all collagen membranes allowed a small number of cells to migrate, and the difference in barrier function ability was not significant. The cross-linked characteristics did not improve barrier ability. The native collagen membrane surfaces allowed evenly scattered proliferation of HGF, while the cross-linked collagen membrane induced patchy proliferation. Statistically significant differences in cell proliferation were found between Jason and BioMend Extend membranes (p = 0.04). Scanning electron microscope showed a compact membrane surface at the top, while the bottom surfaces displayed interwoven collagen fibers, which were denser in the crosslinked collagen membranes. Within the limitations of this study, collagen membranes of different origins and physical properties can adequately prevent the invasion of unwanted cells. Native collagen membranes may provide a better surface for gingival cell attachment and proliferation. [ABSTRACT FROM AUTHOR]

Bone is a heterogeneous, hierarchical biocomposite material made of an organic matrix filled with a mineral component, which plays an important role in bone strength. Although the effect of the mineral/matrix ratio on the mechanical properties of bone during aging has been intensively investigated, the relationship between the mechanical properties and the chemical composition of bone with age requires additional research in juvenile individuals. In this study, bone coupons from bovine and ovine animal species were machined from cortical areas of long bones to quantify whether the variation in mechanical properties at different stages of development is related to the change in the composition of bone tissue. An energy-dispersive X-ray detector (EDX) attached to a scanning electron microscope (SEM) was used to perform a compositional analysis of the tissue. In addition, nanoindentation analyses were carried out to address how the elastic modulus changed with age. Nonparametric statistical analyses found significant differences (p < 0.05) in Ca content and elastic modulus between species, but no differences were found within each species with development. A multiple linear regression model found that the elastic modulus was significantly related to the decrease in P and C in the samples, to the animal species (larger in bovine), and development, although not linearly. This model also found an interaction between Ca and development that could explain the lack of significance of the relationship between the elastic modulus and development in the univariate models. [ABSTRACT FROM AUTHOR]

In this study, microstructural evolution and its effects on mechanical properties across the thickness of a 120 mm Ni-Cr-Mo industrial ultra-heavy steel plate were quantitatively investigated by means of optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and electron back-scatter diffraction (EBSD). The results show that the martensite fraction is 65% at 10 mm and disappears at 40 mm, while granular bainite appears at 35 mm and climbs up to as high as 32% at 60 mm, with M-A constituents significantly coarsened. The strength drops with the gradual coarsening of the laths as well as decreased martensite fraction from the surface to the centre. The toughness is mainly affected by the block size and the morphology and quantity of M-A constituents. This study established a multivariate function between the microstructure and toughness (50% fibre area transition temperature, FATT50) with careful consideration of the influence of effective grain size (EGS) and M-A constituent size distribution. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the preparation of Li-doped ZnO nanostructures through combustion and report on their structural, morphological, optical, and electrocatalysis properties. X-ray diffraction analyses show that the samples have a structure crystallized into the usual hexagonal wurtzite ZnO structure according to the P63mc space group. The scanning electron microscope images conceal all samples' nanosphere bundles and aggregates. The reflectance spectra analysis showed that the direct bandgap values varied from 3.273 eV (for pure ZnO, i.e., ZnL1) to 3.256 eV (for high Li-doped ZnO). The measured capacitance concerning frequency has estimated the variation of dielectric constant, dielectric loss, and AC conductivity against AC electric field frequency. The dielectric constant variations and AC conductivity are analyzed and discussed by well-known models such as Koop's phenomenological theory and Jonscher's law. The Raman spectra have been recorded and examined for the prepared samples. Rhodamine B was electro-catalytically degraded in all prepared samples, with the fastest time for ZnL5 being 3 min. [ABSTRACT FROM AUTHOR]

Due to the special geographical location, climatic characteristics, special soil properties and the flood zone of the Yellow River in Kaifeng, the groundwater level in the lower reaches of the river basin is high and contains much salt. The matrix suction and surface free energy of the Kaifeng city wall earthen site changed under capillary action, resulting in cracking, peeling and efflorescence to varying degrees. In order to reduce the deterioration of the Kaifeng city wall caused by environmental erosion, a select lime with excellent mechanical properties and waterproof methanesiliconic acid sodium salt with excellent water resistance were chosen to reinforce the earthen sites. In this paper, 0%, 3%, 5% and 7% lime, and 0%, 1%, 2% and 3% waterproof materials were selected to determine four types of imitation site soil with 16 different mix proportion samples. Further, samples with different mixing ratios were subjected to direct shear, a disintegration test, and a microscopic scanning electron microscope test. The results show that under different normal stresses, with the increase in waterproof material content, the growth rate of shear strength of imitation site soil ranges from 1.82% to 10.81%. With the increase in lime content, the shear strength of imitation site soil increases rapidly, up to 38.16%. Both materials can improve the shear strength of the soil site. Under reinforcement with the two materials, the cohesive force of the imitation site soil can be improved at a maximum rate of 59.23%, and the internal friction angle changes in the range of 36.72°–41.61°. Compared with the sample without waterproof material, the mass water absorption rate of the sample with waterproof material decreases in the range of 2.76–27.77, and with the increase in waterproof material, the mass water absorption rate of the sample gradually decreases. The chemical reaction products of the waterproof materials and lime can play a filling role in silty clay; filling micro-pores and micro-cracks between soil particles. [ABSTRACT FROM AUTHOR]

In this work, mechanical properties of reinforced polypropylene composites were studied. PP in particulates shape with two different melt flow indexes (MFI) was used, i.e., 3 and 23 g/10 min, namely PP3 and PP23, respectively. Three different materials, namely TiO2 nanoparticle (nTiO2, spherical, 0D), micro-size short carbon fiber (SCF, fiber, 1D), and graphite nanoplatelet (GNP, sheet, 2D), were used as reinforcements/fillers. PP and fillers (in the desired composition) were first pre-mixed by a mechanical mixer. The mixture was then fed to a co-rotating twin-screw extruder for melt-compounding, followed by injection molding to fabricate testing samples. The microstructure and fracture surface of the composites were observed by a scanning electron microscope (SEM). Additionally, tensile, flexural, impact, and hardness tests were conducted to evaluate their mechanical properties. The SEM images stipulate that PP23 had better adhesion and dispersion with the fillers. The results from the SEM images support the mechanical testing results. PP23 composites exhibited more significant improvement in mechanical properties in comparison to PP3. At 5 wt. % filler loading, PP/GNP composite exhibited a greater improvement in mechanical properties compared with two other composites, which are PP/SCF and PP/nTiO2 composites for both PPs. [ABSTRACT FROM AUTHOR]

The effects of La and Y on the microstructure and mechanical properties of cast Al-Si-Cu alloys were investigated by X-ray diffractometer (XRD), optical microscope (OM), and scanning electron microscope (SEM). The results indicated that the addition of La and Y had a great effect on the refinement of α-Al grains, the modification of eutectic Si phase, and the reduction of β-Al5FeSi length in Al-Si-Cu alloys. The A380 + 0.6 wt.% La/Y alloy exhibited the best microstructure and mechanical properties. The UTS and EI of the A380 + 0.6 wt.% La/Y alloy were 215.3 MPa and 5.1%, which were 22.9% and 37.8% higher than those of the matrix alloy, respectively. In addition, neither Al11La3 nor Al3Y generated by the addition of La and Y could not serve as the nucleation core of α-Al grains, so the grain refinement of α-Al originated from the growth limitation and constitutional supercooling. Since La and Y promote twinning generation and constitutional supercooling, the eutectic Si phase also changed from stripe-like to short fibrous or even granular and was significantly refined. Furthermore, thermodynamic calculations indicated that the Al11La3 phase was formed first and the Al3Y phase was generated on the Al11La3 phase. [ABSTRACT FROM AUTHOR]

Al–Zn composite coating can provide effective cathodic protection for E235 steel. This study aims to obtain the Al–Zn composite coating with the best anti-corrosion performance by optimizing the spraying temperature, spraying distance and powder-feeding motor speed. The Al and Zn powders were analyzed by scanning electron microscope (SEM), and the microstructure of the coatings prepared by different process parameters was observed by optical microscope. The mechanical and anticorrosive properties of the coating were evaluated using hardness, porosity, thickness and electrochemical tests. According to the experimental results, when the spraying temperature, spraying distance and powder-feeding motor speed were 500 °C, 27 mm and 1.5 r/min, respectively, the hardness of the coating was 67 HV, the porosity was 0.57% and the thickness was 0.588 mm. The EIS test results show that the coating has the maximum polarization resistance, and therefore the coating has good corrosion resistance at this parameter. [ABSTRACT FROM AUTHOR]

Twin-roll casting (TRC), as a near-net-shape technology, is employed to fabricate age-hardened Al-Mg-Si alloy. Compared with conventional direct chill (DC) casting, the TRC method is much more economical and efficient. In this work, the microstructure, precipitates behavior, and mechanical properties of age-hardened Al-Mg-Si alloy sheet fabricated by TRC were investigated by hardness measurements and tensile tests, metallographic microscopy, field emission gun scanning electron microscope, electron backscatter diffraction, transmission electron microscopy, and differential scanning calorimetry analyses. It was found that the size of recrystallized grains for DC casting alloy with finely dispersed particles was larger than that of TRC alloy with coarse particles. Typical CubeND texture accompanied by P texture formed after solution treatment made the value of r reach ~0.7 in the TRC alloy due to the PSN effect caused by the segregation of particles. More GP zones resulted in the strength of TRC alloy being higher than that of DC casting alloy after T8X treatment. With the time of paint-bake hardening extended to 8 h, few segregation particles remained in the TRC alloy. This decreased the concentration of supersaturated atoms. The hardness of the TRC alloy with the lower density of the β″ strengthening phase was lower compared to the DC casting alloy. [ABSTRACT FROM AUTHOR]

Al-Ti-C master alloy agent is currently the most promising grain refiner. This work investigates the influence of Ti3AlC2 addition (1.0–3.0 wt.%) on the microstructure of a hypoeutectic cast iron (4.7 wt.% Cr, 2.3 wt.% C). Microstructures of the samples were examined by SEM (scanning electron microscope). It was demonstrated that the added Ti3AlC2 did reduce the size of coarse primary carbides. The XRD (X-ray diffraction) pattern shows that Ti3AlC2 is decomposed into TiC in the alloy substrate. The EDS (energy dispersive spectrometer) interfacial element analysis shows that TiC combines well with the matrix interface. As the Ti3AlC2 amount was increased, the finest microstructure was achieved. When 2 wt.% Ti3AlC2 was added, the wear-resistance property of the material improved and became two times harder than the former. However, when 3% Ti3AlC2 was added, TiC gathered at the crystal boundary, which caused a decrease in the wear resistance of the material. [ABSTRACT FROM AUTHOR]

The bending effect of self-catalyst zinc oxide nanowires on a photoconducting behavior has been investigated by in-situ scanning electron microscope method and interpreted by analytical modeling. Zinc oxide NWs tend to incline due to geometric instability and because of the piezoelectric properties, which was confirmed by scanning electron microscope images. A cantilever bending model adequately describes the bending and bundling events, which are linked to the electrostatic interaction between nanowires. The light absorption of zinc oxide nanowires in the visible and near infrared bands has been modelled using the finite difference time domain method. The influence of the density of nanowires (25%, 50%, 75%) and the integration of plasmonic nanoparticles distributed on the seed layer (with varied radii) on the light absorption of zinc oxide nanowires was studied using simulation analysis. We have shown that the geometry of zinc oxide nanowires in terms of length, separation distance, and surface charge density affects the process of zinc oxide nanowires bending and bundling and that absorption will be maximized by integrating Au plasmonic nanoparticles with a radius of 10 nm. [ABSTRACT FROM AUTHOR]

A mixed oxide system consisting of Nb2O5 and Ta2O5, was subjected to annealing in air/hydrogen up to 950 °C for 1–4 h to study its sintering behavior. The thermogravimetric–differential scanning calorimetry (TGA–DSC) thermograms indicated the formation of multiple endothermic peaks at temperatures higher than 925 °C. Subsequently, a 30% Ta2O5 and 70% Nb2O5 (mol%) pellet resulted in good sintering behavior at both 900 and 950 °C. The scanning electron microscope (SEM) images corroborated these observations with necking and particle coarsening. The sintered pellets contained a 20.4 and 20.8% mixed oxide (Nb4Ta2O15) phase, along with Ta2O5 and Nb2O5, at both 900 and 950 °C, indicating the possibility of the formation of a solid solution phase. In situ high-temperature X-ray diffraction (XRD) scans also confirmed the formation of the ternary oxide phase at 6 and 19.8% at 890 and 950 °C, respectively. The Hume–Rothery rules could explain the good sintering behavior of the Ta2O5 and Nb2O5 mixed oxides. An oxide composition of 30% Ta2O5 and 70% Nb2O5 (mol%) and a sintering temperature of 950 °C appeared adequate for fabricating well-sintered oxide precursors for subsequent electrochemical polarization studies in fused salts. [ABSTRACT FROM AUTHOR]

A complex concentrated noble alloy (CCNA) of equiatomic composition (Ag20Pd20Pt20Cu20Ni20–20 at. %) was studied as a potential high—performance material. The equiatomic composition was used so that this alloy could be classified in the subgroup of high—entropy alloys (HEA). The alloy was prepared by induction melting at atmospheric pressure, using high purity elements. The degree of metastability of the cast state was estimated on the basis of changes in the microstructure during annealing at high temperatures in a protective atmosphere of argon. Characterisation of the metallographically prepared samples was performed using a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS), differential scanning calorimetry (DSC), and X–ray diffraction (XRD). Observation shows that the microstructure of the CCNA is in a very metastable state and multiphase, consisting of a continuous base of dendritic solidification—a matrix with an interdendritic region without other microstructural components and complex spheres. A model of the probable flow of metastable solidification of the studied alloy was proposed, based on the separation of L—melts into L1 (rich in Ni) and L2 (rich in Ag). The phenomenon of liquid phase separation in the considered CCNA is based on the monotectic reaction in the Ag−Ni system. [ABSTRACT FROM AUTHOR]

High-entropy alloys are a new generation of materials that have attracted the interest of numerous scientists because of their unusual properties. It seems interesting to use these alloys in biomedical applications. However, for this purpose, the basic condition of corrosion resistance must be fulfilled. In this article, selected corrosion properties of self-composed high-entropy alloys are investigated and compared with conventional biomedical alloys, that is titanium alloys and stainless steels. Corrosive parameters were determined using the potentiodynamic method. X-ray diffraction studies were performed to characterize the crystal structures. Microstructures of the prepared materials were examined using a scanning electron microscope, and surface hardness was measured by the Vickers method. The results show that investigated high-entropy alloys are characterized by simple structures. Three out of four tested high-entropy alloys had better corrosion properties than conventional implant alloys used in medicine. The Al0.7CoCrFeNi alloy was characterized by a corrosion potential of −224 mV and a corrosion current density of 0.9 μA/cm2; CoCrFeNiCu by −210 mV and 1.1 μA/cm2; TiAlFeCoNi by −435 mV and 4.6 μA/cm2; and Mn0.5TiCuAlCr by −253 mV and 1.3 μA/cm2, respectively. Therefore, the proposed high-entropy alloys can be considered as potential materials for biomedical applications, but this requires more studies to confirm their biocompatibility. [ABSTRACT FROM AUTHOR]

Although polyurea has attracted extensive attention in impact mitigation due to its protective characteristics during intensive loading, the ballistic performance of polyurea-reinforced ceramic/metal armor remains unclear. In the present study, polyurea-reinforced ceramic/metal armor with different structures was designed, including three types of coating positions of the polyurea. The ballistic tests were conducted with a ballistic gun; the samples were subjected to a tungsten projectile formed into a cylinder 8 mm in diameter and 30 mm in length, and the deformation process of the tested targets was recorded with a high-speed camera. The ballistic performance of the polyurea-reinforced ceramic/metal armor was evaluated according to mass efficiency. The damaged targets were investigated in order to determine the failure patterns and the mechanisms of interaction between the projectile and the target. A scanning electron microscope (SEM) was used to observe the microstructure of polyurea and to understand its failure mechanisms. The results showed that the mass efficiency of the polyurea-coated armor was 89% higher than that of ceramic/metal armor, which implies that polyurea-coated ceramic armor achieved higher ballistic performance with lighter mass quality than that of ceramic/metal armor. The improvement of ballistic performance was due to the energy absorbed by polyurea during glass transition. These results are promising regarding further applications of polyurea-reinforced ceramic/metal armor. [ABSTRACT FROM AUTHOR]

In this paper, shields made of 1.3964 stainless steel bonded to a fiber laminate were subjected to ballistic impact response of 7.62 × 51 mm ŁPS (light projectile with a lead core) projectiles. Additionally, between the steel sheet metal and the laminate, a liquid-filled bag was placed, which was a mixture of ethylene glycol (C2H6O2) with 5 wt.% SiO2 nanopowder. Numerical modeling of the projectile penetrating the samples was carried out using the finite element method in the Abaqus program. The elasto-plastic behavior of the projectile material and the component layers of the shields was taken into account. Projectile penetration through glycol-filled bag has been performed using the smooth particle hydrodynamics technique. The morphology of the penetration channel was also analyzed using a scanning electron microscope. For the shield variant with a glycol-filled bag between the steel and laminate plates, the inlet speed of projectile was 834 m/s on average, and 366 m/s behind the sample. For the variant where there was no glycol-filled bag between the steel and laminate plates, the inlet and outlet average velocities were 836 m/s, after 481 m/s, respectively. Referring to the steel-glycol-laminate and steel-laminate variants, it can be concluded that the laminate-glycol-laminate is more effective. [ABSTRACT FROM AUTHOR]

As a kind of typical high stacking fault energy materials, recrystallization behavior of high purity Al-0.5%Cu alloy is significantly influenced by the annealing process. In this study, different heating rate, target temperature, and holding time were discovered to have profound impact on the microstructures and textures of Al-0.5%Cu plates. Electron backscatter diffraction (EBSD), scanning electron microscope (SEM), and X-ray diffraction (XRD) were utilized for analyzing the evolution of the microstructure and texture in the subsequent microstructural characterization. Vickers hardness tests were employed for measuring hardness of specimens. The results showed that no obvious recrystallization was observed at lower temperature and the composition of texture influenced by rising temperature, heating rate affected initial recrystallization temperature, grain size, and strength of textures. After recrystallizing completely, the size of microstructures and the distribution of textures had little change with the extension of holding time. [ABSTRACT FROM AUTHOR]

In this study, sodium methylsilicate and lime were selected to prepare the same proportion of Imitation Site Soil, and according to the principle of carbonation reaction of restoration materials, the effect of carbonation reaction on the performance of restoration soil of earthen sites was studied. The study has good significance for the conservation and restoration of earthen sites. The samples were cured with CO2 concentration and curing age as variables. After curing, the samples were tested to determine their water-resistant properties, uniaxial compressive strength, and pH value and a micro scanning electron microscope was used. The results indicated that the carbonation reaction can quickly improve the water resistance and compressive strength of imitation site soil, and reduced the water absorption by 16.67% compared to the specimens conditioned at 0.03% CO2 concentration. The UCS of specimens at 5%, 10%, and 15% CO2 concentrations increased by 72.22%, 131.19%, and 219.27%, respectively, compared with those at 0.03% CO2 concentration after the specimens were environmentally maintained in the carbonation chamber at 0.03%, 5%, 10%, and 15% CO2 concentrations for 120 h, respectively. The internal particle gradation of the imitation site soil improved after carbonation. These results provide a basis for improving the restoration technology of earthen sites. [ABSTRACT FROM AUTHOR]

An in situ tensile test of the ring-rolled GH4169 alloy is performed to investigate the plastic deformation behavior at the micro level. Slip system activations are identified by slip traces captured by a scanning electron microscope and lattice orientation data acquired by electron backscattered diffraction. Our results demonstrated that the fraction of low-angle grain boundaries gradually increased upon tensile deformation, and the misorientation evolution in the grain interior was severely inhomogeneous. The Schmid factors at the grains of interest are calculated for comparison with the actual activated slip systems. Most of the slip system activation coincides with the Schmid law, as opposed to the initiation of other potential slip systems at some grains. [ABSTRACT FROM AUTHOR]

Energy consumption and carbon emissions are lower in the production of belite-ye′elimite-ternesite (C2S-C4A3$-C5S2$, BYT) clinker than Portland cement (PC) clinker. BYT cement can combine the early strength of CSA cements and the durability of belite cements. X-ray diffraction, mercury intrusion porosimetry, isothermal conduction calorimetry and scanning electron microscope were conducted to investigate the hydration process of BYT cement. The hydration products of BYT cement include mainly ettringite, strätlingite and some amorphous AH3 (aluminum hydroxide). Ternesite did prove an early reactivity in BYT cement. The reaction of ternesite with AH3 occurs on the surface of ternesite. Ternesite delays the second heat flow peak of ye′elimite. The strength of BYT cement containing 10% ternesite in the prepared clinker exceeds that of other cement at all ages. [ABSTRACT FROM AUTHOR]

The influence of tempering temperature on the microstructure of 0.5Cr0.4W steels was investigated by scanning electron microscope, and the roles of grain boundary character, dislocation, and Taylor factor in sulfide stress cracking (SSC) resistance were interpreted using the election backscattered diffraction technique. The 0.5Cr0.4W steels tempered at 690 °C, 700 °C, and 715 °C all showed tempered martensites. The specimen tempered at 715 °C exhibited a higher critical stress intensity factor (KISSC) of 34.58 MPa·m0.5, but the yield strength of 800 MPa did not meet the criterion of 125 ksi (862 MPa) grade. When the specimen was tempered at 690 °C, the yield strength reached 960 MPa and the KISSC was only 21.36 MPa·m0.5, displaying poorer SSC resistance. The 0.5Cr0.4W steel tempered at 700 °C showed a good combination of yield strength (887 MPa) and SSC resistance (KISSC: 31.16 MPa·m0.5). When increasing the tempering temperature, the local average misorientation and Taylor factor of the 0.5Cr0.4W steels were decreased. The reduced dislocation density, and greater number of grains amenable to slippage, produced less hydrogen transport and a lower crack sensitivity. The SSC resistance was, thus, increased, owing to the minor damage to hydrogen aggregation. Therefore, 700 °C is a suitable tempering temperature for 0.5Cr0.4W casing steel. [ABSTRACT FROM AUTHOR]

Various contents of carbon fibers (CFs) and potassium titanate whiskers (PTWs) were added to an Fe-based impregnated diamond bit (IDB) matrix to enhance its adaptability to percussive–rotary drilling. A series of mechanical tests were conducted successively to find the effects of the reinforcing materials on the properties of the Fe-based IDB samples. Then, the fracture surfaces of the samples were analyzed via scanning electron microscopy (SEM) and energy-dispersive spectroscopy, and the worn surfaces and abrasive debris of the samples were analyzed using a laser scanning confocal microscope and SEM. The results show that both the CF and PTW can effectively improve the hardness and bending strength of an Fe-based IDB matrix, and those parameters reached their maximum values at the additive amount of 1 wt%. However, the CF had a better enhancement effect than the PTW. Furthermore, the CF improved the impact wear resistance of the IDB matrix, with a minimum wear rate of 2.38 g/min at the additive amount of 2 wt%. However, the PTW continuously weakened the impact wear resistance of the IDB matrix with increases in its content. Moreover, the morphologies of the worn surfaces indicated that the minimum roughness of the CF-reinforced IDB matrix decreased significantly to as low as 4.91 μm, which was 46.16% lower than that without CF, whereas the minimum roughness of the PTW-reinforced samples decreased by 11.31%. Meanwhile, the abrasive debris of the CF-reinforced samples was more uniform and continuous compared to that of the PTW-reinforced samples. Overall, the appropriate addition of CF or PTWs can enhance the mechanical properties of Fe-based IDB matrices, which can be used on different formations based on their impact wear resistance. [ABSTRACT FROM AUTHOR]

In this paper, we conduct a comprehensive investigation into PVA fiber modified with SiO2 to improve the mechanical properties of oil-well cements. Specifically, SiO2 was coated onto the surface of polyvinyl alcohol fiber (PVAF) as its silicon source via a sol-gel process by using tetraethyl orthosilicate (TEOS), while hydrochloric acid and ammonia were respectively used as the catalyst in the sol (hydrolysis) and the gel (condensation) processes. The PVAF microstructure was then characterized with the scanning electron microscope (SEM), while the effects of the modified PVAF on both mechanical and rheological properties of oil-well cements were examined. Due to the fact that SiO2 can be uniformly coated onto the PVAF surface, such modified PVAF can slightly improve the rheology of the cement slurry, while the raw PVAF exhibits poor dispersion at a high dosage. Compared with those of cement stone without PVAF after curing for 28 days at 60 °C, the flexural strength, compressive strength, and elastic modulus of the cement stone incorporated with the modified PVAFs were enhanced by 37.7%, 66.1%, and 50.0%, respectively. The SEM test (EDX) test, XRD test, and thermogravimetric test prove that the SiO2 coating on the PVAF surface can promote the hydration of cement clinker and can react with Ca(OH)2 to generate CSH gel. The SiO2 grafted onto the surface of PVAFs can improve the bond strength at the fiber/cement matrix interface, thus improving the mechanical properties of cement stone. [ABSTRACT FROM AUTHOR]

The significant impact of Nb on ferrite transformation, both in terms of solute drag effect (SDE) and interphase precipitation, was investigated quantitatively. Ferrite transformation kinetics were characterized using thermal expansion experiments and theoretical calculations. The microstructures were characterized using high−temperature confocal laser scanning microscopy (CLSM), a field−emission scanning electron microscope (FESEM), and a transmission electron microscope (TEM). Under a higher driving force, interphase precipitations were observed in the sample with a higher Nb content. A three−dimensional (3D) reconstruction method was used to convert the two−dimensional (2D) image of interphase precipitation into a three−dimensional model for a more typical view. The SDE and interphase precipitation had opposite effects on the kinetics of ferrite transformation. A lower Nb content showed a strong contribution to the SDE, which delayed ferrite transformation. A higher concentration of Nb was expected to enhance the SDE, but the inhibition effect was eliminated by the interphase precipitation of NbC during interfacial migration. Both the experimental results and theoretical calculations confirmed this phenomenon. [ABSTRACT FROM AUTHOR]

The existence of lead-zinc tailings threatens the social and ecological environment. The recycling of lead–zinc tailings is important for the all-round green transformation of economic society. In this study, the possibility of fabricating sintered ordinary bricks with lead–zinc tailings was studied based on orthogonal experimentation, and the phase composition and micromorphology of sintered products were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). With lead–zinc tailings as the main material, and clay and fly ash as additives, the effect of clay content, forming pressure, sintering temperature, and holding time on physical properties of sintered bricks was analyzed. The results show that clay content and sintering temperature have a major effect on compressive strength, while sintering temperature and holding time play an important role in water absorption. During sintering, mica, chlorite, and other components in lead–zinc tailings are decomposed to form albite, hematite, maghemite, and anhydrite, which play a role in the strength of bricks. The optimal process parameters were found to be a ratio of lead–zinc tailings:clay:fly ash = 6:3:1, forming pressure of 20 MPa, firing temperature of 1080 °C, and holding time of 60 min. The corresponding compressive strength and water absorption were 34.94 MPa and 16.02%, which meets the Chinese sintered ordinary bricks standard (GB/T 5101-2017). [ABSTRACT FROM AUTHOR]

This paper provides insights into the four key behaviors and mechanisms of the aging to failure of batteries in micro-overcharge cycles at different temperatures, as well as the changes in thermal stability. The test results from a scanning electron microscope (SEM) and an energy-dispersive spectrometer (EDS) indicate that battery failure is primarily associated with the rupture of cathode materials, the fracturing and pulverization of electrode materials on the anode current collector, and the formation of lithium dendrites. Additionally, battery safety is influenced by environmental temperatures and the battery's state of health (SOH), with failed batteries exhibiting the poorest stability and the highest mass loss rates. Under isothermal conditions, micro-overcharge leads to battery failure without thermal runaway. Thus, temperature stands out as the most influential factor in battery safety. These insights hold significant theoretical and practical value for the development of more precise and secure battery management systems. [ABSTRACT FROM AUTHOR]

The rotor or impeller is a rotational and key part of a pump and compressor. This article presents the detailed development process of a rotor of small size constructed from an EN8 steel cylindrical blank using a novel technique based on a computer numerical control engraving milling machine (CNC-EMM) equipped with a 4 mm tungsten carbide end mill cutter. We fabricated a total of twenty-eight stepped rotors following the Box–Behnken Design (BBD) DoE technique at fourteen distinct combinations of CNC-EMM variable parameters, namely rotational speed, feed, and plunge feed. Average roughness 'Ra', an important surface quality indicator, has been considered and presented in this article, as a quality measure for the fabricated rotors. Feed and plunge feed have been identified as the most influencing variable parameters as per an analysis of variance (ANOVA) test. The lowest average roughness value obtained by this process for the rotor blade was 0.11 µm. A micrograph obtained from a field-emission scanning electron microscope (FE-SEM) showed a uniform and accurate tooth profile along with burr formation at corner edges. This study claims to establish engraving milling as a viable alternative to other manufacturing processes used for rotor blades. The findings of this study are useful to scholars, engineers, and researchers who are exploring new ways to fabricate mechanical parts and components. [ABSTRACT FROM AUTHOR]

Although cemented soil as a subgrade fill material can meet certain performance requirements, it is susceptible to capillary erosion caused by groundwater. In order to eliminate the hazards caused by capillary water rise and to summarize the relevant laws of water transport properties, graphene oxide (GO) was used to improve cemented soil. This paper conducted capillary water absorption tests, unconfined compressive strength (UCS) tests, softening coefficient tests, and scanning electron microscope (SEM) tests on cemented soil using various contents of GO. The results showed that the capillary water absorption capacity and capillary water absorption rate exhibited a decreasing and then increasing trend with increasing GO content, while the UCS demonstrated an increasing and then decreasing trend. The improvement effect is most obvious when the content is 0.09%. At this content, the capillary absorption and capillary water absorption rate were reduced by 25.8% and 33.9%, respectively, and the UCS at 7d, 14d, and 28d was increased by 70.32%, 57.94%, and 61.97%, respectively. SEM testing results demonstrated that GO reduces the apparent void ratio of cemented soil by stimulating cement hydration and promoting ion exchange, thereby optimizing the microstructure and improving water resistance and mechanical properties. This research serves as a foundation for further investigating water migration and the appropriate treatment of GO-modified cemented soil subgrade. [ABSTRACT FROM AUTHOR]

The present study investigates the creep behavior and deformation mechanism of a third-generation single-crystal Ni-based superalloy at 1170 °C under a range of stress levels. Scanning electron microscopes (SEM) and transmission electron microscopes (TEM) were employed to observe the formation of a rafted γ′ phase, which exhibits a topologically close-packed (TCP) structure. The orientation relationship and elemental composition of the TCP phase and matrix were analyzed to discern their impact on the creep properties of the alloy. The primary deformation mechanism of the examined alloy was identified as dislocation slipping within the γ matrix, accompanied by the climbing of dislocations over the rafted γ′ phase during the initial stage of creep. In the later stages of creep, super-dislocations with Burgers vectors of a<010> and a/2<110> were observed to shear into the γ′ phase, originating from interfacial dislocation networks. Up to the fracture, the sequential activation of dislocation shearing in the primary and secondary slipping systems of the γ′ phase occurs. As a consequence of this alternating dislocation shearing, a twist deformation of the rafted γ′ phase ensued, ultimately contributing to the fracture mechanism observed in the alloy during creep. [ABSTRACT FROM AUTHOR]

The activity of biomaterials used during endodontic treatment can be affected by various factors. One of them is the chemical action of the irrigant that they are exposed to. The aim of this multimethod ex vivo study was to evaluate the influence of ethylenediaminetetraacetic acid (EDTA) on the surface appearance and chemical composition of Biodentine used in perforation repair. Twenty material specimens were prepared according to manufacturers' recommendations and divided into two setting-time-based groups, tested after 45 min (group A) and 24 h (group B) of setting. Material was irrigated with 17% EDTA solution with or without simultaneous ultrasonic activation. The surface characteristics and the chemical composition analysis of the Biodentine specimens were performed with the aid of a scanning electron microscope (SEM) and an energy dispersive spectroscopy (EDS) method, respectively. The volumetric loss of material was measured by dedicated digital software in an optical microscope. Statistical analysis was performed. The EDS study confirmed that after the rinsing protocol, the percentage content of elements differed between the groups. The EDTA rinse, whether ultrasonically activated or not, visibly affected the surface appearance and chemical composition of Biodentine. The specimens' surface subjected to irrigation was more irregular under SEM than in a control group. The US activation of the liquid amplified its impact on the tested material. The average volume loss in group A after 5 min irrigation was 3.98 µm3 for each µm2 of the chosen area and it increased up to 7.74 µm3/μm2 after the ultrasonic activation. In group B, indicated volume loss values were 6.30 and 11.70 µm3/μm2 for 5 min irrigation without and with US activation, respectively. Using a 20 min irrigation time and ultrasonic activation increased it up to 32.71 µm3/µm2. Each rinsing protocol involving irrigation with ethylenediaminetetraacetic acid modified the surface features and the chemical composition of the evaluated hydraulic tricalcium silicate cement. Further research is needed to indicate the possible impact of the observed changes on its long-term clinical performance. [ABSTRACT FROM AUTHOR]

Despite numerous studies focused on the hydrothermal (HT) synthesis of fly ash zeolites (FAZs), this method still has many limitations, the main of which is the low yield of zeolites. Hydrothermally synthesized zeolites are typically multiphase and exhibit low purity, which limits their applicability. Pure-phase zeolites have been primarily prepared from filtrates after alkaline mineralization of fly ashes, not directly in suspension. In addition, the published methodologies have not been tested in a wider set of samples, and thus their reproducibility is not confirmed. The aim of the study is to propose a reproducible methodology that overcomes the mentioned limitations. The influence of the Si/Al ratio (1.3:1–1:2), the type and concentration of the activator (2/4 M NaOH/KOH/LiOH), the reagent (30% LiCl), the duration (24–168 h), and the temperature (50–180 °C) of the synthesis phases were studied. The sequence of the synthesis phases was also optimized, depending on the type of heat transfer. The fly ashes were analyzed by wavelength-dispersive X-ray fluorescence (WD XRF), flame atomic absorption spectrometry (F-AAS), and X-ray diffraction (XRD). The energy intensity of the synthesis was reduced through the application of unique microwave digestion technology. Both microwave and combined (microwave and convection) syntheses were conducted. FAZs were identified and quantified by XRD analysis. This study presents a three-stage (TS) hydrothermal synthesis of pure-phase sodalite in suspension. Sodalite (>99 wt.%) was prepared from nine fly ashes under the following conditions: I. microwave phase: 120 °C, 150 min, solid-to-liquid ratio (S/L) 1:5, Si/Al ratio 1:1.5, and 4 M NaOH; II. convection phase: 120 °C, 24 h, S/L 1:40, and the addition of 30 mL of 30% LiCl; and III. crystallization: 70 °C for 24 h. The formation of rhombododecahedral sodalite crystals was confirmed by scanning electron microscope (SEM) images. [ABSTRACT FROM AUTHOR]

The operational suitability of electromagnetic starters equipped with experimental contacts has been substantiated within their use in electrical installations of the agro-industrial sector, which may be affected by the environments containing aggressive components. Tests on commutation wear resistance and investigations on arc erosion of the series-produced contact parts of such starters as PML-1100O4, PML-2100O4 (versions A and B; contact material—CpH-90, CpM-0,2 + M1, KMK-A10m, respectively) and PML-1100O4 starter with the experimental copper-based contact parts (Cu + Nb + Zr + Y2O3; Cu + Mo + MoO3 + C + Ni; Cu + Cr + TiB2 + Nb + C + Zr) have been conducted. The influence of energy parameters of a commutated circuit on the value of electro-erosion wear, the morphology of the working surfaces of contacts and contact resistance have been determined. Investigation results have been obtained by conducting a set of tests on electromagnetic starters at the experimental plant that simulates the operating conditions of the AC-3 application category. The impact of the electric arc of alternative current on the arc erosion of silver-based and copper-based contact materials have been determined by using a scanning electron microscope Cambridge Stereoscan S4-10 equipped with an attachment for X-ray spectroscopic analysis, Link System-290 and an X-ray microanalyzer Camebax SX-50 (CAMECA, Gennevilliers, France). A metallographic analysis of the contact surfaces has been conducted, which contributed to the determination of the patterns of erosive destruction of bridging contacts based on Ag and Cu. Evolution of the eroded morphology of contacts and the surface components of electrical contacts under the influence of an arc have been characterized. In addition, contact mass loss and the dependence of contact resistance have been studied. When manufacturing the experimental contacts, it is possible to abandon the use of silver, which is significantly cost saving, and not to use dangerous contact additives that are hazardous to the environment and people's health. [ABSTRACT FROM AUTHOR]

A Ni60+30%WC composite coating was prepared on the surface of Q235 steel by utilizing a high cooling rate, small thermal deformation of the substrate material, and the good metallurgical bonding characteristics of laser cladding technology. This paper focuses on the study of the composite coatings prepared under different process parameters in order to select the optimal process parameters and provide theoretical guidance for future practical applications. The macroscopic morphology and microstructure of t he composite coatings were investigated with the help of an optical microscope (OM) and a scanning electron microscope (SEM). The elemental distribution of the composite coatings was examined using an X-ray diffractometer. The microhardness and wear resistance of the composite coatings were tested using a microhardness tester, a friction tester, and a three-dimensional (3D) profilometer. The results of all the samples showed that the Ni60+30%WC composite coatings prepared at a laser power of 1600 W and a scanning speed of 10 mm/s were well formed, with a dense microstructure, and the microhardness is more than four times higher than the base material, the wear amount is less than 50% of the base material, and the wear resistance has been significantly improved. Therefore, the experimental results for the laser power of 1600 W and scanning speed of 10 mm/s are the optimal process parameters for the preparation of Ni60+30%WC. [ABSTRACT FROM AUTHOR]