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This paper is a study of the mechanical properties and microstructures of the similar friction weld joints (TiAl6V4 and AA2024) using a servo-controlled Rotary Friction Welding (RFW) system. The friction welding operations were performed with seven different values of the friction pressure in the range of 2–14 MPa. The temperature is recorded during friction welding tests using k-type thermocouples. Tensile tests and microhardness measurements were carried out to obtain the mechanical properties of the friction weld joints. Microstructural changes of individual zone of the friction welds were investigated using an optical microscope (OM), and the fracture surfaces were observed using a scanning electron microscope (SEM). For AA2024, the fracture occurs most frequently in the central zone, resulting in lower tensile strength values, while for TiAl6V4, the fracture is occurs outside the friction weld interface, indicating that the friction weld joint is more resistant than the base metal. Microscopic analysis of the fracture surfaces of the AA2024 samples revealed diverse morphologies, with rough cupular surfaces predominating, indicating a dominant ductile fracture mode. Similarly, TiAl6V4's friction welded specimen also exhibited cupules of various sizes across its surface, primarily associated with a ductile fracture mode. Overall, the optimal friction pressure values (respectively 8 and 10 MPa for TiAl6V4 and AA2024) correspond to the highest values of the mechanical properties. [ABSTRACT FROM AUTHOR]

Dirinaria picta is a lichen species known for its tolerance to air pollution and its ability to accumulate pollutants in its thallus, making it a suitable bioindicator in urban areas. This study aims to assess the response of lichens to air pollution by examining their morphological characteristics, analyzing the presence of magnetic grains, and identifying the origin of elements in their tissues. Samples were collected from three locations in Bandung area which represent polluted areas, namely Juanda Street (JD) and Kebon Kawung (KK), and Padalarang Street (PD) and one location which represent as a control area with low pollution levels, namely Curug Cimahi (CC). Lichen microstructure scanning was performed using a Scanning Electron Microscope (SEM), and the presence of elements was detected through Energy Dispersive X-ray Spectroscopy (EDS). The SEM analysis revealed that samples from areas with higher air pollution levels exhibited obvious damage to their thallus, characterized by a more porous structure and the presence of cuboidal particles. Conversely, samples from control area showed a more compact structure. The EDS observations identified 14 elements present in the lichen tissues, ranked in descending order of abundance: C>Ca>O>Pb>Cu>Mn>Zn>Fe>Cr>Al>Cl>Se>Cd>K. The composition and quantity of these elements in lichen tissues were influenced by the level of air pollution generated by the number of vehicles passing through the area. The more vehicles, the higher the level of air pollution, resulting in greater stress for the D. picta population. [ABSTRACT FROM AUTHOR]

The effects of different quenching methods on the microstructure and mechanical properties of 30MnB5NbTi hot stamping steel are investigated, and the quenched microstructure is characterized by scanning electron microscope (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The mechanical properties are evaluated by uniaxial tensile test. The results reveal that, in comparison to die quenching, oil quenching, or air cooling, water‐quenched samples (tempered after water quenching, die quenching and oil quenching) exhibit the highest ultimate tensile strength (UTS) and yield strength (YS), reaching 2052 and 1422 MPa, respectively. Various quenching methods enable multi‐level strength control for the same steel grade, achieving a strength control range of ≈1000 MPa. The microstructure of samples quenched by water, die, and oil is fully martensite, and martensite exhibited block and lath morphology. With the increase of cooling rate, martensite laths become finer and the prior austenite size decreased. The microstructure of air‐cooled samples is martensite, ferrite, and retained austenite. The strengthening mechanisms of different quenched samples are calculated. The results show that dislocation strengthening and precipitation strengthening are the two dominant strengthening mechanisms in 30MnB5NbTi hot stamping steel. Therefore, the properties of hot stamping steel can be improved by changing the cooling rate by designing physical dies. [ABSTRACT FROM AUTHOR]

This research delved into the structural, morphological, and magnetic characteristics of rare earth doped strontium ferrites (SrRE x Fe 12-x O 19 (x = 0.05–0.2, RE = La, Sm, Eu, Dy, Er, Lu)) synthesized via the sol-gel method. The dopant ion radius is correlated with the performance of the material to a certain extent. Barium and calcium doping and related iron deficiency state experiments were designed to substantiate the reciprocal dependence between ion radius and coercivity. X-ray diffraction results revealed that doping ions had the capacity to modify lattice dimensions. The lattice size does not exhibit a clear linear relationship with the radius of the doping ion, nor does it inherently correlate with the grain size. The scanning electron microscope demonstrated that ion doping had the capacity to influence the size of grains. A general consequence of rare earth doping is the reduction in the saturation magnetization of strontium ferrites. The lanthanide contraction effect significantly influences the changes in coercivity. It is noteworthy that the variations in lattice internal space induced by doping constitute a primary driving factor for the observed coercivity dependence on the radius of the doping ion. [ABSTRACT FROM AUTHOR]

P91 and P92 steels are widely used in nuclear and thermal power plant's high-temperature (650–700 °C) operating components. The welding procedure, base plate composition, filler material composition, and post-weld heat treatment (PWHT) significantly affect the metallurgical characterization of weldments at room temperature. This work focuses on joining P91 and P92 steel by the TIG welding with filler ER90S-B9. The study analyzes the materialization of coarse-grained HAZ (CGHAZ), inter-critical HAZ (ICHAZ), and fine grained HAZ (FGHAZ) under welded and PWHT. PWHT was conducted at 840 °C for 2, 4 and 6h. An optical microscopic (OM) scanning electron microscope (SEM) was employed to characterize the welded and PWHT samples. It was perceived that the tensile strength of PWHT increased as the heat treatment times increased from 2 to 6 h, while the hardness value decreased accordingly. The maximum tensile strength (594.71 MPa) was observed in PWHT_6 h, while the minimum tensile strength (537.52 MPa) was perceived in the as-welded sample. The PWHT_6h reveals the minimum hardness values (271.12 HV) at the fusion zone among all the conditions. The WFZ consisted of an untampered lath martensitic grain structure, demonstrating an average hardness value of 314.15 HV in the PWHT_2h condition. The hardness value in CGHAZ samples for as-welded, PWHT_2h, PWHT_4h, and PWHT_6h was observed at 456.85, 436.81, 368.63, and 327.41 HV, respectively. [ABSTRACT FROM AUTHOR]

Recycling crushed clay bricks (CCB) in concrete is a sustainable and cost-effective process. Huge quantities of crushed clay bricks waste cause many serious environmental problems around the world. To deal with this problem, crushed bricks were recycled in the concrete industry as an alternative to natural resources, and the brick powder was reused as a partial replacement for cement. The objective of this paper is to study the effect of crushed clay bricks on the characteristics of concrete. 7 concrete mixtures containing coarse crushed brick aggregate (CCBA) and fine crushed brick aggregate (FCBA) were prepared as a complete substitute for sand and dolomite, respectively. Clay brick powder (CBP) and silica fume were used as a partial substitute for cement by 5%, 10%, and 15% of its weight. The water-to-cement ratio was 0.35. For comparison, a control mixture was prepared. Various tests were conducted to evaluate the performance of concrete. The results showed that the workability of the different mixtures containing CCB decreased compared to that of the reference mixture. The compressive strength values of mixtures containing CCBA had a clear decrease compared to the reference mix at 7, 28, and 56 days of curing. The modulus of rupture results had the same path as compressive strength results. The thermal conductivity coefficient for mixtures including CCBA decreased compared to the control mix. Scanning Electron Microscope images indicated crystals of calcium silicate hydrate because of the pozzolanic interaction between the brick powder and the fine crushed clay bricks with calcium hydroxide. [ABSTRACT FROM AUTHOR]

The wrought nickel–chromium–cobalt Nimonic 90 alloy is widely used in turbine blades, piston rings and forged tools due to their high stress-rupture strength and creep resistance up to 920∘C. The application components showed unavoidable wear behaviors at high loads due to the reduced resistance of the components. Hence, in order to increase the wear resistance of this alloy, Inconel 625 and Nimonic 90 particle depositions have been carried out on Nimonic 90 substrate through the laser-cladding techniques to study the microstructure, mechanical and tribological behaviors of alloys. The phases, microstructure and microhardness of the claddings were investigated by X-ray diffractometry (XRD), Transmission electron microscopy (TEM), Scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDS) and hardness test, respectively. Results showed that the mean thickness of the interfacial layer of Inconel 625 and Nimonic 90 was 18.51 ± 4 μ m and 90.68 ± 7 μ m, respectively. The microstructure of the cladding surfaces resulted in dendritic and interdendritic structures. An overall analysis found that the gamma-Ni and hard laves phases were presented in Inconel 625 and Nimonic 90 clad surfaces, respectively. Nimonic 90 clad surface had a high hardness and wear resistance compared with Inconel 625 clad surface and substrate due to the present hard laves phase. Besides, the roughness of the Nimonic 90 clad surface was lower compared with the Inconel 625 clad surface and substrate. [ABSTRACT FROM AUTHOR]

To develop microwave‐absorbing properties of dielectric ceramics, B4C/C composite powders were prepared by combustion synthesis with B2O3, polyvinyl alcohol, and Mg as the raw materials in this work. The XRD, Raman, scanning electron microscope with energy‐dispersive spectroscopy, and VNA network analysis carried out the effects of the addition of azodicarbonamide (AC) foaming agent on the phase compositions, microstructure, and dielectric and microwave‐absorbing properties of the products. The results indicated that the addition of an AC foaming agent contributed to the formation of distinct morphologies with a larger specific surface area and uniform distribution of the free carbon in the B4C/C composite powders and improved its graphitization degree, which resulted in the formation of equivalent microcapacitors, enhanced interfacial polarization, improved conductive network, and leading to a low reflection loss (RL) and a broadened effective absorb bandwidth (EAB). Due to the dielectric loss as the dominant loss mechanism, C‐1.5 (1.5 wt.% AC foaming agent addition) exhibits the EAB of 3.02 GHz and the minimum RL (RLmin) of −22.90 dB at the thickness of 2.20 mm. [ABSTRACT FROM AUTHOR]

In this work, microporous MgO–Al2O3 refractory aggregates were prepared with Mg(OH)2 and Al(OH)3 via the in situ decomposition synthesis method. The effect of Al(OH)3 addition on the microstructure and properties of microporous MgO–Al2O3 refractory aggregates was investigated with scanning electron microscope and mercury intrusion porosimetry. The results indicated that the improved green density of the samples and the reaction sintering accelerated the mass transport rate with adding Al(OH)3 from 0 to 4.0 wt%. Besides, a small amount of Al3+ diffused into porous MgO particles, accelerating the merging and growth of nanopores in the porous MgO particles. The intra‐particle pore size and the densification degree of microparticles were increased, and thus the strength of the samples was improved. Due to the formation of Kirkendall voids by interdiffusion of Mg2+ and Al3+, the inter‐particle pore size increased. Adding Al(OH)3 from 4.0 to 17.6 wt%, the Kirkendall voids weakened the mass transport rate and improved the inter‐particle pore size. The merging and growth of nanopores in the MgO particles were limited, resulting in the reduced intra‐particle pore size and increased intra‐particle pore number. The densification degree of microparticles was reduced, and thus the strength of the samples decreased. At the Al(OH)3 addition of 4.0 wt%, microporous MgO–Al2O3 refractory aggregates had the best comprehensive properties, a bulk density of 2.48 g/cm3, an apparent porosity of 29.4%, a median pore size of 1.6 μm with 42.2 vol% nanopores and the thermal conductivity of 4.0 W/(m K). [ABSTRACT FROM AUTHOR]

This study investigates the correlation between coercivity (Hc), grain size (d), and dislocation density in the Permimphy alloy (Fe–80%Ni–6%Mo). The samples used in this study were subjected to varying levels of applied strain through processing by high-pressure torsion. The microstructure and the magnetic coercivity were analyzed using a scanning electron microscope, electron backscatter diffraction and vibrating sample magnetometry. The grain size of the samples varied from 30 to 190 nm. This study demonstrated a strong correlation between Hc and microhardness when d > 3 µm. The results show that the coercivity of the Permimphy alloy follows an inverse V-shape with respect to grain size. The coercivity of the samples decreased despite increasing the dislocation density and the hardness when d < 3 µm. This phenomenon is attributed to the ferromagnetic exchange interaction across multiple grains and leads to the alignment of magnetic moments. [ABSTRACT FROM AUTHOR]

In this article, the effect of Ce element on the microstructure and mechanical properties was studied by Ce addition to the hot‐formed steel. Scanning electron microscope and energy dispersive spectrometer (SEM‐EDS) was used to analyze the improvement effect of Ce on inclusions and the effect of inclusions on fracture behavior; Electron back scattering diffractometer (EBSD) was used to analyze the refinement and strengthening effect of Ce on martensitic grains; transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) was used to analyze the microstructure strengthening effect and microalloying effect of solid solution Ce in hot‐formed steel. Through a systematic analysis of mechanical properties and microstructure, the mechanism of Ce enhances the strength and elongation of hot‐formed steel was clarified. Besides, this work provides a research basis for further improving the safety and machinability of hot‐formed steel. [ABSTRACT FROM AUTHOR]

The harsh service environment of aeroengine hot-end components requires superalloys possessing excellent antioxidant properties. This study investigated the effect of pre-strain on the oxidation behavior of polycrystalline Ni3Al-based superalloys. The growth behaviors of oxidation products were analyzed by scanning electron microscope, transmission electron microscope, X-ray Photoelectron Spectroscopy and Raman spectroscopy. The results indicated that the 5% pre-strained alloys exhibited lower mass gain, shallower oxidation depth and more compact oxide film structures compared to the original alloy. This is mainly attributed to the formation of rapid diffusion paths for Al atoms diffusing to the surface under 5% pre-strain, which promotes the faster formation of protective Al2O3 film while continuing to increase the pre-strain to 25% results in less protective transient oxidation behavior being aggravated due to the increase in dislocation density within the alloy, which prevents the timely formation of the protective Al2O3 film, resulting in uneven oxidation behavior on the alloy. [ABSTRACT FROM AUTHOR]

In this study, La2Zr2O7, Yb2O3 and Gd2O3-doped La 1. 4 (Gd, Yb) 0. 6 Zr2O7 thermal barrier coatings have been manufactured from the crystalline and amorphous feedstock by plasma spraying. The thickness of the bond coat is 100±25 μ m and the thickness of the top coat is 250±25 μ m. Thermal shock tests were carried out in furnace temperature of 1200∘C. The thermal shock tests indicate that lifetime of the La 1. 4 Gd 0. 6 Zr2O7 coating has 55 cycles which is the highest thermal shock lifetime compared to other coatings in this study. The type of feedstock, amorphous or crystalline, strongly affects the thermal shock lifetime of La2Zr2O7 coatings. Coating damage after thermal shock tests was investigated using scanning electron microscope to observe the microstructure and X-ray diffraction techniques to analyze the phase composition. The failure of coatings is mainly in consequence of the accumulation of stress between bond coat–ceramic coat interface due to thermal expansion coefficient differences and thermally grown oxide layer formation during thermal shock cycling tests. [ABSTRACT FROM AUTHOR]

Bi(2/3)‐xSmxCu3Ti4O12 (BSCTO x = 0.05, 0.10, and 0.20) ceramics are synthesized using semi‐wet technique and an extensive investigation into their structural, morphological, and elemental properties, alongside dielectric and impedance behaviors, is meticulously carried out. X‐ray powder diffraction analysis unequivocally confirmed the formation of a monophasic BCTO cubic phase without any discernible secondary phases. and the crystallite size of the BSCTO ceramic, obtained by X‐ray diffraction using Debye Scherrer formula, range from 62 to 81 nm. Rietveld analysis reveals that ceramics have a body centered cubic structure with space group Im‐3. The Scanning electron microscope image displays the dense microstructure of the ceramics, while EDX analysis unveils the elemental composition of resulting products. Doping with Sm3+ induced a notable reduction in grain size, as observed through Scanning electron microscope and Atomic Force Microscope analyses, indicating Sm3+ hindered grain growth during sintering, potentially resulting in reduced dielectric constant (ε′). Dielectric constant and dielectric loss of the composition (x = 0.2) are found to be ≈$ \approx $152 and 0.04, respectively at room temperature (1 kHz). Impedance characteristics revealed a substantial increase in grain boundary resistance, leading to improved dielectric loss. The AC conductivity of BSCTO ceramics exhibited a frequency‐dependent increase satisfying to Johncher's power law. [ABSTRACT FROM AUTHOR]

Due to the poor activation performance and kinetics of Ti50V25Cr25 alloys, the element Zr was added to improve the phase structure of the alloy and achieve a high-performance hydrogen storage alloy. The Ti50−xV25Cr25Zrx (x = 0, 5, 7, and 9) system alloys were prepared by arc melting. The alloys were analyzed using an X-ray diffractometer (XRD), scanning electron microscope (SEM), and differential scanning calorimeter (DSC). The hydrogen storage capabilities of the alloys were also obtained by the Sievert volumetric method. The results indicated that the alloy with Zr added had a combination of the C15 Laves phase and the BCC phase, whereas the Zr-free alloy had a BCC single phase. The partial replacement of Zr with Ti resulted in an increase in the lattice parameters of the main phase. The hydrogen storage kinetic performance and activation of the alloys both significantly improved with an increasing Zr concentration. The time to reach 90% of the maximum hydrogen storage capacity decreased to 2946 s, 230 s, and 120 s, respectively, with the increases in Zr concentration. The initial hydrogen absorption content of the alloys increased and then decreased after the addition of the element Zr. The second phase expanded with an increasing Zr concentration, which in turn decreased the abundance of the BCC main phase. The Ti43V25Cr25Zr7 alloy showed good cycle stability and hydrogen-desorption performance, and it could absorb 90% of the maximum hydrogen storage capacity in around 230 s. The maximum hydrogen-absorption capacity of the alloy was 2.7 wt%. The diffusion activation energy of hydrogen desorption dropped from 102.67 kJ/mol to 92.62 kJ/mol. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the impact of high velocity oxy-fuel (HVOF) spraying parameters on the inflight particle temperature, velocity, and microstructure of FeCrMnCoNi high-entropy coatings (HECs). The sprayed coatings exhibited a typical lamellar structure with a single solid solution FCC phase and minor oxides. Ex-situ characterization of the coatings was conducted using X-ray diffraction, Raman spectroscopy, and high-resolution scanning electron microscope (HR-SEM) to analyze the phase composition, microstructure, and surface morphology. The findings revealed that fuel-rich flames with a higher feed rate resulted in coatings with low porosity and oxidation as well as high deposition efficiency due to the high velocity and low particle temperatures. Additionally, the transverse scratch tests were conducted to determine the cohesive/adhesive nature of the coatings, and the results demonstrated that the cohesive strength between the splats was influenced by the porosity and area fraction of the oxides. Coatings deposited with oxygen-rich conditions showed maximum hardness, but low cohesive strength compared to coatings sprayed using fuel-rich conditions due to higher oxides formation during spraying. The microstructural changes, phase compositions, and microhardness of the coatings were correlated with the scratch resistance of the HECs developed using three distinct spraying conditions. These results suggest that FeCrMnCoNi HECs hold significant potential for surface protection in various industrial and aerospace applications. Moreover, the findings point toward new material design strategies to attain desired microstructure with enhanced mechanical properties. [ABSTRACT FROM AUTHOR]

Aeolian sand and loess are both natural materials with poor engineering-related properties, and no research has been devoted to exploring aeolian sand–loess composite materials. In this study, we used aeolian sand and loess as the main raw materials to prepare unfired bricks by using the pressing method, along with cement, fly ash, and polypropylene fiber. The effects of different preparation conditions on the physical properties of the unfired bricks were investigated based on compressive strength, water absorption, and softening tests and a freeze–thaw cycle test combined with X-ray diffraction and scanning electron microscope analysis to determine the optimal mixing ratio for unfired bricks, and finally, the effects of fibers on the durability of the unfired bricks were investigated. The results reveal that the optimal mixing ratio of the masses of aeolian sand–loess –cement –fly ash–polypropylene fiber–alkali activator–water was 56.10:28.05:9.17:2.40:0.4:0.003:4.24 under a forming pressure of 20 MPa. The composite unfired bricks prepared had a compressive strength of 14.5 MPa at 14 d, with a rate of water absorption of 8.8%, coefficient of softening of 0.92, and rates of the losses of frozen strength and mass of 15.93% and 1.06%, respectively, where these satisfied the requirements of environmentally protective bricks with strength grades of MU10–MU15. During the curing process, silicate and sodium silicate gels tightly connected the particles of aeolian sand and the loess skeleton, and the spatial network formed by the addition of the fibers inhibited the deformation of soil and improved the strength of the unfired bricks. [ABSTRACT FROM AUTHOR]

The stability and dispersion of Copper (Cu) powders in an aqueous medium impacts their performances. Thus the Cu powder suspensions were prepared by adding different stabilizers—sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), polyvinyl pyrrolidone (PVP), and hexadecyl trimethyl ammonium bromide (CTAB); the best surfactant was selected and its stability and dispersion were studied. The study systematically examined the effect of the stability of suspensions via sedimentation analysis, including solid–liquid ratio, the concentration of stabilizer, and dispersion time. The particle size, the stability of suspensions, phase composition, and microstructure of Cu powders were characterized by laser particle size analyzer, zeta potential, X-ray diffraction (XRD), transmission electron microscope (TEM), and scanning electron microscope (SEM). The results indicate that the stability of the suspension is improved with the addition of PVP due to the steric hindrance of PVP, and the growth and agglomeration of particles are retarded by the formation of a thick hydration layer with the optimizing concentrations, dispersion time, and solid–liquid ratio 10 g/L, 30 min, and 1:25, respectively. [ABSTRACT FROM AUTHOR]

The effect of aging treatments at various temperatures on the mechanical properties and microstructure of 10B21 cold heading steel with a 20% reduction in area (ε = 0.1) was investigated. The mechanical properties were evaluated based on tensile tests and hardness tests, while the evolution of microstructure was observed by using an optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). The results reveal that aging treatment enhance the strength and hardness of 10B21 cold heading steel after drawing, and the highest values of strength and hardness are attained at an aging temperature of 300 °C. Specifically, the yield and ultrahigh tensile strength after aging at 300 °C are measured at 620 MPa and 685 MPa, respectively, which are 30 MPa and 50 MPa higher than the cold-drawn sample. Moreover, the hardness after aging at 300 °C reaches 293 HV, which has an increase of 30 HV compared to the cold-drawn state. The improvement in mechanical properties may be related to the strain-aging mechanism and the increased density of dislocations. In addition, the analysis of the TEM results reveal that the presence of the second-phase Ti(C,N) contributes to pinning the dislocations, whereas the dislocations are pinned between the cementite (Fe3C) lamellar and stacked at the grain boundaries, leading to strain hardening of the material. [ABSTRACT FROM AUTHOR]

Developing novel solid oxide fuel cells (SOFCs) with high stability running at low temperatures is an important objective in SOFC science. In the current paper, a comprehensive physics-based microstructure modeling using scanning electron microscope (SEM) image analysis was performed on several anode-support SOFCs operating at low temperatures with high stability. To bridge the gap in the literature regarding an accurate and realistic modeling, a new model was developed based on the variable fuel and air utilization factors and updated microstructure values (e.g., tortuosity, porosity, pore size, grain size). The model accuracy was verified by a thorough point-to-point validation for eight different cells with the configuration of Ni-YSZ (anode), YSZ (electrolyte), and GDC/PNO (cathode). Different temperatures, hydrogen, and air mass flow rates were used, for which an average error of less than 3% in the I-V curves was achieved. The microstructure of the cells, including cathode thickness (15–26 μm), anode-support thickness (350–460 μm), porosity (39 and 43%), grain size (1.1–1.4 μm), and pore radius (0.9–1.1 μm) were varied. Moreover, the effects of the critical operational and design parameters on the overpotential losses and cell performance were studied. The results show that a hydrogen flow rate of 43 sccm was ideal when the cell operated at 0.9 A/cm2 and 700 °C. Moreover, an average anode-support pore radius of 1.75 μm resulted in the best cell performance. It was also concluded that the electrolyte thickness has a higher effect on the cell performance compared to the cathode thickness. • Fabrication and testing of eight anode-supported tublar cells with different microstructures. • Introducing a physics-based microstructure model for SOFC based on variable fuel utilization factor. • Performing a comprehensive SEM image analysis for the fabricated cells. • Achieving an average error of less than 3% for the model compared to the experimental data. • Achieving an average optimum value of 1.75 μm for anode-support pore radius. [ABSTRACT FROM AUTHOR]

In this study, basalt fibers (BFs) and nano-silica (NS) were innovatively combined to reinforce recycled aggregate concrete (RAC) to prepare recycled aggregate concrete (named NBRAC) with better mechanical and microstructural properties as an alternative to ordinary concrete. Different NBRAC specimens were prepared by adjusting the contents of NS and BF; the damage mechanism and mechanical properties of NBRAC were investigated; and the compressive, split tensile, and flexural strengths of NBRAC were evaluated. The microstructure of NBRAC was analyzed by scanning electron microscopy observation. The results showed that the densification of NBRAC was improved under the condition of 50% RA substitution rate and that its compressive, split tensile, and flexural strengths were increased by 6.8%, 16.3%, and 32.7%, respectively, compared with that of natural concrete, which proved that the method was feasible for the preparation of high-performance RAC. Scanning electron microscope image analysis confirmed the improvement effects of NS and BF on RAC, and combined with the experimental data, a composite explanation for the improvement effects of NS and BF on RAC was proposed for the first time. [ABSTRACT FROM AUTHOR]

The disposal of industrial by-product tailings has become the focus of mine follow-up work and an important issue in solving environmental pollution. This study explores the potential of utilizing iron tailings and phosphogypsum as cementitious materials, guided by the concept of comprehensive utilization. The mechanical property of cementitious materials was studied under curing 7 days, 14 days, and 28 days. The characteristics of the pores and products of the cementitious material were extracted and analyzed by industrial computed tomography (CT), X-ray diffraction (XRD), and scanning electron microscope (SEM). In the presence of phosphogypsum, more ettringite was generated in the cementitious system. The macropores in the system were filled, reducing the total porosity fraction of cementitious materials from 24.56% to 18.39%. The reduction of macropores significantly enhanced the compressive strength of cementitious material. The addition of fine phosphogypsum reduced the large porosity of the cementitious materials, which revealed the importance of the size in the cementitious material system. The effect of phosphogypsum content on the pore structure of cementitious material of iron tailings was studied. The new type of low-carbon cementitious material prepared from phosphogypsum and iron tailings provided a novel perspective for the multi-solid waste collaborative disposal in this study. In addition, the large amount of consumption of tailings reduced the pollution to the environment. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to identify the optimal forming angle for the selective laser melting (SLM) process and evaluate the mechanical properties of the SLM-formed GH3536 alloy in the aero-engine field. Design/methodology/approach: Forming the samples with optimized parameters and analyzing the microstructure and properties of the block samples in different forming angles with scanning electron microscope, XRD, etc. so as to analyze and reveal the laws and mechanism of the block samples in different forming angles by SLM. Findings: There are few cracks on the construction surface of SLM formed samples, and the microstructure shows columnar subgrains and cellular subgrains. The segregation of metal elements was not observed in the microstructure. The pattern shows strong texture strength on the (111) crystal plane. In the sample, the tensile strength of 60° sample is the highest, the plasticity of 90° forming sample is the best, the comprehensive property of 45° sample is the best and the fracture mode is plastic fracture. The comprehensive performance of the part is the best under the forming angle of 45°. To ensure the part size, performance and support structure processing, additional dimensions are added to the part structure. Originality/value: In this paper, how to make samples with different forming angles is described. Combined with the standard of forged GH3536 alloy, the microstructure and properties of the samples are analyzed, and the optimal forming angle is obtained. [ABSTRACT FROM AUTHOR]

The deformation aspects associated with the micro-mechanical properties of the powder laser bed fusion (P-LBF) additively manufactured stainless steel 316L were investigated in the present work. Toward that, micro-pillars were fabricated on different planes of the stainless steel 316L specimen with respect to build direction, and an in situ compression was carried out inside the chamber of the scanning electron microscope (SEM). The results were compared against the compositionally similar stainless steel 316L, which was fabricated by a conventional method, that is, casting. The post-deformed micro-pillars on the both materials were examined by electron microscopy. The P-LBF processed steel exhibits equiaxed as well as elongated grains of different orientation with the characteristics of the melt-pool type arrangements. In contrast, the cast alloy shows typical circular-type grains in the presence of micro-twins. The yield stress and ultimate compressive stress of P-LBF fabricated steel were about 431.02 ± 15.51 − 474.44 ± 23.49 MPa and 547.78 ± 29.58 − 682.59 ± 21.59 MPa, respectively. Whereas for the cast alloy, it was about 322.38 ± 19.78 MPa and 477.11 ± 25.31 MPa, respectively. Thus, the outcome of this study signifies that the AM-processed samples possess higher mechanical properties than conventionally processed alloy of similar composition. Irrespective of the processing method, both specimens exhibit ductile-type deformation, which is typical for metallic alloys. [ABSTRACT FROM AUTHOR]

The influence of milling time and volume fraction of reinforcement on the morphology, microstructure, and mechanical behaviors of SiCp-reinforced AA2017 composite powder produced by high-energy ball milling (HEBM) was investigated. AA2017 + SiCp composite powder with different amounts of SiC particles (5, 10, and 15 vol%) was successfully prepared from gas-atomized AA2017 aluminum alloy powder with a particle size of <100 μm and silicon carbide (SiC) powder particles with an average particle size of <1 μm. An optical microscope (OM), X-ray diffraction (XRD), and scanning electron microscope (SEM) were utilized to characterize the microstructure of the milled composite powder at different milling periods. The results indicated that the SiC particles were homogeneously distributed in the AA2017 matrix after 5 h of HEBM time. The morphology of the particles transformed from a laminar to a nearly spherical shape, and the size of the milled powder particles reduced with increasing the content of SiC particles. The XRD analysis was carried out to characterize the phase constituents, crystallite size, and lattice strain of the composite powders at different milling periods. It was found that with increasing milling time and SiC volume fraction, the crystallite size of the aluminum alloy matrix decreased while the lattice strain increased. The average crystallite sizes were reduced from >300 nm to 68 nm, 64 nm, and 64 nm after 5 h of milling, corresponding to SiC contents of 5, 10, and 15 vol%, respectively. As a result, the lattice strain increased from 0.15% to 0.5%, which is due to significant plastic deformation during the ball milling process. XRD results showed a rapid decrease in crystallite size during the early milling phase, and the minimum grain size was achieved at a higher volume fraction of SiC particles. Microhardness tests revealed that the milling time has a greater influence on the hardness than the amount of SiC reinforcements. Therefore, the composite powder milled for 5 h showed an average microhardness three times higher than that of the unmilled powder particles. [ABSTRACT FROM AUTHOR]

Copper-clad aluminum wires have a high risk of electrical fire, and welding marks are easily affected by factors such as high temperature and fire water in the actual fire. To accurately identify the overcurrent fault, an electrical fault simulator was used in this study to simulate the overcurrent fault condition of a copper-clad aluminum at a current of 52.5–105 A. Then the microstructure characteristics such as metallographic structure, welding hole elements, and so on under different treatment methods were also analyzed using the metallographic microscope and SEM/EDS. The results of the study are summarized as follows: (1) under the method of natural cooling, the metallographic structure of the welding mark were mainly columnar crystals and dendritic crystals with a few holes in it. And we found that the maximum particle size and average particle size have a quadratic function relationship with the current value; (2) under the water-cooling method, the welding mark was mainly columnar crystals with a large number of holes in them. At a current of 75 A, the welding mark holes consisted of Al and Cu elements, while at the rest of the current value, they consisted of Al, Cu, and O elements; (3) when the temperature was raised to 450 °C, the welding trace has different elements at different currents. At the temperature of 650 °C, a large number of equiaxed crystals appeared in the welding trace, with a few holes in which at a current at 105 A only. Our study has provided a basis for the investigation of electrical fire accidents and the technical identification of the causes. [ABSTRACT FROM AUTHOR]

The effect of finishing rolling reduction on microstructures and textures of grain oriented silicon steel was researched by optical microscopy, zeiss ultra 55 Scanning Electron Microscope (SEM) and Electron Backscatter Diffraction (EBSD) technique severally. The results show that the grain size of hot rolled sheets and decarburized strips decreases, while the center grain size of the normalized sheet increases with the increase of the finishing rolling reduction. The pearlite content increases with the increase of the finishing rolling reduction after normalization. Compare with the previous research, the effect of finishing rolling reduction on the grain size of primary recrystal-lization is greater than that of roughing rolling reduction, and large rolling reduction is beneficial to the formation of {110}<001> texture. [ABSTRACT FROM AUTHOR]

Nanobubble water with the ability to capture carbon dioxide (CO 2) was used as the mixing water for the development of Carbon Consuming Concrete (CCC). The mechanical properties, volume stability, and pore structures were initially evaluated. Scanning electron microscope (SEM) image was analyzed to confirm formation and calcium component on the surface. Differential thermogravimetry (DTG) analysis and nuclear magnetic resonance (NMR) spectroscopy were used to evaluate the reactivity of cement according to mixing water type. The ability was confirmed in priority that convert calcium hydroxide (CH) into calcium carbonate (CaCO 3) by utilizing abundantly captured CO 2. The nanobubble increased the calcium content and ratio of micropores, while the total porosity decreased when CO 2 gas was injected. Depending on the mixing water type, each specimen showed strength in the production of different major components (C-S-H, CH, and CaCO 3), affecting the compressive strength development, and the injection of CO 2 gas also affected shrinkage behavior. • Concrete with CO 2 -capturing nanobubbles achieves excellent compressive strength. • Nanobubbles in concrete suppress the carbonation shrinkage. • The utilization of nanobubbles improves C-S-H production. • Abundant CO 2 condition increases the chance of calcium ions to react. • A synergistic effect of nanobubbles and CO 2 leads to higher CaCO 3 production. [ABSTRACT FROM AUTHOR]

The effective properties of lithium-ion battery (LIB) cathode are determined by both the volume fractions of constituents and the morphological features of microstructure. However, it is difficult to establish an accurate quantitative relationship between the macroscopic effective properties and microstructural features. Deep learning techniques, due to their exceptional nonlinear fitting capabilities, have been widely applied in various complex fields. Our study presents a generation scheme of numerous three-dimensional (3D) digital microstructures of cathode, using a deep convolutional neural network (CNN)-based stochastic reconstruction algorithm combining with the scanning electron microscope (SEM) images. The reconstructed samples are substituted with the corresponding finite element (FE) models, and the effective mechanical and electrochemical properties are assessed through the FE-based homogenization theory. Finally, the generated cathode samples and their effective properties are used to train the 3D CNN for performance prediction. This study demonstrates that the deep learning approaches can accurately and rapidly reconstruct the microstructure of cathode and predict their effective properties. Furthermore, the established framework can be extended to other heterogeneous materials. • Cathode microstructure feature extraction based on transfer learning is proposed. • A CNN-based stochastic reconstruction method for microstructures is developed. • CNN and homogenization theory are used for properties prediction of microstructures. [ABSTRACT FROM AUTHOR]

• Synthesis the pure and metal doped magnesium aluminate spinel (MAS, MgA12O4) nanopowders using sol-gel method and characterized by different technique. • Measurement the optical properties of pure and metal doped MAS. • Nano powder has been applied as an adsorbent for BCG dye removal. • Optimization of different factors affecting the efficiency of the prepared MAS as an adsorbent for BCG dyes removal. • The equilibrium time for MAS nanopowder was 120 min. for BCG dye with removal efficiency of 94.60 %. A synthetic material having a cubic crystal structure and exceptional chemical, thermal, dielectric, mechanical, and optical capabilities is magnesium aluminate (MgAl 2 O 4) spinel. These characteristics made magnesium aluminium oxide (MgAl 2 O 4) an essential material for optically transparent windows, domes, armour, and some refractory applications. This research proposes an innovative and low-cost method for producing spinel magnesium aluminate (MgAl 2 O 4). Sol-gel auto-combustion method synthesis approach by ammonium hydroxide precipitation and citric acid as a fuel were used to create MgAl 2 O 4 nanocrystalline materials. The gels were dried at 120 °C while being doped with various vanadium ion concentrations with the same amount of rare earth Eu3+ ions and then calcined at 1100 °C for 8 h. Highly crystalline MgAl 2 O 4 :V3+:Eu3+ was obtained under fuel-rich conditions only. Physical and chemical methods, including X-ray diffraction, scanning and transmission electron microscopes, Fourier transform infrared spectroscopy, Raman spectroscopy, UV–VIS-NIR spectrophotometry and photoluminescence analysis, were used to characterize the produced spinel materials. The effects of adsorbent dosage, contact time, and initial concentrations on total bromocresol green (BCG) removal from wastewater were studied using real wastewater. Optimal conditions were found for total BCG removal. BCG removal and adsorption capacity of MgAl 2 O 4 :0.05V3+:0.011Eu3+ nanoparticles were achieved as 96.40 % and 90.10 %, respectively. In addition, other optimum conditions of adsorbent dosage and contact time were found as 1.5 g/L and 120 min. in this study, respectively. The removal of BCG using MgAl 2 O 4 :V3+:Eu3+ NPs was fitted with Langmuir isotherm kinetic model. The results indicated that MgAl 2 O 4 :V3+:Eu3+ nanospinel was suitable adsorbents for the removal of BCG from industrial wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, the fabrication of single grain bulks (Y,Er)Ba 2 Cu 3 O 7−x "(Y,Er)−123" superconductors is well studied to enhance high superconducting performance in the mixed binary system between yttrium and erbium elements. A series of isothermal experiments of mixed (Y,Er) 2 BaCuO 5 "(Y,Er)−211" binary system has been prepared at various constant temperatures for 50 hours to optimize the heating pattern to produce large-sized (Y,Er)−123 bulks single domain. (Y,Er)−123 bulks were fabricated using the infiltration growth (IG) process. All samples obtained were studied by X-ray diffraction (XRD), Scanning electron microscope (SEM), Superconducting quantum interference device (SQUID), and trapped field measurements. In isothermal experiments, it revealed that the optimum temperature obtained to grow a good (Y,Er)−123 bulks was at 985 °C. All samples showed T c-onset from 89 K to 91 K indicating all samples show superconducting nature. Microstructural analysis indicated that the presence of non-superconducting (Y,Er)−211 fine particles within the (Y,Er)−123 matrix improved the J c values up to 41.60 kA/cm2. On the other hand, slow cooling bulk (Y,Er)−123 has been conducted after obtaining the optimum growth temperature window from the isothermal experiment. (Y,Er)−123 bulks were fabricated using a slow cooling IG process. It revealed that the homogenous distribution of (Y,Er)−211 particles in the (Y,Er)−123 matrix improved the superconducting performance, J c, and trapped field. As a result, J c obtained for a single domain of (Y,Er)−123 bulk was 43.03 kA/cm2 at 77 K, H// c -axis and self-field. • This approach is useful and simple to obtain a good optimum temperature for binary system Y,ErBCO. • We use Y211 and Er211 powders synthesis by conventional solid-state method. • An isothermal study was conducted to produce Y,Er-BCO bulk superconductor. • High critical current density, J c was greatly improved. [ABSTRACT FROM AUTHOR]

The microstructure and properties of the aged Cu-Cr-Zr-Nb alloy were studied by means of hardness tester, universal tensile testing machine, conductivity meter, X-ray diffraction, scanning electron microscope, and transmission electron microscope. The results indicated that the hardness and TS (tensile strength) of the Cu-Cr-Zr-Nb alloy increased first and subsequently decreased with increasing the aging temperature. Nevertheless, the electrical conductivity is gradually increasing. The aged Cu-Cr-Zr-Nb alloy was mostly made up of Cu matrix, Cr particles, Cr 2 Nb, and CuZr compounds. Due to the effects of dislocations accumulated by cold drawing and twins produced during the aging process, the softening temperature of the alloy reached 590 ℃. When the Cu-Cr-Zr-Nb alloy was aged at 490 ℃, < 111 > replaced < 110 > in the optimal orientation of the alloy, and the KAM (kernel average misorientation) value inside the alloy was the largest. The alloy exhibited great comprehensive properties at 490 ℃ for 1 h, with a hardness of 144.4 HBW, a TS of 521 MPa, and an electrical conductivity of 78.3%IACS. The contribution value of YS (yield strength) at different aging temperatures was further calculated. The computational results showed that precipitation strengthening was the main strengthening mechanism of the Cu-Cr-Zr-Nb alloy, and fine-grained strengthening and dislocation strengthening simultaneously played a supplementary role. • Due to the effects of dislocations accumulated by cold drawing, precipitation strengthening of Cr and twins produced during the aging process, the softening temperature of the Cu-Cr-Zr-Nb alloy reaches 590 ℃. • The Cu-Cr-Zr-Nb alloy exhibits great comprehensive properties at 490 ℃ for 1 h, with a hardness of 144.4 HBW, a tensile strength of 521 MPa, and an electrical conductivity of 78.3 %IACS. • The computational results show that precipitation strengthening is the main strengthening mechanism of the Cu-Cr-Zr-Nb alloy. [ABSTRACT FROM AUTHOR]

The internal micro-structure of glass and carbon fibre-reinforced polymer (FRP) rebars subjected to tensile loading was investigated using micro computed tomography (μCT) and scanning electron microscopy (SEM) images. Three dimensional (3D) and two dimensional (2D) reconstructed μCT images were used to study and quantify the void volume and its distribution along with FRP rebar samples after being subjected to tensile loads. The void volume was observed to increase in all samples as the tensile load on the samples was increased. Acoustic emission (AE) monitoring during the tensile loading was also employed to establish a correlation between the AE parameters and damage evolution in the FRP samples. Cumulative energy of AE signal in frequency domain was used to monitor the progression of the internal damage in the FRP reinforcing rebars. A high correlation was observed between the void volume measured by μCT and SEM and the cumulative energy of the AE signal. [Display omitted] [ABSTRACT FROM AUTHOR]

For the present investigation, Tungsten heavy alloys (WHAs), (90-x)W-6Ni-4Cu-xLa 2 O 3 are synthesized using the powder metallurgy route by liquid phase sintering at 1400 °C for 1 h in hydrogen atmosphere. The effect of variation of La 2 O 3 (Lanthanum oxide) dispersion in W-Ni-Cu alloy (0, 0.1, 0.5, 1.0, 1.5, and 2.0 wt%) on microstructural evolution was investigated using a scanning electron microscope (SEM) and transmission electron microscopy (TEM). The distribution of the tungsten, matrix, and La 2 O 3 were analyzed using X-ray energy dispersive spectroscopy (EDS). The influence of La 2 O 3 content on the densification behavior was also determined. The stereological quantifications were done on particle size and contiguity. The lowest W particle size was observed in sample of 2.0 wt% La 2 O 3 added WHA. However, this sample was found to have more porosity. The W particle size was reduced by about 30% with 2.0 wt% addition of La 2 O 3. The maximum value of bulk hardness of about 320 HV 5 was observed in 1.0 wt% La 2 O 3 content WHA. The three-point bend test was performed to determine the bending behavior of these alloys. The alloy with 1.0 wt% La 2 O 3 showed the maximum compressive strength of 1481 MPa and bending strength of 1021 MPa. Fractography revealed W-W interface de-cohesion fracture mechanism to operate pre-dominantly. W particle cleavage fracture mode was observed to increase with the addition of La 2 O 3 up to 1.0 wt% in the WHAs. • W-Ni-Cu alloys with La 2 O 3 processed via powder metallurgy LPS at 1400 °C. • With 2.0 wt% La 2 O 3 in W-Ni-Cu alloy reduces W particle size by 30 %. • The addition of 1.0 wt% La 2 O 3 turns out to give the best mechanical property. • Quantification of operational fracture modes attempted. [ABSTRACT FROM AUTHOR]

Developments in engineering and medicine have allowed patients' health and quality of life to be supported by implants. Unfortunately, widely used titanium-based alloys with aluminum and vanadium are not ideal materials. The first problem is a mechanical mismatch between human bone and the implant material, and the second issue is the presence of Al or V, which are harmful for the human body and health. This article focuses on the holistic design and production of titanium-based materials with vital elements. The zoned, gradient element can exhibit better mechanical properties and improve the connection between the implant and the bone. The samples in two constructions were built with two different zones. The powders for samples were prepared using the powder metallurgy technique with sieve separation. Phillips X-ray X′Pert diffractometer and PDF4 + database performed the phase composition analysis. The Scanning electron microscope allow the samples observation. Stereological methods assessed porosity and PAR M370 Scanning Electrochemical Workstation. The designed technology based on the powder metallurgy method allows for producing functional, two-zoned graded materials with variable porosity. The phase composition analysis confirmed partially synthesis. Additionally, the observation of the microstructure of the sintered samples revealed the presence of two permanently connected zones. Preliminary mechanical research was conducted to evaluate the potential use of the material as an implant material. The proposal to use two-zone construction of components for implants is dictated by the possibility of personalizing implants for patients, taking into account personal characteristics and needs. [Display omitted] • The functionally graded materials based on vital elements were successfully fabricated using powder metallurgy method. • Highly porous FGM with interconnected porosity was prepared by powder metallurgy. • The porous and microstructure evolution in each gradient layer of FGM is revealed. • The effect of Tin use as Process Control Agent were confirmed and allow to obtain more uniform powders. [ABSTRACT FROM AUTHOR]

The Mg-Ni-based alloys have been extensively investigated as negative electrode materials in Nickel-Metal Hydride (Ni-MH) batteries. In this work, two Mg-Ni-based samples (Mg 71 Ni 29 and Mg 72.6 Ni 25.3 Gd 1.1) were prepared by means of melting. The X-ray diffraction (XRD), scanning electron microscope (SEM), galvanostatic charging/ discharging and other electrochemical measurements were used for the investigation. The results show that the Mg 71 Ni 29 and Mg 72.6 Ni 25.3 Gd 1.1 alloys include the characteristic peaks of Mg 2 Ni and the less strong characteristic peaks of Mg and MgNi 2 phases. The diffraction peak of the major phase Mg 2 Ni of the Mg 72.6 Ni 25.3 Gd 1.1 alloy is shifted to a small angle and its unit cell volume increases. With the addition of Gd, the alloy electrodes exhibits better cycling stability. After 50 charge/ discharge cycles, the capacity retention rate of the alloy electrode increase from 16% (Mg 71 Ni 29) to 22% (Mg 72.6 Ni 25.3 Gd 1.1). However, the maximum discharge capacity of the alloy electrode decrease from 134.3 mAh/g (Mg 71 Ni 29) to 91.9 mAh/g (Mg 72.6 Ni 25.3 Gd 1.1). The Mg 72.6 Ni 25.3 Gd 1.1 alloy possess lower limiting current density I L and exhibit relatively high corrosion resistance against the alkaline solution. After Gd doping, the charge transfer capacity of the Mg 72.6 Ni 25.3 Gd 1.1 alloy surface is increased. • The addition of Gd positively impacts the cycling stability of the alloy electrodes. • The Gd-doped alloy exhibits the superior corrosion resistance compared to the Gd-free alloy. • The electrode surface of the Gd-doped alloy demonstrates an augmented capacity for charge transfer. • The solid solubility of Gd atoms in the Mg-Ni-based alloys were verified. [ABSTRACT FROM AUTHOR]

In the soybean β-conglycinin system, subunit composition has an important influence on its emulsification properties. To elucidate the mechanism of subunit action in the emulsification process, the separated and purified β-subunit and the mixture α- and α′-subunits (referred to αα′-subunit) were remixed in varying proportions, and then the physicochemical properties and structural properties of the subunit emulsifying system were characterized. The results demonstrated that when the ratio of αα'-subunit to β-subunit was 5:5, the subunit aqueous dispersion system exhibited a minimum particle size of 47.58 nm, a maximum solubility of 87.21%, and the emulsification stability and emulsification activity were also optimal. Scanning electron microscope (SEM) images revealed excellent cross-linking between αα′-subunit and β-subunit, forming a protein network structure that provided a structural basis for its emulsification. The emulsion with a subunit ratio of 5:5 exhibited the highest fraction of interfacial protein adsorption of 23.43% and the largest interfacial protein concentration of 11.79 mg/m2. Inter-subunit adsorption and emulsion formation were primarily driven by hydrophobic interactions, with the β-subunit exhibiting a higher affinity for adsorption than the αα′-subunit. The action mechanism of the subunits in the emulsion formation was proposed as a " three-stage " process, including establishing an initial weak protein network structure within the aqueous dispersion, followed by developing an emulsion interface layer and ultimately culminating in forming an emulsion gel network structure. Elucidating the emulsifying mechanism at the subunit level is crucial for enhancing the theoretical framework of soybean protein emulsification. [Display omitted] • The subunit system had the best emulsifying activity at a 5:5 subunit ratio. • Emulsion exhibited the most distinct gel network structure at a 5:5 subunit ratio. • Hydrophobic interactions were the primary driving force for emulsion formation. • A "three-stage" subunit emulsification mechanism was proposed. [ABSTRACT FROM AUTHOR]

The utilization of industrial waste-based geopolymer has emerged as an environmentally sustainable approach with a low carbon footprint in place of ordinary Portland cement (OPC) for ground improvement. This study aims to investigate the impact of ground-granulated blast furnace slag (GGBS) and dolomite-based geopolymer on the mechanical and microstructural properties of soft clays. A series of unconfined compressive strength (UCS) tests and pH tests were conducted to evaluate the effect of precursor (binder) content, GGBS and dolomite (S:D) ratio, NaOH:Na 2 SiO 3 (NH:NS) mass ratio, and curing period on the strength development of GGBS and dolomite based geopolymer treated kaolin clay. A series of consolidated undrained (CU) static triaxial tests were performed on 28 days cured specimens with different S:D ratios and optimum NH:NS mass ratio to determine the axial stress-strain characteristics. Moreover, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) tests were conducted to analyze the microstructure characteristics of GGBS and dolomite-based geopolymer. Experimental results indicate that the optimum NH:NS ratio for only GGBS (S:D ratio of 20:0) treated clay was 50:50, whereas, for S:D ratios of 18:2, 16:4, and 14:6, the ratio was 25:75. The addition of dolomite up to 4% with GGBS and NH:NS ratio of 25:75 significantly enhanced the 28 days compressive strength to 116.8% compared to pure GGBS-based geopolymer treated clay. Furthermore, the compressive strength of the clay stabilized with a precursor of S:D ratio of 16:4 and NH:NS ratio of 25:75 was 26.30%, 32.59%, and 38.35% higher than the 20% OPC stabilized clay for the 7, 14, and 28 days curing period, respectively. Moreover, the toxicity characteristic leaching procedure (TCLP) results showed that heavy metals concentration was much lower than their respective US Environmental Protection Agency (USEPA) specified standard limit. The findings of this study provide effective utilization of GGBS and dolomite as a new eco-friendly geopolymer for stabilizing soft soil. • The mixing ratios of (NaOH:Na 2 SiO 3) and (GGBS and dolomite) for kaolin clay stabilization were studied. • The UCS, pH concentration, and triaxial stress-strain responses were determined. • The increase in UCS was observed for GGBS-dolomite admixed kaolin clay. • The microstructural and toxicity characteristic leaching procedure (TCLP) analysis was performed. [ABSTRACT FROM AUTHOR]

Soilcrete is produced by adding a curing agent, such as cement, to the soil and mixing it thoroughly to form a solid, stable substance, but usually with poor early strength. To improve the early strength and stability of soilcrete, in this paper, solid waste materials such as mineral powder, and natural gypsum powder were added proportionately to replace parts of cement (called composite curing agent). The unconfined compressive strength (UCS), and dry-wet cycle strength of soilcrete were tested to evaluate the optimum mix design. The scanning electron microscope (SEM) and XRD test were applied for investigating the mechanism of early strength of solid waste-based soilcrete. The results show that the optimal mix ratio of cement and mineral powder is 4:6, the 7-day UCS is 1.61 MPa, and the 28-day UCS is 3.37 MPa. The composite curing agent mixed with gypsum powder and water glass has a good curing effect on silt and clay respectively, and the 28-day strength of the clay specimen can reach 3.97. During the dry-wet cycle test, the strength of the soilcrete increases first and then decreases with the number of cycles. The SEM results show that the soilcrete particles were denser, had more hydration products, and the soil particle morphology changed from loose to aggregated, accompanied by a decrease in pores. The study provides a cheaper and high-performance composite curing agent based on solid waste materials for soilcerte than conventional cement, which can promote the application in such field. • An early-strength, low-cost solicrete was proposed using solid waste materials, namely mineral powder and natural gypsum. • The UCS (Unconfined Compressive Strength), dry-wet cycle strength, and soil types of soilcrete were tested systematically. • The mechanism of the new solid waste material on soilcrete was revealed through SEM, XRD, and hydration analysis. [ABSTRACT FROM AUTHOR]

This study focuses on a holistic approach to investigate the microstructural, mechanical, durability, environmental, and economic properties of lightweight self-compacting mortars (LWSCM) produced using different aggregate types (natural, recycled, lightweight) and supplementary cementitious materials (SCM). Within the scope of this study, 22 different LWSCM series were designed, 4 of which were reference, and silica fume (SF) and fly ash (FA) were used as SCM. Compressive and flexural tests were performed for mechanical tests at 7, 28, and 180 days. Significant improvements in flexural and compressive strengths were observed for 10% SF and 15% FA substitution. Total water absorption, capillarity, porosity, density, and sulfate resistance tests were carried out to investigate the durability properties. All mortar series exposed to sulfate solution significantly reduced flexural and compressive strength. Among the sulfate-exposed specimens, the mortar series containing 10% SF showed the most considerable flexural and compressive strength reductions. The global warming potential (GWP), waste generation (WG), and energy consumption (EC) were considered to evaluate environmental properties. Significant reductions in GWP and EC values were observed for mortar series with 30% SCM. Similarly, significant decreases in WG values were obtained with the increased use of recycled aggregate and SCM. Scanning electron microscope analyses were performed to examine the microstructural properties and detailed evaluations were made. Significant gains were achieved in economic properties due to the use of SCM, with total costs decreasing by approximately 10%, especially in series with 30% SCM. Considering the thousands of buildings constructed after the earthquake, sustainable development, and circular economy goals, using recycled aggregates and SCM to reduce the consumption of natural aggregates and cement has made significant contributions by making holistic evaluations. [Display omitted] • Detailed assessments of CDW were made with a holistic approach. • RA can be an alternative to NA for sustainable development and circular economy. • Usage of SCMs has significant positive impacts on EC and GWP. • Significant improvements in economic properties were achieved due to using SCM. • RA and SCMs were evaluated as alternative solutions for NA and cement consumption. [ABSTRACT FROM AUTHOR]

As an environmentally friendly material, alkali-activated fly ash-slag (AAFS) is considered as a promising alternative cement because of its excellent mechanical properties and thermal stability. Nevertheless, high temperature induced damage in AAFS can potentially bring serious risks for its practical applications. This paper presents a systematic experimental study on behaviour of AAFS paste subjected to elevated temperatures up to 800 °C in terms of microstructure as well as thermal and mechanical properties. Microstructural evolution was characterised by means of Rietveld-based quantitative X-ray diffraction (QXRD), backscattered scanning electron microscope (BSEM) and X-ray microcomputed tomography (XCT), while thermal and mechanical properties were evaluated from thermogravimetric analysis (TGA), thermal deformation and compressive and flexural strengths. Results indicate that the compressive strength of AAFS paste rises by 77.5 % at 200 °C, followed by a mitigation from 200 to 600 °C and a regain at 800 °C. Different phases in AAFS paste including unreacted particles, reaction products and pores took up 30 %, 67.7 % and 2.31 % at ambient temperature, and 4.95 %, 84.8 % and 10.3 % after exposure to 800 °C, respectively, suggesting the recrystallisation with the formation of nepheline and gehlenite. In addition, the relationships between microstructural characteristics including three-dimensional (3D) pore structure features and thermal and mechanical properties of AAFS paste at elevated temperatures were explored and discussed in depth to gain insights into the underlying degradation mechanisms including pore pressure build-up, thermal gradient and phase transformation. [ABSTRACT FROM AUTHOR]

• Investigate the influence of Cu interlayer on of DB IN718/SS-304L interface. • Cu interlayer significantly reduced the formation of IMCs and carbides. • Joint strength of 143 MPa was achieved without Cu interlayer. • Joint strength was improved by 134% using Cu interlayer. • Microhardness was reduced by 17% with the Cu interlayer. Diffusion bonding (DB) of AISI 304L austenitic stainless steel (SS-304L) and Inconel 718 with and without Cu interlayer was performed at 950 °C for 90 min under vacuum of 8x10−2 MPa. The resulting mechanical, microstructural, and compositional analyses of the bonded interfaces were analyzed using lap shear and microhardness tests, optical and scanning electron microscopes (OM and SEM) equipped with energy-dispersive spectroscope (EDS) and X-ray diffraction (XRD). It was observed that the bonding interface without Cu interlayer was comprised of TiC, NbC, Mn 23 C 7 , Cr 23 C 6 , Cr 3 C 2 , μ-phase (Fe 2 Nb), NiTi 2 , and FeTi. However, these carbides and intermetallic compounds (IMCs) were eliminated with the insertion of the Cu interlayer. This enhanced the joint strength from 143 to 334 MPa and reduced the interfacial hardness by 17 %. [ABSTRACT FROM AUTHOR]

Thanks to their setting ability, hydraulic binder materials (e.g. , cements, plasters) are used for a wide variety of applications (e.g. , construction, medical). The setting reaction occurs through a dissolution–precipitation mechanism during which initial particles dissolve releasing ionic species from which new crystals precipitate. The development of such a microstructure governs the final properties of the material and are thus of uttermost interest. In this paper, the in operando study of the precipitation of gypsum crystals from the dissolution of bassanite particles using a specific cell for scanning electron microscope (SEM) observation is presented. Image analysis based on segmentation enabled to give quantitative results on the growth of crystals at global and local scales. Single crystal facets are indexed based on crystallography and literature results, which enables the quantification of crystal growth rates for the indexed crystallographic planes. Different growth regimes are identified; they are attributed to the transition from unfavored to the most favored crystal facets known for gypsum. The { 111 } and { 110 } planes were the fastest growing planes, whereas the { 120 } and { 010 } planes were the most stable and grew slowly. [Display omitted] • Evolution of gypsum plaster was analyzed during setting in conditions of use in SEM. • Kinetics of the growth of ¿100 gypsum crystals was computed from image analysis. • Growth rates of the gypsum facets were computed from crystallographic indexation. • A same gypsum crystal may experience different growth regimes along time. • A slower growth is experienced by crystals with thermodynamically unstable facets. [ABSTRACT FROM AUTHOR]

Nano-calcium carbonate (nano-CaCO 3) has garnered significant attention due to its remarkable efficacy in enhancing the properties and microstructure of concrete. In this study, the wet carbon conversion method was used to synthesize solid nano-CaCO 3 from CO 2 , which was then added to AAS. Subsequently, the compressive strength and resistivity of the AAS mortar were assessed, and the AAS paste underwent microscopic characterization using experimental methods, including X-ray diffraction (XRD) and Fourier-transformed infrared (FTIR), and scanning electron microscope (SEM) et.al. The effects of the nano-CaCO 3 on the microstructure, mechanical characteristics, and durability of the AAS were determined. The microscopic analysis results clearly demonstrate that the nano-CaCO 3 prepared using this method exerts significant physical and chemical effects, leading to a notable improvement in the compactness of the AAS microstructure. Moreover, the experimental findings provide further confirmation that the addition of nano-CaCO 3 results in a substantial enhancement of both the compressive strength and resistivity of AAS mortar, particularly in the early stages. Specifically, the inclusion of 6% nano-calcium carbonate led to a remarkable 29.8% increase in compressive strength at 1 curing day. Furthermore, the analysis of carbon dioxide emissions from AAS reveals that incorporating nano-CaCO 3 effectively reduces the carbon footprint associated with AAS. This implies that adopting this approach not only enhances the performance of AAS but also contributes to a reduction in the environmental impact, thus actively promoting sustainable construction and engineering projects. • The wet carbon conversion method synthesizes nano-CaCO 3 to enhance alkali-activated slag (AAS) performance. • Nano-CaCO 3 enhances AAS microstructure compactness through physical and chemical effects. • Nano-CaCO 3 reacts with the aluminum phase in AAS, forming carboaluminate. [ABSTRACT FROM AUTHOR]

The closed working condition of grouting materials leads to insufficient curing water supply during their strength development. In this work, the superabsorbent polymer (SAP) was used as the internal curing agent for grouting material. The effects of SAP content on the rheological and mechanical properties of grouting material were studied under various water-cement ratios (w/c) and curing environments. The time-dependent variation of fresh slurry's viscosity was measured by Brinell viscometer. The pore structure and micromorphology characteristics were analyzed by Mercury Intrusion Porosimetry (MIP) and Scanning Electron Microscope (SEM). The results indicate that the addition of SAP increases the viscosity of fresh slurry and decreases its fluidity, thereby improving the slurry's internal uniformity at a higher w/c. And in its actual working condition, grouting material's strength can be boosted with less than 0.3% SAP dosage. Although SAP will introduce some irregular mesoscopic pores (0.2 − 0.3 mm), the MIP data analysis proves SAP refines the microscopic pore structure of grouting materials. SEM data analysis proves SAP optimizes the microstructure of grouting material, which cured in dry environment. In general, SAP improves the internal uniformity of grouting material by absorbing excess mixing water and gradually releasing it to promote cement hydration, which improves the strength of grouting material. Hence, SAP is a practicable internal curing agent for grouting material and 0.2% is the recommended dosage. • Investigations were done on how SAP affected grouting material performance. • SAP increases the viscosity and improves the internal uniformity of the slurry. • SAP optimizes the microscopic pore structure of the material. • SAP demonstrates a good internal curing effect in sealed and dry environments. [ABSTRACT FROM AUTHOR]

The microstructure of a surimi product determines its quality. Dense phase carbon dioxide (DPCD) can induce surimi gel formation, and the gel strength of the product are significantly better than that of heat-induced gels. The study analysed the changes of the surimi from golden pompano gel strength during the process of DPCD-induced gelation, and the changes of microstructure based on quantitative analysis of scanning electron microscope (SEM) image using ImageJ 1.42 software. The correlations between gel strength and microstructure was investigated. The results showed that the DPCD treatment significantly increased the cross-linking degree (CLD) and gel strength of surimi, compared with the raw surimi. The CLD and gel strength of surimi increased with the increase of DPCD treatment pressure, temperature and time. Quantitative microscopic analysis revealed that the number of pores (n) in the surimi gels increased and then decreased. The apparent porosity (ƞa), average pore area (Aa), average pore perimeter (Pa), fractal dimension (Df) and pore equivalent diameter (d) increased with the increase of DPCD treatment pressure, temperature and time. Correlation analysis showed that the CLD , ƞa , Aa , Pa , Df , d and median pore perimeter (Pc-50) were strongly positively correlated with the gel strength. In contrast, lacunarity (L) is strongly negatively correlated with the gel strength. The linear correlation coefficients between the CLD , ƞa and Df and the gel strength are 0.97, 0.95 and 0.96, respectively. These results provide a technical basis for DPCD to process high-quality surimi products. These findings also offer a novel approach for the testing and evaluating of the quality of surimi products. [Display omitted] • Quantitative index system for protein gel microstructure proposed. • Cross-linking and gel strength are strongly positively correlated. • Lacunarity and gel strength are strongly negatively correlated. • Micro-quantitative systems require combining multiple indicators to analyse. [ABSTRACT FROM AUTHOR]

A new metal-matrix composite, fine Ti(C, N) particles reinforced CoCrFeNiTi high-entropy alloy (HEA), were successfully fabricated via mechanical alloying and spark plasma sintering process. Graphite carbon nitrides (g-C 3 N 4) particles and equiatomic CoCrFeNiTi HEA powders were used as the original materials. The microstructural investigations have been carried out with scanning electron microscope (SEM) and high-resolution transmission electron microscope (HRTEM), and the results reveal that the increase in strength can be ascribed to grain refinement and dislocation strengthening, particularly the fine Ti(C, N) particle strengthening. The fracture modes of composites are mainly combination of brittle fracture with ductile fracture. An interesting microstructural feature is that the fine HEA grains are distributed within Ti(C, N) particles forming a core-shell structure, which further improves the fracture toughness of the composites. The final composite (Ti(C, N)/CoCrFeNiTi HEA) shows exhibits the best combination of compressive strength and fracture toughness, which are 2965 MP and 12.4 MPa m1/2, respectively. The present study not only expands the application field of g-C 3 N 4 but also provides a new idea for the preparation of composites reinforced with Ti(C, N) particles. [Display omitted] • A novel metal-matrix composite, consisting of fine Ti(C, N) particles reinforced CoCrFeNiTi (HEA), has been successfully fabricated. • Micromorphology and mechanical characteristics of the composites are investigated • An interesting microstructure feature revealing that the HEA matrix phase is present inside the Ti(C, N). • The final Ti(C, N)/CoCrFeNiTi HEA composite exhibits exceptional compressive and bending strengths of 2965 MPa and 2257 MPa, respectively. [ABSTRACT FROM AUTHOR]

The dissimilar welded joints of Q&P980 and Q&P1180 steels with and without paint-baking heat treatment were investigated and their microstructures were characterized using confocal laser scanning microscope (CLSM), electron backscatter diffraction (EBSD), scanning electron microscope (SEM) and transmission electron microscope (TEM) in order to understand the change of mechanical performances of the welded joints. The two Q&P steels have slight differences in compositions, but the obviously varying fraction of tempered martensite and thus the difference in the tensile strength. Prior to paint-baking heat treatment, the dissimilar welds exhibit a lower martensite fraction of the intercritical heat-affected zone (ICHAZ) in the Q&P980 side compared to the Q&P1180 side, and it is not affected by the paint-baking treatment. After the treatment, the occurrence of carbides and the coarsening of martensite in the whole welded joint, as well as the decomposition of retained austenite in the ICHAZ, are observed. The paint-baking treatment also causes the decreasing microhardness values of all regions. Especially, the significantly decreasing microhardness in the fusion zone compared to other heat-affected zones results in a partial pull-out failure mode compared to a full pull-out failure mode without paint-baking treatment. The change in failure mode and the softening of the martensitic matrix are found to be responsible for the increase in the peak load and the energy absorption of the dissimilar welded joint of Q&P980 and Q&P1180 steels. • Microstructures of the dissimilar welded joints of Q&P980/Q&P1180 were characterized. • Paint-baking treatment improved the mechanical performance of the dissimilar welded joints. • The failure mode of the dissimilar welded joints changed after the paint-baking treatment. • The significantly decreasing microhardness in the fusion zone was caused by the paint-baking treatment. • The mechanism of increasing the mechanical performance of the dissimilar welded joints was proposed. [ABSTRACT FROM AUTHOR]

Multi-component Ti 16.667 Zr 16.667 Hf 16.667 Ni 25 Co 10 Cu 15-X Mn X at.% (X = 0, 1, 3, 5 and 7) high-entropy shape memory alloys (HESMAs) were prepared by arc-melting and then microstructures, transformation temperatures, phase constituents and superelastic properties were investigated by scanning electron microscope observation, differential scanning calorimetery, X-ray diffraction and dynamic mechanical analysis in tensile mode, respectively. The microstructure of solution-treated TiZrHfNiCoCuMn HESMAs specimens consisted of (NiCoCuMn)-rich matrix, (TiZrHf) 2 (NiCoCuMn)-type phase and (TiZrHf)(NiCoCuMn)-type phase. The area fraction of (TiZrHf) 2 (NiCoCuMn)-type phase increased from 1.7 to 5.1% with increasing Mn content from 0 to 7 at.%. The area fraction of the (TiZrHf)(NiCoCuMn)-type phase increased from 1.9 to 17.2% with increasing Mn content from 3 to 7 at.%. -ΔH mix effect was dominant over ΔS mix and δ effects for phase constitution in TiZrHfNiCoCuMn HESMAs. The martensitic transformation start temperature decreased with the addition of Mn content up to 3 at.% and then increased with increasing Mn content from 3 at.% to 7 at.%. TiZrHfNiCoCuMn HESMAs showed clear superelasticity and the total recovered strain decreased with increasing Mn content. • Multi-component Ti 16.667 Zr 16.667 Hf 16.667 Ni 25 Co 10 Cu 15-X Mn X at.% (X = 0, 1, 3, 5 and 7) high-entropy shape memory alloys (HESMAs) were designed. • This work provided theoretical and experimental information for the phase selection in high entropy shape memory alloys. • -ΔH mix is dominant over ΔS mix and δ for phase constitution in present studied HESMAs. [ABSTRACT FROM AUTHOR]