Table of contents

In the present review, the effect of porosity on the mechanical properties of the fabricated parts, which are additively manufactured by powder bed fusion and filament extrusion-based technologies, are discussed in detail. Usually, additive manufacturing (AM) processes based on these techniques produce the components with a significant amount of pores. The porosity in these parts typically takes two forms: pores with irregular shapes (called keyholes) and uniform (spherical) pores. These pores are present at different locations, such as surface, sub-surface, interior bulk material, between the deposited layers and at filler/matrix interface, which critically affect the corrosion resistance, fatigue strength, stiffness, mechanical strength, and fracture toughness properties, respectively. Therefore, it is essential to study and understand the influence of pores on the mechanical properties of AM fabricated parts. The technologies of AM can be employed in the manufacturing of components with the desired porous structure through the topology optimization process of scaffolds and lattices to improve their toughness under a specific load. The undesirable effect of pores can be eliminated by using defects-free raw materials, optimizing the processing parameters, and implementing suitable post-processing treatment. The current review grants a more comprehensive understanding of the effect of porous defects on mechanical performance and provides a mechanistic basis for reliable applications of additively manufactured components.

A noval study on the fabrication of virgin and nickel (Ni) doped stannic oxide (SnO₂) thin films with different doping extent have been conducted to augment the properties of stannic oxide thin films to incorporate into the electric cell which utilizes sun's energy. The influence of the Ni doping with various extents on the structural, optical and magnetic properties of the different synthesized samples of stannic oxide thin films are investigated byX-ray diffraction (XRD), Scanning electron microscopy (SEM), UV-Visible spectrophotometer and Vibrating Sample Magnetometer (VSM). All the fabricated samples of SnO₂: Ni(1at%, 2at%, 3at% and 4at%) exhibited tetragonal structure of stannic oxide. The fusion of Ni into the stannic oxide lattice makes imperfection in the crystal and the presence of additional peaks confirms that the nickel domination is well observed. Increase in the extent of Ni doping causes diminution in optical band gap. The magnetic study reveals that the ferromagnetic signal is gradually enhanced with augment in doping concentration.

Herein, we reported a simple template method for preparation of fluorescent copper nanomaterials, using Duplex oligonucleotide (dsDNA) as the template. The as-prepared copper nanomaterials had good sensing performance, excellent stability and ultrafine size through the characterization of UV–vis absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM). Experimental results showed that the fluorescence of copper nanomaterials was linearly quenched by the Fe³⁺ concentrations in the range of 5–100 μM,The detection limit was 5 μM. And when the temperature is between 25 °C and 70 °C, the fluorescence intensity of copper nanomaterials presents a good linear relationship.

Magnetite nanoparticles constitute a class of nanoparticles which is easily manipulated using a magnetic field. Magnetite nanoparticles doped with ruthenium (Ru) ions [Ru_xFe_(3−x)O₄] were synthesized via co-precipitation method where 0.0 ≤ x ≤ 0.5 with step 0.1. The obtained nanopowder was investigated via x-ray diffraction, FTIR, FESEM. It was shown that Ru ions were incorporated successfully into a magnetite structure with a slight influence on the value of the lattice parameter which increased from 8.354 Å at x = 0.0 to be 8.403 Å at x = 0.3, while crystallite size deteriorated from 20.1 nm at x = 0.0 to be around 3 nm at x = 0.3. In addition, the surface roughness average was influenced by the dopant content, where it decreased from 35.6 nm at the pure magnetite to be 25.87 nm at x = 0.3. The ICP examination indicated that the measured contents of Ru ions through competitions were around 41 ppm and increased to 190 ppm comparing with 43 and 199 ppm as a theoretical value both x = 0.1 and 0.5. Regarding magnetic properties, the coercivity raised from 40.11 Oe and raised 44.66 Oe for x = 0.0 and 0.5, respectively. This manipulated behavior of magnetite due to dopant suggests that desired properties could be achieved via the dopant strategy to be used for several applications.

Recent experiments and density functional tight-binding (DFTB) calculations indicated the nonlinear elastic properties of graphene. However, this nonlinear stress-strain relationship has not been applied to the carbon nanotubes (CNTs) that can be viewed as graphene sheets that have been rolled tubes. In this paper, using the nonlinear stress-strain relationship of graphene, a new Bernoulli-Euler beam model of single-walled carbon nanotubes (SWCNTs) is presented for the first time. The static bending and the first-order mode forced vibrations of SWCNTs are investigated according to the new model. The results indicate that the nonlinear stress-strain relationship has a significant influence on the mechanical properties of SWCNTs.

The purpose of the research was to form a Ti-Ta-N- system bioinert coating on Ti6Al4V alloy surface as well as to study its structure and properties. The main contribution of the research is in the following. Electro-explosion spraying of tantalum coating on VT6 titanium alloy surface was pioneered in the research. After that the processing of the coating by low-energy high-current electron beam and subsequent nitriding was carried out in a single technological cycle. It has been established that a nanocrystalline coating based on tantalum, nitrogen and titanium was formed as a result of the technological operations. The phase composition of the coatings has been detected. The variations in crystal lattice parameters being formed in coating of phases and coherent scallering regions of these phases depending on power density of electron beam have been determined. Structural characteristics of the coatings at nano- and microlevel have been detected. Tests of coatings for nanohardness, the Young modulus, wear resistance and friction factor have been carried out. By all technical characteristics Ti-Ta-N-system coating exceeds titanium of VT6 grade. The cause of the increase in mechanical characteristics of the Ti-Ta-N-system coating is their nanostructural state and strengthening phases. Tests for proliferation activity of fibroplasts and antimicrobial activity have shown better results in comparison with VT6 titanium alloy as well. It is due to escape of vanadium ions from VT6 alloy into nutrient cell medium and their destructive effect on cell cultures. Variations in proliferation and antimicrobial activity develop due to amplification of cell proliferation. A complex of the obtained characteristics makes it possible to recommend Ti-Ta-N-system coating for its application as a bioinert coating on different implants in furure.

Groundwater mostly contains many impurities thus can not be consumed as drinking water directly. The acceptable limit of fluoride in drinking water is 0.5–1.5 mg l⁻¹ recommended by World Health Organization (WHO). In this research, a novel nanofiber hybrid; based on Chitosan (CTS) and Eggshell (EGG) was prepared via electrospinning technique and investigated for deflouridation from aqueous solution. SEM images reveal bead-free, smooth morphology and the FTIR confirmed the presence of chitosan and egg within the novel nanofiber blend. The defluoridation efficiency was assessed by varying the different parameters like pH, mass of nanofibers, contact time and initial concentration for adsorption. Studies revealed that CTS/EGG nanofibers hybrid shows incredible adsorption efficiency of 86%. Furthermore, isotherm studies show that the Langmuir isotherm model was well fitted for both CTS and CTS/EGG nanofibers.

Nanoparticles (NPs) with different shape, size, architecture and composition were studied for their application as photo-thermal agents in the area of cancer nanomedicine. Out of them, gold nanoparticles (Au NPs) depending on their in vivo biocompatibility provide a simple thermal ablation platform. However, fabrication of these Au NPs showing appropriate properties for photo-thermal function requires complex routes utilizing hazardous chemicals as capping agents which may cause in vivo concerns. In this study, the fabricated Au NPs utilizing biosynthetic approach having near-infrared (NIR) absorbance assisting photo-thermal treatment could be a possible alternative. Herein, anisotropic Au NPs were fabricated utilizing an aqueous extract of Ceratonia siliqua (carob) which acts as both stabilizing and reducing agent. The biosynthesized Au NPs were exposed to density-gradient centrifugation for the optimization of NIR absorption in 800 to 1000 nm wavelength range. Colloidal Au NPs showed outstanding contrast enrichment for ultrasound imaging, and also Au nanoplates were obtained by density gradient centrifugation can function as a NIR absorbing agent for efficient photothermal killing of Hep-G2 liver tumor cells in vitro with negligible cytotoxicity to active cells. Furthermore, the present approach recommends an innovative way for treating theranostic cancer.

Nonlinear bending and nonlinear free vibration analysis are presented for FG nanobeams based on physical neutral surface concept and high-order shear deformation beam theory with a von Kármán-type equations and including thermal effects. The material properties are temperature-dependent and vary in the thickness direction. Nonlinear bending approximate solutions and free vibration solutions for present model with fixed supported boundary conditions are given out by a two-step perturbation method. Some comparisons are presented to valid the reliability of the present study. In numerical analysis, the effects of the volume fraction, nonlocal parameter, strain gradient parameter, and temperature changes on nonlinear bending and vibration are investigated.

Gadolinium aluminate (GdAlO₃, GAP) is a rare earth compound with perovskite structure. Its optical isotropic structure prevents the defects of refractive index difference in any direction. GAP has unique and excellent properties in electricity, magnetism, luminescence and catalysis, especially as a high-quality luminescent matrix material. Sol-gel method has the advantages of accurate control of chemical composition, particle size and purity of products. The main preparation parameters include chelating agent concentration, alcohol water ratio, calcination temperature and so on. In this paper, the citric acid chelating agent was used to prepare gadolinium aluminate nanoparticles by sol-gel method, thermogravimetry-differential thermal analysis (TG-DTA), x-ray diffraction (XRD) and scanning electron microscope (SEM) were employed to analyze the effects of chelating agent, dispersant, solvent and calcination temperature on the phase and morphology changing in precursor and final product. The results show that GAP nanoparticles with high degree of crystallinity, nearly spherical morphology and 60–100 nm particle size can be obtained at the molar ratio of citric acid to cationic of 1:1, the ammonium citrate to citric acid of 1.5:1 and the calcination temperature of 900 °C for 4 h. When the calcination temperature is higher than 1100 °C, a new phase of Gd₃Al₅O₁₂ (GdAG) will be formed with calcination neck shape.

The optical properties of gold nanoparticles such as strong extinction and surface plasmon resonance can be adjusted by altering the structure, which was used widely in the surface enhanced Raman scattering (SERS). In this paper, the optical properties of gold nanoparticles were investigated by using the Finite-Difference Time-Domain (FDTD) method. The influences of AuNP-size and NP-NP-spacing on the local electric field and extinction properties were analyzed in detail. The results showed that the electric field intensity of AuNPs increased rapidly with the increasing size. Meanwhile, the formant appeared blue shift and the peak intensity increased first and then decreased with the increase of NP-NP-spacing. The theoretical calculation results are concordant with experimental results. The FDTD simulation results of this paper have a guiding significance in SERS areas.

A homogeneous CuO-ZnO nanostructure with tunable morphology and optical band structure is successfully synthesized via a hydrothermal method under the different dopant mole ratios of Cu. The robust correlation between the crystallite size, surface morphology, optical band gap alteration of the synthesized CuO-ZnO and its performance in photoelectrochemical (PEC) activity are investigated and compared to the reference ZnO based photocathode. In this report, it is found that the morphology of hexagonal ZnO nanorod is changed to nanosheet and vertically align CuO-ZnO based nanograss after the Cu incorporation. This result is mainly due to the composition phase change after the excessive incorporation of Cu metal into ZnO lattice. Furthermore, the optical band gap of the sample also presented a bathochromic shifted after the Cu insertion. The measurements on PEC activity of CuO-ZnO nanostructure was performed under the irradiation of a 100 mWcm⁻² Xenon light in 0.5M Na₂SO₄ electrolyte. Among the sample, 0 Zn:1 Cu exhibited a highest photocurrent density which is 5 fold as compared to its reference ZnO samples. This finding could be due to the highest surface active area and lowest optical energy band gap in the 0 Zn:1 Cu nanograss that eventually contributes to a high free electron density that facilitates the charge transport in the photoelectrochemical cells. This novel approach could provide an alternative to the future solar hydrogenation application.

Solid insulation defects are a major cause of power failures. Incorporation of micro and nanoparticles in the solid insulation materials has proven its advantage. It has been reported that nanocomposites are far superior in terms of insulation to microcomposites because of larger interphase area between nanofillers and polymer in nanocomposites. In addition to that nature, size, shape, concentration and alignment of nanofillers affect the properties of resulting nanocomposite insulation. A lot of work has reported the effect of nanofiller's nature, size and concentration but very little is reported on the effect of filler's shape and alignment on the insulation and dielectric properties. In this paper nanocomposite dielectrics with nanofillers of various shapes and alignment are modelled by varying their permittivity using finite element method. To characterize the effect of various shapes and orientation electric field intensity and energy density models are computed. Simulations are performed using AC/DC module of COMSOL Multiphysics. The results revealed that shape and alignment of nanofillers are the two key factors in tuning the breakdown strength and permittivity of nanocomposite dielectrics for their applications in insulation as well as high voltage capacitors.

Simple methodology was developed to synthesize copper oxide nanoparticles (CuO NPs) using mucus of Channa striatus (C. striatus). The mucus of C. striatus is known for its biological properties due to the presence of numerous amino acids. This mucus was used as stabilizing agent for CuO NPs synthesis from copper acetate. The prepared CuO NPs were characterized by fourier transforms infrared spectrometer (FTIR), powder x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), energy dispersive x-ray analysis (EDX) and transmission electron microscope (TEM) coupled with selected area diffraction pattern (SAED). The FTIR study suggested the utilization of mucus in the synthesis of CuO NPs. The XRD data also confirmed formation of pure crystalline phase of CuO NPs. Fish mucus stabilized CuO NPs exhibited significant activity against HeLa cells. The results of cell death clearly indicated that the synthesized CuO nanoparticles could be served as a biomaterial for anticancer treatment.

In this study, SiC reinforced aluminum (Al) metal matrix composites were prepared by microwave sintering. The effects of SiC content, pressure and sintering temperature on the density, hardness and microstructure of the composites were investigated. It was found that the relative density of SiC/Al composites is 98.43% when the content of SiC is 5 Vol%. When the SiC content is 15 vol%, the sintering temperature is 770 °C and the pressure is 250 MPa, the density and hardness of the composites SiC/Al composites are 96.14% and 130 HV, respectively. And the SiC particles can be uniformly dispersed in the Al matrix by microwave sintering.

Effects of alkaline earth metal elements and their synergistic roles with Ta for the modified Li₇La₃Zr₂O₁₂ (LLZO) are discussed. Li_7.1La₃Zr_1.95M_0.05O₁₂ (M = Mg, Ca, Sr, Ba) with the substitution of alkaline earth metal ions for Zr⁴⁺ and Li_6.5La₃Zr_1.35Ta_0.6M_0.05O₁₂ (M = Mg, Ca, Sr, Ba) with the co-substitution of alkaline earth metal ions and Ta⁵⁺ for Zr⁴⁺ are prepared. The sole substitution of alkaline earth metal elements for Zr in LLZO have little effects on improving ionic conductivity, while the modified LLZO with synergistically co-doping Ta and alkaline earth metal elements can achieve the great enhancement of ionic conductivity. The order of ionic conductivity influenced by Ta⁵⁺ and alkaline earth metal ions (Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺) co-substitution for Zr⁴⁺ demonstrates a strong correlation with ionic radii of Mg²⁺/Ca²⁺/Sr²⁺/Ba²⁺. Particularly, the enhanced Li_6.5La₃Zr_1.35Ta_0.6Mg_0.05O₁₂ with the joint substitution of Mg and Ta delivers a highest ionic conductivity of 3.45 × 10⁻⁴ S cm⁻¹ at room temperature.

Ultrasonic assisted grinding (UAG) has been considered as a prominent processing method of the reaction bonded silicon carbide (RBSiC). To improve the knowledge of UAG process, both conventional grinding (CG) and UAG were used to process the RBSiC for in-depth investigation. Grinding forces, surface topographies, and subsurface damages during CG and UAG were compared. Furtherly, the ground surface was analyzed on aspects of both topographical characteristics and material removal mechanism. The results indicated that the removal of material is mainly achieved by the intersections of cracks initiated from both big SiC particles and mixture area of silicon matrix and small SiC grains. The crack propagation during UAG was more intensified due to the ultrasonic impact, which results in higher efficiency of machining RBSiC.

To scan a vehicle's environment frequency modulated continuous wave (FMCW) radar sensors are essential. The implementable driver assistance systems based on these sensors increase the comfort of an automobile. When integrating them into the car, the radar sensor's cover must be taken into account. These parts serve as protection against external chemical and mechanical influences, but they should also support the vehicle design and appearance. Usually, painted polymer components are used as a radome. Depending on their material parameters (i.e. relative permittivity and loss-tangent) polymer covers lead to reflections and absorption, which may impair the radar performance, if they are not properly designed from a microwave point of view. For an appropriate design procedure, the polymer properties, have to be known precisely beforehand or need to be analyzed in realistic experimental configurations. Within this paper it is shown by measurements around the 80 GHz automotive radar bands and calculations based on the polymers repeating unit that the relative permittivity can be estimated from knowledge of the molecule structure. This allows the calculation of the relative permittivity of polymer molecules that have not yet been measured in the W-band at 80 GHz at a very early stage of the design process. Additionally it is shown that it has to be taken into account if the polymer is semi-crystalline or amorphous. Furthermore, the density or crystallinity has to be known.

Space charge accumulation is one of the key factors restricting the manufacture and application of high-voltage direct current (HVDC) cables. Semi-conductive shielding layer plays an important role in uniform electric field in HVDC cable, and its own emission properties directly affect the space charge behaviours in the insulation material. In the paper, charge injection property from semi-conductive layer to insulation layer have been focused emphatically based on experiment and simulation. The charge injection characteristics of semi-conductive layer under two typical electrode configurations of 'Metal-Insulation layer-Metal' (M-I-M) and 'Semi-conductive layer-Insulation layer-Metal' (S-I-M) have been studied. The conductive current and depolarization current of the insulation layer are compared. Finally, effect of particle size and concentration of carbon black (CB) in the semi-conductive layer on the interfacial electric field has been studied by electric field simulation. The experimental results show that the charge injection from the semi-conductive layer is more obvious under the action of low electric field of 5 kV mm⁻¹ due to effect of CB particles. It can be seen from the depolarizing current curve that the charge injection quantity with S-I interface is greater than that of M-I interface. Further calculation results show that the maximum distortion electric field increases slightly with the increase of CB size. When CB content is 25%, the electric field distortion caused by interface CB particles is about twice of the average electric field (5 kV mm⁻¹), increasing from 9.61 kV mm⁻¹ at 10 nm to 10.15 kV mm⁻¹ at 50 nm. The reduction of CB size in the semi-conductive layer within a certain range is conducive to the reduction of the interface electric field. The maximum distortion field gradually decreases with the increase of CB content at a certain range.

In this scientific article, the potential of producing a highly capable sensor by the addition of electric conductive carbon black (CB) to polymer composite was studied, and the effects of various carbon black content on ethylene-butene copolymer (EBC) on rheological and electromechanical were investigated. Electric conductive composites have many attempts at producing original material in technology as a sensor. The amount of (0, 4.07, 6.31, 8.71, and 11.28) volume % of CB was introduced to EBC using Brabender, mixed, and homogenized for 5 min at 180 °C. The dynamic mechanical analysis (DMA) and electromechanical test show that the addition of CB to the EBC would increase the viscosity, modulus, while electric resistance significantly decreased and changed greatly with elongation. The modulus increased from 8.9 to 15 MPa by increase of from 15 to 25 wt% of CB while the gauge factor decreases for about five times by increasing the CB from 15 to 25 wt% under 5 N force. These works demonstrate the possibility of producing strain sensors using a cheap and versatile technique, with potential health and electromechanical sensors.

This work attempts to study the effects of the addition of graphene nanoplatelets (xGNP) on the rheology properties of new version of polyurethane copolymer with 1,5 pentane diol as chain extender , containing a high amount of hard blocks. Two- step polymerisation was employed to synthesise this kind of polymer. The thermal and electrical conductivity of this copolymer was also investigated. Meanwhile, the rheology response has been analysed by measuring the viscosity It was found that the viscosity increases by 68% and 2 × 10⁵% at loadings of 0.5 wt.% and 15 wt.% of xGNP, respectively, compared with that of neat polyurethane copolymer. This means that the melt viscoelastic behaviour of highly rigid polyurethane copolymer (HRPUC) is influenced by the presence of xGNP contents, transforming the behaviour of nanocomposite from liquid-like to solid-like. This result was attributed to the network formation and interaction between hard segments of the HRPUC structure and xGNP due to strong shear thinning behaviour. In addition, the thermal conductivity of HRPUC increases to 0.97 W m⁻¹.k (410%), electricity conductivity rose to 10² s m⁻¹ (1000%). SEM morphology images showed overall dispersion of xGNP in the HRPUC, implying a reduction in the interspacing of flakes with increasing xGNP concentration. Further investigation into HRPUC morphology and its nanocomposites was conducted using the TEM method, illustrating that the xGNP stacking resulted from poor ability to disperse at greater loadings of xGNP.

The upsurge of immunocompromised patients has led to extensive study of fungal infections with Candida albicans being the frontline model of pathogenic yeast in humans. In the quest to find novel antifungal agents, this study reports the potential usage of wild-type C. albicans strain C86 to biosynthesise silver nanoparticles by microwave assisted technique. Visual colour change and UV-spectrophotometer were used for primary detection of silver nanoparticles. Additionally, the FTIR peaks confirm the particles' formation and surface characterisation techniques such as FESEM and EDX suggests that the silver nanoparticles were sized in the range of 30–70 nm. Furthermore, pioneering work of homologous recombination technique was systematically employed to delete uncharacterized gene orf19.3120 (CNP41) in the C86 strain creating the deletion strain C403 of C. albicans. To amalgamate the two significant findings, biosynthesized silver nanoparticles were subjected to antifungal studies by disk diffusion assay on the strain C403 that lacks the gene orf19.3120 (CNP41) of C. albicans. As a synergetic approach, combinational effect was studied by incorporating antifungal drug fluconazole. Both individual and enhanced combinational antifungal effects of silver nanoparticles and fluconazole were observed on genetically modified C403 strain with 40% increase in fold area compared to wild-type C86 strain. This can be attributed to the synergetic effect of the bonding reaction between fluconazole and AgNPs. Taken together, this first-ever interdisciplinary study strongly suggests that the CNP41 gene could play a vital role in drug resistance in this fungal pathogen.

Forcespinning technique was used to fabricate sub-micron size polycaprolactone (PCL) fibers. Forcespinning method uses centrifugal forces for the generation of fibers unlike the electrospinning method which uses electrostatic force. PCL has been extensively used as scaffolds for cell regeneration, substrates for tissue engineering and in drug delivery systems. The aim of this study is to qualitatively analyze the force spun fiber mats and investigate the effect of the spinneret rotational speed on the fiber morphology, thermal and mechanical properties. The extracted fibers were characterized by scanning electron microscopy differential scanning calorimetry, tensile testing and dynamic mechanical analysis. The results showed that higher rotational speeds produced uniform fibers with less number of beads. The crystallinity of the fibers decreased with increase in rotational speeds. The Young's modulus of the forcespun fibers was found to be in the range of 3.5 to 6 MPa. Storage and loss moduli decreased with the increase in the fiber diameter. The fibers collected at farther distance from spinneret exhibited optimal mechanical properties compared to the fibers collected at shorter distances. This study will aid in extracting fibers with uniform geometries and lower beads to achieve the desired nanofiber drug release properties.

β-tricalcium phosphate (β-TCP, Ca3(PO4)2) is biodegradable ceramics with chemical and mineral compositions similar to those of bone. It is a potential candidate for bone repair surgery, and substituting the Fe ions can improve its biological behavior. In this study, we investigated the effect of Fe ions on the structural deviation and in vitro behavior of β-TCP. Fe-doped β-TCP were synthesized by the co-precipitation method, and the heat treatment temperature was set at 1100 °C. The chemical state of the Fe-doped β-TCP was analyzed by x-ray photoelectron spectroscopy, while structural analysis was carried out by Rietveld refinement using the x-ray diffraction results. Fe ions existed in both Fe²⁺ and Fe³⁺ states and occupied the Ca-(4) and Ca-(5) sites. Fe ions enhanced the degradation of β-TCP and resorption behavior onto the surface of β-TCP during the immersion test. As a result, Fe ion improves the initial cell adhesion and proliferation behavior of β-TCP.

The good rate capability and longer cyclic performance are the two key features electrochemical capacitors that are highly dependent on the electrochemical stability, structure, electrical conductivity, composition, and nature of the charge storing-mechanism involved by its electrodes. Herein, we fabricated layered Co(OH)₂ and their nanocomposite with carbon nanotubes (CNTs, 5%) via a two-step approach for electrochemical applications. The as-prepared nanocomposite based electrode displays good specific capacitance (Cs), negligible capacity fade, and promising rate capability on electrochemical tests via a three-electrode configuration. More precisely, the nanocomposite based electrode showed Cs of 802 Fg⁻¹ at 0.5 Ag⁻¹ and loss just 3.8% of its initial capacitance (at 1st cycle) after 5000 cyclic tests. Furthermore, the nanocomposite electrode lost around 14% of its initial capacitance on increasing the current density from 0.5 to 5 Ag⁻¹ that reveals its novel rate capability. The observed superior electrochemical aptitude of the fabricated nanocomposite is credited to the layered nanoarchitecture of the Co(OH)₂ and CNTs matrix. The CNTs-matrix, because of their lower properties, performs multiple roles to improve the supercapacitive performance of the whole composite. Firstly, they accelerate the charge transfer within the nanocomposite matrix due to its higher electrical conductivity. Secondly, they facilitate mass transport due to its hollow structure. Thirdly, they sandwich between the layers of Co(OH)₂ and suppress the stacking process. Fourthly, the added CNTs itself act as a capacitive supplement and further improve the specific capacitance of the nanocomposite. Finally, CNTs buffers the whole nanocomposite against the volume expansion during the continuous cyclic tests. The electrochemical and structural stability of Co(OH)₂/CNTs sample was also evaluated by EIS and PXRD characterizations after electrochemical tests. The acquired result showed that fabricated nanocomposite has great potential for advanced energy storage applications.

The catalytic filter was fabricated by supporting selective catalytic reduction (SCR) catalyst on the low-density ceramic (LDC) for the removal of dust and nitrogen oxides (NO_x) in the flue gases at relative low temperature. MnO_x–ZrO₂/TiO₂ catalyst was selected as SCR catalyst. The NO_x and dust removal efficiency, filter resistance, regeneration performance and anti-sulfur performance were investigated. The result showed that the NO_x removal efficiency at 180°C reached 98.4% (1 m/min filtration velocity) for 6 wt% MnO_x–ZrO₂/TiO₂ catalytic filter with Mn/Zr molar ratio of 2. Furthermore, MnO_x–ZrO₂/TiO₂ catalytic filter performed good anti-sulfur performance. In the presence of 10 vol% water vapor and 100 ppm SO₂ at 180 °C, the NO_x removal efficiency for MnO_x–ZrO₂/TiO₂ catalytic filter could retain up to 83.2% and it could recover to 91.8% when the water vapor and SO₂ were cut off. MnO_x–ZrO₂/TiO₂ catalytic filter showed the high dust removal efficiency of 99.99% and the low filter resistance of less than 200 Pa. The filter resistance of MnO_x–ZrO₂ /TiO₂ catalytic filter could maintain 235.7 Pa after 200 times pulse blowback. The result illustrated that MnO_x–ZrO₂/TiO₂ catalytic filter showed good regeneration performance.

Graphene oxide (GO) has attracted much attention in anticorrosive coating applications due to its excellent mechanical properties, thermochemical stability and large specific surface area. In this paper, aniline trimer modified GO composites (ATGO) were prepared through modifying GO at different temperatures of 65 °C, 80 °C, 95 °C, and 110 °C, respectively. Aniline trimer modified GO composite coatings (ATGO/EP) were then prepared by adding different quantities of ATGO to epoxy coating, with the mass fractions of 0.05%, 0.1% and 0.3%, respectively. The resulting composite coatings were then sprayed onto Q235 steel plates for characterization and anticorrosion testing. A series of characterization methods such as x-ray diffraction (XRD), Raman spectra, Fourier transform infrared spectroscopy (FT-IR), Atomic force microscopy (AFM) and Transmission electron microscopy (TEM) were used to prove that aniline trimer was successfully grafted on GO. The optimal reaction temperature for ATGO preparation was determined to be 95 °C. Using anticorrosive tests such as Electrochemical impedance spectroscopy (EIS), salt spray test and adhesion test, it was proven that the addition of ATGO can significantly promote anticorrosion performance of epoxy resin (E-44). The optimal addition amount of ATGO to prepare composite coatings was determined to be 0.05 wt%. Its coating resistance after soaking in 3.5% NaCl solution for 10 days was 6.87 × 10⁶ Ω, which was two orders of magnitude higher than the 3.89 × 10⁴ Ω of pure epoxy coating. The importance and originality of this study is that it explores an effective way to improve the anticorrosion performance of epoxy coatings.

Occurrence of magnetic-correlation-phenomena in multi-layered carbon-materials has recently attracted an important attention for applications in magnetic devices and spintronics. In this study, exfoliated highly-oriented-pyrolytic-graphite (HOPG) lamellae exhibiting hexagonal-Moiré-superlattices, with periodicity of ∼13 nm (1st category, θ_rot ∼ 1.09° ) and ∼36 nm (2nd category, θ_rot ∼ 0.39°) were investigated. Raman-spectroscopy evidenced weak D, D' and intense G bands. In 1st category, magnetization versus field, ZFC- FC magnetic-curves from 2 K to 300 K and T-ESR revealed presence of uncorrelated and correlated ferromagnetic clusters at T* ∼ 150 K together with a critical transition at T_c ∼ 50 K, compatible with percolative-ferromagnetic-correlation. Comparative measurements on the 2nd category, revealed an analogue trend, with at T* ∼ 50–60 K together with an irreversibility at T_c ∼ 40 K, indicative of competing ferromagnetic/antiferromagnetic-correlations.

In this work, quinoa straw (QS) is considered as a sustainable biomass resource to produce adsorbent materials for wastewater treatment. Two materials, a porous carbon material derived from QS (PCQS) and a Fe₃O₄-containing composite material based on the PCPS (Fe₃O₄@PCQS), were prepared. PCQS was prepared via carbonization and subsequent chemical activation of the QS using NaOH. Thereafter, PCQS was characterized by SEM, TEM, XRD, IR, XPS, and N₂ adsorption-desorption analysis. As a carbon material with heterogeneous pores, PCQS has a BET specific surface area of 3435.21 m² g⁻¹, which is about 175 times higher than that of the precursor QS (19.60 m² g⁻¹). The PCQS had an adsorption capacity of 1778.1 mg g⁻¹ toward rhodamine B (RhB), and the adsorption followed pseudo-second-order kinetics and the Freundlich isotherm model. The PCQS was further modified by synthesizing Fe₃O₄ magnetic nanoparticles on the surface of PCQS to give Fe₃O₄@PCQS. The adsorption capacity of Fe₃O₄@PCQS toward RhB reached 1156.2 mg g⁻¹, and it could be rapidly separated from water by applying an external magnetic field. The PCQS and Fe₃O₄@PCQS exhibited acceptable reusability which was evaluated through ten successive adsorption/desorption cycles. In summary, the adsorption capacities of PCQS and Fe₃O₄@PCQS toward RhB are comparable with most current adsorbents, including the graphene-based materials, which shows that QS is a promising biomass feedstock to prepare carbon-based materials and composites.

Ab-initio framework investigation of structural stability and thermophysical behavior of two Co-based Heusler alloys is carried out using spin-polarized calculations at high temperature and pressure. The structural characterization in nonmagnetic and ferromagnetic states reveals the ordered ferromagnetic Cu₂MnAl-prototype structure as stable phase. The optimized lattice constant is found to be consistent with the available experimental value. The continuity in the P–V plot indicates the absence of any structural phase transition from highly symmetric cubic structure to other structural phase. The band structure profile shows perfect half-metallic character with integral 3.00 μ_B magnetic moment for Co₂VSn and 4.00 μ_B for Co₂VSb according to the Slater-Pauling rule. Elastic constants convey that these alloys are mechanically stable with a high Debye and melting temperatures. With the incorporation of modified version of Beck-Johnson potential these alloys displays a perfect half-metallic character having an indirect band gap of 1.12 eV and 1.34 eV in spin down orientation of Co₂VN (N = Sn, Sb) Heuslers respectively. The density of states along with their corresponding band structure delivers the semiconducting nature of alloys in spin down channel for the present set of alloys. Semi-classical Boltzmann theory for heat transport is used to check the applicability of the material for thermoelectric technology. Insight into variation of lattice thermal conductivity shows an exponential decreasing trend for both the compounds intriguing their experimental exploration. Also, a detailed description of thermodynamic behavior of the vital quantities like entropy, thermal expansion, Grüneisen parameter and specific heat were examined using quasi harmonic Debye approximation.

Two groups of low carbon steel with ultra-micro amount (less than 20 ppm) rare earth lanthanum and without rare earth element were taken as experimental objects. Continuous cooling transformation curves of two kinds of low carbon steels were drawn by Formaster-F II automatic phase transformation instrument, alloy phase method and hardness method. According to the measured CCT curve, the microstructure and hardness of low carbon steel under different cooling rates were studied and analysed. The results show that the addition of ultra-trace rare earth elements can increase the A_c1 and A_c3 points of low carbon steel by about 20 °C; the starting temperature of martensite transformation M_S point decreased by 19 °C, and the end temperature M_f point decreased by 6 °C; at low cooling rate, the transformation range of ferrite is increased and that of pearlite is decreased; the starting temperature of bainite B_s point increased by 20 °C, and the end temperature of bainite B_f increased by 13 °C; at low cooling rate, the ferrite transformation range becomes larger, while at high cooling rate, the ferrite transformation range becomes smaller.

In this paper, the plasmon resonance on electrochemically modified titanium surfaces synthesized by anodic dissolution method has been studied in the presence with gold ablative nanoparticles. The permittivity functions and reflection coefficients of p- and s-polarized light spectra on the titanium oxide surface of various modification (roughness) have been analyzed. Spectral features of the negative refractive index in the area of surface plasmon generation on the rough titanium-oxide film interface have been also presented in this paper.

In this study, AgGaSe₂ single crystal was successful grown by vertical gradient freezing method. Meanwhile, the precipitates on AgGaSe₂ single crystal were investigated by x-ray photoelectron spectroscopy (XPS). This technique was recommended as a practicable method to study the precipitates while they are difficult to be detected by other measurements owing to their components and fairly low content. In addition, Energy Disperse Spectroscopy (EDS) and x-ray diffraction (XRD) were employed to characterize the quality of the as-grown AgGaSe₂ single crystal. The EDS results indicate a slight deviation from stoichiometric ratio along growth defects. The XRD results manifest that AgGaSe₂ crystal has single phase and high purity. The XPS results indicate that precipitates exist on as-grown AgGaSe₂ single crystal mainly in the form of Ga₂Se₃. Ga₂O₃ and Ag₂O were detected by XPS on the polished surface of the as-grown crystal wafer which was regarded as an oxide layer. The study on precipitates may provide important reference for growth process improvement and post-treatment to obtain high quality AgGaSe₂ single crystal.

Hybrid organic-inorganic lead halide perovskites (HOIPs) have appealed to researchers on account of excellent optoelectronic properties. Compared with films which possess grain boundaries, HOIPs single crystals with fewer defects behave excellent transport and recombination performances. In the family of HOIPs, single crystals of MAPbX₃ (MA = CH₃NH₃⁺, X = Cl, Br or I) are recognized as the most competitive candidates for optoelectronic applications. However, the photodetectors based on MAPbX₃ have difficulties in detecting weak signals for lacking of gains without structure optimizations and extra energy transfer channels. In this study, taking advantage of MAPbBr₃ single crystal (100) facets, planar metal-semiconductor-metal (MSM) photodetectors were fabricated with Au zigzag electrodes and modified Au nanoparticles (NPs) to realize localized Au surface plasmons (SPs). Compared to device without Au NPs, 2 times enhancement of photocurrent and responsivity have been achieved under 630 nm photon irradiation and 5 V bias. Furthermore, the surface metal structures can inhibit ionic migration to a certain extent. Potential mechanisms of the enhancements and suppressions are discussed in details to reveal the applications of this technique.

RF magnetron-deposited Si\In₂O₃:Er films have the structure of the single-crystalline bixbyite bcc In₂O₃ nanowires bunched into the columns extended across the films. The obtained films have a typical In₂O₃ optical band gap of 3.55 eV and demonstrate the 1.54 μm Er³⁺ room temperature photoluminescence. The current across the film flows inside the columns through the nanowires. The current through the MOS-structure with the intermediate low barrier In₂O₃:Er dielectric was investigated by the thermionic emission approach, with respect to the partial voltage drop in silicon. Schottky plots ln(I/T²) versus 1/kT of forward currents at small biases and backward currents in saturation give the electron forward n-Si\In₂O₃:Er barrier equal to 0.14 eV and the backward In\In₂O₃:Er barrier equal to 0.21 eV.

We proposed a micro mean-field Monte Carlo (MMFMC) method based on Metropolis single spin flip algorithm to calculate the thermodynamic properties of three-dimensional ferromagnet describerd by Heisenberg model. In MMFMC method, the actions of the neighboring spins on the selected spin is replaced approximately by their expected values multiplied by the exchange interactions between them, thus each spin is in a quantum state obtained by solving single spin Hamitonian in every MC step. The magnetization, internal energy, specific heat, longitudinal and transverse susceptibilities are calculated for SC, BCC and FCC ferromagnets with arbitray spin quantum number and single-ion anisotropy. it is found that the system shows phase transition phenomenon from paramagnetic to ferromagnetic phase with temperature decreasing, and the Curie temperatures obtained are consistent with those obtained by other theories.

Core–shell Fe₃O₄@Ag magnetic nanoparticles (MNPs) integrated with a Wheatstone bridge-giant magnetoresistance (GMR) sensor provide access to GMR-based biosensors. The Fe₃O₄ nanoparticles synthesized using the coprecipitation method demonstrated 77 emu g⁻¹ of magnetization saturation (M_S), 51 Oe of coercivity (H_C), and particle size of 11 nm. Furthermore, core–shell Fe₃O₄@Ag MNPs prepared by the aqua-solution method possessed 53 emu g⁻¹ of M_S, 145 Oe of H_C, and 17 nm of particle size. This high M_S of nanoparticles not only offer a large induced magnetic field but is sufficient for particle penetration within the biofilms. It was discovered that the sensor can distinguish between the bare Fe₃O₄ with the Fe₃O₄@Ag nanoparticles through an output voltage increase corresponding to a decrease in M_S. The output signal of the sensor responds linearly to an increase in the core–shell Fe₃O₄@Ag nanoparticle concentration, owing to an increase in the induced-field. The sensor exhibits better sensitivity when applied in detecting less than 2 g L⁻¹ of nanoparticle concentration, that is, 0.76 mV per unit of concentration (g/L).

Electromagnetic interference produced by high-speed electrical and electronic systems (i.e., base stations, mobile phones, radar, television and radio transmitters) that facilitate daily life also caused a pollution to be dealtwith as a part of daily life. Increasing use of electronic devices arising from the rapid developments in science and technology increased electromagnetic interference in electronic devices well besides the electromagnetic pollution in the environment. Therefore, there is a tremendous need to develop effective protection against the negative effects of electromagnetic interference. The objective of this paper is to make the composite boards from the recycling of Tetra Pak packages and to investigate the effect of aluminum additive on absorption efficiency of electromagnetic interference at various frequencies. Experimental results showed that as the ratio of aluminum additive rate in the composite material increased, the attenuation ratio increased.

This paper aims to calculate the photonic band structure in a distributed Bragg reflector pillar. The one-dimensional periodic photonic pillar consists of alternating layers of GaAs and air. We consider the dependence of the GaAs dielectric constant on the hydrostatic pressure at a fixed temperature value. The guided-mode expansion method is employed in the case of the photonic pillar; on expanding the magnetic field of the pillar into the basis of guided modes of a homogeneous waveguide, a linear eigenvalue problem is obtained. It is observed that the photonic band structure consists of true-guided modes outside the light dispersion in the effective core, and the radiative modes are located above the light dispersion. When the pressure is increased at a given temperature, the dielectric band exhibits a shift to higher frequencies, while the air band exhibits a slight shift to lower frequencies, resulting in a decrease in the width of the photonic band gap. The calculation of the photonic pillar fundamental mode did not yield a cutoff frequency.

In this study, we grew CuO doped potassium tantalum niobate (Cu:KTN) crystals with a uniform superlattice structure by the off-center top-seeded solution growth (TSSG) method. The process of crystal superlattice structure formation was observed under a polarizing microscope at variable temperatures. It was found that the formation of the superlattice structure in the crystal was closely related to the formation process of the domain structure in the crystal. The 90° domain structure in the crystal promoted the formation of the superlattice structure in the crystal. The purpose of the formation of the superlattice structure is to enable the crystal to reach a more stable state. The clear diffraction effect of the crystal superlattice structure is similar to the x-ray diffraction phenomenon of low-temperature crystals, and it exists in the crystal in a three-dimensional structure.

RNiO₃ perovskites have been described to present thermally driven metal-insulator transitions (at T_MI) as a function of the rare-earth ion size (R = Pr to Lu). Aiming to extend the stability range of RNiO₃ for smaller R³⁺ ions, we prepared Lu_1−xSc_xNiO₃ (x = 0, 0.1, 0.2) perovskites, being Sc³⁺ ions substantially smaller than Lu³⁺, by using a multi-anvil high-pressure synthesis device at 10 GPa. We have studied the structural evolution of Lu_0.9Sc_0.1NiO₃ by synchrotron x-ray diffraction (SXRD) from room temperature to 350 °C. The symmetry of the lattice evolves from monoclinic (P2₁/n) to orthorhombic (Pbnm) upon heating across T_MI (≈320 °C), with the existence of two chemically and crystallographically distinct nickel sites in the insulating, monoclinic regime, whereas the metallic phase has a single NiO₆ environment. A simultaneous structural and electronic transition implies an abrupt evolution of the lattice parameters and size of the NiO₆ octahedra upon entering the metallic regime, leading to the merging of the disproportionated Ni-O bond lengths. The magnetic properties correspond to the establishment of antiferromagnetic correlations at the Ni sublattice; a decrease of the T_N ordering temperature from 122 K (x = 0) to 113 K (x = 0.2) is observed as the Sc content increases, which is concomitant with a more distorted perovskite structure.

The polarization and strain response of electrically poled lead zirconate titanate ceramics was reinvestigated under low-to-medium electric field loading. A phenomenon that is usually ignored was pointed out and discussed. That is, under low-to-medium cyclic electric field loading, remnant strains measured under a negative electric field loading are larger than those measured under a positive electric field loading. Here, 'positive' and 'negative' mean that the applied electric field is aligned or antiparallel to the pre-poling direction of the material, respectively. Moreover, a reverse trend was observed for remnant polarizations. Texture-dependent domain switching, defect dipole reorientation, and interactions between them were used to rationalize this phenomenon. In addition, the equation ${\rm{S}}\,=\,\left({{\rm{d}}}_{{\rm{init}}}+\alpha {{\rm{E}}}_{{\rm{0}}}\right)\ast {\rm{E}}\pm \tfrac{\alpha }{{\rm{2}}}\left({E}_{0}^{2}-{E}^{2}\right),$ which is used to describe the strain response, was modified by taking the asymmetry of the electric field versus strain curve into consideration. The modified equation can better describe the strain response than the original equation.

Recently, a novel nitrogenated holey two-dimensional material, C₂N, has been successfully synthesized via a simple wet-chemical reaction. Its merits have drawn much attention from the scientists. However, to the best of our knowledge, few reported works employed C₂N as photovoltaic materials and the practical solar cells based on C₂N have not been fabricated in lab. In this work, we carried out simulation using Scaps-1D to investigate the influences of different parameters on the C₂N based solar cell. By varying the acceptor density, layer thickness, defect density of C₂N and changing different N layers coupling with C₂N, we found out that suitable acceptor density, around 10¹⁵cm⁻³, large layer thickness of C₂N and low defect density were key factors to obtain high-performance solar cells. Small band offset also played an importance role in enhancing the performance of photovoltaic materials. With optimized parameters, C₂N coupling with CdS as heterojunction can achieve an efficiency of over 17%. This work may provide valuable insights into future design of C₂N based solar cells.

The electronic structure and optical properties of intrinsic and doped Ca₂Ge have been calculated by using the first-principles calculation method based on density functional theory. The doping content of As were 2.08% and 1.04%, respectively, and the doping concentrations of Ga were same with As. The band gap of intrinsic Ca₂Ge is 0.556 eV, and that decreased to 0.526 eV and 0.548 eV with respect of As doping amount of 2.08% and 1.04%. Meanwhile, the band gap is 0.25 eV when the doping amount of Ga was 1.04%, and the band gap is 0.23 eV for Ga was 2.08%. The band structures results shown that the Fermi levels of As-doped (2.08% and 1.04%) are moved into the bottom of conduction band. The electronic density of sates shown that the electronic configurations at the top valence band and bottom conduction band were changed as As and Ga doped. The dielectric function results shown that the maximum value of 52.7 and 97.53 were respectively obtained at 0 eV for the 2.08% Ga-doped and the 1.04% As-doped. Moreover, the phenomenon of strong metallic reflection has been found in the energy range of 6.0 ∼ 8.5 eV, and the metal reflection characteristics of intrinsic Ca₂Ge was greater than the doped Ca₂Ge. Analyzing the energy-loss function, it indicating that the energy region of appearing energy loss can be altered by doping As and Ga or changing their doped concentration.

Calcium oxalate film was prepared by a novel two-step method on the surface of the marble substrate. The seed film was coated by a chemical reaction process, providing a good connection to the marble surface. Meanwhile, calcium oxalate solution was interwoven into the seed film to form a continuous network at room temperature. The x-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis results indicated that the calcium oxalate film prepared by the two-step method showed a more intensive crystallinity degree and homogenous than that by the traditional oxalate treatment method (a scattered seed film). Subsequently, it was found such calcium oxalate film is feasible for preventing the marble substrate from chemical weathering. Furthermore, the change of the chromatic value, water absorption properties and adhesion strength of the marble substrates by the film is minimal. This method overcomes the limitations of traditional oxalate treatment process and has great potential for the protection of marble artifacts.

In this work, Ca₃Ti₂O_7-xF_x thin films on (110) SrTiO₃ substrates were prepared by two steps as deposited via pulsed laser deposition and fluorinated with polyvinylidene fluoride. Despite the unchanged crystal structure of the fluorinated films, the changed valence state can be used to confirm the incorporation of F⁻¹ and the weakened chemical bond of Ca–O. Furthermore, we found that the photoelectric switch can be observed at a wide range of light wavelength from 405 nm to 808 nm. It is found that the photosensitivity of 4 × 10⁴ (405 nm) in the fluorine has been increased by two orders of magnitude, which is most likely due to the deep energy levels in the reduced band gap of 2.3 eV. This work paves the way for the enhanced photoconductive devices via the anionic defect engineering.

Nucleation plays a critical role in many natural and technological processes, and nucleation control requires detailed understanding of nucleation process at atomic level. In this study, we investigate the atomistic mechanism of heterogeneous nucleation in generic systems of liquid/substrate with positive lattice misfit (the solid has larger atomic spacing than the substrate) using molecular dynamics (MD) simulations. We found that heterogeneous nucleation process in such systems can be best described by a 3-layer nucleation mechanism: formation of the completely ordered first layer with an epitaxial relationship with the top surface of the substrate; formation of vacancies in the second layer to accommodate lattice misfit; and creation of a nearly perfect crystal plane of the solid in the third layer that demarcates the end of nucleation and the start of crystal growth. This 3-layer nucleation process creates a 2D nucleus (a plane of the solid phase), which contrasts with the hemisphere of the solid (a 3D nucleus) in the classical nucleation theory (CNT). It is expected that this 3-layer nucleation mechanism will provide new insight for nucleation control through effective manipulation of the liquid/substrate interface.

This work developed an effective and promising lubricant containing Zn nanoparticles and polyethylene glycol (PEG) base oil to deal with the tough problem of boundary lubrication for steel/Ti6Al4V. Tribological tests were carried out to investigate the boundary lubrication performances and the generation process of boundary protective films on the worn surface. Results showed that low and steady friction coefficient curves could be obtained by PEG suspensions with Zn nanoparticles after a very short 'run-in' period, and the main wear volume of Ti6Al4V was occurred during the 'run-in' period. The ZnO boundary protective films generated on the counterfaces of the Ti6Al4V disk and steel ball during the friction process. This strong and steady oxide films could effectively prevent direct contact between frictional pairs and provide excellent boundary lubrication performances. This work will contribute to the development of high performance lubricants for titanium alloys

The influence of silicon carbide (SiC) addition to W-Ni-Cu-based heavy alloys has been investigated in the present study. The powders of W-Ni-Cu with varying percentages of SiC were blended and sintered using conventional and Spark Plasma Sintering (SPS) techniques. The sintered samples were characterized to determine the density, microstructure, and mechanical properties. The alloy (W-7Ni-3Cu-0.5SiC) exhibits high ultimate tensile strength 430 MPa for conventional sintering and 831 MPa for spark plasma sintering, relative sintered density 71.84% and 88.25% of conventional sintered and spark plasma sintering, respectively. After the tensile test, the fracture surfaces show a mixed-mode fracture consisting of brittle W/W intergranular and ductile mode of fracture in the matrix.

In this report, the effects of magnetic fields by using Helmholtz coils on the microstructures and mechanical properties of sand-casting Al-Cu alloys were firstly investigated. Due to the magnetic field stirring effect during the solidification process, the average grain size of sand-casting A201 ingots decreased, and the uniformity of α-Al grain increased. The grain refinement by the magnetic fields equipped with Helmholtz coils enhanced the mechanical properties of sand-casting A201 ingots, including hardness, yield strength, ultimate tensile strength and elongation. Meanwhile, according to the characterization of x-ray diffraction, preferred orientation (111) planes of α-Al phase was observed as the increase of the magnetic field. The magnetic field of Helmholtz coils provided the Lorenz force to agitate the melt during the solidification of sand-casting Al-Cu ingots, which had influence on the migration of solid-liquid interface and the rotation of the single-crystal nucleus. In summary, an easy and low-cost technique was proposed to improve the mechanical properties of sand-casting A201 alloys.

In order to investigate the corrosion behavior of Inconel 625 deposited metal in molten KCl and MgCl₂, the corrosion behavior of deposited metal immersed in molten salt for 60 h at 700 °C and 900 °C was studied by static corrosion immersion method. X-ray diffraction (XRD) and Geminisem300 were used to systematically study the phase composition, corrosion morphology and element distribution of the deposited metal. The results show that: the corrosion weight loss of the deposited metal showed an increasing trend at both temperatures, but the increasing range was different in different time intervals. The corrosion weight loss of the deposited metal increased slowly in the first 10 h, and increased sharply in the 10 h–60 h. It can be found that 10 h is the cut-off point of corrosion behavior. The corrosion rate is 0.03 mm/year at 700 °C and 0.50 mm/year at 900 °C for 10 h. The corrosion resistance of the deposited metal at 700 °C is better than that at 900 °C, which is due to the formation of dense MgO on the surface of the deposited metal at 700 °C, which hinders the corrosion reaction; at 900 °C, the content of CrCl₃ on the surface of the deposited metal increases, resulting in a 'shell breaking effect', which destroys the MgO shell and forms NiCr₂O₄ with spinel structure. Its corrosion resistance is thus weakened.

Titanium alloys and nickel-based alloys have their own unique properties, and the bimetallic structure composed of the two alloys can be widely used in the aerospace field. However, the bimetallic structure which is fabricated by directly joining titanium alloys and nickel-based alloys via traditional methods is more sensitive to cracks due to the formation of intermetallic compounds. In this work based on laser additive manufacturing (LAM) technology, the TC4/IN718 bimetallic structure without metallurgical defects (such as cracks) was successfully fabricated via a Ta/Cu multi-interlayer. The test results indicated that the Ta/Cu multi-interlayer could effectively avoid the generation of Ti–Ni and Ti–Cu intermetallic compounds between TC4 and IN718. A good metallurgical combination was formed in each interface from TC4 to IN718 without metallurgical defects. The phase evolution from the TC4 region to the IN718 region was as follows: α-Ti → α-Ti + β-Ta → β-Ta → β-Ta + γ-Cu → γ-Cu → γ-Cu +γ-Ni + laves → γ-Ni + laves. The ultimate tensile strength of the bimetallic structure at room temperature was 369.32 MPa.

An Mg-3Al-1Zn-xSn (x = 0, 3, 6, 9) alloy was prepared by die-casting and analyzed by XRD, SEM, and EBSD. The microstructure, second phase, and grain orientation of the AZT31x alloy were characterized. As the Sn content increased from 3 wt.% to 9 wt.%, the tensile and yield strength of the alloy were effectively improved. With the addition of Sn, the grain size of alloys decreases gradually blocking the dislocation by the grain boundary and the dispersion of the Mg₂Sn second phase in the AZT31x(x = 3, 6, 9) alloys contributes to the strength via grain boundary pinning. According to theoretical analysis and calculation, the high strength of AZT319 alloy is partly attributed to the grain fine strengthening $\left({\sigma }_{{H}_{P}}=13.76\,{\rm{Mpa}}\right.$) and second phase strengthening $\left({\rm{\Delta }}\sigma =9.27\sim 12.67\,{\rm{MPa}}\right).$ The total increased strengthening value is lower than experimental value (${\rm{\Delta }}\sigma =31.82\,{\rm{MPa}}$). The ratio about ${\tau }_{prism}$/${\tau }_{basal}$ and ${\tau }_{\left\langle c+a\right\rangle }$/${\tau }_{basal}$ in die-cast alloys tensioned to 0.08 deformation gradually decrease, which can reflect that high-Sn content contributes to the strain hardening behavior. The ductility of AZT313 alloy was lightly improved due to the {10-12} tensile twins. When excessive Sn was added, the Mg₂Sn second phase coarsened and acted as the nucleus of micro-cracks during the stretching process, thereby reducing the ductility of the alloy.

Beryllium is considered as a candidate of ITER first-wall (FW) armor and neutron multiplier in fusion reactors. To assess the irradiation resistance of CN-G01 beryllium, which has been accepted as an alternative ITER-grade beryllium in China, 180 keV helium ions with fluences of 1.0 × 10¹⁷ ions cm⁻², 5.0 × 10¹⁷ ions cm⁻² and 1.0 × 10¹⁸ ions cm⁻² were implanted at room temperature. The theoretical simulation of energy loss, damage distribution and helium concentration were proceeded by SRIM. In this paper, we report the experimental exploration of ion fluence effect on surface morphology and microstructure of irradiated samples. Field Emission Scanning Electron Microscope (FESEM) analysis depicted the formation and growth of helium bubbles at different irradiation ion fluences. No obvious exfoliation or cavities was observed on the surface at all ion fluences, suggesting a reliable radiation resistance of CN-G01 beryllium. Atomic force microscopy (AFM) morphology showed that the maximum height of bubbles was 47.8 nm. Surface roughness values increased slightly due to the formation of defects and bubbles on the irradiated beryllium surface. Nevertheless, the structural analysis demonstrated by grazing incidence x-ray diffraction (GIXRD), indicated an obvious preferred orientation on (101) peak at various ion fluences. Annihilation of defects caused by a small rise of the localized temperature could explain the increasing intensity of diffraction peak (101).

The effect of direct quenched (DQ) and tempering temperature on the microstructure and mechanical properties of high strength steel were studied by means of SEM, EBSD, TEM and mechanical properties test. The results showed that in DQ state, the tensile strength could reach 1420 Mpa, the yield strength could be 1050 Mpa, and the elongation was about 9.0%, impact energy at −20 °C was 59 J. High density entangled dislocation was distributed inside the lath and at the boundary. A small amount of Nb and Ti carbide was precipitated at the dislocation and lath boundary, and a small amount (about 2.15%) of residual austenite distributed between the lath. With the tempering temperature rising from 500 °C to 720 °C, the tensile strength of the experimental steel decreased from 1220 MPa to 840 MPa, the yield strength decreased from 1190 MPa to 780 MPa, the elongation increased from 10% to 13%, and the impact energy at −20 °C increased from 84 J to 153 J. When the tempering temperature rised from 500 °C to 640 °C, the structure was mainly composed of lath martensite and a large number of dislocations were still distributed inside the lath. The size of carbides precipitated inside and on the boundary of the lath was about 20–30 nm. When tempered at 680 °C, the structure was mainly composed of martensite and a small amount of polygonal ferrite. There were still a large number of entangled dislocations inside and on the boundary of martensite. The carbide precipitate at the matrix boundary and dislocation line was obviously coarsening (70–80 nm). When tempered at 720 °C, the microstructure was mainly polygonal ferrite, the dislocation density in the matrix significantly decreased, and the carbide precipitated at the matrix boundary and dislocation line significantly coarsened (about 100 nm). With the tempering temperature rising from 500 °C to 720 °C, the proportion of small-angle grain boundary was gradually decreased from 88.64% to 70.50%.

In this paper, rare earth element yttrium (Y) was selected to be doped into AlCoCrFeNi_2.1Y_{x (x = 0, 0.1%, 0.3%, 0.5%, and 1.0%)} high-entropy alloy in order to refine grain and increase yielding strength. The precipitation behavior of the Y-rich nano-phases in the face centered cubic (FCC (L1₂)) phase and the body centered cubic (BCC (B2)) phase was investigated by x-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and differential scanning calorimetry. Refined crystal grains were observed due to the high-density precipitation. The nano-phase within the BCC(B2) phase was (Al-Ni-Y)-rich phase and single cubic (SC) structure. The nano-phase formed within the FCC (L1₂) phase was (Fe-Co-Cr-Y)-rich phase and FCC structure. Fine (Al-Ni-Y)-rich nano-particles were formed due to the addition of Y and the amount of the nano-phase increased with increasing Y content. The adoption of Y promoted dispersed precipitation of (Al-Ni-Y)-rich nano-phase under deformation. The more Y content, the more nano-precipitates. When Y =1.0 at.%, the lamellar structure was transformed into bamboo-like structure in the BCC phase due to the segregation of Y. Double yielding phenomenon occurred during the compression deformation of the AlCoCrFeNi_2.1Y_x alloys (when x ≥ 0.5 at.%) and caused an increase of yielding strength by 40%. It was since the barrier effect of both the (Al-Ni-Y)-rich nano-precipitation and the (Fe-Co-Cr-Y)-rich nano-phases on the dislocations within grains and grain boundaries led to the second yielding. With the further increase of Y content, the lamellar BCC phase was separated from the bamboo-like BCC phase owing to the super-saturated precipitation and segregation of Y at the solidification front of B2 phase, leading to a degradation of mechanical properties.

In this article, for the first time, the forming limit diagram (FLD) and mechanical properties of aluminum foil samples processed by the accumulative roll bonding (ARB) process have been studied experimentally. For this purpose, thin aluminum foils with a thickness of 200 microns have been produced using ARB in five passes at ambient temperature. By rising the number of ARB passes, the ultimate tensile strength (UTS) enhanced drastically, and at the end pass of ARB, it reached 393 MPa, about 5.9 times larger than the initial sample. Also, during the ARB process, the applied strain increased, and the thickness of the layers decreased, and the bonding quality between layers improved. SEM images of tensile fracture surface after five cycles showed the mechanism of fracture retained ductile. However, due to the unevenly applied strain, the dimples were drawn in different directions, and their depth and number were reduced relative to the raw material. The area under the FLDs, a criterion of formability, declined sharply after the first pass and then increased at a low rate until the final pass. The trend of similar changes of formability in the tensile (elongation) and Nakazima tests (FLDs) was reported. Responsibility for all mechanical properties and ductility changes is related to the ARB process's nature and the two dominant mechanisms of strain hardening and grain refinement.

This work shows that heat input is an important parameter that influences microstructural changes in the heat-affected zones (HAZs) of TIG-welded 6061-T6 alloy joints and their fatigue behavior. Double-shielded TIG samples were welded using various heat input parameters and a gas mixture of 50% He and 50% Ar was used to produce an improved weld penetration, their mechanical properties and microstructures of the samples were compared to those of the unwelded alloy. The mechanical properties of the aluminum alloys and the welding zones were evaluated by performing tensile and fatigue tests. The fatigue behaviors of the 6061-T6 joints welded with different heat inputs were assessed by performing cyclic fatigue experiments. Their microstructures were examined via optical microscopy and scanning electron microscopy (SEM). Grain coarsening was observed in the fusion zones (FZs), and heat input during TIG welding made the HAZs larger. Applying the lowest heat input value yielded samples with poor ultimate tensile strength, which was attributed to partial penetration and the presence of pores in the welded joints. The oxygen content of the weld pool depended directly on the shielding method and the surface temperature distribution.

In order to expand the application prospects of LZ91 magnesium alloy, improve its tensile strength and yield strength. In this paper, the asynchronous rolling and cumulative rolling technology are combined in the large plastic deformation technology, and the LZ91 magnesium alloy after coating the aluminum foil by the asynchronous accumulative roll bonding is performed. The analysis shows that the asynchronous accumulative roll bonding technology accumulates a large amount of deformation energy storage inside the material through large plastic deformation, and refines the grain to the micro-nano level, which increases the strength of the LZ91 magnesium alloy by 86% and the hardness by 63.97%. Improve the internal structure and application performance of the material.

High-iron red mud presents a problem due to its alkalinity which leads to significant risks to the environment. In order to realize the harmless and large-scale utilization of high-iron red mud, the smelting reduction experiments were carried out to investigate the reaction mechanism for extraction iron from high-iron red mud. FactSage 6.4 software was used to conduct thermodynamic analysis of the carbon thermal reduction system. The results showed that the direct reduction with carbon involved a process of Fe₂O₃ → Fe₃O₄ → FeO → Fe, in which the theoretical required molar ratio of C/O (oxygen in Fe₂O₃) was 1:1. The maximum degree of iron extraction was 92.8% with anthracite as reductant and 88.8% without anthracite smelting at 1500 °C for 30 min in a graphite crucible. XRD was conducted to analyze the mineral phase of the samples and slags. The results showed that the minerals contained in high-iron red mud were hematite, quartz, rutile, and sodium aluminosilicate hydrate. The blank sample was consisted of hematite, nepheline quartz, and the reduced slag without quenching consisted of perovskite and gehlenite, indicating that the reaction processes occurred from sodium aluminosilicate hydrate to nepheline and then occurred from nepheline to gehlenite in slagging process. The overall smelting reduction process was described as three mass transfer steps and three chemical reaction steps. These results provide useful information for large-scale and harmless utilization of high-iron red mud.

Mg-8.3Gd-3.2Y-0.4Zr alloy underwent severe plastic deformation at 420 °C using 4-pass isothermal repetitive upsetting-extrusion (RUE) process. The deformation uniformity in different regions of the same sample after 4 passes of RUE was studied. The results showed that though there was slightly uneven deformation, the isothermal RUE process can improve uniformity. The strain in the central area is relatively small, and there are more deformed large grains. The dynamic recrystallization fraction at different positions is above 0.5, forming a more uniform microstructure, with the minimum average grain size being 10.66 μm. Discontinuous dynamic recrystallization and continuous dynamic recrystallization occur at the same time, which promotes grain refinement and improvement of microstructure uniformity. Dynamic recrystallization weakens the texture, resulting the similar texture intensity of different positions of the sample. The bottom edge position with the most uniform microstructure obtained the best tensile properties, UTS reached 323 MPa.

Microstructure evolution during the hot forming shows a significant impact on material's mechanical properties. To explore the deformation characteristics of 5CrNiMoV steel, numerical simulation and microscopic phase-field simulation of the multi-direction forgings were carried out. The strain distribution at each pass was investigated and the evolution of temperature, effective strain, effective strain rate, and grain size was acquired. The hot forging trials were carried out and three typical regions of forgings were taken to study the microstructure evolution. Detailed microstructure characterizations showed that the constructed parent austenite grain size of the forging in typical regions was slightly larger than the simulation results due to the grain coarsening during the air cooling. There were large amounts of high angle grain boundaries (HAGBs) for the occurrence of complete dynamic recrystallization and many bulging grain boundaries showed that discontinuous dynamic recrystallization (DDRX) could be the governing mechanism of nucleation and growth of dynamic recrystallization (DRX). Besides, the hot deformation texture changed significantly during the non-isothermal forging and the texture component differed remarkably at different regions of the forging. The main hot deformation texture components were Cube {001}<100> and Goss{011}<100>.

The vacuum horizontal continuous casting method was used for preparing Cu-4.5 wt.% Ag alloy rod containing few oxygen. The evolution of microstructure was observed by metallographic microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the hardness and electrical conductivity of Cu-4.5 wt.% Ag alloy aged at 450 °C for 12 h were increased by 60 HV and 12 %IACS than solution treated alloy. TEM observation showed that the continuous precipitates of Ag are uniformly distributed in matrix with the form of particles and strips. Through calculation, the strength increment of peak aged Cu-4.5 wt.%Ag alloy from solid solution hardening and precipitation hardening are 86 MPa and 136 MPa, respectively.

In this study, Mg-13Gd-4Y-2Zn-0.5Zr alloys were fabricated and subjected to 3 passes of cyclic expansion-extrusion with an asymmetrical cavity (CEE-AEC). The influence of the CEE-AEC together with the heat treatment on the microstructural characteristics and hardness were investigated systematically, through optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Vickers hardness testing machine. The results illuminated that the introduction of the strains through CEE-AEC has a significant effect on the heat treatment of the specimens. The precipitation of the second phases particles was remarkably accelerated, including the lamellar phases in solution treatment, the grain boundary precipitates and the equilibrium β phases in ageing treatment. Likewise, the hardness of the investigated samples was obviously improved by the comprehensive effect of the CEE-AEC together with the heat treatment, and the peak aging time of the CEE-AEC samples was substantially advanced relative to the as-cast ones. The enhanced hardness owned relatively high thermal stability in the ambient temperature. The precipitation sequence of 3 CEE-AEC passes alloy aged at 225 °C was as follows: supersaturated solid solution Mg (S.S.S.S)→β'' (DO₁₉)→β' (bco)→β₁ (fcc)→β (fcc).

Functionally graded Al6061-SiC composites are widely used in the manufacturing of bearing surfaces, bushes, gears, cylinder liners, pistons and camshafts. However, due to the poor density and higher level of porosity, the usages of Al6061-SiC composites are limited. The Purpose of the study is to improve the wear behaviour of the Al606l–SiC composites to widen the engineering application of the Al6061 alloy. In this present work, an effort is made to examine the dry sliding wear characteristics on a newly developed hybrid metal matrix composite of Al6061%-5%SiC-x TiB₂ (x = 2%, 4%, 6%, 8% and 10 wt%) fabricated by stir casting route. The Wear Rate and Coefficient of Friction were examined using a Pin-on-Disc tribometer at various dry sliding conditions. The results of the experimental studies revealed that with the addition of secondary hard ceramic TiB₂ particles, the wear behaviour was found to be significantly improved on the hybrid composite due to the new formation of Mechanically Mixed Layer (Fe₂O₃ layer). The Coefficient of Friction showed a decreasing trend in the case of varying loads and sliding distances. Conversely, the COF exhibit an increasing trend concerning the sliding velocities. The results have shown that the highly concentrated Al6061—5%SiC—10%TiB₂ hybrid composite achieved the least COF values of 0.26, 0.31 and 0.29 at higher applied load (40N), sliding distance (2000 m) and sliding velocity (2.61 m s⁻¹) conditions respectively. The worn surface of the hybrid composite indicates fine grooves with minimal abrasion.

A novel nano-WC/Cu-based composite with nanometer WC dispersed in the copper matrix was successfully prepared by vacuum hot-pressing sintering. The effects of different hot-pressing sintering temperatures on the microstructure, conductivity, strength, and hardness of the composite were investigated. As a result, with the increase of temperature, the distribution of nano-WC particles in the matrix is more even, and the relative density can reach about 100% when sintering temperature increase to 1075 °C. The electrical conductivity of the composites sharply increases from 62.5 to 90%IACS when sintering temperature increase from 950 °C to 1100 °C. Furthermore, as the sintering temperature rises from 950 °C to 1100 °C, the ultimate tensile strength gradually increases from 123 to 425 Mpa, and the hardness increases from 127.5 to 150 HV. In addition, the composite also displayed excellent resistance to high temperature softening at 800 °C.