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To understand the relationship between the process-microstructure-mechanical properties of the high-pressure die-casting (HPDC) AE44 magnesium alloy, 3D reconstruction and 2D characterization were carried out on the HPDC castings produced with different process parameters (low slow-shot speed, fast slow-shot speed, solidification pressure). Microstructural characterization revealed that the formation of shrinkage pores are closely related to ESCs, which were mainly controlled by the low slow-shot speed in shot sleeve (ESCs growth time) and fast slow-shot speed into the die cavity (distribution of ESCs). In addition, solidification pressure can significantly reduce the shrinkage porosity in the center by improving the feeding capacity of liquid metal. Tensile fracture revealed that the tearing ridge is mainly evolved from the slip band of ESCs. The quantity and distribution of ESCs determine the fracture mode of castings. The relationship between mechanical properties of castings and the morphology of ESCs and porosity is also statistically discussed. [ABSTRACT FROM AUTHOR]

The spark plasma sintering (SPS) technique was found to effectively improve the mechanical properties of TiB 2 –SiC ceramic by forming a unique interlocking structure. This study investigated the phase transition process of the hexagonal micro-platelets TiB 2 powders with self-assembled structure during the molten-salt-mediated carbothermal reduction and its effect on promoting the mechanical properties of TiB 2 -based ceramics. It was found that the SPS approach ensured a highly densified TiB 2 –SiC ceramics with enhanced Vickers hardness of 21.0 ± 1.3 GPa and fracture resistance of 7.8 ± 0.3 MPa m1/2. The performance enhancement of the resultant TiB 2 –SiC composite was attributed to the interlocking structure from the original anisotropic TiB 2 powders, which could effectively absorb the energy and facilitate the crack deflection. [ABSTRACT FROM AUTHOR]

WCoB based cermet is a potential hard alloy to replace WC-Co cermets with high hardness and corrosion resistance. WCoB based cermets with different Cr doping contents were fabricated by spark plasma sintering in liquid phase sintering stage. The densification behavior, phase composition, microstructure and mechanical properties of Cr doped WCoB cermets were investigated by XRD, EDS and SEM. Due to the lower density of Cr, the density of WCoB cermets decreased with the increasing of Cr doping content. The phase composition consisted of Cr doped WCoB, unreacted W, Co–Cr binary binder phase. When the doping content exceeded 11.736 wt%, the Cr enrichment zones appeared, which was harmful to the TRS. The increasing of Cr doping content contributed to the increase of unreacted W phases content and the formation of pores. The maximum value of Vickers hardness was 1751 Hv0.5 at 9.356 wt% Cr doping content. The variation trend was explained by first principle calculation, which is consistent with Hv-Zhou hardness model. • The Cr doped WCoB cermets were studied by SPS in liquid sintering stages. High Cr doping content leaded to the increment of hardness and the formation of Cr enrichment zones. • The first-principle calculation was performed to study the hardness of Cr doped WCoB structures by four hardness models. • EDS analysis indicated similar variation trend of theoretical hardness and experimental hardness, which proved the correctness of first principle calculation. [ABSTRACT FROM AUTHOR]

WCoB based cermets were prepared by spark plasma sintering at sintering temperature among 600°C-1200 °C. The phase evolution was investigated by detecting density behavior, phase composition, microstructure and mechanical properties during sintering process. The sintering process can be divided into three stages: powder densification, solid phase reaction and liquid phase sintering. WCoB hard phase forms at 1000 °C during solid phase sintering, showing better mechanical properties than Co 2 B, especially on Vicker's hardness. WCoB hard phase forms on the basis of Co 2 B binary boride and its content increases in liquid phase sintering stage with high density. The Vicker's hardness and transverse rupture strength (TRS) reach the maximum value of 1262 Hv and 1212 MPa at 1200 °C and 1170 °C, respectively. The fracture toughness reaches the maximum value of 21.8 MPa m1/2 at 1050 °C, and the inter-granular fracture is the main fracture mechanism. [ABSTRACT FROM AUTHOR]

CO 2 mineralisation by recycled concrete is a novel approach of carbon capture and utilisation to improve the sustainability of concrete products, which has attracted increasing attention in recent years. This paper presents a comprehensive review on carbonation mechanisms related to CO 2 mineralisation and hydration, microstructure and multiscale mechanical properties of concrete containing carbonated recycled concrete fines and aggregates, with special focus on the chemistry-microstructure-property relationships. The carbonation kinetics of recycled fines in aqueous environment exhibit a typical particle size effect, while the high pozzolanic reactivity of carbonated recycled fines can facilitate the nucleation and stabilization of hydration gels and contribute to the rapid hydration of cement paste. Carbonated recycled aggregates are favourable in enhancing the micro-mechanical properties of interfacial transition zone in concrete through the synergic effects of physical interlocking and chemical bonding. Compared to concrete with plain recycled aggregates, up to 33.0%, 12.1% and 28.7% rises in compressive, splitting and flexural strengths of concrete can be achieved under 100% replacement of carbonated recycled aggregates. Due to the Stefan effect, concrete with carbonated recycled aggregates has higher dynamic peak stress but lower strain-rate sensitivity of elastic modulus than concrete with plain recycled aggregates. The global CO 2 mitigation capacity of recycled concrete varies from region to region and thus reasonable transportation network and high-efficient carbonation process are essential to ensure a balance between the environmental and economic benefits. This review summarises the recent advances in the field and discusses some future research opportunities to develop low-carbon concrete with recycled concrete as a carbon sink. [ABSTRACT FROM AUTHOR]

• Specific heat capacity of micro-fibre reinforced mortar was measured. • Effects of w/c ratio, fibre type and elevated temperature were considered. • A micromechanical model was developed to predict the effective specific heat. • Thermal expansion coupling effect on specific heat was quantitatively analysed. The temperature dependency of specific heat capacity is crucial for thermo-mechanical analysis of fibre reinforced cementitious composites. In this study, a combined experimental and theoretical analysis was conducted to characterise the role of micro fibres in tailoring the specific heat capacity of cementitious composites at elevated temperatures. The specific heat capacity of cement mortar reinforced with four types of fibres, including polypropylene, basalt, carbon and glass fibres, was measured by means of a transient method at up to 400 °C. Based on the effective medium theory, a multiscale homogenization model was developed to predict the specific heat capacity evolution of cementitious composite with temperature from micro to macro level. The results indicate that within the measured temperature range, the addition of 2.0 vol% polypropylene and glass fibres lead to the maximum rise or drop in specific heat capacity of mortar by 8.7% and 14.1%, respectively. In addition, the thermal expansion of polymer fibre was proved to effectively enhance the specific heat capacity of mortar due to thermal expansion coupling effect. The parametric analysis suggests that stiffer inclusions with high thermal expansion govern the effective specific heat capacity coupled with thermal expansion, while the composite incorporated with softer inclusions is insensitive to the variation in thermal properties of inclusions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrasound and microwave decreased the fluidity of immobilized water and free water. • Ultrasound and microwave reduced the particle size of MP and decreased the solubility. • Ultrasound and microwave promoted the unfolding of α-helix structures of MP. • Ultrasound and microwave facilitated the formation of more compact microstructures. • Ultrasound–microwave combination treatment has synergistic effect. The objective of this study was to evaluate the effects of single ultrasound (360 W, 20 min), single microwave (10 W/g, 120 s) and ultrasonic–microwave combination treatment on shrimp surimi gel properties. The structure and physicochemical properties of myofibrillar protein (MP) were also determined. Low-field nuclear magnetic resonance showed that the fluidity of water molecules and the moisture content decreased, the stability and water holding capacity (WHC) increased after single ultrasound, single microwave and ultrasonic–microwave combination treatment. Compared with the traditional water bath treatment, ultrasound and microwave treatment reduced the total sulfhydryl content and promoted the formation of intermolecular disulfide bonds and hydrophobic interactions, which improved the compactness of the network structure of shrimp surimi gel. Moreover, Fourier transform infrared spectroscopy and sodium dodecyl sulfate–polyacrylamide gel electrophoresis analysis revealed that these treatments not only inhibited the degradation of MP, but also decreased the α-helix content and increased the β-sheet content. The three treatments also significantly reduced the particle size and decreased the solubility of MP. Overall, the effect of ultrasonic–microwave combination treatment was superior to that of either single treatment. [ABSTRACT FROM AUTHOR]

An inexpensive boric acid (H 3 BO 3 ) and borax (Na 2 B 4 O 7 ·10H 2 O) mix was used as a source of boron with different composition ratios, and urea was used as a nitrogen source, in flowing ammonia atmosphere, for the preparation of hexagonal boron nitride (h-BN) with different micro-morphologies. Under a certain synthesis process, the effects of the molar ratio of borax and boric acid (or simply the boron source composition ratio for short) on the phase composition of the sample were studied; the work also explored the effect of boron source composition ratio on the micro-morphology, adsorption desorption isotherm and specific surface area of the h-BN powder. The main purpose of this work was to determine the optimum composition ratio of preparing spherical mesoporous h-BN and ensure that the micro-mechanism underpinning the formation of spherical mesoporous h-BN was understood. The results showed that at the optimum boron source composition ratio of 1:1, globular mesoporous spheres with a diameter of approximately 600–800 nm could be obtained with the highest pore volume and specific surface area (230.2 m 2 /g). [ABSTRACT FROM AUTHOR]

Highlights: [•] Multifunctional micro-/nano-structured MnO2 is synthesized in large scale. [•] The material exhibits excellent performance for arsenic removal. [•] Spectra study reveals the surface reaction mechanism. [•] Membrane fouling mechanism indicates the recyclability of the material and membrane. [Copyright &y& Elsevier]

Abstract: This paper presents an experimental investigation on influence of liquid physical properties and channel diameter on gas–liquid flow patterns in horizontal circular microchannels with inner diameters of 302, 496 and 916μm. Several liquids with different physical properties, i.e. water, ethanol, three sodium carboxymethyl cellulose (CMC) solutions (0.0464%, 0.1262%, 0.2446% CMC) and two sodium dodecyl sulfate (SDS) solutions (0.0608%, 0.2610% SDS) are chosen as working fluid and nitrogen as working gas. By using a high-speed photography system, flow patterns such as bubbly flow, slug and unstable slug flow, churn flow, slug-annular and annular flow are observed and identified on the flow regime maps. The results show that the liquid physical properties (viscosity and surface tension) and channel diameter affect the flow pattern transitions remarkably. Comparison with existing models in literature implies that these transitions cannot be well predicted. As a result, an effort is put into the proposition of a new empirical model taking the effects of channel size and liquid physical properties into account. [Copyright &y& Elsevier]

Abstract: In/Pd-doped SnO2 is synthesized via a sol–gel method and coated on a silicon substrate with Pt electrodes to fabricate a microstructure sensor. The sensor shows high response to CO with very low cross response to common interference gases at an operating temperature of 140°C. Especially, the sensor can detect CO down to 1ppm (the response value is about 3), and the response time and recovery time are about 15 and 20s, respectively. These results make our sensor a good candidate in practical CO sensors. [Copyright &y& Elsevier]

Surface coatings with the improved antibacterial capability and osteogenic activity are highly favoured for titanium (Ti)-based orthopaedic implants. Herein, Ag, Zn co-modified titania was synthesized using the micro-arc oxidation (MAO) technique with Ag nanoparticles (NPs) as Ag sources and ZnO NPs as Zn sources. The synergistic effects of Ag and ZnO additions not only result in the significant modification of their existing forms, but also promote the formation of two different types of Ca P phases, namely Zn-incorporated dicalcium phosphate dihydrate (DCPD) crystal and submicron-sized amorphous Ca P phase deposition of porous appearance. Anti-corrosion, antibacterial and osteogenic experiments prove that the synthesis strategy of Ag, Zn co-modified titania provides a promising way for Ti-based bioceramic coatings for orthopaedic implants. • The Ag, Zn co-modified titania has been successfully fabricated in the electrolyte containing Ag and ZnO nanoparticles. • Zn-incorporated dicalcium phosphate dehydrate crystal and amorphous Ca P phase are formed. • The synergistic effect of Ag and ZnO enhances the corrosion resistance and biological performances of titania. [ABSTRACT FROM AUTHOR]

Abstract: Polarization switching-induced shielding or anti-shielding of an electrically permeable crack in a mono-domain ferroelectric material with the original polarization direction perpendicular to the crack is simulated by a phase field model based on the time-dependent Ginzburg–Landau equation. The domain wall energy and the long-range mechanical and electrical interactions between polarizations are taken into account. The phase field simulations exhibit a wing-shape-switched zone backwards from the crack tip. The polarization switching-induced internal stresses shield the crack tip from applied mechanical loads. A local J-integral is numerically calculated and used as a failure criterion to illustrate the polarization switching-toughening. The result indicates that an applied uniform electric field parallel to the original polarization direction reduces the apparent fracture toughness, while an applied uniform electric field anti-parallel to the original polarization direction enhances it. [Copyright &y& Elsevier]

• AlCoCrFeNiSi x high-entropy alloy coatings on AISI 304 stainless steel were synthesized by laser cladding. • Nano-sized precipitates with spherical shape are found in the coatings. • The influence of Si element on dislocation densities is explored in detail. • Dislocation strengthening is confirmed as the primary strengthening mechanism of the coatings. AlCoCrFeNiSi x high-entropy alloy coatings were synthesized by laser cladding. The effect of Si element on the phase constitution, microstructure, and microhardness of the coating was investigated. The results show that the main phase in the coatings are disordered solid solution with a body-center cubic (BCC) structure. A small quantity of nano-sized precipitates of ordered BCC AlNi phase are distributed in the grain. The dislocation density and the microhardness increase linearly with the increase of the Si content. The improvement of the microhardness is due to the solid-solution strengthening, precipitation strengthening, and dislocation strengthening, and the quantitative analysis reveals that dislocation strengthening plays a dominant role. [ABSTRACT FROM AUTHOR]

In this work, three hyperbranched polysiloxanes with methacrylate (HSiM), epoxy (HSiG) and methacrylate/epoxy groups (HSiMG) were prepared through the hydrolysis of γ-glycidoxypropyltrimethoxysilane (γ-GPS), γ-methacryloxypropyltrimethoxysilane (γ-MPS) and their binary blends. The results indicated that methacrylate groups could accelerate the condensation reaction, thus producing more branching sites with a branching degree of 0.67 for HSiMG. In addition, the effects of terminal groups on the microstructural and thermal properties of the post-cured hyperbranched polysiloxanes were evaluated. Consequencely, the UV-cured HSiM produced more cracks at a higher temperature due to a tighter crosslinked structure. The thermal-cured HSiG decomposed at a lower temperature. While the dual-curing PHSiMG had a more stable structure and relatively excellent thermal stability, based on sequential free-radical photopolymerization and epoxy anionic polymerization. Thus, this work provides a promising approach for structural design and optimization of the polysiloxane. Image 1 • Terminal groups of silane have an effect on hyperbranched polysiloxane structure. • Methacrylate groups could accelerate the condensation reaction. • The combination of epoxy and methacrylate makes the structure more stable. [ABSTRACT FROM AUTHOR]

Comparison of three-dimensional (3D) printing and cast methods on the mechanical properties of cementitious materials is the basis for intelligent construction development. To achieve this, a series of experiments including the uniaxial tensile, compressive, flexural and interlayer bonding tests of mould-cast and 3D printed (3DP) specimens are conducted to investigate the effects of different preparation technologies on the microstructure and hardening properties of limestone calcined clay cement (LC3) based engineered cementitious composites (ECC). Results indicate that the tensile strength and strain capacity of the printed LC3-ECC decrease by 16.6%–22.7 % and 43.3%–54.6 % compared to the cast specimens, while it still possesses a strain capacity of 2 % and multiple cracking behaviour. The compressive and flexural properties of the printed LC3-ECC both show significant anisotropy, the maximum values of which are observed in the Z- and Y- directions, respectively. The interlayer bonding strength increases by 54.3%–91.9 % at 28 d compared to that at 7 d due to the hydration of LC3. The pore structure of the printed LC3-ECC is denser than that of the cast LC3-ECC, with more regular arrangement and finer size of pores. The macro-micro properties correlation analysis proves the better comprehensive performance of printed LC3-ECC relative to casted LC3-ECC, as well as reveals the relationship between pore structure and anisotropy. In terms of material sustainability, 3DP-LC3-ECC has a significant reduction in energy and carbon emissions compared to typical M45-ECC, contributing to the environmental development. [ABSTRACT FROM AUTHOR]

The high-energy mechanical milling procedure was used to manufacture the as-milled Pr 5 Mg 85 Ni 10 alloys of 5 h, 10 h, 20 h, and 30 h respectively. We have been successful in obtaining a variety of nanocrystalline and amorphous alloys with varying amounts of each. The primary phase in the interior structure of the alloys is still Mg 2 Ni and Mg, which corresponds to the second phase PrMg 12. The products of saturated hydrogen absorption include MgH 2 , Mg 2 NiH 4 , and PrH 2.93 , while the products of complete hydrogen release include Mg, Mg 2 Ni, and PrH 2. According to the findings, the amount of time spent ball-milling the alloys is the primary component that determines how well they function in terms of the dynamic performance of hydrogen absorption and desorption. The dynamic performance of the alloy in terms of hydrogen absorption and desorption is enhanced with the increasing time spent ball-milling the material. In the same vein, the alloy that has been milled for ten hours has the most desirable thermodynamic characteristics. [ABSTRACT FROM AUTHOR]

• Experimental study on dynamic splitting tensile properties of ECC at elevated temperatures. • Mechanical properties of ECC increased first and then dropped at elevated temperatures. • Dynamic splitting tensile properties of ECC went up with the rising strain rate. • ECC exhibited tensile failure first and then coupled tensile-shear failure. This paper presents a systematic study on dynamic splitting tensile properties of polyvinyl alcohol (PVA) fibre reinforced engineered cementitious composites (ECC) after exposure to elevated temperatures up to 800 °C under strain rates of 4.34 to 10.95 s−1. A series of tests were conducted to characterise the weight loss, elastic modulus, uniaxial tensile properties, static and dynamic splitting tensile behaviour, and pore pressure, as well as the chemical and microstructural evolution of ECC. Results indicate that the dynamic splitting tensile properties of ECC went up with the increasing strain rate regardless of heated temperatures due to strain rate effect. The dynamic splitting strength, dynamic increase factor and energy dissipation of ECC reached the maximum values at 105 °C, which can be ascribed to the enhanced fibre-matrix bond and further hydration of fly ash. However, the dynamic tensile properties of ECC reduced at over 250 °C due to the melting of PVA fibres, thermally induced microcracks and dehydration of hydration products. At 800 °C, the dynamic splitting tensile strength and dissipated energy of ECC dropped by 81.0–83.2% and 88.4–89.1% over the measured strain rate range, relative to that at 20 °C. In addition, the main role for resisting dynamic loading was gradually transferred from fibre debonding-elongating action to crack propagation at over 400 °C. Accordingly, the failure patterns of ECC changed from tensile failure with the main central crack to coupled tensile-shear failure with multiple cracks. [ABSTRACT FROM AUTHOR]

To make the steel/iron composites with better comprehensive mechanical properties, a novel iron matrix composite reinforced with three-dimensional core-shell structure (CS) reinforcing particulates is designed and fabricated via powder hot-pressing sintering process. Studies have shown that the CS consists of isolated soft W core and dense hard shell, that is, showing the structural characteristics of "inner soft and outer hard". When the carbon content of the raw material powder Fe–W–C ternary system is 0, 0.5, 1.0, 1.5 and 2.0 wt%, the CS of W@(Fe 7 W 6 + Fe 2 W), W@Fe 3 W 3 C, W@(W 2 C + WC + Fe 3 W 3 C) Ⅰ , W@(W 2 C + WC + Fe 3 W 3 C) Ⅱ , and W@(W 2 C + WC + Fe 3 W 3 C) Ⅲ is formed in the matrix, respectively. The formation of CSs with different characteristics is mainly due to the diffusion of Fe atoms and/or C atoms into the W lattice to undergo a diffusion-type solid state phase transformation to form corresponding compounds and the formation kinetics of different phases determined by different carbon concentrations. Furthermore, the results of nanoindentation and Vickers indentation show that the hardness of the shell layer is much greater than that of the metal W core and matrix, but its plastic deformation rate is much smaller than that of the metal W core and matrix. The metal W core and the iron matrix can significantly inhibit the length of the crack propagation, thereby improving the toughness of the composite. And the hard shell layer with high volume fraction can significantly improve the strength of the composite. Therefore, the iron matrix composite reinforced with three-dimensional CS reinforcing particulates is expected to obtain good toughness and excellent strength, and this work may provide a new strategy for the structural design of steel/iron materials. • A novel core-shell structure (CS) reinforced iron matrix composite is fabricated. • The CS consists of isolated soft W core and dense hard shell. • The formation of CSs with different morphologies depends on the carbon concentration of the system. • The composites have high hardness and toughness at same time. [ABSTRACT FROM AUTHOR]

Abstract: Phase-field simulations of spinodal decomposition in Fe–Cr alloys with dislocations were performed by using the Cahn–Hilliard diffusion equation. The stress field of dislocations was calculated in real space via Stroh’s formalism, while the composition inhomogeneity-induced stress field and the diffusion equation were numerically calculated in Fourier space. The simulation results indicate that dislocation stress field facilitates, energetically and kinetically, spinodal decomposition, making the phase separation faster and the separated phase particles bigger at and near the dislocation core regions. A tilt grain boundary is thus a favorable place for spinodal decomposition, resulting in a special microstructure morphology, especially at the early stage of decomposition. [Copyright &y& Elsevier]

To elucidate the mechanism behind the heterogeneity in the water distribution during the drying process of medicinal chrysanthemum (Imperial chrysanthemum), and thereby optimize the drying process, this study introduced an innovative approach by incorporating tempering into the drying process and evaluated the effects of hot air drying (HAD), infrared-assisted hot air drying (IR-HAD), and tempering-incorporated IR-HAD (TD+IR-HAD) on the water status, microstructure, and phytochemicals of dried chrysanthemums. Results showed a significant difference in the rate of dehydration between the central and marginal parts of chrysanthemums. The highest difference in moisture content value (1.34 g water/g dry matter) was observed between these two parts for samples subjected to 2.5 h of IR-HAD drying. Consequently, the sample subjected to 2.5 h of IR-HAD drying was selected for tempering. After the optimal tempering treatment (12 h), the samples were subjected to an additional 0.5 h of IR-HAD drying. This incorporated drying method (TD+IR-HAD) effectively reduced the drying time and energy consumption. Transverse relaxation curves and microstructural observations further confirmed that these reductions were related to the enhancement of water mobility and the formation of microchannels during tempering. As a result, chrysanthemums dried using TD+IR-HAD showed increased contents of chlorogenic acid, luteolin, total phenolic, total flavonoid, antioxidant capacity, and the number of volatile compounds compared to HAD and IR-HAD. Overall, these results highlight the potential of TD+IR-HAD as a promising drying technique for enhancing the value and applications of medicinal chrysanthemums in industrial settings. [Display omitted] • The water status and distribution in chrysanthemums were first investigated. • The central part of the chrysanthemum showed a lower dehydration rate. • Tempering enhanced water mobility and promoted water redistribution in samples. • The required drying time and energy consumption were reduced by tempering. • Tempering effectively preserved phytochemicals and volatiles in dried samples. [ABSTRACT FROM AUTHOR]

AlCoCrFeNiSi x (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) high-entropy alloy (HEA) coatings were deposited on the surface of AISI 304 stainless steel via laser cladding technology with different content of Si element. The evolution in microstructure, microhardness, and wear behavior of the coatings was investigated comprehensively to explore the effect of Si element. The results showed that the HEA coatings consisted of disordered Fe-Cr and ordered Al-Ni solid solution phases with a body-centered cubic (BCC) structure. Si element dissolved into the solid solutions, leading to lattice distortion. As Si content increased, the microstructure was refined, and a small quantity of Cr 23 C 6 phase was precipitated along the grain boundaries. The microhardness of the coatings was linearly proportionate to Si content. The quantitative analysis revealed that the improvement of microhardness was dominated by the effect of dislocation strengthening, rather than solution strengthening and fine-grain strengthening. With the increase in Si content, the average friction coefficient and wear rate of the HEA coatings were all reduced remarkably, and the main wear mechanism evolved from adhesive wear, abrasive wear and delamination wear to oxidation wear. These phenomena were believed to be associated with the formation of the oxide film on the worn surface, which was identified as Fe 2 O 3 , Fe 3 O 4 , Cr 2 O 3 , SiO 2 , and SiO. • The phase structure of AlCoCrFeNiSi x high entropy alloy coating is identified. • The influence of Si element on microhardness is quantitatively analyzed. • The wear mechanism and performance of different Si contents is explored in detail. • The composition of the oxide film on the worn surface is determined. [ABSTRACT FROM AUTHOR]

Flexible pressure sensors have attracted great interest due to their application potential in healthcare monitoring, electronic-skin and human-machine interfaces. To satisfy the requirements from practical applications, the sensors with high sensitivity, broad linearity range and low detection limit are urgently desired. Here, flexible pressure sensors with the negative replica (N-Sensor) and the positive one (P-Sensor) of the irregular surface microstructures are systemically investigated to achieve high performances. As revealed by the in situ observation method, the positive replica which mainly contained convex microstructures exhibits smaller initial contact area and could be compressed more easily than the negative one with porous surface. Therefore, the performances of the P-Sensor including sensitivity, linearity range and detection limit are greatly improved. The P-Sensor exhibits high sensitivity of 163.4 kPa−1 over a broad linearity range of 0–140 kPa, low detection limit of 1.3 Pa, fast response time (<10 ms) and good stability (>8000 cycles), which is one of the best results for flexible pressure sensors. Attributed to these excellent performances, the P-Sensor well performs in the measurements of human pulse, tactility and plantar pressure, showing great application potentials in human daily life. Image 1 • Using negative and positive replicas of irregular microstructures manipulate the performance of flexible pressure sensors. • The sensors with positive replica achieve high sensitivity over a broad linearity range. • The flexible pressure sensors show great application potentials in human daily life. [ABSTRACT FROM AUTHOR]

Inclined epitaxial La 1−x Ca x MnO 3 films based on the light-induced transverse thermoelectric (LITT) effect have attracted significant attention in fast light/thermal detection. In this work, a series of inclined La 1−x Ca x MnO 3 (0.1≤x≤0.8) films are fabricated based on a home-designed MOCVD system by adjusting the ratio of La/Ca sources. The composition-induced microstructure for La 1−x Ca x MnO 3 films is revealed. La 1−x Ca x MnO 3 tends to form a single orientation under a small lattice mismatch with the substrate, while with a multi-domain structure under an obvious mismatch, significant lattice distortions are observed in the films. With increasing Ca content, the electrical conductivity gradually increases, which is responsible for enhanced response voltage from 5.5 V for Ca10 to 25.5 V for Ca40. However, with a further increase in conductivity, the response voltage gradually decreases, which may be attributed to the deteriorated anisotropic Seebeck coefficient. Benefitting from enhanced conductivity, the response time decreases from 2984 ns for Ca10 to 58 ns for Ca60, which increases to 80 ns for Ca80 due to enhanced phonon scattering originating from the lattice distortions. This work may serve as a reference for modulating the LITT effect based on electron/phonon transport for other material systems applied in fast light/thermal detection. [Display omitted] • Inclined La 1−x Ca x MnO 3 (0.1≤x≤0.8) with good biaxial texture are prepared by MOCVD. • Composition-induced microstructure is revealed for La 1−x Ca x MnO 3 films. • Increased conductivity conduces to enhance LITT voltage and reduce response time. • Enhanced phonon scattering from lattice distortions prolongs the response time. [ABSTRACT FROM AUTHOR]

The present work investigates the change in the microstructure and the improvement in the mechanical property of ternary Mg-Al-Gd alloys induced by a static magnetic field of 1 T, applied during homogenization at 525 °C. The application of the magnetic field increases the concentration of Gd in α-Mg from 7.16 to 9.00 wt% in the alloys homogenized under the same heat treatment condition without magnetic field to 10.65–11.41 wt%. A higher solid concentration of Gd gives a higher solution strengthening. The width of the 15R-type long-period stacking ordered (LPSO) laths in the homogenized alloys is significantly reduced to 46.9 nm from 236.2 nm by the magnetic field. The ultimate compression strength is enhanced by the magnetic field from 447 MPa to 473 MPa. • A 15R-type long period stacking ordered phase is identified in Mg-Al-Gd alloy. • Magnetic heat treatment refines the LPSO phase in Mg-Al-Gd alloy. • Magnetic heat treatment enhances the mechanical properties of Mg-Al-Gd alloy. [ABSTRACT FROM AUTHOR]

The study investigated the effect of nickel content on the microstructure and mechanical properties of Cu–12Al-xNi alloys prepared using powder metallurgy. The results indicated that the alloys investigated consisted of α-Cu and γ 2 (Al 4 Cu 9), containing less than 4 wt% Ni content. The α-Cu phase gradually increased, while the γ 2 (Al 4 Cu 9) phase gradually decreased as the sintering temperature increased. Both the strength and hardness of the alloy thus reduced. When the Ni content increased above 4 wt%, the NiAl phase precipitated at the grain boundaries, which resulted in an increase in the strength of the alloy. Additionally, the tensile strength reached a maximum of 390 MPa when the Ni content reached 6 wt%. The decrease in the tensile strength for higher Ni content was attributed to the formation of a NiAl phase network. And the addition of nickel did not significantly alter the sintering density of the alloy. The mechanisms of microstructure evolution and strengthening mechanisms were investigated and discussed. [ABSTRACT FROM AUTHOR]

Diamond-like carbon (DLC) composite films doped with ceria were synthesized on LY-12 aluminum alloys by electrodeposition. The effects of ceria concentration on the microstructure, microhardness, wear and corrosion behavior of the composite film were investigated via Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), micro-Vickers tester, friction and wear tester and electrochemical workstation. Meanwhile, the growth mechanism of the films was explored. Results proclaimed that the loose honeycomb structure of the films was replaced by a compact granular structure as the ceria concentration increased to 1.16 ×10−3 mol/L. Raman spectra showed the typical amorphous characteristics of DLC film. The intensity ratio of G-line and D-line (I D /I G) diminished from 0.59 to 0.47, the G-line shifted to the lower frequency and the G FWHM increased, demonstrating that the CeO 2 /DLC composite film deposited at optimal ceria contains the higher sp3-C content. XPS analysis revealed that the binding mode of ceria is physically doped. Furthermore, the CeO 2 /DLC composite film exhibits superior anti-wear and anti-corrosion ability, which is primarily due to the compact structure and high microhardness. Double Ni-Cu interlayer are prepared and CeO 2 nanoparticles were successfully encapsulated in diamond-like carbon (DLC) films on LY-12 aluminum alloy substrates by electrodeposition. [Display omitted] • Ceria was successfully encapsulated in diamond-like carbon film to improve the mechanical, tribological and electrochemical properties. [ABSTRACT FROM AUTHOR]

Abstract: A microstructure sensor based on hierarchically porous ZnO nanosheet (NS) thin films has been achieved by using a facile two-step solution phase method. The transparent ZnO seed-layer covered on both the conducting electrodes and the insulating SiO2 spacer regions acts as lattice-matched template, on which the assembly of ZnO NS thin films has been subsequently completed via a facile solvothermal process. The phase purity, morphology, and structure of the as-prepared NSs are investigated, and the results reveal that ZnO NSs, grown vertically on the substrate, exhibit hierarchically porous nanostructure with subunits of nanoparticles. The gas-sensing properties exhibit not only high response to CO with the response time of 25s, but also low cross response to common interference gases at the operating temperature of 300°C. [Copyright &y& Elsevier]

Abstract: The effect of applied mechanical strains on the ferroelectric and dielectric properties of a model single crystal is investigated using a phase field model based on the time-dependent Ginzburg–Landau equation, which takes both multiple-dipole–dipole-electric and -elastic interactions into account. The evolution of the ferroelectric domain structure is simulated at different temperatures and applied strains. The results show that the paraelectric/ferroelectric phase transition temperature linearly increases with the applied mechanical strain under mechanical clamping conditions. Analogous to the classical Ehrenfest equation, a thermodynamics equation is derived to describe the relationship between the transition temperature and the applied strain. The change in the domain structure with temperature under applied inequiaxial strains is different from that under applied equiaxial strains. The simulations also illustrate the changes in the coercive field, the remanent polarization and the nonlinear dielectric constant with the applied strain. [Copyright &y& Elsevier]

Polarization switching in a ferroelectric subjected to an electric field or a stress field is simulated using a phase-field model based on the time-dependent Ginzburg–Landau equation, which takes both multiple-dipole–dipole–electric and multiple-dipole–dipole–elastic interactions into account. The temporal evolution of the polarization switching shows that the switching is a process of nucleation, if needed, and growth of energy-favorite domains. Macroscopic polarization and strain are obtained by averaging polarizations and strains over the entire simulated ferroelectric. The simulation results successfully reveal the hysteresis loop of macroscopic polarization versus the applied electric field, the butterfly curve of macroscopic strain versus the applied electric field, and the macroscopically nonlinear strain response to applied compressive stresses. [Copyright &y& Elsevier]