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The as-cast sheet of Cu-bearing non-oriented electrical steel with a width of 300 mm and a thickness of 2.4 mm was prepared by the twin-roll strip casting process. The effects of nucleation and growth of recrystallized grains at different annealing temperatures on the evolution of the microstructure and texture of annealed sheet were studied. In addition, the magnetic and mechanical properties of the final sheets were analyzed. The results show that the shear band in the cold-rolled sheet can promote the formation of {100} texture at the initial stage of recrystallization, regardless of high or low-temperature annealing. The combination of low-temperature nucleation and subsequent high-temperature growth is more conducive to the formation of strong {100} texture and has higher preparation efficiency than only through low-temperature annealing. It also indirectly indicates that moderate nucleation and preferential growth are important for the formation of strong beneficial texture. Combined with the subsequent aging treatment, the low-temperature nucleation sheet can obtain an excellent match between mechanical properties and magnetic properties. [ABSTRACT FROM AUTHOR]

With the rapid development of wearable, flexible, and portable electronic devices, triboelectric nanogenerators (TENG) as a possible power source with the features of miniature and flexibility have attracted tremendous research interest. In this respect, we prepared a stretchable and shape-adaptive silicone rubber-based triboelectric nanogenerator, with MoS2/GO in the friction layer to capture electrons. It is found that a large number of micropores are generated in the silicone rubber matrix, providing more sites for charge generation. In addition, the rough surface led to a greater contact area for harvesting environmental mechanical energy more effectively. By optimizing the fabrication process, the TENG displays output voltage, current density, and average power density up to ∼200 V, ∼25 μA, and ∼1.3 mW, respectively in single-electrode mode. In addition, it has good flexibility and water resistance and can be worn on skin or cloth to harvest energy from different body motions. Therefore, the device in this work with enhanced power output, stability, and portability is suitable for practical application to power wearable electronic devices from manual activities. A robust and novel textile-TENG for energy harvest was developed, which is constructed from the flexible conducting textile and MoS2/RGO doped super-soft silicone rubber. The resulting film possesses good triboelectric performance and has the ability to harvest energy from different human motions. We found that the obtained TENG shows portable, lightweight, and sustainable properties, indicating its promising potential for applications in flexible and miniaturized green electronics. [ABSTRACT FROM AUTHOR]

Abstract: Aerogels are porous materials but show poor mechanical properties and limited functionality, which significantly restrict their practical applications. Preparation of highly bendable and processable aerogels with multifunctionality remains a challenge. Herein we report unprecedented superflexible aerogels based on polyvinylpolydimethylsiloxane (PVPDMS) networks, PVPDMS/polyvinylpolymethylsiloxane (PVPMS) copolymer networks, and PVPDMS/PVPMS/graphene nanocomposites by a facile radical polymerization/hydrolytic polycondensation strategy and ambient pressure drying or freeze drying. The aerogels have a doubly cross‐linked organic–inorganic network structure consisting of flexible polydimethylsiloxanes and hydrocarbon chains with tunable cross‐linking density, tunable pore size and bulk density. They have a high hydrophobicity and superflexibility and combine selective absorption, efficient separation of oil and water, thermal superinsulation, and strain sensing. [ABSTRACT FROM AUTHOR]

Abstract: Aerogels are porous materials but show poor mechanical properties and limited functionality, which significantly restrict their practical applications. Preparation of highly bendable and processable aerogels with multifunctionality remains a challenge. Herein we report unprecedented superflexible aerogels based on polyvinylpolydimethylsiloxane (PVPDMS) networks, PVPDMS/polyvinylpolymethylsiloxane (PVPMS) copolymer networks, and PVPDMS/PVPMS/graphene nanocomposites by a facile radical polymerization/hydrolytic polycondensation strategy and ambient pressure drying or freeze drying. The aerogels have a doubly cross‐linked organic–inorganic network structure consisting of flexible polydimethylsiloxanes and hydrocarbon chains with tunable cross‐linking density, tunable pore size and bulk density. They have a high hydrophobicity and superflexibility and combine selective absorption, efficient separation of oil and water, thermal superinsulation, and strain sensing. [ABSTRACT FROM AUTHOR]

Three 4.5 wt% Si steel thin sheets with different thicknesses were efficiently fabricated by twin-roll strip casting, warm rolling and cold rolling followed by final annealing. A comprehensive investigation from the workability of the as-cast strip to the magnetic property of the produces was performed to illustrate the superiority of the new materials. The results show that the as-cast strip, which has a much lower Vickers hardness than that of the 6.5 wt% Si steel, is suitable for rolling processing. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies confirm that no ordering phase exists in the as-cast strip. The cold-rolled thin sheets exhibit good surface quality without edge cracks. Furthermore, all the three 4.5 wt% Si steel thin sheets possess relative strong <100>//ND texture and present high magnetic inductions and low iron losses after finial annealing. [ABSTRACT FROM AUTHOR]

Highly thermally stable zirconia/silica composite aerogels are prepared via a supercritical deposition method, which involves the deposition by zirconium alkoxide and partially hydrolyzed alkoxysilane during high-temperature ethanol supercritical fluid drying. The zirconia crystal growth and phase transition of the composite aerogels upon heat treatment are effectively inhibited by supercritical deposition, which significantly enhances the thermal stability of the aerogels. The resultant zirconia/silica composite aerogels exhibit a high specific surface area of 172 m 2 /g and a large pore volume of 0.97 cm 3 /g after heat treatment at 1000 °C. The resultant materials are promising candidates as high-temperature catalysts, catalyst supports, thermal insulators, etc. [ABSTRACT FROM AUTHOR]

The evolution of {411}<148> texture in a promising twin-roll strip casting of 4.5 wt% Si electrical steel was skillfully investigated. The results show that the selective growth mechanism, caused by orientation pinning, is responsible for the formation of the sharp {411}<148> component which is beyond the preferred nucleus spectrum. [ABSTRACT FROM AUTHOR]

High-surface-area carbon aerogels are synthesized by pyrolysis of nanocellulose aerogels that are prepared by dissolving of cellulose microcrystalline in NaOH aqueous solutions followed by gelation, regeneration and freeze drying or supercritical CO 2 drying. The obtained carbon aerogels are further treated via a CO 2 activation process. The result shows that the nanocellulose aerogels dried by supercritical CO 2 exhibit a high specific surface area (299 m 2 /g) and the obtained carbon aerogels preserve the interconnected 3D nanostructure and have a high specific surface area of 892 m 2 /g and a high pore volume of 1.80 cm 3 /g, which increase to 1873 m 2 /g and 2.65 cm 3 /g respectively after CO 2 activation. The highly porous and interconnected nanostructure provides efficient migration of electrolyte ions and electrons, which makes the resultant activated carbon aerogels exhibit excellent electrochemical performance for supercapacitors. The specific capacitances reach 302 and 205 F/g at a current density of 0.5 and 20 A/g respectively within a potential window of −1.0 to 0 V in 6 M KOH solution. The capacitance retains 92% after 4000 cycles of charge/discharge, implying a good cycling stability. [ABSTRACT FROM AUTHOR]

Heat-resistant, strong titania aerogels are prepared via a novel supercritical deposition method. This deposition process is based on deposition by partially hydrolyzed titanium alkoxide and alkoxysilane during high-temperature supercritical fluid drying. The nanoparticles are significantly reinforced, and the crystal growth of titania upon heat treatment is effectively restricted by supercritical deposition, which leads to the enhanced mechanical strength and heat resistance of titania aerogels. The Young’s modulus of the resulting titania aerogel is enhanced up to 4.2 MPa. The specific surface area of the optimized titania aerogel increases up to 147 m 2 /g and the corresponding linear shrinkage decreases to as low as 11% after heat treatment at 1000 °C. This may significantly contributed to the high-temperature applications of titania aerogels in thermal insulations, catalysts, catalyst supports, etc. [ABSTRACT FROM AUTHOR]

Robust,highly thermally stable, MOx/(MOx–SiO2)/SiO2core–shellnanostructured metal oxide aerogels witha MOxcore and (MOx–SiO2)/SiO2shell are producedvia novel alkoxide chemical liquid deposition techniques. The core–shellnanostructure not only significantly reinforces the nanoparticlesbut also effectively inhibits the crystal growth and phase transitionof metal oxide upon heat treatment, which enhances the heat resistancefrom approximate 400–800 °C up to 1000–1300 °C.The resultant core–shell nanostructured Al2O3, ZrO2, and TiO2aerogels can supportat least 5800 times their weight and exhibit high surface areas of139, 186, and 154 m2/g after fired at 1300, 1000, and 1000°C, respectively, which are the highest surface areas for metaloxide aerogels ever reported. We demonstrate that the core–shellZrO2and TiO2aerogels show enhanced adsorptionand photocatalytic performances, respectively, for dye after firedat 1000 °C. The core–shell Al2O3aerogel/mullite fiber/TiO2composite possesses ultralowthermal conductivities of 0.058, 0.080, and 0.11 W/mK at 800, 1000,and 1200 °C, respectively, which are the lowest values for inorganicaerogels ever reported. The resulting materials are promising candidatesas high-temperature (400–1300 °C) thermal superinsulators,adsorbents, and catalysts. [ABSTRACT FROM AUTHOR]

Abstract: Alumina aerogels were prepared by a sol–gel method combined with the ethanol supercritical drying technique using aluminum tri-sec butoxide and nitric acid as the precursor and catalyzer respectively. This method affords high-surface-area alumina aerogel monoliths without the use of complexing agents. The structure and morphology of the aerogels were investigated by TEM, XRD, FTIR and BET techniques. The results confirmed that the as-prepared alumina aerogel possessed a network microstructure made up of pseudoboehmite fibers and a surface area of 690m2/g. It was transformed to γ-Al2O3 after heat treatment at 800°C without a significant loss in surface area. DMA analysis and hotdisk thermal analysis were performed to characterize the mechanical and thermal properties of the samples. The results indicated that the alumina aerogel was robust and exhibited excellent thermal insulating properties. The elastic modulus was up to 11.4MPa after drying, which is the one of the highest modulus of alumina aerogels ever reported. The thermal conductivities at 30°C and 400°C were 0.028W/mK and 0.065W/mK respectively. [Copyright &y& Elsevier]

• A Fe-4.5 wt% Si steel casting strip with equiaxed grains was fabricated by twin-roll strip caster. • Slight reduction of second cold rolling promoted the formation of strong {1 0 0} 〈0 0 1〉 and near Goss orientation texture. • Steel sheet experienced one-stage cold rolling exhibits the highest tensile strength. • Excellent performance of mechanic and magnetic properties was fabricated by the two-stage medium reduction cold rolling. A 4.5 wt% Si as-cast strip with equiaxed grains microstructure fabricated by twin-roll caster was subjected to three different cold rolling and final recrystallization annealing processes. The results revealed that the rolling process has a significant effect on the evolution of microstructure and texture of the strip-cast 4.5 wt% Si non-oriented electrical steel. Moreover, both mechanical and magnetic properties of the steel exhibited various characteristics because of different rolling routes. After short-time annealing at high temperature, the steel sheet experienced one-step cold rolling exhibits the highest tensile strength. Regarding two-step cold rolling, better magnetic properties were obtained after a second cold rolling with a slight reduction. The excellent performance of mechanic and magnetic properties can be fabricated by two-step medium reduction cold rolling. [ABSTRACT FROM AUTHOR]

Highly stretchable aerogel films are attractive for advanced next‐generation stretchable electronics. However, it is a great challenge to achieve high stretchability for aerogel films. Here, several types of unprecedented ultra‐stretchable semiconducting polymer‐based aerogel films with crimpled porous structures are developed via crosslinking and template methods combined with uniaxial and biaxial pre‐stretching strategies. The semiconducting aerogel films obtained by uniaxial pre‐stretching exhibit ultrahigh stretchability up to 100–200%, while those obtained by biaxial pre‐stretching show high biaxial stretchability up to 50%. The resulting aerogel films show strain‐insensitive electrical and joule heating properties. A prototype of the aerogel film‐based stretchable organic electrochemical transistor (OECT) is developed for the first time. Benefiting from their unique porous structures, the aerogel film‐based OECTs exhibit enhanced on/off ratio and transconductance compared with corresponding dense film‐based OECTs, high stretchability up to 100%, and high stretching stability with 10 000 stretching cycles under 30% strain. It is demonstrated that the aerogel film‐based OECTs can be applied as high‐performance stretchable artificial synapses and biosensors. This work gives a versatile strategy toward highly stretchable aerogel films promising for flexible electronics. [ABSTRACT FROM AUTHOR]

MXene‐based aerogels are promising candidates for wearable electronics due to their unique structures and properties. However, the reported MXene‐based aerogels show poor stretchability, significantly restricting their applications in wearable electronics. Herein, unprecedented highly stretchable MXene‐based aerogels with crimpled and reentrant microstructures are developed via synergistic assembly of MXene and flexible polymers combined with uniaxial and biaxial hot‐pressing strategies. The uniaxially hot‐pressed MXene‐based meta‐aerogels show compressed and crimpled microstructures and combine ultrahigh stretchability up to 427%, high elasticity, high compressibility, high fatigue resistance upon compression and stretching, and near‐zero Poisson's ratios. The biaxially hot‐pressed MXene‐based meta‐aerogels exhibit reentrant microstructures and achieve high stretchability and negative Poisson's ratios upon stretching in different directions, which have never been realized by traditional aerogels. It is demonstrated that they can be used for ultrabroad‐range pressure/strain sensors, highly stretchable triboelectric nanogenerators, and smart thermal management with tunable thermal insulation and Joule heating performances achieved by stretching. This work opens a new way to highly stretchable aerogels with near‐zero and negative Poisson's ratios promising in wearable electronics, nanogenerators, thermal management, energy storage, etc. [ABSTRACT FROM AUTHOR]

Transparent sapphire and magnesium aluminum spinel (MgAl 2 O 4) ceramic was first brazed using La 2 O 3 -SiO 2 -B 2 O 3 -Nb 2 O 5 (LSBN) or La 2 O 3 -SiO 2 -B 2 O 3 -Nb 2 O 5 -MgO (LSBNM) glass filler. The Al 2 O 3 layer was formed at MgAl 2 O 4 /LSBN interface or sapphire/LSBNM interface, which caused the decrease of light transmission of joints. To avoid the formation of this interface layer, sapphire/LSBN/LSBNM/MgAl 2 O 4 joints with double glass interlayers were fabricated by using a two-step joining method consisting of high-temperature coating and low-temperature bonding. After the first step of high-temperature coating, no interfacial layer was observed in sapphire/LSBN glass and MgAl 2 O 4 /LSBNM glass samples. During the bonding process, low bonding temperature (750 °C) resulted in cracks and unbonding, while high bonding temperature (950 °C) caused the crystallization of glass interlayers. However, when the bonding temperature was 850 °C, the in-line transmission and shear strength of the sapphire/MgAl 2 O 4 joints reached 78.3% and 52 MPa, respectively. [ABSTRACT FROM AUTHOR]

Transparent sapphire and magnesium aluminum spinel (MgAl 2 O 4) ceramic was first brazed using La 2 O 3 -SiO 2 -B 2 O 3 -Nb 2 O 5 (LSBN) or La 2 O 3 -SiO 2 -B 2 O 3 -Nb 2 O 5 -MgO (LSBNM) glass filler. The Al 2 O 3 layer was formed at MgAl 2 O 4 /LSBN interface or sapphire/LSBNM interface, which caused the decrease of light transmission of joints. To avoid the formation of this interface layer, sapphire/LSBN/LSBNM/MgAl 2 O 4 joints with double glass interlayers were fabricated by using a two-step joining method consisting of high-temperature coating and low-temperature bonding. After the first step of high-temperature coating, no interfacial layer was observed in sapphire/LSBN glass and MgAl 2 O 4 /LSBNM glass samples. During the bonding process, low bonding temperature (750 °C) resulted in cracks and unbonding, while high bonding temperature (950 °C) caused the crystallization of glass interlayers. However, when the bonding temperature was 850 °C, the in-line transmission and shear strength of the sapphire/MgAl 2 O 4 joints reached 78.3% and 52 MPa, respectively. [ABSTRACT FROM AUTHOR]

The isothermal oxidation behavior of 17Cr-0.85Si-0.5Nb-1.2Cu ferritic stainless steel in air was studied from 850°C to 1050°C by analyzing its weight gain after oxidation. The kinetic curves were plotted using the oxidation weight-gain data, and the structure, surface morphology, and element distribution of the oxide films were analyzed by XRD, SEM, and EDS. The results showed that the oxidation kinetics curves at 850°C and 950°C followed a parabolic law, and a continuous and dense oxide film composed of Cr2O3 and MnCr2O4, FeCr2O4, and Cu-Cr rich spinel was formed, which reveals that the steel displayed good oxidation resistance. When the temperature was increased to 1050°C, the oxidation kinetics curves gradually changed from parabolic to linear after 40 h exposure, which indicated that the oxidation resistance significantly worsened. A lower oxidation resistance was observed at 1050°C due to the formation of a large amount of Fe2O3 on the surface and the volatilization of the inner Cr2O3 layer. [ABSTRACT FROM AUTHOR]

The La 2 O 3 -SiO 2 -B 2 O 3 (LSB) glass filler with high softening temperature was first used to join MgAl 2 O 4 ceramic. An interfacial layer composed of Al 2 O 3 was formed due to the solubility difference of MgO and Al 2 O 3 in the LSB glass filler. As a result, the addition of Al 2 O 3 into the LSB glass filler caused the increase of interfacial layer thickness. On the contrary, the addition of MgO into the LSB glass filler led to the decrease of interfacial layer thickness. When the adding content of MgO was 6 wt%, the interfacial layer disappeared and completely amorphous brazing seam was obtained. The in-line transmittance of joints decreased with the increase of the thickness of interfacial layer. The optimal in-line transmittance of joint bonded with La 2 O 3 -SiO 2 -B 2 O 3 -MgO (LSB6M) glass filler reached 82.9% at 1000 nm. Meanwhile, the average flexural strength of joints was about 196.2 MPa, which was equal to the strength of MgAl 2 O 4 substrate. [ABSTRACT FROM AUTHOR]

Neuromorphic visual system with image perception, memory, and preprocessing functions is expected to simulate basic features of the human retina. Organic optoelectronic synaptic transistors emulating biological synapses may be promising candidates for constructing neural morphological visual system. However, the sensing wavelength range of organic optoelectronic synaptic transistors usually limits their potential in artificial multispectral visual perception. Here, retina‐inspired optoelectronic synaptic transistors that present broadband responses covering ultraviolet, visible, and near‐infrared regions are demonstrated, which leverage the wide‐range photoresponsive charge trapping layer and the heterostructure formed between PbS quantum dots and organic semiconductor. Simplified neuromorphic visual arrays are developed to simulate comprehensive image perception, memory, and preprocessing functions. Benefitting from the flexibility of the charge trapping and organic semiconductor layers, a flexible neuromorphic visual array can be fabricated, having an ultralow power consumption of 0.55 fJ per event under a low operating voltage of −0.01 V. More significantly, an accelerating image preprocessing effect can be observed in a wide wavelength range even beyond the perception range of the human visual system, due to the gate‐adjustable synaptic plasticity. These devices are highly promising for implementing neuromorphic visual systems with broadband perception, increasing image processing efficiency, and promoting the development of artificial vision. [ABSTRACT FROM AUTHOR]

In this work, S30432 steel containing trace TiC/TiB 2 nano-particles was manufactured, and the effects of TiC/TiB 2 nano-particles on the microstructure and room and high-temperature mechanical properties of the S30432 steel were investigated. The addition of trace TiC/TiB 2 nano-particles can reduce the grain size from 19 ± 2.3 μm to 13 ± 4.5 μm. This is because the nano-particles provide efficient nucleation sites and constrain dendrite growth. Trace nano-particles can simultaneously enhance the strength and plasticity of the S30432 steel at room temperature. At high temperature of 600 °C, the S30432 steel with trace TiC/TiB 2 nano-particles can still maintain high strength and plasticity. However, as the ambient temperature increases, the strength increment of the S30432 steel with trace TiC/TiB 2 nano-particles decreases gradually, while the elongation increment significantly increases. The dynamic recrystallization process is promoted by the addition of nano-particles, causing an increased softening degree. Trace TiC/TiB 2 nano-particles exhibit good plasticizing effect. [ABSTRACT FROM AUTHOR]

In order to study the effect of the rolling process and aging on the microstructure evolution and mechanical and tribological properties of the material, room-temperature rolling (RTR), cryogenic rolling (CR), and deep cryogenic treatment after rolling (RTR + DCT) experiments were carried out on a Cu-1.0Cr-0.1Zr alloy by a large plastic deformation process. Alloy plates were aged at 550 °C for 60 min. Different rolling processes and aging treatments have different effects on the microstructure and properties of alloy plates. The alloy plate is rolled and deformed, and the grains change from equiaxed to layered. Compared with RTR and RTR + DCT treatment, CR can promote the precipitation of the Cr phase and the degree of grain fragmentation is greater. After aging treatment, the Cu-Zr mesophase compounds in the microstructure increased, the alloys treated with CR and RTR + DCT appeared to be partially recrystallized, and the number of twins in the CR alloy plate was significantly more than that of RTR + DCT. The ultimate tensile strength of the alloy plate reached 553 MPa and the hardness reached 170 HV after cryogenic rolling with 90% deformation, which indicates that CR treatment can further improve the physical properties of the alloy plate. After aging at 550 °C for 60 min, the RTR 90% + DCT alloy plate has a tensile strength of 498 MPa and an elongation of 47.9%, which is three times that of the as-rolled alloy plate. From the research on the tribological properties of alloy plates, we learned that the main wear mechanisms in the wear forms of CR and RTR + DCT alloy plates are adhesive wear and abrasive wear. Adhesive wear is dominant in the early stage, while abrasive wear is the dominant mechanism in the later stage of wear. The friction coefficient of the CR 90% alloy plate in the TD direction is close to 0.55, and the wear rate is 2.9 × 10−4 mm3/Nm, indicating that the CR treatment further improves the wear resistance of the alloy plates. [ABSTRACT FROM AUTHOR]

Broad‐range‐response pressure‐sensitive wearable electronics are urgently needed but their preparation remains a challenge. Herein, we report unprecedented bioinspired wearable electronics based on stretchable and superelastic reduced graphene oxide/polyurethane nanocomposite aerogels with gradient porous structures by a sol‐gel/hot pressing/freeze casting/ambient pressure drying strategy. The gradient structure with a hot‐pressed layer promotes strain transfer and resistance variation under high pressures, leading to an ultrabroad detection range of 1 Pa–12.6 MPa, one of the broadest ranges ever reported. They can withstand 10 000 compression cycles under 1 MPa, which can't be achieved by traditional flexible pressure sensors. They can be applied for broad‐range‐response electronic skins and monitoring various physical signals/motions and ultrahigh pressures of automobile tires. Moreover, the gradient aerogels can be used as high‐efficient gradient separators for water purification. [ABSTRACT FROM AUTHOR]

Broad‐range‐response pressure‐sensitive wearable electronics are urgently needed but their preparation remains a challenge. Herein, we report unprecedented bioinspired wearable electronics based on stretchable and superelastic reduced graphene oxide/polyurethane nanocomposite aerogels with gradient porous structures by a sol‐gel/hot pressing/freeze casting/ambient pressure drying strategy. The gradient structure with a hot‐pressed layer promotes strain transfer and resistance variation under high pressures, leading to an ultrabroad detection range of 1 Pa–12.6 MPa, one of the broadest ranges ever reported. They can withstand 10 000 compression cycles under 1 MPa, which can't be achieved by traditional flexible pressure sensors. They can be applied for broad‐range‐response electronic skins and monitoring various physical signals/motions and ultrahigh pressures of automobile tires. Moreover, the gradient aerogels can be used as high‐efficient gradient separators for water purification. [ABSTRACT FROM AUTHOR]

A novel La 2 O 3 -Al 2 O 3 -SiO 2 (LAS) glass was used as filler to join transparent sapphire for obtaining high strength and high light transmittance joints. The results show that the LAS glass filler had compatible coefficient of thermal expansion (CTE) with sapphire and excellent wetting ability on sapphire. During the joining process, no interfacial reaction occurred and the brazing seams were in a completely amorphous state under fast cooling conditions (~50 °C/min). With increased joining temperature, the mutual dissolution and diffusion between sapphire and the LAS filler were enhanced. The flexural strength of joints first increased and then decreased with an increase in the joining temperature from 1400 °C to 1550 °C. The optimal flexural strength of joint reached 325 MPa, which almost was the same as the strength of sapphire substrate. At 500 nm, the in-line transmittance of this joint was 80.5%, which was close to that of sapphire (84.2%). [ABSTRACT FROM AUTHOR]

Effects of ZrO 2 content on the crystallization kinetics, formation mechanism of voids and mechanical property of Dy 2 O 3 –Al 2 O 3 –SiO 2 glass were studied. The crystallization method of DAS glasses transforms from surface crystallization into bulk crystallization with an increase in ZrO 2 content from 0-3% to 6–9%. When ZrO 2 content is 0–3%, the crystalline phases of DAS glass ceramics are Dy 2 Si 2 O 7 and Al 2 O 3 , accompanied by formation of voids. When ZrO 2 content is 6–9%, the DAS glass ceramics consist of Dy 2 Si 2 O 7 , Al 2 O 3 and ZrO 2. At the same time, no voids are found in the glass ceramics. Therefore, formation of voids during crystallization can be attributed to combined effect of the crystallization method and the density difference before and after crystallization. In addition, for glassy samples, the flexural strength increases from 80.4 MPa to 219.3 MPa with an increase in ZrO 2 content from 0% to 9%. Moreover, crystallization further improves the mechanical properties of the DAS glass ceramics with bulk crystallization method. [ABSTRACT FROM AUTHOR]

[Display omitted] • Irregular lamellae in the eutectic CoCrFeNiHf HEA exhibit poor thermal stability. • The existence of orientation relationship between FCC and Laves phases in regular lamellae ensures good thermal stability. • The good thermal stability keeps good plasticity after annealing. In order to explore the thermal stability of eutectic high-entropy alloys (EHEAs), two EHEAs with regular lamellae and irregular lamellae are specifically investigated. Regular lamellae exhibit much better thermal stability than irregular lamellae predominantly due to the existence of an orientation relationship between FCC and Laves phases in the regular lamellae. As a result, the regular lamellae shows relatively constant plasticity after annealing up to 900 °C; whereas, the plasticity is deteriorated in the irregular lamellae due to microstructure coarsening. [ABSTRACT FROM AUTHOR]

In this work, the AlSi10Mg alloys with distinct molten pool structures, namely fish-scale and lamellar, were fabricated by using selective laser melting (SLM) technology. The effects of solid solution temperature on the microstructural evolution and mechanical properties of the two types of alloys were systematically investigated. The relationship among initial structure, heat treatment and mechanical properties was revealed. The experimental results showed that for the alloy with fish-scale structure, Si diffused more easily after solid solution treatment due to the finer eutectic network, resulting in a larger Si particle size. At 510 °C, the nano Si particles in the fish-scale sample basically disappeared, but a small amount of nano Si particles still existed in the lamellar sample, leading to a bimodal distribution in the Si particle size. Different sizes and distributions of Si particles present different strengthening mechanisms and affect the nucleation and growth of recrystallized grains in the α-Al matrix, leading to significant differences in mechanical properties. The strength of the lamellar sample decreased with increasing the temperature, and the abnormally growth of grains could be found after being treated at 510 °C, resulting in a poor mechanical property. The strength of fish-scale sample first decreased and then increased with the increase of solid solution temperature. When the alloy with fish-scale structure was solid solution treated at 510 °C, Si particles could promote the nucleation of recrystallized grains but hinder their growth, and the ultimate tensile strength decreased from 478.8 MPa of SLMed state to 393.4 MPa, a reduction of 17.8%, while the elongation increased from 7% to 21%, an increase of 300%, showing an excellent overall mechanical property. Therefore, the present study demonstrates that adjusting the SLMed molten pool structure and heat treatment parameters is necessary to obtain a good combination of microstructure and mechanical property. • SLMed AlSi10Mg alloys with different initial structures have distinct mechanical behaviors after heat treatment. • The size and distribution of silicon particles affect the recrystallisation behavior of α -Al. • The relationship among initial structure, heat treatment and mechanical properties was analysed. • Synergistic optimization of SLM and heat treatment parameters was achieved. [ABSTRACT FROM AUTHOR]

Transparent MgAl 2 O 4 ceramics were bonded by using CaO-Al 2 O 3 -SiO 2 (CAS) glass filler. The CAS glass filler exhibited the same thermal expansion behavior as MgAl 2 O 4 ceramic and excellent wetting ability on the surface of MgAl 2 O 4 ceramic. When the cooling rate of 15 °C/min was used, no interfacial reaction was observed and the amorphous brazing seam could be obtained. However, low joining temperature (1250 °C) led to the formation of pores and high joining temperature (1400 °C) resulted in the formation of cracks. Furthermore, the slow cooling rate of 5–10 °C/min induced the crystallization of CaAl 2 Si 2 O 8 and Mg 2 Al 4 Si 5 O 18 due to the dissolution of MgAl 2 O 4 substrate. The optimal flexural strength of 181–189 MPa was obtained when the joining temperature and cooling rate were 1300–1350 °C and 15 °C/min respectively. Moreover, the in-line transmittance of the joint at 1000 nm was 82.1%, which was slightly lower than that of MgAl 2 O 4 ceramic (85.6%). [ABSTRACT FROM AUTHOR]

The oxidation behaviors of Al-free and 1Al ferritic heat-resistant stainless steels (FHSSs) at 1100 °C were investigated. After oxidation for 100 h, the Al-free FHSS had triple oxide layers of a first layer Fe 2 O 3 + MnCr 2 O 4 , a second layer MnCr 2 O 4 + Cr 2 O 3 + MnO, a third layer SiO 2 and oxides of Nb and Ti. The 1Al FHSS had double oxide layers of a first layer Ti-bearing (Al, Cr) 2 O 3 particles, a second layer dense (Al, Cr) 2 O 3. The (Al, Cr) 2 O 3 layer with self-repairing feature can reduce the thickness of oxide layer by 515 times, and reduce the oxidation weight gain rate of the FHSS by 5 orders of magnitude. • The addition of Al reduces the oxidation weight gain rate by 5 orders of magnitude at 1100 °C. • The addition of Al reduces the thickness of oxide layer by 515 times at 1100 °C. • The addition of Al produces an oxide layer with self-repairing characteristics at 1100 °C. [ABSTRACT FROM AUTHOR]

To meet the increasing demands of sustainability and eco-friendliness, biopolymer-based hydrogels combining flexibility and ionic conductivity have drawn great attention for green and wearable sensors. However, the preparation of transparent, flexible, durable, and highly sensitive biopolymer hydrogel-based sensors for strain/pressure and humidity sensing remains a challenge. Herein, a facile one-step strategy is proposed to fabricate transparent, highly flexible, and multifunctional starch/polyacrylamide double-network hydrogels based on natural renewable starch. The resultant hydrogels exhibit fast self-adhesive ability and present high flexibility attributing to the double network consisting of cross-linked starch and polyacrylamide. Then the hydrogels can be assembled as transparent, self-adhesive, flexible, highly sensitive, and multifunctional strain/pressure and humidity sensors for accurate healthcare monitoring. The hydrogel-based sensor shows ultrahigh sensitivity to humidity (35–97% relative humidity). The multifunctionality and biological advantages of starch-based hydrogels offer potential applications in next-generation green and wearable electronics. [Display omitted] • A transparent and flexible starch/PAM hydrogel was achieved by a simple method. • The hydrogel exhibited high sensitivity for humidity and strain/pressure sensing. • A multifunctional wearable starch/PAM hydrogel-based sensor was fabricated. [ABSTRACT FROM AUTHOR]

• The developed advanced FE model with consideration of material inhomogeneity and surface morphology mcan provide accurate simulation results. • The blank holder-die gap has tiny influence on the maximum drawing force, while strongly impacts contacts on the blank holder and die. The relatively small gap is favourable to thickness evenness without an increase of fracture risk. • Shape accuracy of different parts on the drawn cups is complex due to combined influence of the gap, material heterogeneity and surface morphology. • The in-process springback caused by proper geometry parameters of the gap and cocorner radii corner radii of the die and blank holder benefits MDD. • Small manufacturing error is tolerable, however, affects wear and service life of the MDD tools. Image, graphical abstract Micro-deep drawing (MDD) is a promising micro-manufacturing technology. Size effects complicate and signify the influence of the blank holder-die gap on MDD, which was investigated in this study. Annealing of SUS304 foils of 50 µm thick was conducted to obtain various grain sizes. Micro-tensile testing was carried out to acquire the stress-strain curves of the foils, followed by MDD experiments. Advanced FE models were developed to simulate the MDD process taking into account material inhomogeneity and surface morphology of the foils at micro-scale. Bending dominates the early stage of MDD. A combination of proper gap size and punch/die corner radius may incur in-process springback before the occurrence of the maximum drawing force, benefiting the MDD process. A relatively small gap is favourable to a uniform distribution of wall thickness without obviously increasing the risk of fracture. It also improves the overall shape accuracy of outer surface whilst may result in the inner surface distortion. The complex development of the shape accuracy in three defined areas on the drawn cup can be attributed to the integrated effect of the gap size, material inhomogeneity and surface morphology of the foil. The combined design and multi-object optimisation of the gap size and the corner radii of punch and die should be conducted for improving the MDD process. [ABSTRACT FROM AUTHOR]

• Preparation of PPCAs via different CLD methods: SCLD and DCLD methods. • Endow PPCAs with both superior mechanical property and high thermal stability. • Introduction of PI chains into the PVPMS backbone by SCLD method. In this study, the polyimide-polyvinylpolymethylsiloxane composite aerogel (PPCA) was synthesized by two different methods, stepwise chemical liquid deposition (SCLD) and direct chemical liquid deposition (DCLD). It is found that polyimide (PI) chains can only be introduced into the backbone of amine-modified polyvinylpolymethylsiloxane (PVPMS) by SCLD method. The introduced PI can further crosslink with PVPMS to form a PI-PVPMS cross-linked network structure, which makes the skeleton dense and endows the sample with high mechanical strength. For DCLD method, PI chains can only be coated on the surface of the sample rather than the whole skeleton, which leads to a loose internal structure. Furthermore, samples prepared by SCLD method possess higher initial thermal decomposition temperature compared with that by DCLD method. [ABSTRACT FROM AUTHOR]

Resilient, fire-retardant and mechanically strong polyimide-polyvinylpolymethylsiloxane (PI-PVPMS) composite aerogels have been prepared via stepwise chemical liquid deposition (SCLD). The synthesis is based on the formation of PI-PVPMS crosslinked network structure with (3-aminopropyl)trimethoxysilane (APTMS) as a coupling agent to provide reactive sites on the backbone. We successfully realize the PI in-situ growth on the whole super-flexible PVPMS gel skeleton with this simple method. The effect of APTMS amount and deposition time on the properties of final samples is deeply investigated. The resultant PI-PVPMS composite aerogels show excellent mechanical and thermal properties. They can support at least 10,000 times of their own weight and can recover 20% from a 60% of compressive strain, with an elastic modulus of 32 MPa. For thermal performance, they can maintain their structural integrity after being subjected to the alcohol lamp outer flame of around 650 °C for 30 min. These results together with the simple synthesis process demonstrate the potential for construction materials using PI-PVPMS composite aerogels. Furthermore, the SCLD synthesis method could also be applied to prepare other composite aerogels, especially for those containing complex polymer. Unlabelled Image • We successfully realize the in-situ growth of polyimide on the super-flexible PVPMS gel skeleton. • The PI-PVPMS composite aerogel shows both resilient mechanical property and high thermal stability. • The synthesis method has the potential to realize the large-scale production of PI-PVPMS composite aerogels. [ABSTRACT FROM AUTHOR]

Porous alumina aerogel synthesized by sol–gel method was used as facile and sensitive surface‐enhanced Raman scattering (SERS) platform. In a simple "drop‐test" SERS detection, low concentration dye solution mixed with silver nanoparticles was directly dropped on the surface of aerogel platform for SERS detection immediately. The pore structure of alumina aerogel was tuned by adding PEG‐400 and varying the gelation temperature. The effects of surface morphology and pore size of alumina aerogel platform on SERS performance of crystal violet (CV) were investigated. The result shows that large specific surface area and interconnected pore network of aerogel are helpful for fast permeation of solution, generation of "hot spots," and adsorption of probe molecules. The Raman signal of CV was largely enhanced, enabling a detection concentration to 5 × 10−10 M with a SERS enhancement factor of 3.4 × 107. The SERS enhancement of alumina aerogel platform is remarkably improved with the increase of specific surface area and pore size, which is also confirmed by the finite‐difference time‐domain simulation. Moreover, the relative standard deviation of SERS intensity at 1619 cm-1 band for 5 × 10−8 M CV on aerogel platform is about 12%, indicating a good reproducibility. [ABSTRACT FROM AUTHOR]

Keywords: broadband; neuromorphic visual systems; optoelectronic synaptic transistors; quantum dots EN broadband neuromorphic visual systems optoelectronic synaptic transistors quantum dots 1 1 1 08/10/23 20230808 NES 230808 B Broadband Optoelectronic Synapses b In article number 2302885, Jia Huang, Jianhua Zhang, Lize Xiong, and co-workers report retina-inspired optoelectronic synaptic transistors that present broadband responses. Simplified neuromorphic visual systems are developed to simulate comprehensive image perception, memory, and preprocessing functions in a wide wavelength range from ultraviolet to near-infrared, even beyond the sensing range of the human visual system. Broadband, neuromorphic visual systems, optoelectronic synaptic transistors, quantum dots. [Extracted from the article]

In this work, a high-strength Al–Cu–Mg–Si alloy was prepared by a selective laser melting (SLM) process with blended powders consisting of AlSi10Mg and microsized pure Cu powders. The influence of Cu addition on the microstructure and mechanical properties of AlSi10Mg alloy has been systematically investigated. The Al–Cu–Mg–Si alloy has a hardness of 173 HV, an ultimate tensile strength of 732 MPa, and a yield strength of 389 MPa, reaching the level of high-strength aluminum alloys. Such increase in the strength and hardness can be attributed to the refinement of eutectic network, enhanced solid solution strengthening and elimination of fracture-prone heat affected zone (HAZ). In addition, the formation of the GP zone caused by adding Cu promotes the precipitation of Si particles within the eutectic network, and Si particles, as the non-shear deformed second-phase, can significantly increase the Orowan strengthening effect. After aging at 180 °C for 2 h, the hardness and yield strength of the alloy are increased to 183 HV and 522 MPa respectively. The presence of the θ′-Al 2 Cu phase and the high-density of Si particles after 2 h of peak aging further increases the strength and hardness of the alloy. [ABSTRACT FROM AUTHOR]

Abstract Carbon fiber-reinforced polymer (CFRP) composites have excellent structural properties and potential multifunctionality, but thermal conductivity enhancement is desired to meet the heat transfer requirement due to low thermal conductivity in the through-thickness direction. The micro-nano boron nitride (BN) fillers were incorporated into the CFRP by the acetone vehicle-solvent to prepare three phase composites with relatively high thermal conductivity. Three prediction models were presented to estimate the thermal conductivity of composites respectively based on component configurational correlation, filler penetration degree, and ease of conductive chains formation. Most predicted results for modified composites show good agreement with experiments. The effects of vehicle-solvent concentration on microsurface morphology of prepreg and thermal conductivity of composites were conducted, and the thermal modification mechanism was explored based on above-mentioned and filler distribution. The tensile responses of modified composites also show obvious difference as the variation of vehicle-solvent concentration. The degradation of mechanical property suggests that it is a couple of potential challenges between structural property and thermal functionality. [ABSTRACT FROM AUTHOR]

Abstract A novel method was developed to uniformly disperse sub-micron TiO 2 opacifier into fiber reinforcements using agar and silica as binders via freeze drying. TiO 2 opacifier/ fiber/ alumina-based aerogel ternary (TFA) composites with high strength and excellent high-temperature thermal insulation were successfully prepared by sol-gel route, impregnation process and supercritical fluid drying. The microstructure, mechanical and thermal insulation properties of TFA composites were investigated comprehensively. The results show that the mechanical property of TFA composites can be significantly enhanced by mullite fiber felt and the incorporation of SiO 2 binder. The effect of TiO 2 opacifier on the high-temperature thermal conductivity was studied by adjusting the content of TiO 2 from 0 to 15 wt%. The obtained TFA composites exhibit high Young's modulus of up to 3.58 MPa and low high-temperature thermal conductivities of 0.129 W/m·K at 800 °C and 0.168 W/m·K at 1000 °C, respectively. The mechanism of heat transfer in TFA composites at high-temperature was also analyzed. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

In this study, an AlSi10Cu4Mg alloy was prepared by selective laser melting (SLM) using a mixture of pre-alloyed AlSi10Mg and elemental Cu powders, followed by aging at 180 ℃ for 2 h. The high-temperature tensile properties of both the SLMed and SLM-aged samples were tested in the temperature range of 200–400 ℃, and the microstructure changes during deformation were compared. At the temperature of 200 ℃, the SLMed sample exhibits outstanding tensile properties with an ultimate tensile strength (UTS) of 327±2 MPa and an elongation (EL) of 25.5±0.5 %. This is mainly related to the strain hardening that caused by the accumulation of anomalous dislocations near the high-volume fraction of Si nano-particles within the grains. For the SLM-aged sample, the aging treatment is found to further increase the strength, yielding a UTS of 381±3 MPa. The metastable transition of the Al 2 Cu phase indirectly promotes the precipitation of the nano-sized Si phase during the aging process. As the testing temperature increases, the strength increment of the SLM-aged sample gradually diminishes, while the elongation increment increases. Due to the limited intrinsic thermal stability of Si nano-particles and θ′ phase, the coarsening of the precipitates can weaken the strengthening effect. The dynamic recrystallization process can be accelerated by the aging treatment, thereby helping to improve the elongation. [Display omitted] • The high-temperature tensile properties of AlSi10Cu4Mg alloy prepared by SLM were evaluated. • The SLMed AlSi10Cu4Mg alloy exhibited outstanding comprehensive tensile properties at 200 ℃. • The metastable transition of the Al 2 Cu phase facilitates nano-sized Si precipitation during aging process. • The strength increment of SLM-aged sample gradually diminishes with increasing testing temperature while the elongation increment increases instead. [ABSTRACT FROM AUTHOR]

Highly stretchable elastomeric multiwall carbon nanotubes – poly (glycerol sebacate) (MWCNT-PGS) nanocomposites were prepared by mixing conductive multiwall carbon nanotubes (MWCNTs) with PGS prepolymer and curing at 120 °C. The incorporation of conductive filler increases the matrix crosslinking density and mechanical stiffness without loss of the flexibility and elasticity of the polymeric network with low mechanical hysteresis behaviour. The percolation threshold for the electrical conductivity was found to be ∼1 wt% of MWCNTs. The piezoresistive behaviour of the prepared samples shows a negative gauge factor (GF) between −0.5 and −0.8 under uniaxial tensile stress, probably due to geometrical factors, whilst under 3-point bending the calculated GF values were positive and a maximum GF = 42 was achieved for the samples with 2 wt% MWCNTs. Overall, the unique property combination between the MWCNTs and the PGS make them potentially suitable for the development of large deformation piezoresistive sensors, especially for biomedical engineering applications, flexible and wearable devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • The addition of Al increases the nucleation rate of the Cu-rich phase. • The addition of Al can increase the coarsening rate of the Cu-rich phase. • The addition of Al changes the crystal structure of the Cu-rich phase. • The addition of Al hinders the coarsening of the Cu-rich phase into a rod shape. • The Al-containing Cu-rich nanoprecipitates are rich in high-density edge dislocations. In this article, scanning electron microscopy, energy dispersive spectroscopy, and transmission electron microscopy were used to characterize the precipitation behaviour of the Cu-rich phase in Al-free and 1Al Cu-bearing ferrite stainless steels; and further, the effects of Al addition on the precipitation and coarsening of the Cu-rich phase and its mechanism were analysed. The results show that Al increases the nucleation rate of the Cu-rich phase, and refines Cu-rich nanoprecipitates after ageing for 1 min. The Cu-rich phase with four crystal structures-BCC, 9R, twin FCC, and non-twin FCC were found in the Al-free sample during ageing. However, only Cu-rich phase with BCC and BCT structures were observed after Al addition. There are high-density edge dislocations in Al-containing Cu-rich nanoprecipitates. These dislocations can be used as a diffusion channel for solute atoms, increasing the coarsening rate of the Cu-rich phase. However, with the extension of the ageing time, dislocations in the Cu-rich phase will be annihilated owing to the thermal activation and the decrease of the Al concentration in the Cu-rich phase, which will lead to a decrease in the dislocation density in Al-containing Cu-rich phase. Finally, the promotion effect of Al on the coarsening of the Cu-rich phase is weakened. [ABSTRACT FROM AUTHOR]

In the present study, the evolution and strengthening effect of precipitates in 17Cr ferrite stainless steel during the creep process are investigated. The precipitates are characterized by scanning electron microscopy, energy dispersive spectroscopy and transmission electron microscopy. Moreover, the interactions between the precipitates and the grain boundary and dislocation are quantitatively analysed. The results show that Cu- and Nb-rich phases are formed during the creep process. The stress concentration at the tip of the precipitates, the stacking fault at the precipitate edge and the internal dislocation can promote the nucleation of the Nb-rich phase. The Nb-rich precipitates can provide the driving force for the nucleation of Cu-rich particles through stacking fault, dislocation entanglement and internal dislocation. At 700 °C, as the creep time increases, the pinning effect of precipitates on the grain boundary increases linearly, while the pinning effect on the dislocation decreases. As the creep temperature increases, a peak pinning effect on the grain boundary is observed at 750 °C, and the pinning effect of the precipitates on dislocation decreases gradually inside the grain. The formation of dislocation networks at grain boundaries can delay pinning effect reduction of the Nb-rich phase, and the main blocking mechanism of precipitates on dislocation movement is bypassing. The precipitation strengthening effects of Cu- and Nb-rich phases are also compared with each other. • The precipitation rule of Cu-rich phase is BCC → Non-twin 9R → FCC. • The orientation relations of the precipitates with matrix are revealed. • The Nb-rich phase mainly pins the grain boundary, while the motion of dislocation is easy to be blocked by the Cu-rich particles. • The dislocation networks promote nucleation of precipitates. • The strengthening effect of Cu- and Nb-rich phases is compared. [ABSTRACT FROM AUTHOR]

• The cross-linked PI-PVPMS network structure endowed LPA with superior property. • The skeleton of PVPMS can weaken the effect of PI rigidity on the properties of LPAs. • PPCA with outstanding properties can be prepared with lower cost monomers of PI. The properties of linear polyimide aerogels (LPAs) were improved by introducing the network structure of polyvinylpolymethylsiloxane (PVPMS) into that of LPAs. The formed doubly cross-linked polyimide (PI)-PVPMS network structure endowed samples with resilience and fire-retardant property. On the one hand, the PI-PVPMS composite aerogels (PPCAs) can recover to 20% of their own height rather than exhibit almost no resilience after compression. On the other hand, they can maintain high structural integrity instead of showing drastic volume shrinkage after prolonged burning. Moreover, our results showed that the introduced network structure of PVPMS not only weakened the effect of PI rigidity on the structural properties of LPAs, but also played a leading role in the physical properties of synthesized PPCAs. The obtained PPCAs with different PI rigidity exhibited similar microstructure and properties, which indicated that the lower cost monomers of PI could be selected to prepare PPCAs and promote the large-scale production. [Display omitted] [ABSTRACT FROM AUTHOR]

Herein, the precipitation behavior of 17Cr-0.86Si-1.2Cu-0.5Nb ferritic stainless steel during isothermal aging is studied by using scanning electron microscopy, energy dispersive spectrometer and high-resolution transmission electron microscopy. Moreover, the influence of aging temperature and time on hardness is systematically investigated. The results reveal that the Cu-rich phase mainly precipitates below 750 °C, whereas the Nb-rich phase precipitates above 750 °C. The Cu-rich phase exhibits an evolution behavior of B2-9R-FCC and the coarsening rate of Cu-rich phase increases by two orders of magnitude from 650 to 750 °C. Furthermore, the side of rod-shaped Cu-rich phase maintains incoherent interface with the matrix, however, the tip of Cu-rich phase exhibits a coherent interface with the matrix with an orientation relationship of 01 1 ¯ α / / 1 ¯ 11 Cu. The Nb-rich phase includes Fe 2 Nb, Fe 3 Nb 4 Si 5 , CrNbSi, (Fe,Cr,Si) 2 Nb, and Nb 2 C phase after thermal aging. At T < 750 °C, both sides of the Nb-rich phase provide nucleation points for the Cu-rich phase. At T = 850 °C, the tip of Cu-rich phase provides a nucleation site for Nb-rich precipitation. A coherent interface can be found between (Fe,Cr,Si) 2 Nb and Cu-rich phases, and the Cu-rich phase grows along (311) crystal planes of (Fe,Cr,Si) 2 Nb. Finally, the hardness change with aging time shows a single peak feature at T < 750 °C and a double-peak at 850 °C. The occurrence of aging peak is delayed and the peak values gradually decrease with the increase of aging temperature. • The copper rich phase has the precipitation rule of B2-9R-FCC. • The complex precipitation behavior of Nb, Cu and Si existed in the steel. • The Nb- and Cu-rich phases have interdependent growth relationship. • The coarsening rates of Cu- and Nb-rich phases were calculated. • The precipitation of the Cu-rich phases delays the occurrence time of aging peak. [ABSTRACT FROM AUTHOR]

Graphene is regarded as a promising, environmentally friendly candidate for lubricant additives. This work presents a coated nanocomposite with hard-core and soft-shell as lubricant nanoadditive. Three morphological ZnO nanoparticles are synthesized as the core to prepare ZnO@graphene core-shell nanoadditives. A four-ball machine is used to evaluate the anti-friction and anti-wear properties. The effects of ZnO morphology and concentration on the tribological behaviors and worn-out appearance are discussed. The compositional variation of wear scar is characterized to explore the possible anti-wear mechanisms. Researches suggest sheet-like ZnO is more ideal morphology, and ZnO@graphene hard core-soft shell nanostructure is more suitable for dynamic friction environment. The synergistic effect can effectively maintain load capacity and stability of lubricating film, exhibiting excellent tribological property. • A coated nanocomposite with hard core and soft shell is presented as lubricant additives. • Three morphological ZnO nanoparticles are synthesized as the core to prepare ZnO@graphene core-shell nanoadditives. • The compositional variation of wear scar is characterized to explore the possible anti-wear mechanisms. • The synergistic effect can effectively maintain the load capacity and stability of lubricating film. [ABSTRACT FROM AUTHOR]