Search

Ammonia becomes one of the indispensable raw materials in production and life, with the continuous development of industry. Ammonia pollution of the environment is becoming more and more serious, so the adsorption of ammonia is essential. In this paper, a new biochar material based on tannic acid was developed. The tannic acid was self-polymerized using different activators (K2CO3, KHCO3, KOH). Tannic acid biochar (TAB-X) was obtained by pyrolytic carbonization reaction at 800 ℃. The biochar was treated with phosphoric acid 10% by mass (TAB-X-10%PO4), and unlike other biochar materials, the specific surface area and hydroxyl content were increased after acidification, but there were no acidic functional groups. It is noteworthy that the specific surface area of TAB-KOH increased from 22 m2/g to 667 m2/g after acidification. The adsorption capacity of ammonia vapor reached 342.6 mg/g. It is proposed that the adsorption mechanism is an adsorption process in which hydroxyl groups on the surface of TAB-X firstly adsorb water, and after that ammonia gas is then dissolved in the water molecules on the surface of the biochar. These results highlight the great potential of TAB as an adsorbent for the adsorption of ammonia, in addition to the low price of raw materials and the simple preparation conditions of this preparation process, which corresponds with the conditions for mass production as well as practical application. [ABSTRACT FROM AUTHOR]

In this paper, a novel composite phase change material (CPCM) is prepared with inorganic PCM through impregnation and dispersion method which can be used for thermal management applications. Inorganic PCMs have high latent heat and good thermal conductivity and are non-flammable, but there exist leakage (shape stability) and corrosion problems. To overcome these issues, a porous structured material is impregnated with the inorganic PCM (disodium hydrogen orthophosphate dodecahydrate). The CPCM is prepared by loading various wt% of expanded graphite and boron nitride nanoparticles with the PCM, and characterization is performed to find the thermal properties and stability. The findings from FTIR and XRD analyses validate both the chemical compatibility and crystalline nature of the samples. DSC thermographs reveal the CPCM5 sample has a latent heat value of 168.05 J/g during the heating process, an encapsulation efficiency of 78.8% and a thermal conductivity of 4.69 W/mK. The thermal stability and resistance to corrosion of the composite samples are also enhanced. The best composite PCM sample is then selected, and subsequently, the thermal performance of the heat sink is experimentally investigated. The thermal performance of rectangular cavity heat sink filled with CPCM5 is the highest for various power sources and temperatures with a maximum enhancement ratio of 6.57. [ABSTRACT FROM AUTHOR]

The development of metal–organic frameworks for carbon dioxide (CO2) capture has drawn considerable interest among researchers with MIL-101(Cr) gaining significance owing to its high stability. This paper investigates the one-step synthesis of MIL-101-NH2(Cr) by using guanidine hydrochloride as a mediator under relatively mild conditions (aqueous phase, reaction temperature of 120 °C, and without the use of mineralization agents such as hydrofluoric acid). MIL-101-NH2(Cr) not only exhibited a high specific surface area with a Lewis-base site-rich ligand but also possessed a good CO2 adsorption capacity of 3.96 mmol/g at 1 bar. Furthermore, diethylenetriamine (DETA) was loaded into MIL-101-NH2(Cr) to design a new CO2 adsorbent DETA@MIL-101-NH2(Cr). The loaded material maintained the original structure and also displayed an improved adsorption capacity of 0.29 mmol/g under low (< 0.11 bar) CO2 partial pressure. The absorbents possessed good selectivity, stability, and recyclability which make them ideal candidates for CO2 capture. [ABSTRACT FROM AUTHOR]

In this paper, two hydrated double salts, whose chemical formulas are K2Mn0.15Co0.85(SO4)2(H2O)6 (KMn/Co) and K2Mn0.16Zn0.84(SO4)2(H2O)6 (KMn/Zn), were crystallized via solvent slow evaporation. The structural, thermal, and vibrational properties were explored and discussed. Furthermore, a study of geometric, electronic, and thermodynamic (entropy, enthalpy, and free energy) parameters was performed based on computational calculations. Single-crystal X-ray diffraction indicated that the compounds belong to the family of mixed Tutton salts with monoclinic symmetry, space group P21/c ( C 2 h 5 ), and occupancy factors of Mn0.15/Co0.85 (KMn/Co) and Mn0.16/Zn0.84 (KMn/Zn). Additionally, the intermolecular contacts and total empties in the unit cells were determined by Hirshfeld surfaces and crystal voids, respectively. The two crystals exhibited thermal stability around 333 K (Mn–Co) and 348 K (Mn–Zn). Above these temperatures, endothermic and exothermic events characteristic of dehydration, crystallization, solid–solid transition, and melting are recorded. Furthermore, KMn/Co and KMn/Zn exhibited significant energy densities, making them promising candidates for thermochemical energy storage systems. An energy band gap of 4.13 eV and 4.49 eV was predicted for KMn/Co and KMn/Zn, respectively. These findings are characteristic of insulating materials with major contributions from p orbitals in the valence and conduction bands. Using group theory and density functional theory (DFT), it was suggested that the two compounds have a total of 183 optical modes in the spectral region from 30 to 3600 cm−1. Furthermore, experimental and calculated Raman and infrared spectra showed a good correlation. Our data suggest that the KMn/Co and KMn/Zn salts present promising thermo-structural results, showing that they can be used in heat-storing thermochemical devices due to their low dehydration temperatures, high dehydration enthalpies, and good energy density. [ABSTRACT FROM AUTHOR]

In this paper, linear low-density polyethylene (LLDPE) fibers were stabilized by ultraviolet ray (UV) irradiation, which provided a new treatment method for fabricating carbon fiber precursors. LLDPE chips were blended with a photo-initiator 4-chlorobenzophenone (4-CBP) and a crosslinker 1,2-polybutadiene (1,2-PB) to obtain spun particles, and then they were melt spun into the fibers. Then, UV irradiation of the as-spun fibers was performed to obtain precursors. An orthogonal experimental design investigated the effects of the ingredient ratio LLDPE:1,2-PB and UV irradiation time on the fiber gelation. The results show that the factor's order of influence was: ingredient ratio > UV irradiation time. The fiber gelation reaches a maximum of 67.51% at a dosage ratio of LLDPE:1, 2-PB of 97:2, and a UV irradiation time of 30 min. The UV irradiation introduced the crosslinking structure of LLDPE fibers, and the melting temperature of UV-XLPE fibers shifts toward lower temperatures, and the crystal size of the fibers decreased with increasing UV irradiation time. However, longer irradiation time does not beneficially affect the gelation degree. The low cost and feasible crosslinking method in this study offer the possibility of wide application of low-cost polyethylene-based carbon fibers. [ABSTRACT FROM AUTHOR]

The frequent outbreak of infectious respiratory diseases, such as the recent COVID-19 epidemic, raised the importance of indoor air quality. Removing microorganisms from indoor air is critical to improve indoor air quality. Numerous studies in recent years have been published on developing antimicrobial materials and technologies for antibacterial and antiviral applications. This study critically reviews the recent antimicrobial advances for improving indoor air quality. This paper provides a comprehensive analysis of the antimicrobial mechanisms, development of materials, and deployment strategies, as well as a performance evaluation of the antimicrobial implication for indoor air quality. Furthermore, the challenges and opportunities of future research directions are also highlighted. [ABSTRACT FROM AUTHOR]

Green and intelligent manufacturing has become the key direction of industrial production development. In-situ measuring and sintering simulation technologies play a key role in the modification of ceramic materials and the optimization of the sintering process. These two techniques can significantly alleviate the problems of wasted energy and resources in the ceramics production process, thus promoting the green development of the ceramics industry. Although both techniques have been widely used in the field of ceramic sintering, there is a lack of a comprehensive review of their applications. To better promote the application of these two technologies, this paper provides the first overview of the progress of the application of ceramic sintering in-situ measuring technology and systematically reviews the current research status of ceramic sintering simulation technology. Then it looks forward to the application prospect of these two technologies, synthesizes these two technologies, constructs the framework of digital twin ceramic sintering system for the first time, and analyzes the important role of these two technologies in the digital twin ceramic sintering system. [ABSTRACT FROM AUTHOR]

In this paper, the mechanical damage behavior is investigated based on the characteristic roughness on the surface and the orientation of superficial structures. The main goal is to explore the surface roughness on mechanically loaded copper conductors as a lifetime indicator. For this purpose, copper conductors are mechanically stressed in accordance with EN 50,396 and then examined metallographically and microscopically. The microstructure examination shows that the roughness is caused by material extrusion and cracks due to work hardening in the surface area. Using confocal microscopy, it is shown for the first time that significant formation of surface roughness takes place over the service life of copper conductors. The roughness increases monotonically, but not linearly with number of cycles, due to internal microstructural processes and can be divided into three sections. First inspections of the conductor surface over lifetime show a correlation between the intensity of structures orientated 45° to the loading direction and the roughness. This phenomenon, already known from microscopic slip lines, is thus also evident in macroscopic roughness formation and is well founded by the research theory on material extrusion along dislocation lines. In summary, a lifetime determination is possible based on its developing roughness which enables the utilization as a sensor element. [ABSTRACT FROM AUTHOR]

It is vital to reveal the effect of microstructure features on the corrosion behavior of pure aluminum anode in alkaline electrolyte for Al-air batteries. In this paper, we extensively studied the influence of mechanical deformation on the corrosion microstructure and then corrosion features of pure aluminum anode. The results demonstrate that the cold-rolling deformation could facilitate the grain size refinement of pure aluminum. Surprisingly, the aluminum anodes with smaller grain sizes and larger grain boundary areas could effectively improve the corrosion resistance. The further characterization of the microstructure indicates that the deformation is capable of causing the fracture of the cathodic secondary phase precipitate clusters thus weakening the galvanic corrosion effects. The results of this paper could gain insights into the design and processing of pure aluminum for Al-air battery. [ABSTRACT FROM AUTHOR]

Bacterial cellulose (BC) is a pure biopolymer with abundant sources. BC has been used in wound dressings, artificial blood vessels, bone tissue engineering, and other applications because of its microporosity, superior water retention, thermal stability, and biocompatibility. The tensile strength of pure BC in wet state is weak, and the water holding capacity is above 90%, which limits its application. However, the mechanical properties of dehydrated BC are excellent at the expense of toughness, which is not enough to meet the demand of high additional-value materials, such as high strength flexible electronic device substrate, wearable electronic devices, vibration film for microphone and earphone, and others. Therefore, it is of great importance to systematically investigate the strategies to improve the mechanical properties of BC. Herein, this paper demonstrates the intrinsic factors affecting the mechanical properties of BC, along with the strategies to enhance the mechanical properties. Compared with the well-known adhesion reinforcement and chemical modification, six strategies to enhance the mechanical properties were discussed thoroughly in this paper. In addition, layer-by-layer self-assembly and orderly arrangement of fibrils are proposed in this paper to improve the mechanical properties of BC, which have not been described in detail in previous literature. [ABSTRACT FROM AUTHOR]

This review article focuses on the role of nanotechnology (NT) in the development of advanced organic and inorganic photodetectors and their potential applications in the coming decades. We initiate the article with an overview of NT and potential applications of Nanotechnology in the twenty-first century ranging from Semiconductor manufacturing to Medical Imaging to Renewable energy to Quantum computing to Opto-electronics. The second part of the article delved into specific details on the role of nanotechnology and nanomaterials in developing advanced Photodetectors (PDs) and specifically discussing the internal functioning of near-infrared (NIR) photodetectors. Subsequently we focused on the performance metrics of PDs and types of PDs namely Organic Photodetectors (OPD) and Inorganic Photodetectors (IPD). We continued our in-depth discussion on OPDs and IPDs elaborating their structural features, operation mechanisms, types, performance optimization and role of functional nanomaterials. The final part of this review focuses on key applications of photodetectors e.g., retinal implant, biomedical imaging, personalized health monitoring, telecommunication, and military applications etc. Finally, we concluded the review paper discussing future opportunities and challenges regarding applications of NIR photodetectors in the twenty-first century. [ABSTRACT FROM AUTHOR]

Organic phase change materials (PCMs) have received increasing attention for their applications in the fields such as solar energy storage and thermal management. Low thermal conductivity is a major key issue that hinders their practical applications. It has become a research hotspot to investigate the three-dimensional (3D) network method to improve the thermal performance of organic PCMs compared with the traditional blending method. Thermally conductive fillers form a 3D network in the resin matrix, which can enrich the thermal conductive pathway and effectively enhance the thermal conductivity. This paper mainly summarizes the research progress, preparation methods and influencing factors of composite PCMs, focusing on the methods of constructing 3D thermal conductivity network. It is hoped to provide reference or suggestion for the preparation of novel PCMs. [ABSTRACT FROM AUTHOR]

Intermetallic compounds, due to their well-defined stoichiometry, arrangement of atoms and controlled crystal structure, are a promising alternative to expensive noble metal catalysts. In this paper, the catalytic properties of Al-13.5 at.% Cr and Al-13.5 at.% V alloys, corresponding to the quasicrystalline approximants Al45Cr7 and Al45V7, were investigated for the first time. The alloys in the form of fragmented brittle ribbons were produced by the melt-spinning. The microstructure of the ribbons, both in the as-spun state and after heat treatment (100 h at 600 °C), was characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. In the as-spun state, the ribbons showed a multiphase microstructure. In addition to the Al45Cr7 phase in the Al-Cr alloy and the Al3V phase in the Al-V alloy, they also contained α(Al) solid solution and icosahedral quasicrystalline phases. After heat treatment, the alloys became almost single phase, consisting mainly of stable monoclinic phases: Al45Cr7 or Al45V7. The catalytic performance of the phenylacetylene hydrogenation reaction was tested on as-spun and heat-treated alloys that had previously been pulverized and sieved to select a powder fraction of less than 32 µm. All the tested materials show high substrate conversion, above 80% after 1 h reaction, along with high activity rate. The homogenized powders demonstrated a slightly better properties in relation to as-spun materials. These results confirm the potential of intermetallic catalysts, including the tested alloys, in hydrogenation reactions and verify the possibility of using the metallurgical method to obtain catalytically active materials. [ABSTRACT FROM AUTHOR]

In this paper, the electrical response of a carbon black polylactic acid 3D printed polymer is characterised in detail by a combination of advanced experimental techniques at different scale lengths. The electrical properties as a function of the temperature become repeatable after the second heating cycle, exhibiting different trends as a function of the printing parameters. Joule heating and oven-heating techniques have been compared, showing the advantages of the Joule heating method to maintain electrical conductivity due to the lower thermal inertia. Small-Angle X-Ray Scattering has been employed to discern the underlying physics, showing the crucial role of crystallinity, filler dispersion and carbon black aggregates to form an effective segregated conductive network. This investigation provides guidelines to produce 3D-printed devices with a reliable electrical response and the governing equations to operate them with sufficient accuracy for engineering applications. [ABSTRACT FROM AUTHOR]

The current study suggested that nano-scale twins in magnesium alloys can significantly affect the elastic limit, ultimate strength and corrosion performance. However, the complicated process of nano-scale twins preparation limits its industrial application. In this paper, the microstructure with submicron twins and precipitates of ZK60 magnesium alloy was designed by room temperature multi-directional forging (MDF) process, aiming to improve the enhancement effect of submicron twins by compensating the denseness of coherent interfaces with diffusely distributed precipitates. The results show that the MDFed ZK60 alloy can obtain high strength (yield stress (YS): 248.5 MPa, ultimate tensile strengths (UTS): 371.4 MPa). Good comprehensive mechanical properties can be finally achieved after heat treatment at 150 °C (YS: 226.5 MPa, UTS: 352.6 MPa, elongation: 17.1%). Submicron lamellar {10–12} twins were formed within the alloy due to the small strains in multi-passes of forging. During heat treatment at 150 °C, a large amount of β1' phase was diffusely precipitated within the matrix and twins. The presence of precipitates effectively increases the denseness of dislocation motion barriers in submicron twins, which enables twin-boundary enhancement of ZK60 magnesium alloy. This work provides a new idea for the design of low-cost magnesium alloy forgings in industry. [ABSTRACT FROM AUTHOR]

Inconel 625 flux-cored wire is widely used in the repair of solar energy storage pipelines because of its excellent corrosion resistance. In the application environment of molten salt pipeline containing high-temperature chloride, the surface of the repaired pipeline is easy to deposit salt film, which leads to high-temperature hot corrosion. In this paper, in order to study the hot corrosion mechanism of Inconel 625 cladding metal. Inconel 625 cladding metal was prepared by MAG welding. The corrosion behavior of Inconel 625 cladding metal under isothermal (800 °C) and thermal cycle (600–800 °C) conditions in KCl-MgCl2 (60–40 mol %) molten salt environment was investigated. The results showed that the corrosion rate of Inconel 625 cladding metal was 12.39 μm/year under 72-h isothermal conditions, and the corrosion products mainly included MgO and NiCr2O4. Under the condition of 3 thermal cycles, the corrosion rate of the sample was 11.21 μm/year, and the corrosion products mainly included MgO, NiCr2O4 and Cr2O3. This was because the Cr2O3 protective shell dissolved and fell off under isothermal conditions. Besides, the hot corrosion path penetrated along the random HAGBs. The larger number of HAGBs increased the diffusion path of Cr element, which led to increased corrosion under isothermal conditions. Under the condition of thermal cycle, there was an intermittent cooling effect, and the corrosion time was less at the highest temperature, which improved the stability of the Cr2O3 protective shell. At the same time, it reduced the number of HAGBs and reduced the penetration path of hot corrosion. The diffusion coefficient of Cr element was reduced by 55.6%, which reduced the corrosion rate. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms behind sintering Cu-Ag core–shell nanoparticles can help us optimize the sintering process parameters and design the core–shell structure to achieve the desired sintering structure. In this paper, we employed molecular dynamics simulations to investigate the sintering behaviors and mechanisms of CS NPs, taking into account the effects of shell thickness, particle size, and temperature. Our results revealed that dislocation loops in Cu-Ag CS NPs played a crucial role in sintering by emitting dislocations that facilitated crystal evolution, thereby reducing the number of amorphous structures. The state of dislocation loops could be controlled by shell thickness and NP size. As the shell thickness decreased to 0.5 nm, the structure of the dislocation loops could not be generated due to the extremely chaotic and thin Ag atoms. Furthermore, for NPs of the same size, the CS NP with a 0.5-nm shell thickness was the most active. Despite the neck not consisting of a Cu core, the Cu core, particularly its interface, could still participate in the sintering process. At 900 K, limited interface diffusion could be activated. [ABSTRACT FROM AUTHOR]

Graphene oxide-based fire alarm sensors have received the most extensive research. Various organic and inorganic flame retardants and reducing agents as well as conductive fillers have been used to improve the temperature sensitivity of graphene oxide-based fire sensors. However, the effect of graphene oxide (GO) itself has sometimes been neglected by many researchers, since the synthesis of different structures of GO has received little attention. Here, we prepared two sensors, including the fire alarm based on GO synthesized at low temperatures (LGO) and the fire alarm based on GO synthesized by the conventional Hummers method (HGO). Compared with the HGO-based fire alarms, the improved temperature sensitivity of the LGO-based fire alarms is mainly due to the lower thermal decomposition temperature of the oxygen-containing functional groups in the LGO sheets. Interestingly, the LGO-based fire alarm has a response time of ~ 148 s at 150 °C, while the HGO does not respond. This finding will provide new ideas for the design of advanced GO-based fire alarm sensors. The low-temperature synthesized graphene oxide/nano-graphite (LGO/G) composite film can be applied as desirable smart fire early warning sensor material. [ABSTRACT FROM AUTHOR]

In this paper, performance of ZrO2 and CeO2 supported Ni catalysts on CO2 hydrogenation reaction was investigated in continuous flow reactor. The results revealed that Ni/ZrO2 catalyst exhibited superior performance compared to Ni/CeO2, with a CO2 conversion rate of 71.84%, a CH4 formation rate of 21.03 mmol g−1 h−1, and excellent reaction stability at 400 °C. And the activation energy of Ni/ZrO2 was lower than that of Ni/CeO2. N2 adsorption–desorption, SEM, XRD, XPS, CO2-TPD and O2-TPO analysis results suggest that Ni/ZrO2 is a multi-stage pore material, which has slit holes formed by the accumulation of sheet-like particles, as well as a superior dispersion of Ni on ZrO2. Moreover, Ni/ZrO2 shows higher alkalinity and remarkable resistance to carbon accumulation. DFT calculations demonstrated that CO2 can be more easily adsorbed on ZrO2 surface, and one O-terminus of CO2 is closer to top sites of ZrO2, which is favorable for electron transfer and promotes the activation of CO2. [ABSTRACT FROM AUTHOR]

As a typical mimic of natural enzymes, carbon-based peroxidase-like nanozymes have developed vigorously recent years, which are widely used in biomedical research. In this paper, borocarbonitride nanotubes (BCNNTs) were synthesized via assembly and pyrolysis of small organic molecules achieving boron (B) and nitrogen (N) co-doping in carbon nanotubes. As non-metallic nanozymes, BCNNTs exhibited high peroxidase-like activity and photothermal conversion capability, which were applied to bacterial colorimetric point-of-care testing (POCT) and in situ synergistic inactivation. By BCNNTs functionalized with specific antibody of Staphylococcus aureus, sensitive visible and rapid POCT of Staphylococcus aureus was accomplished. Right after the bacterial assay, the bacterial inactivation proceeded efficiently owing to both the catalytic decomposition of H2O2 and photothermal disinfection induced by BCNNT nanozymes, that eliminated bacterial contamination and further transmission without delay. The multifunctional BCNNT nanozymes possessed high peroxidase-like activity, photothermal property, good biocompatibility and stability, which had great potentials in food safety testing, environmental monitoring, and microbial control and therapy. [ABSTRACT FROM AUTHOR]

The impact of solute Al on the penetration of Cu atoms into the Fe grain boundary (GB) in the Fe–Cu embrittlement system was investigated by performing molecular dynamics simulations. Furthermore, the first principle density functional theory calculation was also employed to determine the binding properties and the electronic structure of GBs doped with solute atoms. The inhibition mechanism of liquid metal embrittlement (LME) cracks in the Fe–Cu system by Al was analyzed at the atomic scale by conducting simulations and calculations. The results show that the diffusion rate of Al along with the GB direction was much higher than that of Cu, and the preferential penetration and segregation of Al atoms acted as a barrier layer. Moreover, the addition of Al reduced the potential energy of Cu atoms, thus stabilizing their motion. These factors significantly inhibited the diffusion of Cu atoms along with the GB direction. The binding property of Fe GB doped with a high concentration of Cu was severely deteriorated, while the Al doping improved the atomic bonding. GBs with higher binding properties are less susceptible to fracture and groove under the application of tensile stress. This paper presents a novel perspective on the inhibition mechanism of LME cracks by doping a third component to inhibit the penetration of embrittlement atoms. [ABSTRACT FROM AUTHOR]

NiTi alloy has excellent corrosion resistance and wear resistance, and is an important protective coating being developed for marine equipment. In this paper, the crack and pore-free high-quality NiTi coatings were firstly synthesized in situ by extreme high-speed laser cladding (EHLA) technology under high temperature oxidation environment. The effects of laser power of EHLA on the temperature field, stress field and coating properties of NiTi coatings were studied by combining finite element calculation and experiments. The results show that a corrosion-resistant and wear-resistant TiO2 oxide film was generated in situ on the coating surface during EHLA process. Furthermore, the denser oxide film can be obtained by proper annealing treatment, and the wear resistance and corrosion resistance of the sample can be further improved. This provides a feasible fashion for EHLA to in situ synthesize wear-resistant and corrosion-resistant alloy coatings with low defects. [ABSTRACT FROM AUTHOR]

In this study, we utilized experiments and the Visco-plastic Self Consistent (VPSC) model to investigate the tensile mechanical behavior and texture evolution of the new weak texture Mg–1Al–0.5Mn–0.3Gd magnesium alloy, unlike the traditional strong basal texture. The result showed that the weak texture magnesium alloy exhibited good isotropic behavior during the tensile in various directions. In addition, we observed that it displayed similar macroscopic mechanical behavior and microscopic texture evolution rules. In particular, the increase in the prismatic < a > slip was significant in the early stages of plastic deformation, leading to a slightly higher flow stress along the rolling direction (RD) compared to the transverse direction (TD). In order to study the effect of {10–12} twinning on mechanical behavior and texture evolution, some scholars adopted inhibition of their activation for verification. However, in this paper, the effects of {10–12} twinning on mechanical behavior and texture evolution of magnesium alloys were verified by comparing only activating and only inhibiting {10–12} twinning, it was found that the activity of {10–12} twinning can significantly reduce the yield strength and strain hardening rate of the weak texture magnesium alloy during the tensile along TD. [ABSTRACT FROM AUTHOR]

Copper/steel composite is a kind of composite with excellent performance and broad application prospects. In this paper, the micro-morphology and structure of the interface of copper/steel composite prepared by the hot-dip casting were observed by scanning electron microscope and transmission electron microscope, and the formation mechanism of the interface area was explored. The results show that the hot-dip casting temperature has a great influence on the micro-structure and morphology of the copper/steel interface area. When the hot-dip casting temperature is lower than 1125 °C, the copper/steel interface area is basically in a straight line. Even if the hot-dip casting time is extended, the interface characteristics change little. At 1100 °C, the copper-rich phase precipitated at the interface area is the coherent precipitates of Cu and BCC-Fe, with the crystal orientation <110> and the diameter about 10 nm ~ 30 nm. When the hot-dip casting temperature reaches 1150 °C, the copper/steel interface area begins to appear new micro-morphology, and the range of new micro-morphology becomes larger and larger with the increase in the hot-dip casting temperature and the extension of the hot-dip casting time. At 1200 °C, the copper-rich phase precipitated at the interface is the coherent precipitates of FCC-Cu and FCC-Fe, with the crystal orientation <100> and the size similar to that at 1100 °C. In the process of the hot-dip casting, the formation of the copper/steel interface area experienced three stages: the co-temperature of copper/steel and the wetting of copper liquid on solid steel, the formation and transformation of the solid–liquid mixed layer between steel and copper liquid and the evolution stage of the liquid–solid mixed layer during cooling and solidification. This kind of interface zone with gradual structure tightly connects the steel matrix and solidified copper together, to form a copper/steel composite with strong bonding. [ABSTRACT FROM AUTHOR]

Due to the machining-induced residual stress while processing, the machining distortion of thin-walled 7050 aluminum alloy parts occurs easily, which greatly affects the pass rate of the products. Herein, electromagnetic coupling treatment (EMCT) was proposed to relieve the residual stress of 7050 aluminum alloy. It was found that EMCT had a significant effect on residual stress relief (13.3–89.7%). The energy input by EMCT promoted the movement of dislocation, resulting in the uniform distribution of microplastic strain, the release of stored elastic strain energy, and the residual stress relief, ultimately. A numerical simulation method to visualize the evolution of the electromagnetic field, the stress, and the strain in the materials was proposed to explain the causes of microplastic strain. Specimen #5 with the optimal EMCT processing parameter (1.5 T, 1.5 V) was considered to be the most effective for both residual stress relief and mechanical property enhancement, in which the residual stress decreased by 85.1% and the tensile strength increased by 8.3%. In this paper, it is proposed that EMCT can be used as an effective method to reduce the residual stress of 7050 aluminum alloy. Moreover, it has certain technical reference value for the study of residual stress relief of other thin-walled part materials. [ABSTRACT FROM AUTHOR]

In the past two decades, humidity actuators have received extensive attention from researchers due to their merits of simple stimulation, no pollution, programmable actuation behaviour, and simple structure. However, in order to perform more complex and difficult tasks, it is indispensable to enhance the response speed of the humidity actuators. Therefore, we mainly discuss the influence of materials and structure on the response speed of the actuators in this paper. In this review, the materials of the actuators include inorganic materials, polymers, biomaterials, hybrid materials, and structural materials. According to the structures, the actuators can be divided into monolayer film and multilayer film types. In addition, the applications of humidity-driven actuators in humidity detection, soft robot, self-power and medical equipment are introduced, providing a reference for the large-scale application of humidity actuators. Finally, this review also considers the practical challenges faced by humidity-driven actuators, summarizes how these challenges affect the potential applications of the actuators, and prospects for the future development trend of the actuators. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries, as a research hotspot, are expected to address the need for energy storage systems with high energy density. However, the slow reaction kinetics of polysulfides due to the loss of electrical contact of soluble polysulfides and further shuttle effect hinder the further progression of Li–S batteries. This paper reviews the recent efficient approach to remedy the above issues: active site construction in the electrode materials or separators. The active site construction includes the increasing surface area, inducing molecular and single-atom catalysts, inducing heteroatomic doping, vacancies, or functional group. The high specific surface area can provide more sites for loading sulfur and also the more active sites for adsorption. Many porous materials are designed to provide more transfer paths for ions. Molecular and single-atom catalysts use some catalysts such as Fe–N–C or single metal atoms in various matrixes, representing the high catalytic activity. Defects can improve the electronic conductivity to quicken lithium ions diffusion in electrode materials, but also render more active sites to enhance catalytic activity and adsorption of electrode materials, accelerating the conversion of long-chain polysulfides to the next short-chain polysulfides and final products Li2S2/Li2S. The common active site construction and characterization methods of diversiform materials, for example, carbon materials, metal oxides, metal sulfides, and some other metal-free materials, are reviewed in this paper. [ABSTRACT FROM AUTHOR]

Based on density functional theory, this paper uses first-principles methods to study the stability, electronic properties, anisotropy, thermodynamic properties, and optical properties of compound MB2 (M = V, Nb, Zr). The enthalpy of formation indicates that the compound MB2 is energy stable. Studying its electronic properties, it is concluded that the compound MB2 (M = V, Nb, Zr) has metallic properties from the band structure and density of states diagram. The analysis of the differential charge density shows that the binding force between B–M and M–M atoms is greater than that of B–B. The results of elastic performance research show that VB2, NbB2, and ZrB2 exhibit brittleness and are brittle materials. Moreover, VB2, NbB2, and ZrB2 also meet the mechanical stability standards. Research shows that the anisotropy of MB2 is: NbB2 > VB2 > ZrB2.The quasi-harmonic Debye model is used to study the thermodynamic properties of compound MB2 (M = V, Nb, Zr). We analyzed the change curve of heat capacity, volume, thermal expansion coefficient, and Debye temperature at 0–1600 K and 0–100GPa. According to the analysis of thermodynamic properties, MB2 also satisfies the thermal stability condition. Finally, this paper studies the absorption and reflection of light by MB2. It is found that absorption and reflection are relatively strong in the ultraviolet region. [ABSTRACT FROM AUTHOR]

In this paper, the chemical composition of 7Mo-alloyed super austenitic stainless steel was optimized and the principle of composition designing of Fe-24Cr-(22-x)Ni-7Mo-xCo (x = 0, 2, 4) alloys was discussed. Thermodynamic calculation, as well as microstructure observation, was carried out to investigate the precipitation behavior of Fe-24Cr-(22-x)Ni-7Mo-xCo alloys aged at 700–1100 °C. The results demonstrated that none of second phase was detected at 700 °C aging and at least three different types of precipitates, σ phase, χ phase and M23C6 were identified after aging at 800–1100 °C for 2 h. At all aging temperature, the intermetallic σ was determined as the dominant second phase. For alloys of 22Ni, 20Ni2Co and 18Ni4Co, the area fraction of precipitates increased first and then decreased with temperature increasing from 700 to 1100 °C. The 1000 °C was determined as the most sensitive temperature for this alloy. Furthermore, the area fractions of second phase of 20Ni2Co (x = 2) at all temperatures were lower than that of 22Ni (x = 0) and 18Ni4Co (x = 4). In addition, the characteristics of cellular precipitates growing have been disclosed in this paper. Compared with nickel-based alloy, the addition of cobalt did not affect the misfit between σ phase and austenite matrix, which is probably due to the high content of nitrogen in Fe-24Cr-(22-x)Ni-7Mo-xCo alloys. [ABSTRACT FROM AUTHOR]

To find a new type of sensing material with high sensitivity to acetone gas, in this paper, a first-principles method based on density functional theory was used to study the gas-sensing mechanism of perovskite-type ZnSnO3 to acetone. A hydrothermal method was used to prepare perovskite-type ZnSnO3, and perform a gas sensitivity test. Calculated results demonstrate that acetone molecules interacted strongly with the ZnSnO3(001) surface with pre-adsorbed O2− and O−, accompanied by charge transfer that can change the resistance of the material. This phenomenon provides the basis for using ZnSnO3 as an acetone gas-sensitive sensing material. The experimental results showed that the perovskite-type ZnSnO3 has a sheet structure with micro-holes on the surface, which can promote responsivity to acetone gas. The gas sensitivity test indicated the optimal operating temperature is 350 °C, the response/recovery time is 4 s/27 s. The sensitivities of the synthesized ZnSnO3 nanosheet that in this paper to 100 ppm and 10 ppm acetone gas are 125.444 and 8.37, respectively. In the five-week stability and repeatability test, the sensitivity to 10/100 ppm acetone of sheet-like ZnSnO3 sensor could still maintain at 89.64% and 94.74% of the first test result. This study provides theoretical guidance for the development of acetone gas sensors. [ABSTRACT FROM AUTHOR]

In the last years, a large number of new biocompatible materials for 3D printers have emerged. Due to their recent appearance and rapid growth, there is little information about their mechanical properties. The design and manufacturing of oral appliances made with 3D printing technologies require knowledge of the mechanical properties of the biocompatible material used to achieve optimal performance for each application. This paper focuses on analysing the mechanical behaviour of a wide range of biocompatible materials using different additive manufacturing technologies. To this end, tensile and bending tests on different types of recent biocompatible materials used with 3D printers were conducted to evaluate the influence of the material, 3D printing technology, and printing orientation on the fragile/ductile behaviour of the manufactured devices. A test bench was used to perform tensile tests according to ASTM D638 and bending tests according to ISO 178. The specimens were manufactured with nine different materials and five manufacturing technologies. Furthermore, specimens were created with different printing technologies, biocompatible materials, and printing orientations. The maximum allowable stress, rupture stress, flexural modulus, and deformation in each of the tested specimens were recorded. Results suggest that specimens manufactured with Stereolithography (SLA) and milling (polymethyl methacrylate PMMA) achieved high maximum allowable and rupture stress values. It was also observed that Polyjet printing and Selective Laser Sintering technologies led to load–displacement curves with low maximum stress and high deformation values. Specimens manufactured with Digital Light Processing technology showed intermediate and homogeneous performance. Finally, it was observed that the printing direction significantly influences the mechanical properties of the manufactured specimens in some cases. [ABSTRACT FROM AUTHOR]

In order to inhibit the corrosion of ADC12 aluminum alloy caused oxalic acid in engine coolant, corrosion inhibitor technology is usually used because of its simple operation, low cost, no impact on metal heat dissipation, and effectively suppressing metal corrosion at a lower concentration. In this paper, the corrosion inhibition, long-term and adsorption mechanisms of humic acid (HA) on ADC12 aluminum alloy were studied using electrochemical testing, surface analysis techniques, and theoretical calculations. The results showed that HA was a mixed corrosion inhibitor that followed the Langmuir adsorption model and belonged to physical chemical mixed adsorption. The corrosion inhibition efficiency of HA was the highest at a concentration of 1500 ppm and enhanced with the extension of soaking time. After soaking for 72 h, the corrosion inhibition efficiency of HA reached its maximum (92.7%), indicating that HA had a good long-term corrosion inhibition effect. HA had a high adsorption energy on the surface of ADC12 aluminum alloy, and HA molecules adsorbed on its surface through the carboxyl groups linked to N atom to form a protective corrosion inhibitor film, effectively inhibiting its corrosion. [ABSTRACT FROM AUTHOR]

In preparing flexible sensors, electrohydrodynamic inkjet printing technology is a commonly used method to print and pattern functional inks uniformly with high precision. This paper reviews the latest research results of functional inks for manufacturing flexible sensors using electrohydrodynamic inkjet printing (E-jet) technology. Firstly, the functional inks are categorized into metal nanomaterial inks, carbon material series inks, and organic polymer inks, as well as ceramic nanoparticle inks and metal oxide inks, and the processing of these functional inks in the fabrication of flexible sensors is discussed in detail, while the advantages and limitations of different types of functional inks are compared. Finally, the challenges facing the printing and manufacturing of flexible sensors by E-jet technology are discussed, and the future development prospects are envisioned to promote the further development and application of flexible sensors manufactured by E-jet technology. [ABSTRACT FROM AUTHOR]

In this paper, plasma arc welding (PAW) and plasma arc welding combined with gas tungsten arc welding (PAW + GTAW) were used to weld TC4 titanium alloy plate (thickness of 8 mm). The relationship between mechanical properties, corrosion resistance, phase composition, and microstructure of PAW welded joint (P) and PAW + GTAW welded joint (P + G) was compared. Tensile test and microhardness results show that P + G welded joints exhibit superior mechanical properties compared to P welded joints. The polarization curves and EIS results of both P and P + G samples were compared. The surface morphology of the samples was evaluated, and the potential corrosion mechanism of P and P + G samples was provided. The research results reveal that the PAW + GTAW welding has positively affected the corrosion performance of TC4 alloy welded joints. The improved corrosion resistance of welded joints is associated with a low β/α phase volume ratio, small grain size, and HAGB content. [ABSTRACT FROM AUTHOR]

In this paper, silver plating of PS microspheres using chemical plating method to prepare Ag@PS composite microspheres, the purpose is to achieve good absorbing performance. The phase composition, microstructure, dielectric, and absorbing performance of the Ag@PS microspheres with different silver contents are analyzed. The results show that the augment in silver content can make the coating of Ag@PS composite microspheres denser. When the silver content augments from 10 to 25%, ε′ augments from 11.06–13.66 to 8.85–20.84, and ε″ augments from 2.55–5.01 to 10.67–20.4, so the dielectric properties are improved. To further improve the absorption performance, Ag@PS composite microspheres are combined with a frequency-selective surfaces (FSS). When c = 18.5 mm, A = 4.4 mm or 4.6 mm, and H = 3.0 mm, the RL of the Ag@PS composite microsphere in the 8.2–12.4 GHz is less than − 10 dB. Therefore, the addition of FSS is of great help in improving the absorbing property of Ag@PS microspheres. [ABSTRACT FROM AUTHOR]

The aerospace industry requires a reliable solder with a melting point of about 240 °C that does not produce tin whiskers. The Pb–16Sn–7.5Sb-based solders, with a melting point of about 240 °C, would be the candidate solders. This paper studied the microstructure and shear strength of the Pb–16Sn–7.5Sb–xAg/Cu solder joints. The Cu3Sn formed at the interface of Pb–16Sn–7.5Sb–xAg/Cu after soldering at 260 °C. The thickness of Cu3Sn IMC is proportional to the square root of time until the SbSn phase in the solder is exhausted. Adequate Ag addition in Pb–16Sn–7.5Sb solder increases the activation energy of Cu3Sn, inhibiting the rapid growth of Cu3Sn. Therefore, after soldering for 5 min, the thickness of Cu3Sn layer in Pb–16Sn–7.5Sb/Cu solder joint is 2.2 μm, which is reduced to 1.2 μm in Pb–16Sn–7.5Sb–1Ag/Cu solder joint. The shear strength of the solder joint increases with the thickness of the Cu3Sn layer when the thickness of the Cu3Sn layer is below 1.2 μm, then decreases when the Cu3Sn layer is too thick. The solder joint, with a thin and flat Cu3Sn IMC layer, shows high shear strength. After soldering for 5 min, the shear strength of the Pb–16Sn–7.5Sb–1Ag/Cu solder joint achieves 32 MPa, about 60% higher than the Pb–16Sn–7.5Sb/Cu joint. [ABSTRACT FROM AUTHOR]

Lamellar heterostructures containing gallium nitride (GaN) have excellent photoelectric properties and also play an important role in lighting, the quantum field, and other fields. Exploring the nanoscale processing of lamellar heterostructure GaN is crucial to the manufacturing of high-performance devices based on heterostructure GaN. In this paper, the microstructure, surface morphology, dislocation length, Von Mises stress, temperature, number of removed atoms, and surface roughness of lamellar heterostructure GaN were systematically investigated using molecular dynamics simulation. The results show the presence of a large number of phase transitions, dislocation growth, and stress during nanogrinding; moreover, temperature also increases during this process. Furthermore, increasing the grinding speed will inhibit dislocation growth; increasing the grinding depth will cause extensive damage to the material surface. Therefore, this study presents a theoretical basis for the processing of lamellar heterostructure GaN. [ABSTRACT FROM AUTHOR]

Graphene, due to its unique zero-bandgap, single-layer structure, and outstanding properties, has attracted more than a decade of research interests. In the upstream of graphene research, laser manufacturing with high-energy density, non-contact nature, and efficiency has been extensively investigated by numerous scholars for the purpose of fabricating or manipulating graphene. Downstream in the application domain, graphene demonstrates substantial practical applications across sectors such as energy, heat dissipation, medicine, and sensors. While there exist reviews on both the upstream synthesis and downstream applications of graphene, a comprehensive overview specifically focusing on the interaction between lasers and graphene and their implications in the sensing field is currently lacking. This paper addresses this gap by summarizing various methods of preparing graphene such as laser direct writing, laser-assisted chemical vapor deposition, and laser reduction of graphene oxide and reviews the applications of these methods in the field of sensors. This review presents an outlook on the promising future of graphene-based sensing technology. [ABSTRACT FROM AUTHOR]

Acylhydrazone bonds can participate in dynamic exchange reactions under acid-stimulated conditions, and disulfide bonds can participate in dynamic exchange reactions under thermally stimulated conditions. It is of great significance to prepare epoxy vitrimer that can rapidly self-repair under acid and thermal stimulation conditions. In this paper, vanillin was used as raw material, and monomer (VAN-AD) containing acylhydrazone bond was synthesized by reaction with adipic dihydrazide. Then, VAN-AD and 4-aminophenyl disulfide (SS) were cured together with glycerol triglycidyl ether to prepare an epoxy vitrimer with acylhydrazone and disulfide dual dynamic covalent bonds. Where VAN-AD provides some of the flexible chain segments and acylhydrazone bonds and SS provides the aromatic phenyl and disulfide bonds. The material was prepared in a simple process and under mild condition, and the properties of the material were optimized by changing the ratio of VAN-AD to SS. The Tg of the material was 50 °C when the ratio of SS was the highest, the thermal stability was enhanced with the increase of the ratio of SS, and the maximum tensile strength up to 50.9 MPa, and the material can be completely degraded by DMF with 5% HCl. It is worth noting that the material shows rapid self-healing properties under acid-heat conditions, self-healing rates up to 97.37%, and the tensile strength can reach 26 MPa after repair. The material can be successfully remodeled by hot pressing for 1 h at 140 °C and 10 MPa. [ABSTRACT FROM AUTHOR]

Modification of the surfaces of polymeric scaffolds is often required to make the material suitable for specific tissue engineering applications. Physico-chemical properties of scaffolds can be altered using various methods, such as plasma treatment, laser processing, chemical modifications, grafting with nanoparticles, or surface coating. In this paper physico-chemical modification of polycaprolactone (PCL) surface fibers was performed by exposing PCL samples to simultaneous soft X-ray/extreme ultraviolet (SXR/EUV) radiation and low-temperature, SXR/EUV-induced, nitrogen, and oxygen plasmas. The physical and chemical changes on modified PCL surfaces were examined using a scanning electron microscope and X-ray photoelectron spectroscopy, respectively. The effects of physico-chemical scaffold surface changes were verified with biological tests, i.e., MTT assay and immunofluorescence on murine osteoblast cell line (7F2). It was found that exposure of scaffolds to ionizing radiation and low-temperature plasmas induced strong chemical changes on their surface, i.e., appearance of various new chemical groups. Also, smoothing of the surface of PCL fibers, i.e., disappearance or significant reduction of the size of micropores on their fibers was also observed. Increased viability and adhesion of 7F2 osteoblasts on modified PCL samples after 24 h cell culture compared to non-treated PCL was also confirmed. [ABSTRACT FROM AUTHOR]

CeO2 has high elastic modulus and thermal stability, as well as good surface effects, making it ideal as a reinforcement for aluminum matrix composites. In this paper, the interfacial relationships between Al and CeO2 was studied by first-principles calculation, and the nucleation mechanism of aluminum matrix growth on CeO2 substrate was discussed. First, the Al/CeO2 interface matching crystal surface was identified as the Al(111)/CeO2(111) interface. Then, the surface work function was calculated for all surfaces constituting the Al(111)/CeO2(111) interface, and the results showed that the Al(111) loses charge more easily than CeO2(111). Subsequently, the interface energy and work of adhesion of the Al(111)/CeO2(111) interface were calculated, and the results showed that the interface energy of O1–Al was the smallest (0.07 J/m2), the work of adhesion of O2 interface energy of O1–Al was the smallest (0.07 J/m2), the work of adhesion of O2–Al was the largest (9.36 J/m2)Al was the largest (9.36 J/m2). Finally, the combined properties of the Al(111)/CeO2(111) interface were analyzed by the electronic properties at the interface, and the results showed that The Al(111)/CeO2(111) interface is a mixture of ionic and covalent bonds. Therefore, the calculated results confirm that the effectiveness of CeO2 as a heterogeneous nucleation substrate for Al. This study provides a theoretical basis for the nucleation mechanism of the heterogeneous nucleation interface between CeO2 and aluminum matrix. [ABSTRACT FROM AUTHOR]

Microalloying is an effective method to regulate the mechanical properties of deposited metal. In this paper, ERNiMo-2 deposited metals with different Si content were prepared. The influence of Si element and thermal exposure treatment on microstructure evolution and high-temperature mechanical properties of ERNiMo-2 deposited metal was investigated. The results show that the size and distribution density of eutectic carbides increased significantly with the addition of Si while more M2C nano-sized carbide particles were observed around the eutectic carbide. Thermal exposure treatment hardly influence the size and distribution of the eutectic carbides, but significantly promote the formation of nano-sized carbide particles. The tensile results at 700 °C show that the density of precipitated carbides and the yield strength of deposited metal increased significantly with the increase of Si content. The thermal exposure would soften the deposited metal because of the obvious decrease of dislocation density and the unobvious strengthening effect from nano-sized carbide particles. The research results are significant for optimizing the composition of ERNiMo-2 welding wire and improving the mechanical performance of welded components. [ABSTRACT FROM AUTHOR]

The ordered γ′-(Ni, Cu)3Al is a crucial strengthening phase that improves the high-temperature resistance of Cu-based alloys, so it is important to predict the kinetic evolution of the composition and microstructure of the phase for high-temperature applications. Herein, this paper discusses the temporal evolution of the composition and coarsening of the γ′ phase in a model ternary Cu50Ni37.5Al12.5 (at%) alloy during isothermal aging at 600, 700, 800, and 900 °C for 1–36 h. It is found that the γ′ phase composition evolves linearly toward a binary γ′ phase as the aging time increases during the process of aging at 800 and 900 °C, which cannot be predicted by the ternary phase diagrams alone. Meanwhile, through the utilization of the aforementioned linear law, the γ phase composition can be predicted at a given temperature within the alloy by determining the volume fraction of the γ′ phase. Additionally, the activation energy for coarsening decreases, and the coarsening rate of the γ′ phase increases owing to the higher diffusion rate of Cu at high temperatures. The addition of microalloying elements with strong enthalpic interactions is beneficial for reinforcing the structural stability of the γ′ phase. This work provides a simple method for the compositional analysis and performance prediction of Cu–Ni–Al alloys at elevated temperatures and sheds light on the subsequent compositional design and optimization of Cu-based high-temperature alloys. [ABSTRACT FROM AUTHOR]

In this paper, the initiation of interfacial damage in SnPb alloy was investigated at the atomic scale through molecular dynamics simulations. The focus was primarily on the structural stability of the Sn/Pb interface with different orientations, the formation energies of vacancies in different Sn/Pb interfaces, and the short-range interactions between dislocations and the Sn/Pb interface. The results revealed a correlation between the interfacial energies of all four Sn/Pb interfaces and the disorder of Sn and Pb atoms near the interface, where a more regular atomic arrangement resulted in lower interfacial energy. The vacancy formation energies near the Sn/Pb interfaces varied depending on the interface type, although all types contributed to reducing these energies. Furthermore, the Sn/Pb interface acts as a barrier to dislocations in both Pb and β-Sn phases, while leading to the cross-slip of screw dislocations in the Pb phase. Edge dislocations in the β-Sn phase induce significant strain localization at the interface, initiating interfacial damage and crack nucleation. These findings are highly significant for understanding damage mechanisms in SnPb alloy and advancing high-performance solder development. [ABSTRACT FROM AUTHOR]

In this paper, B2-FeAl based metal-intermetallic laminate (MIL) composites with and without NiTi shape memory alloy fibers were fabricated by two-step vacuum hot pressing combined with "multi-thin foils" stacking configuration. The microstructure of the composites were studied by scanning electron microscopy and electron backscattered diffraction. Compressive mechanical properties of the composites under quasi-static conditions and high strain rates are investigated via an Instron 5500R load frame and a Split Hopkinson Pressure Bar, respectively. Quasi-static compression stress–strain curves under the strain rate of 10–3/s at 20 °C and dynamic stress–strain curves under the strain rates of 1500/s and 2500/s at 0 °C, 20 °C and 80 °C were obtained, and fracture behavior of the composites were analyzed. The experimental results indicated that the strengths of the composites decreased unexpectedly under high strain rates compared to that under quasi-static condition whether or not NiTi fibers were introduced. Partial phase transition from austenite to ferrite occurred in metal layer during either quasi-static or dynamic compression process. During quasi-static compression, deformation was mainly concentrated in the metal layer. By contrast, metal layers and intermetallic layers exhibit similar deformation capacity during the dynamic loading process, thus, cracks easily appeared in intermetallic layers, causing the premature failure of the composites. Even so, B2-FeAl based MIL composites still possess the best dynamic mechanical properties in the MIL composites family to date. The strength of NiTi fiber reinforced composite is basically higher than that of the counterpart without NiTi fibers at each testing temperature, and fewer microcracks appeared in the intermetallic layer of the former. The reinforcing mechanism was discussed in details. [ABSTRACT FROM AUTHOR]

Lightweight strategy is essential for the development of transportation vehicles and aerospace industries. As a type of lightweight material, high-strength aluminum alloys are limited to service temperatures below 200 °C due to the rapid coarsening of strengthening nano-precipitates, which cannot satisfy the increasing demands of practical applications. High-temperature applications beyond 250 °C become the bottle-neck problem of Al alloys. In this paper, we review existing literature on the improvement of high-temperature performance of aluminum alloys by stabilizing nano-precipitates. On the basis of atomic-scale microstructure regulation, several design strategies, such as interface segregation, co-precipitation, core/shell structure, and interstitial ordering, have been proposed, resulting in the development of a number of heat-resistant Al alloys for use at 300–400 °C. Moreover, the fundamental theories of solid-state phase transformation, especially precipitation aging and coarsening, are correspondingly advanced on the frontiers of science. [ABSTRACT FROM AUTHOR]

With development of present energy-saving society, lightweight and green development in the automotive and aerospace industries have put forward urgent demands for heat-resistant cast aluminum alloys. Present cast aluminum alloys are of lightweight and have excellent mechanical properties when serving in ambient environment. However, when serving at temperatures of 200–300 ℃ or even higher, the alloys inevitably soften and the high-temperature mechanical properties decline rapidly, hardly meeting the requirements for high-performance equipments. This paper summarizes the development process of classic heat-resistant aluminum alloys, especially the microstructural characteristics of heat-resistant cast aluminum alloys in the past decade, and reviews the current microstructure tuning strategies of heat-resistant aluminum alloys from the aspects of intrinsic heat resistance of the second phases, phase interface modification, diffusion-controlled phase transition, grain boundary stabilization and composite material design. Finally, we propose the prospects for the future development of heat-resistant aluminum alloys. [ABSTRACT FROM AUTHOR]

The application of cast magnesium alloy components is increasing in recent years, especially in the new energy automotive and transportation industries. As component application scenarios become increasingly complex, the performance of cast magnesium alloys needs to be further enhanced. Significant progress has been made in casting technology and the design of cast magnesium alloys. In addition, some new application of cast magnesium alloy components is also developed recently. This paper provides an overview of the current status of high-performance cast magnesium alloys, including the alloy design, casting techniques, control of casting defects, and applications of cast magnesium alloys. Based on the issues and challenges identified here, some future research directions on cast magnesium alloys are suggested. [ABSTRACT FROM AUTHOR]

Additive manufactured (AM) technology as a novel fabrication method provides an unprecedented ability to completely design parts freely and breaks through the limitations of traditional approaches to manufacture complex structural parts. Meanwhile, magnesium (Mg) and its alloys as the lightest structural metal materials are among the most promising materials and always catch research attention. The combination of AM and Mg alloys would certainly provide new impetus for the practical application of Mg alloys. Although the research of AM-Mg alloys has made some progress and some AM-Mg alloys with impressive properties have been developed, there are still some intractable issues that hinder the further development and application of AM-Mg alloys. This paper provides a short review of the recent progress achieved in AM-Mg alloys, with a specific focus on selective laser melting (SLM), wire-arc additive manufacturing (WAAM), and solid-state AM technologies including additive friction stir (AFS) and friction stir additive manufacturing (FSAM). The defects, microstructure, and mechanical properties of AM-Mg products are summarized based on the type of AM technique. Besides, the effect of post-treatment on macro- and microstructures of SLM-Mg and WAAM-Mg alloys is also summarized. In addition, further perspectives and potential research directions are proposed for the development of AM-Mg alloys. This review could provide insights into the development of AM-Mg alloys with enhanced mechanical properties and promote the application of AM-Mg alloys. [ABSTRACT FROM AUTHOR]

Carbon materials have excellent thermophysical properties, and different dimensions of carbon materials are attractive candidates for enhancing high-performance aluminum matrix composites for thermal management. This paper reviews the preparation processes of carbon/aluminum composite materials in various dimensions and summarizes the main factors affecting the thermal conductivity of carbon/aluminum composites from the perspectives of metal matrix, reinforcement, and interface. Finally, we summarize the experimental progress of interfacial modification of different carbon/aluminum composites and put forward the future research direction in this field. [ABSTRACT FROM AUTHOR]