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Springback is one of the most interesting mechanical phenomena for bent metals after stress/strain release. Most previous studies investigate the springback behaviors of metals only with low bending angles; rarely do studies investigate these metals under large bending angles. Here, we investigated the springback behaviors of twin-structured Ni nanowires (NWs) at various bending angles through in-situ experiments and molecular dynamics (MD) simulations. We discovered that the springback angle and deformation mode of twin-structured Ni NWs can be divided into three stages, which have rarely been reported. The results revealed that, as the maximum bending angle increases, the plasticity of the NWs transfers from partial dislocations parallel to the twin boundaries (TBs) to extended and full dislocations on multiple slip systems, and then to grain boundary (GB) generation. Unlike previous studies which suggested that deformation-induced dislocations and GBs are irreversible, our results show that these defects are reversible upon unloading. The different recoverable abilities of these deformation-induced defects lead to a bending-angle-dependent springback phenomenon. [Display omitted] • Metallic nanowires exhibit notable springback under bending and unbending stress. • Twin-structured Ni nanowires show ultra-large springback at high bending angles. • Three stages of springback behavior emerge as bending angles increase beyond 30°. • Molecular dynamics simulations reveal how bending-induced defects affect recoverability. [ABSTRACT FROM AUTHOR]

A nanostructured solid solution of SnSe 1−x S x with x = 0.5 synthesized by mechanical alloying and its structural stability was studied by calorimetric measurements under high pressure conditions. The structural behavior under pressure was investigated using angle-dispersive X-ray diffraction in a synchrotron source and first-principles density functional theory (DFT) calculations. The variations of the cell structure phases were described by a third-order Birch–Murnaghan equation of state. Image 1 • The nanostructured SnSSe was obtained by mechanical alloying and submitted to high-pressures. • The unexpected isotropic unit cell behavior was observed. • An orthorhombic - orthorhombic phase transition happens around 14 GPa. [ABSTRACT FROM AUTHOR]

Due to the high theoretical capacity, metal selenides are considered to be promising materials for energy storage. Unfortunately, their practical use is still hampered by their flat electronic conductivity, large volume change and poor ion transport kinetics. In this work, a general synthesis method is presented for the preparation of metal selenides embedded in N-doped carbon nanofibers with in-situ grown carbon nanotubes (CNTs) on the surface (MSe 2 @NCF/CNTs, M=Co, Ni, Fe) as binder-free anodes for sodium-ion batteries. Metal precursors can be used as catalysts and as active materials after selenization treatment. The metal selenides are dispersed in the carbon nanofibers and CNTs, which effectively prevents agglomeration of the particles. The in-situ grown CNTs are strongly coupled to the surface of nanofibers, which improves the electrical conductivity, allows for efficient electrolyte infiltration and buffers the volume expansion during the charge/discharge processes. As a result, CoSe 2 @NCF/CNTs achieves extremely high reversible capacity, stable cycling stability (441.2 mAh g−1 after 1000 cycles at 200 mA g−1), and excellent rate properties (375.4 mAh g−1 at 2 A g−1) when used as binder-free anodes for sodium-ion batteries. The fast charge transport and Na+ diffusion rates, as well as a pseudocapacitance Na+ storage mechanism, are revealed by kinetic analysis. This synthetic approach is extendable to assembling CNTs in-situ on other substrates for advanced energy storage systems. [Display omitted] • A method for growing CNTs in-situ is developed. • Metal precursors can be used as catalyst and active materials after treatment. • The method is universal and can be extended to other substrates. • MSe 2 @NCF/CNTs show excellent performance as binder-free anodes for SIBs. • The Na+ storage performance is evidenced by kinetic analysis. [ABSTRACT FROM AUTHOR]

Abstract A high temperature interface deformation test system was built for failure analysis of YSZ thermal barrier coatings during 1100 °C thermal shock and thermal cycles. The strain distribution and evolution law near the thermal barrier coatings interface were in-situ real-time observed and measured by the developed high temperature interface deformation test system. After repeated thermal shock, crack initiation vertical to the interface will periodically come into being at the location of strain concentration area near the ceramic top coat surface. These cracks extend from the top coat surface to the interface, of which the period of crack agrees well with the theoretical analysis. EDS analysis indicate that the inter-diffusion lead to an influential tensile strain in the interface area and bond coat layer. Tensile tests indicate that with increase of thermal shock times, not only the bonding strength of the TBCs decreases, but also the tensile failure location change significantly. Highlights • In-situ real-time deformation/strain measurement near TBCs interface. • Strain evolution law of TBCs interface during heating and cooling stage. • Failure behavior and failure rule near TBCs interface during thermal shock. [ABSTRACT FROM AUTHOR]

Abstract γ-phase based titanium aluminide has continuously been attractive because of its potential application in modern light-weight, high-temperature turbines, such as aircraft engines. However, it suffers from its poor plasticity and during manufacturing and processing. In recent years, wire-arc additive manufacturing process has been proved feasible of fabricating γ-phase based titanium aluminide structures with full density and relatively lower cost compared to traditional powder metallurgy processing. In the present research, the temperature process of a single-pass deposition process during the additive manufacturing was simulated as a linear heating (up to 1623 K) and cooling process in a vacuumed furnace, and in-situ investigated using neutron diffraction. As a result, compared to the initial as-fabricated state, the volume fraction of α 2 -phase increased by 2.54% after the heat treatment. Crystallographic aspects, specifically the α/α 2 ↔ γ phase transformation and lattice evolutions of γ-phase are discussed in detail. According to the results obtained, the γ → α 2 transition temperature in the present binary alloy is 1393 K, which largely deviates from earlier results collected from γ-phase based titanium aluminides with Nb addition. Also, the lattice evolutions of γ-phase in a function of time/temperature are linear fitted and responses of lattice strains (a , c axis and volumetric) to temperature are calculated. Highlights • Thermal phase evolutions in Ti-45Al alloy is recorded in-situ with neutrons. • α/α 2 ↔ γ phase transformation recorded by neutron is 1393 K. • Responses of γ-phase lattice strains to temperature are calculated. [ABSTRACT FROM AUTHOR]

Abstract This study was conducted to obtain a type of aluminum matrix composites exhibiting a good strength and certain ductility at high temperature. The 25 vol% TiO 2 -75 vol%2024 Al systems were selected to fabricate the (Al 3 Ti+Al 2 O 3)/2024 Al composites with residual ∼32 vol% Al matrix through powder metallurgy. The (Al 3 Ti+Al 2 O 3)/2024 Al exhibits a good strength and certain ductility at high temperature as in the design. The microstructure of (Al 3 Ti+Al 2 O 3)/2024 Al composites was investigated. It was discovered that the in-situ Al 3 Ti reinforcement was in coarse block-shaped particles of approximately 6.9 μm in size and the Al-Al 3 Ti interface was clean. The Al 2 O 3 particles were in the nano-scale and distributed in the Al matrix in a cluster form. The high temperature compression testing of the composites was conducted at the temperatures of 573 K, 623 K, 673 K, 723 K and 773 K with the strain rate of 10−3 ∼ 0.42 s−1. The results demonstrated that the composites exhibited higher strength at the same high temperature than the other Al matrix composites with a similar volume fraction. The massive Al 3 Ti and Al 2 O 3 phases played a load bearing role at high temperatures. The residual ∼32 vol% Al matrix led the composites to acquire certain ductility. Graphical abstract Image 1 Highlights • In-situ (Al 2 O 3 +nano-Al 2 O 3)/2024 Al composites were produced by TiO 2 and 2024 Al. • The composites exhibited high strength properties between 573 K-773 K. • The composites exhibited a certain ductility for residual ∼32 vol% Al matrix. [ABSTRACT FROM AUTHOR]

In this paper, in-situ submicron TiB 2 particles (2.5 wt.%) reinforced AZ91 matrix composites are processed by the master alloy method combined with an optimized SHS technique. The effect of TiB 2 particles on the microstructure, ageing behavior and mechanical properties of Mg matrix composites is investigated. The results reveal that only TiB 2 phase is in-situ formed in the Al-TiB 2 master alloy and exhibits the size distribution of 100 nm–700 nm. Compared with the unreinforced AZ91 alloy, the grain size and morphology of Mg 17 Al 12 phase in as-cast composites are much refined. The ageing process of composites is accelerated and the peak-aged time of composites decreases from 42 h to 22 h significantly with the introduction of TiB 2 particles. Large numbers of fine Mg 17 Al 12 in composites preferentially precipitate at grain boundaries and near TiB 2 particles regions. In addition, the hardness, yield strength, ultimate tensile strength and elongation of as-cast composites are improved by 16.1%, 53.0%, 26.3% and 25.6%, respectively. After T6 heat treatment, the strength of composites is increased further due to large amounts of submicron Mg 17 Al 12 phase, and the age hardening efficiency of composites is higher than that of AZ91 alloy. [ABSTRACT FROM AUTHOR]

One-pot in-situ method was one of crucial industrial techniques to construct heterojunctions, while some intermediate reaction mechanisms of photocatalysts in this procedure were not specific enough. Herein, a new intermediate products driven one-pot in-situ method was investigated for construction of BiOCl/WO 3 that applied in photocatalytic water splitting. According to some characterizations, the hydrochloric acid and water were recognized as important intermediates controlling on growth of BiOCl/WO 3 heterojunction. Under significant effects of Z-scheme structure and internal electric fields, the BiOCl/WO 3 showed enlarged light absorption and enhanced photo-induced carriers separation ability that its O 2 and H 2 evolution rates were improved effectively, in which the optimal photocatalytic O 2 (994.5 µmol/g∙h) and H 2 evolution activity (83.4 µmol/g∙h) were ∼ 2.5 and 4.5 times higher than that of the single BiOCl, respectively. Due to compact interfacial connection between BiOCl and WO 3 after in-situ synthesis, the heterojunction showed a high stability and recyclability for potential industrial applications. We believe that the facile synthetic method was essential for more researches on heterojunction materials and their industrial applications. [Display omitted] • A new intermediate products driven one-pot in-situ method was investigated. • A Z-scheme BiOCl/WO 3 heterojunction was effectively constructed. • The light absorption and photo-electrons transfer ability of BiOCl/WO 3 enhanced. • The BiOCl/WO 3 exhibited enhanced photocatalytic H 2 and O 2 evolution rates. • The facile synthetic technique was potential for industrial applications. [ABSTRACT FROM AUTHOR]

Near β titanium alloys with excellent properties are increasingly preferred for aerospace structural applications, among which the alloys with in-situ precipitated silicides are especially intriguing. Here in this work, based on the low-density, high strength and comparable thermal expansion coefficient to titanium of Ti 5 Si 3 , a novel high-strength titanium alloy with in-situ Ti 5 Si 3 precipitate has been developed and further heat treated to regulate the microstructure and properties. The results revealed that the in-situ precipitates including both the needle-shaped secondary α -Ti in the β -Ti matrix and the spherical Ti 5 Si 3 in proximity of α / β phase boundaries contributed to the superior strength and ductility for the alloy after the optimal heat treatment at 800 °C for 40 min. Specifically, it exhibited an ultimate strength of 944.1 MPa and an elongation value of 12.5% with excellent work hardening behavior and ductile fractography including abundant tear edges and dimples. This work validated the strategy of introducing in-situ titanium silicides to stabilize the microstructure and enhance work hardening for developing novel titanium alloys with adjustable and superior properties. • A novel near β titanium alloy with in-situ precipitate of Ti 5 Si 3 was developed. • The σ f and ε of the H3 sample achieved high values of 944.1 MPa and 12.5%. • The work hardening rate and strain hardening exponent during tension were analyzed. • In-situ needle-shaped α -Ti and spherical Ti 5 Si 3 led to the superior performances. [ABSTRACT FROM AUTHOR]

In order to evaluate the applicability of metal-filled carbon nanotubes, it is crucial to understand their behaviour in the presence of electric currents. In this work we exploit the significant advantages of combining in situ experiments with scanning transmission electron microscopy in annular dark-field mode and related analytical techniques to gain further insights into the electrical transport induced transformations in Fe-filled P,N-doped multi-wall carbon nanotubes. With these synergistic analysis techniques, we could monitor in real time the dynamical effects that take place in the carbon nanotubes and their Fe filling as a consequence of the passing of an electric current and subsequent Joule heating. A detailed analysis of the formation, evolution and composition of intermediate phases has been possible employing in situ experiments with transmission electron microscopy, scanning-transmission electron microscopy and analysis techniques. We show that a multistage process occurs in which the Fe filling reacts with nitrogen to form an intermediate alloy phase, which then decomposes. The presence of high concentrations of nitrogen within the inner channel of the tube is found to be crucial to this process. [ABSTRACT FROM AUTHOR]

A novel high-vanadium based hard composite coating was synthesized from premixed powders (V, Cr, Mo, Ti, Nb) on ductile iron (DI) substrate via atmospheric plasma beam surface alloying process. The graded coating can be divided into three distinct zones: upper alloyed zone (AZ) rich with spherical primary and eutectic submicron carbides, middle melted zone (MZ) with fine white iron structure embedded with high-carbon martensite and lower heat affected zone (HAZ) where martensite/ledeburite double shells were substantially formed. Spherical or bulk-like primary carbides with diameter <1 μm in the middle AZ were formed via in-situ reactions between alloy powders and graphites in DI, presenting a refined microstructure similar to high vanadium-containing tool steel. Microstructural characterizations indicate the carbides are chiefly globular MC-type particles mixed with hard-phases such as M 2 C, M 7 C 3 , M 23 C 6 , and martensite. EDS mappings show that MCs (M = V, Ti, Nb) form together while M 2 C-type carbides tend to locate at the grain boundary or around the MC particles. Ti and Nb occur in the MC-type primary carbides besides V and TiC even features as nuclei. Though dependent upon the size, shape, type and distribution of carbides, the microhardness was obviously enhanced in both AZ and MZ. [ABSTRACT FROM AUTHOR]

This study reports the effect of phase distribution on crack propagation in a dual phase AlCoCrFeNi high entropy alloy (HEA) under tensile loading. The alloy is characterized by the presence of a brittle disordered BCC phase that can be toughened by precipitation of a ductile FCC phase during homogenization heat treatment. The stress and strain partitioning between the two phases is of paramount importance to determine the mechanical response of this alloy. The as-cast alloy was subjected to homogenization at 1273 K for 6 h to prevent the formation of detrimental sigma phases and to precipitate the ductile FCC phase. In-situ tensile test in a scanning electron microscope with an electron backscatter diffraction facility was carried out to understand the micro-mechanisms of deformation of the alloy. Precipitation of the FCC phase at the BCC grain boundaries reflected the effect of the FCC phase on crack deflection and branching during propagation. The strain partitioning between the two phases and the evolution of misorientation distribution was investigated. It is observed that the presence of ductile FCC high entropy phase can impart good room temperature ductility to the brittle BCC phase. As there are very few investigations performed on the dual phase HEAs, a proper microstructural design can be be achieved and can be utilized to toughen the brittle HEAs. [ABSTRACT FROM AUTHOR]

Li 3 FeN 2 displays rich and complex structural response upon electrochemical oxidation/reduction. During the first lithium deintercalation, 4 voltage plateaus corresponding to a total charge transfer of 1.14 e − per iron cation take place. Combining operando Mössbauer spectroscopy and X-ray diffraction, we evidence 3 biphasic reactions involving four orthorhombic phases. Despite a derived anti-fluorine type structure, Li 3 FeN 2 oxidation induces a unidirectional contraction along b axis. Mössbauer spectroscopy established a partial iron oxidation (∼90%). Therefore the participation of the nitrogen network as additional redox center is suggested to explain the observed extra capacity. Moreover, an unexpected low spin to high spin crossover took place for ∼10% of Fe 3+ during the oxidation of Li 3 FeN 2 . Based on the cationic mixing recently demonstrated and the anisotropic structural response, two possible explanations are discussed; (i) a significant deformation of 8 g lithium sites, which contain ∼10% of iron cations or (ii) migration of these cations into the neighboring octahedron 8 j . This High Spin Fe +3 contribution remains almost constant until the end of the oxidation. [ABSTRACT FROM AUTHOR]

In this study, a Cu matrix composite is synthesized reinforced by an in-situ three-dimensional graphene network (3D-GN) grown through chemical vapor deposition (CVD). Nano Cu powders and polymethylmethacrylate (PMMA) are employed as matrix and carbon source respectively. PMMA is dispersed on Cu powders after ball-milling. During the CVD process, carbon atoms from pyrolyzed PMMA diffuse and precipitate on Cu powders. By inheriting the morphology of Cu powders, carbon atoms build a 3D-GN in-situ on Cu powders. A bulk 3D graphene/composite with 0.5 wt% graphene is obtained by vacuum hot-press sintering. The favorable interfaces that crucial to the achievement of exceptional mechanical properties of a bulk composite are verified by TEM and SEM characterizations. A yield strength and tensile strength of 290 MPa and 308 MPa respectively are achieved of the composite. The structure of 3D-GN is well preserved in the bulk composite. We demonstrate that the 3D-GN serves as an effective obstacle to the propagation of dislocations by TEM further. [ABSTRACT FROM AUTHOR]

The in-situ TiC and TiB reinforced titanium matrix composites were fabricated by laser powder fusion (LPBF) of B 4 C/Ti powder mixture, and the influence of scan strategy on the microstructure morphologies and corrosion resistance in NaCl solution were also investigated. The experimental results reveal that anodic dissolution of titanium matrix is accelerated and thus facilitates the formation of the TiO 2 passive layer on the surface of the LPBF-produced (TiC+TiB)/Ti composites owing to the in-situ TiC and TiB reinforcements acting as micro-cathode in NaCl aqueous solution. The island scan strategy tends to result in a net-shaped distribution of TiC and TiB reinforcements and pore defects, which causes the inhomogeneity of galvanic couples and resultant TiO 2 passive layer. Fortunately, the scan strategies of XY + 30° and XY + 67° can alleviate the thermal accumulation and leads to the transformation of refinements distribution to radial-shaped arrangement, which favors for the homogeneity of galvanic couples and resultant TiO 2 passive layer. Moreover, the scan strategy of XY + 90° generates a refinement and increased volume fraction of reinforcements and micro-galvanic couples, which significantly facilitates the formation of a thicker and less-defective TiO 2 passive layer, thus leading to better corrosion resistance with a larger value of R f. Furthermore, the corrosion mechanism of LPBF-produced (TiC+TiB)/Ti composites has also been discussed in detail based on the Electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy results. [Display omitted] • Scan strategy affects the microstructure morphology of (TiC+TiB)/Ti composite. • The TiC and TiB acting as micro-cathode further accelerate the dissolution of titanium. • In-situ TiC and TiB strengthen the stability of TiO 2 passive film. [ABSTRACT FROM AUTHOR]

MAX phase materials, the precursors of MXenes (2D transition metal carbides, carbon nitrides, and nitrides), have become increasingly popular in electrochemical applications. In this study, we have successfully prepared Ti 2 SnC with high lithium capacity via the in-situ formation of SnO 2. Results show that there are TiC nanowhiskers and SnO 2 inside the Ti 2 SnC MAX calcined at 800 ℃, and the initial specific capacity could reach 377 and 371 mAh·g−1 at high current densities of 400 mA·g−1 and 1.0 A·g−1, respectively. These values are higher than those of most MAX phase materials reported in previous studies, such as Ti 3 SiC 2 and Nb 2 SnC, but the stability and rate performance are inferior, which is a direction for the future. This paper provides a new pathway for the application of MAX phases in electrochemistry, which has more in-depth application prospects. ● Ti 2 SnC with in-situ formation of SnO 2 was successfully prepared by a calcination method. ● The Ti 2 SnC layered structure slows down the volume expansion of in-situ prepared SnO 2. ● This anode material performed a better specific capacitance, arriving at 377 mAh/g at the current density of 1.0 A/g. [ABSTRACT FROM AUTHOR]

The present study (part B) is a direct continuation of the leading study (part A), in which we had introduced extruded aluminum (Al) + 8.8 and 14.7 vol% aluminum nitride (AlN) metal matrix composites (MMC) manufactured at a cost-effective industrial scale and targeted for structural load-bearing applications with an expected service at elevated temperatures. In the leading study the processing, microstructure of nitrided and extruded Al-AlN MMC and the thermal stability of the extruded Al-AlN MMC as reflected in changes to their tensile mechanical properties induced by annealing up to 600 °C were elaborated. In the present ensuing study we discussed in details the mechanical, thermal and creep properties, active strengthening mechanisms, and microstructure-property relations of Al-AlN MMC annealed at 500 °C for 24 h, which were examined in a broad temperature range of 22–500 °C. In addition to increased Young's modulus Al-AlN MMC showed high tensile strengths determined at 300 °C, which were superior to any conventional Al alloy, accompanied with reasonably high ductility. At the same time Al-AlN MMC preserved excellent creep performance, which was superior to the heat resistant reference alloys, reduced coefficient of thermal expansion and reasonable thermal conductivity. The results confirmed that reported thermally stable Al-AlN MMC may be considered a promising material with an appealing set of the properties directed for load-bearing structural applications with an expected service at elevated temperatures. • in-situ Al-AlN MMC fabricated by cost-effective approach realized at a large scale. • The mechanical, thermal and creep properties of Al-AlN MMC determined at 22–500 °C. • Active strengthening mechanisms and microstructure-property relations discussed. • An attractive set of the properties at 300 °C superior to conventional Al alloys. • A promising material for structural applications with service at high temperatures. [ABSTRACT FROM AUTHOR]

Highlights: [•] Zn addition significantly improved tensile strength and ductility of ZK60A alloy. [•] Zn addition enabled high aspect ratio nanorod formation insitu, for the first time. [•] Mainly non-basal slip was induced by β nanorods during tensile deformation. [•] Zn addition improved compressive strength (per strain level) of ZK60A alloy. [•] HSZ formation from the tip of one β nanorod to another was observed. [ABSTRACT FROM AUTHOR]

Abstract: Three-dimensional (3-D) MnO2–carbon nanotube (CNT) nanocomposites were prepared by a simple one-pot hydrothermal method. An electrode was then prepared with these nanocomposites. For comparative investigation, MnO2 microspheres were also hydrothermally prepared without adding CNTs. The as-synthesized MnO2 microspheres were then mechanically mixed with CNTs to prepare a subsequent electrode. The samples were characterized by electron microscopy, X-ray diffraction, and electrochemical methods. It has been revealed that a 3-D conductive network of CNTs was formed with microspheres of MnO2 nanorods interwoven with and connected by CNTs. As a result, the hydrothermally mixed MnO2–CNT electrode showed a higher specific capacitance than the mechanically mixed electrode. It has therefore been concluded that the hydrothermal mixing method yields a more homogeneous product that is better suited to take full advantages of both the high capacitance of MnO2 and the high electrical conductivity of CNTs. The 3-D MnO2–CNT nanocomposites reported herein have provided a promising electrode material for supercapacitors and other electrochemical energy storage/conversion devices. [Copyright &y& Elsevier]

Nano-oxides with low cost are a promising class of reinforcing materials that can be added into solder to enhance reliability of resultant joints. However, the poor interfacial bonding with solder matrix has long been a barrier to its transition from laboratory science to real engineering application. In this study, rare earth Pr and Al 2 O 3 nanoparticles (NPs) were co-added into Sn-0.3Ag-07Cu (SAC0307) solder to solve it, and thermal cycling reliability of resultant joint was found to be much more enhanced when compared to the joints individually added with Pr or Al 2 O 3 NPs. This was attributed to a synergistic effect in-situ built between Pr atoms and Al 2 O 3 NPs, in the form of Pr-coated Al 2 O 3 NPs. This structure helped most Al 2 O 3 NPs maintain nano-scaled during thermal cycling, and thus continuously inhibited the coarsening of interfacial microstructure for a long time. Kinetic analysis showed that the average interfacial IMCs growth coefficient at SAC0307-Pr-Al 2 O 3 /Cu interface was about 5.0 × 10−11 cm2/h, lower than that at SAC0307/Cu, SAC0307-Pr/Cu and SAC0307-Al 2 O 3 /Cu interface. [Display omitted] • Nano-oxides strengthening to joint reliability is expected to become real. • Co-doping Pr and Al 2 O 3 NPs synergistically enhanced joint thermal cycling reliability. • A synergistic relationship was in-situ built between Pr and Al 2 O 3 NPs. • The Al 2 O 3 NPs/solder interface strength was strengthened. [ABSTRACT FROM AUTHOR]

Abstract: The paper reports the study on the synthesis and characterization of nanocomposites reinforced with in-situ intermetallic compounds via mechanical–thermal activation. The Al matrix bulk hybrid nanocomposites are synthesized by an aluminothermic reduction reaction between the nanocrystalline Al and TiO2 powder blends. The nanocrystalline powder mixture of Al and TiO2 is synthesized by high-energy ball milling. The milled powders are characterized by differential thermal analysis (DTA), X-ray diffraction (XRD) and electron microscopy. The powder compacts after thermal treatment are characterized by XRD and electron microscopy. The microhardness of the in-situ composite is in the range 3.4–4.2GPa and it is probably attributed to the nanosized reinforcements and ultrafine grain structure of the Al matrix. A suitable combination of the mechanical milling and thermal treatment can lead to the synthesis of Al-based nanocomposites by the solid-state processing route for the present system. [Copyright &y& Elsevier]

• In-situ Al-AlN MMCs fabricated by cost-effective approach realized at a large scale. • The Al+Mg+Sn powder blanks nitrided in a gaseous N 2 followed by a hot extrusion. • The microstructure of extruded MMCs consisted of Al grains with the size of ~1.8 µm. • The Al grains decorated by the evenly dispersed areas rich in AlN nanocrystals. • The stable AlN dispersoids effectively stabilized Al grain structure up to 500 °C. This study introduces in-situ aluminum (Al)-aluminum nitride (AlN) metal matrix composites (MMCs) manufactured by a powder metallurgy (PM) cost-effective approach realized at a large industrial scale. The Al-AlN MMCs were targeted for structural load-bearing applications with an expected service at elevated temperatures not normally associated with a use of conventional Al-based alloys and MMCs. Commercial Al, magnesium, and tin powders were processed by readily available PM techniques of blending, cold isostatic pressing (CIP), a solid-state nitridation in a static gaseous nitrogen, and a hot direct extrusion. Two sound voids free Al + 8.8 and 14.7 vol% AlN MMCs were reproducibly fabricated in a form of the long extruded bars with the cross-section of 80 × 15 mm. The microstructure of nitrided and extruded MMCs was presented in details. A typical yolk-shell-like microstructure of Al metallic core and nitrided layer was formed homogenously in a volume of the CIP bulky (~25 kg) billets upon nitridation. The microstructure of extruded Al-AlN MMCs consisted of Al grains elongated into the extrusion direction. The Al grain structure was embedded with the evenly distributed micrometric regions formed by a high density AlN nanocrystals in Al matrix. A stability of the tensile mechanical properties of as-extruded Al-AlN MMCs was pursued in transversal and longitudinal directions after the annealings performed at 300–600 °C for 24 h. Owing to an effective stabilization by the stable and fine AlN dispersoids by Zener pinning action no major changes to the mechanical properties took place after annealing up to 500 °C. [ABSTRACT FROM AUTHOR]

Metal/alloy matrices have been previously reinforced with ceramic nanoparticles, but such reinforcements tend to agglomerate, have weak interfaces, and are expensive. Polymer-derived ceramics (PDCs) based composites can potentially overcome these shortcomings. These composites are obtained from the preceramic polymers after pyrolysis. These polymers are inexpensive, can be fragmented to the nanoscale, and pyrolyzed in-situ. Friction stir processing (FSP) was used to fragment and disperse the polymer within an Al-Mg alloy. The PDC particles pinned the dislocations and grain boundaries. The composite exhibited a microstructure resulting from dynamic recrystallization with an average grain size of ~1 µm. It also exhibited both high strength (96% and 24% improvement in the yield and tensile strength, respectively) and good ductility. Interestingly, the serrations in the tensile curves commonly observed in Al-Mg alloys due to the Portevin-Le Chatelier (PLC) effect was reduced in the composite. • Al matrix composite reinforced with in-situ formed polymer-derived ceramic was fabricated using friction stir processing. • It exhibited high strength (96% and 24% improvement in the yield and tensile strength, respectively) and good ductility. • The amplitude of the serrations in the tensile curve due to the Portevin-Le Chatelier effect was reduced in this composite. [ABSTRACT FROM AUTHOR]

The demand for energy storage equipment in the information age era is becoming increasingly scarce, but manganese-based metal oxides with large potential windows and multivalent states were developed and used as high-performance electrode materials for energy storage. MnO 2 array grow on the carbon sphere as the precursor and then obtain multi-types and hierarchical of manganese metal oxides through gradient carbonization. The surface crystal phase changes with temperature, and the electrochemical performance shows obvious imparity. In addition, the carbon spheres gradually disappear with increasing temperature forming a hollow shell structure, which is conducive to sufficient contact between electrolyte and electrode material. It found that the annealing temperature can change the surface oxide morphology of MnO 2 /C, and it can know that the temperature promotes the conversion of MnO 2 to Mn 2 O 3 and Mn 3 O 4. Based on the oxides of different crystal phases, the electrochemical properties are more distinctive due to their different structures. The rod-like nanoarray Mn 2 O 3 /C composites derived from annealing the precursors at 600 °C show high specific capacity and rate performance under a very large potential window of 0~1.2 V (show a remarkable specific capacitance of 277.0 F·g−1 at a current density of 1.0 A·g−1). Considering practical application, the as-assembles Mn 2 O 3 /C//Na 2 SO 4 //Mn 2 O 3 /C symmetrical supercapacitors device exhibits a maximum energy density of 80.35 Wh·kg−1 at a power density of 500 W·kg−1, which can be applied promising storage materials for information age. [Display omitted] • Oxide nanowires grow uniformly on the surface of carbon spheres in situ. • The annealing temperature greatly affects the phase transition and structure. • Carbon-enriched Mn x O y and derived nanosphere have excellent electrochemical performance. • It is found that the electrochemical performance is greatly affected by the morphology and structure. • The Mn 2 O 3 /C//Na 2 SO 4 //Mn 2 O 3 /C exhibits a high energy density of 80.35 Wh·kg-1 at a power density of 500 W·kg-1. [ABSTRACT FROM AUTHOR]

• Ti 2 AlNb-based alloys are in-situ manufactured by DWAAM technology. • Hot-wire technology is introduced to overcome the problem of the obvious difference in physical properties between two wires. • Composition distribution and macrosegregation mechanism of the in-situ prepared alloy are revealed. • Microstructure and mechanical properties of the in-situ prepared alloy are studied. • The integration of material-preparation and parts-processing is attractive for industrial production. For the reason of high temperature strength, high oxidation resistance and low density, Ti 2 AlNb-based alloy is expected to replace nickel-based alloy in the range of working temperature 600–800 °C and become a new generation of high-temperature structural alloys in the aerospace industry. However, Ti 2 AlNb-based alloys have great high-temperature deformation resistance and high brittleness, which greatly restricts its preparation and processing using traditional technology. In this research, an innovation method named double-wire arc additive manufacturing technology was adopted to in-situ manufacture Ti-22Al-24Nb (at%) alloy, and the TiNb and pure Al wire with designed feeding speed were taken as raw materials. The deposited component was investigated systematically. Results show that the composition error between the average testing value and designed value are under 1.1%, but there are also existing local segregation of composition and microstructure. The segregation phenomenon further deteriorates its mechanical properties, which means the ultimate tensile properties and elongation under room temperature and high temperature (650 °C) are 504 ± 38.59 MPa, 0.41 ± 0.03% and 375 ± 32.60 MPa, 0.76 ± 0.05% respectively on average. At the same time, the prepared alloy exhibits fully lamellar structure and XRD results show that the basic composition phases B2, O and α 2 of the Ti 2 AlNb-based alloy successfully appeared. The in-situ manufacturing method demonstrated in this work is expected to significantly promote the wider application of AM due to its low cost advantage and high flexibility. [ABSTRACT FROM AUTHOR]

The present study demonstrates the direct observation of pore formation by rapid release of vacancies in ultrafine grain (UFG) Al-0.4at%Zr alloy during in-situ annealing in a scanning transmission electron microscope. The ultrafine grain structure was preliminary obtained by high pressure torsion processing at a hydrostatic pressure of 6 GPa up to 10 revolutions. In-situ annealing reveals the rapid formation of pores in triple junctions (TJs) of grain boundaries (GBs) during the first few minutes followed by their subsequent slow resorption with the complete disappearance of some of them. During annealing, no noticeable displacement of GBs is observed. By considering the evolution of non-equilibrium GBs inherited by the severe plastic deformation, a theoretical description is suggested which describes: (i) the pore formation at disclinated TJs as a thermodynamically driven process of free volume dissolution through generation of vacancies, which then migrate to the TJs and coagulate at them with growth of the pores diminishing the strain energy of the TJ disclinations, and (ii) further decrease of the TJ disclination strain energy through the climb of extrinsic GB dislocations towards the disclinated TJs, accompanied with dissolution of the TJ pores by emission of vacancies which provide the dislocation climb. The rapid release of excess vacancies during the early stage of heat treatment is consequently identified as a phenomenon responsible for accelerated atomic mobility. This work hence provides a new perspective for understanding the accelerated precipitation kinetics observed in severely deformed alloys. ga1 • It is demonstrated that grain structure of a severely deformed Al-alloy store large amounts of vacancies. • Vacancy release by the rearrangement of near equilibrium grain boundaries is followed by in-situ annealing in STEM. • The kinetics of pore formation and dissolution has been followed by in-situ STEM observations. • Theoretical models are provided that reproduce the formation and dissolution of pores formed by vacancy condensation. • A proportion of stored vacancies may be responsible for faster precipitation kinetics in severely deformed alloys. [ABSTRACT FROM AUTHOR]

In the present research, to further reduce the fabrication and forming cost of NiTi alloy, an innovative wire-arc additive manufacturing process (WAAM), which is simultaneously an in-situ alloying process, has been applied to fabricate polycrystalline Ni 53 Ti 47. The as-fabricated alloy is subsequently subjected to a necessary post-production annealing for additively manufactured metals. During the thermal cycle, to characterize the obtained phases in the Ni 53 Ti 47 alloy and provide dynamic lattice evolution information, neutron diffraction is conducted to the heated sample in real time. It is found that the metastable Ni 4 Ti 3 phase is only obtained in the heat-treated alloy while the as-fabricated NiTi alloy produced by WAAM contains only NiTi and Ni 3 Ti. The generated Ni 4 Ti 3 precipitates have increased the NiTi phase micro strains. The hcp -Ni 3 Ti lattice evolution is found inducing converse lattice shrinkage and expansion in bcc -NiTi lattice during the dissolution and precipitation of Ni 3 Ti, respectively. The WAAM induced residual stress in the as-fabricated alloy is tensile and during the residual stress relief, the thermal expansion rate of Ni and Ni 3 Ti are reduced. In addition, the thermal expansion coefficient of NiTi and Ni 3 Ti is measured according to the neutron Rietveld refinement as 0.040 × 10−3 °C−1 and 0.036 × 10−3 °C−1, respectively. Image 1 • Neutrons are conducted in-situ to the phase evolutions in additively manufactured Ni 53 Ti 47 alloy. • The as-fabricated Ni 53 Ti 47 alloy contains only NiTi and Ni 3 Ti without Ni 4 Ti 3 phase. • Responses of bcc-NiTi and hcp-Ni 3 Ti phase lattice strains to temperature are calculated. [ABSTRACT FROM AUTHOR]

Aluminum matrix composites (AMCs) with high volume fraction of reinforcement exhibit superior mechanical properties at the expense of ductility. To overcome this shortcoming, a dual matrix composite microstructural design has proven to be beneficial in increasing the ductility while maintaining the optimal strength. In the present investigation, an in-situ dual matrix composite from Al-TiO 2 system was successfully fabricated by a mechanical and thermal synthesis process via powder metallurgy route. The in-situ dual matrix composite microstructure comprises of Al-Al 2 O 3 -Al 3 Ti composite regions separated by ductile unmilled outer Al matrix. The composite region provides strength to the dual matrix composite while the outer Al matrix provides plasticity during deformation. The differential scanning calorimetry (DSC) technique was used to analyze the chemical reactions occurring during the synthesis. A comparative study on the microstructure evolution of in-situ single and dual matrix composites was done using XRD, SEM, EDS and EBSD. The in-situ dual matrix composite shows lower microhardness and compressive strength with significant increase in ductility and wear resistance compared to the in-situ single matrix composite with the same amount of reinforcement. • Al based in-situ dual matrix composite from Al-TiO 2 system is reported for the first time. • A comparative study of the same with single matrix composite is illustrated. • The mechanical properties of the same is also explored in depth. [ABSTRACT FROM AUTHOR]

The temperature required for growth of mullite whiskers in heat-resistant adhesive was decreased to 700 °C based on solid-liquid-solid (S-L-S) mechanism. The bonding strength was increased by 23.1% (700 °C) ∼ 60.7% (1200 °C), and the maximal 32.3 MPa was achieved after sintered at 1200 °C. Moreover, the whiskers-grown adhesive also displayed better anti-damage capacity, and multiple grading fractures occurred during the test procedure, which was mainly due to the pull-out mechanism. [ABSTRACT FROM AUTHOR]

In the present research an Fe–Fe 3 Ni functionally graded material has been fabricated using an innovative wire-arc additive manufacturing process. Considering the residual bcc -α-Fe in the bulk material, a homogenization heat treatment is conducted to the as-fabricated alloy to transform the residual bcc lattice into fcc structure. During the entire heat treatment, the phase evolution process in Fe–Fe 3 Ni functionally graded material is in-situ characterized using the high-intensity neutron diffraction instrument WOMBAT, therefore the temperature profile is set linear to accurately extract phase volume fractions and thermal lattice strains in the specific regions. According to the results, the as-fabricated functionally graded material contains both fcc -Fe 3 Ni and bcc -α-Fe, while after heat treatment the bcc -α-Fe is dissolved into the Fe 3 Ni matrix and leads to lower hardness in the alloy. Also, the detected phase evolutions are mainly performed by the low Ni content section of the Fe–Fe 3 Ni functionally graded material. In addition, compared to the bcc lattice in the as-fabricated functionally graded material, the dissolved Fe more considerably restraint the Fe 3 Ni lattice deformation thus a much lower thermal expansion coefficient is measured from cooling than the heating process. • Neutrons are conducted in-situ to the phase evolutions in Fe–Fe 3 Ni FGM. • bcc -α-Fe phase in the as-fabricated Fe–Fe 3 Ni FGM are dissolved by the heat treatment. • Responses of bcc-α-Fe and fcc-Fe 3 Ni phase lattice strains to temperature are calculated. [ABSTRACT FROM AUTHOR]

A unique process to prepare composite coating on titanium alloy by electron beam cladding is explored for improving durable oxidation resistance. The composite coating can be divided into two layers, including in-situ fabricated transition layer and pure Al layer. The isothermal oxidation tests are carried out at 973 and 1073 K. The composite coating reduced the oxidation rate to approximately 1/10 and 1/4 that of the substrate due to formation of Al 2 O 3. It can be obtained by the oxidation rate that the diffusion coefficient of composite coating is 4 × 10 − 20 m2/s, which is lower than 1 × 10 − 18 m2/s of the substrate. It indicated that the composite coating improves the oxidation resistance by inhibiting the diffusion of O. Although the oxidation rate of pure Al coating is similar to that of composite coating, the largest bonding force and completed structure after 20 cycles thermal shock of composite coating reveals that composite coating can improve the durability of oxidation resistance due to providing match CTE, which will improve the oxidation resistance further. • The composite coatings are composed of the middle transition layer and a pure Al layer via EB cladding. • The preparation technology provides a method to inform α-Al 2 O 3 at the surface. • The composite coatings are effective to protect TC11 from the inward and outward oxidation at 700 and 800 °C. • Mechanisms for improving oxidation resistance and bonding performance are discussed in detail. • The final oxidation rate is 0.0002 and 0.0022 mg2/cm4 ⋅ h at 700 and 800 °C. [ABSTRACT FROM AUTHOR]