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In our present work, TiN suspension was sprayed onto the 316 stainless steel substrate using the suspension high velocity oxy fuel thermal spray. An in-situ reaction between TiN and O 2 occurred during the spray process to form TiO 2 and TiN/TiO 2 composite coatings were fabricated. The phase evolution, microstructures and tribological properties of TiN/TiO 2 composite coatings were studied. Results showed that the interface between the coating and the substrate was well bonded, which was mainly owing to the in-situ reaction heat and the sufficient deformation of particles. The structure of molten particles, small grain size and low porosity could contribute to improving the mechanical and tribological properties of the in-situ coating. A schematic exfoliation process of TiN/TiO 2 composite coating was proposed to analyze the failure of coatings. The antiwear mechanisms of the TiN/TiO 2 composite coatings were discussed. The good cohesive bonding strength and high hardness of the TiN/TiO 2 composite coating, the pinning role of TiN in crack propagation, and the newly formed TiO 2 in the friction layer during the sliding test contributed to the improvement of tribological properties for the TiN/TiO 2 composite coating. This work could provide a reference for the application of TiN/TiO 2 composite coating in the field of friction and wear. [ABSTRACT FROM AUTHOR]

Novel dual plate-like grains of (Ti, Zr)B 2 and W 2 B 5 toughened solid solution composites were fabricated by the in-situ reaction spark plasma sintering at 1800 °C using (Ti, W)C and ZrB 2 powders. The composites were predominated and composed of the (Zr, Ti, W)C solid solutions and plate-like (Ti, Zr)B 2. In the (Ti, W)C-ZrB 2 reaction system, W promotes the anisotropic growth of (Ti, Zr)B 2 grains, while Ti makes the formation reactions of W x B y thermodynamically feasible. When the addition of ZrB 2 exceeds 40 mol%, W begins to be boronized into W x B y which is mainly composed of plate-like W 2 B 5. The (Ti, W)C-50 mol% ZrB 2 composite with dual plate-like grains of (Ti, Zr)B 2 and W 2 B 5 exhibited the best comprehensive mechanical properties of hardness of 26.5 GPa, flexural strength of 620 MPa, and fracture toughness of 6.6 MPa·m1/2, which provide a new approach for the enhanced toughness without the introducing of metal impurities. • Dual plate-like grains of (Ti, Zr)B 2 and W 2 B 5 toughened (Zr, Ti, W)C ceramics were fabricated by the in-situ reaction SPS. • Ti makes the formation of W x B y thermodynamically feasible, while W promotes the anisotropic growth of (Ti, Zr) B 2 grains. • The 50ZB exhibited a high fracture toughness of 6.6 MPa·m1/2, which provide a new approach for the enhanced toughness. [ABSTRACT FROM AUTHOR]

Multiphase composites of lithium ceramics have emerged as a prominent area of research in the development of advanced solid tritium breeding materials. In this study, Li 2 TiO 3 /Li 2 SiO 3 co-doped Li 4 SiO 4 ceramic pebbles were prepared through an in-situ reaction between Li 4 SiO 4 and TiO 2. The objective of this study is to enhance the thermal cycling stability of Li 4 SiO 4 by impeding the grain boundary migration of Li 4 SiO 4 under high temperature conditions. The effects of the in-situ generated Li 2 TiO 3 /Li 2 SiO 3 particles on the microstructure, crush load and thermal cycling stability of Li 4 SiO 4 ceramic pebbles were investigated. The in-situ formed Li 2 TiO 3 and Li 2 SiO 3 particles effectively hindered the grain growth and minimized the formation of large intracrystalline pores in Li 4 SiO 4. At a sintering temperature of 900 °C, the Li 2 TiO 3 /Li 2 SiO 3 particles are beneficial in increasing the crush load of Li 4 SiO 4 ceramic. However, at lower sintering temperatures, their impact was counterproductive. An increase in the volume fractions of the Li 2 TiO 3 /Li 2 SiO 3 had a positive effect on grain refinement but a negative effect on crush load. The Li 2 TiO 3 /Li 2 SiO 3 co-doped Li 4 SiO 4 ceramic pebbles exhibited excellent structural stability during thermal cycling. The optimum mechanical stability was achieved at a TiO 2 addition of y = 0.1. The in-situ generated fine second phase particles effectively impeded grain boundary migration at high temperatures, providing a viable strategy for improving the thermal stability of Li 4 SiO 4 tritium breeders. [ABSTRACT FROM AUTHOR]

[Display omitted] Low photo-induced carrier recombination rate, exceptional light absorption, and advantageous recycling performance are crucial attributes of semiconductor photocatalyst for wastewater purification. Herein, based on in-situ reaction, close-contact S-scheme bismuth chromate/bismuth oxide/ferroferric oxide@porous carbon microspheres (Cr 2 Bi 3 O 11 -Bi 2 O 3 /Fe 3 O 4 @PCs) (F-CBFP) was fabricated using alginates as precursor. Due to the abundance of functional groups on the porous carbon (PCs), Bi 2 O 3 and Cr 2 Bi 3 O 11 nanoparticles (NPs) are in situ deposited onto the highly conductive 3D magnetic porous Fe 3 O 4 @PCs microsphere surface, which not only form tight interfacial contacts and reduces interfacial potential barriers but also prevent agglomeration or shedding of the NPs during photocatalytic reactions. Moreover, density functional theory (DFT) calculations further confirm that the formation of a robust built-in electric field (BIEF) within F-CBFP prompts photo-induced electrons in the conduction band (CB) of Bi 2 O 3 to combine with holes in the valence band (VB) of Cr 2 Bi 3 O 11 , effectively constructing a S-scheme heterojunction system. Also, Fe 3 O 4 can act as a Fenton catalyst, activating the H 2 O 2 generated by Cr 2 Bi 3 O 11 under illumination. In wastewater treatment, the obtained F-CBFP shows remarkable photo-Fenton degradation (towards methyl orange (97.8 %, 60 min) and tetracycline hydrochloride (95.3 %, 100 min)) and disinfection performance (100 % E. coli inactivation), and exceptional cyclic stability. [ABSTRACT FROM AUTHOR]

Novel plate-like (Ti, Zr)B2 toughened (Zr, Ti, W, Ta)C medium-entropy ceramics were designed based on the atomic scale, nanoscale, and microscale, and prepared via the in-situ reaction hot-pressing adopting (Ti, W, Ta)C and ZrB2 powders. The multiphase ceramics were primarily composed of the (Zr, Ti, W, Ta)C matrix and plate-like (Ti, Zr)B2. When the addition of ZrB2 exceeds 50 mol%, the residual ZrB2 causes the secondary primary phase to change from (Ti, Zr)B2 to (Zr, Ti)B2. The improvement of fracture toughness is primarily influenced by the plate-like (Ti, Zr)B2 on crack propagation mechanisms such as bridging effect and crack deflection. (Ti, W, Ta)C- 50 mol% ZrB2 (raw powder composition) exhibits outstanding mechanical properties, boasting a Vickers hardness of 24.9 GPa, fracture toughness of 5.5 MPa·m1/2, and flexural strength of 552 MPa, which present a novel avenue for achieving a synergistic enhancement in Vickers hardness and fracture toughness within medium-entropy carbide ceramics.

Copper matrix composites with dual-scale particles were fabricated through casting with reaction. Ultrasonic vibration has been successfully introduced into the melt at about 1523 K while the microstructural development and mechanism of copper matrix composites with high-performance through a novel method of casting with ultrasonic vibration treatment are investigated. When ultrasonic vibration is applied, the distribution of micro-scale particles is greatly improved. Primary Cr phase convents to non-dendrite and large aggregates of ZrB2 particles are disrupted into small clusters because of acoustic cavitation and acoustic streaming. The ultimate tensile strength and elongation of Cu-1wt%Cr-0.3 wt%Zr-1wt%ZrB2 composite in as-cast state were 321 MPa and 14.37 %, recording a 28.4 % and 14 % increment respectively compared with the sample without treatment. After solution treatment, deformation and aging subsequently, the uniform distribution of reinforcements also decreases the average transverse grain thickness and increases the dislocation density which improve the comprehensive properties.

This study undertakes vacuum pressureless brazing of SiC ceramics with TiSi 2 powder, achieving MAX bonding. Microscopic characterization elucidates the microstructural evolution of the joined seam across various brazing temperatures and durations. The formation process of Ti 3 SiC 2 is detailed through thermodynamic and kinetic analyses. At 1550 ℃ for 30 min or 1600 ℃ for 15 min, the filler undergoes in-situ reaction with SiC, yielding a dense, continuous Ti 3 SiC 2 (MAX) phase, with no other phases observed. This suggests that increased temperature reduces MAX synthesis time. However, prolonged brazing causes voids in the center of the joined seam. Si volatilization was key for Ti 3 SiC 2 in-situ formation, and this reaction equation was proposed. Maximum average shear strength at room temperature is 127.15 MPa at 1550 ℃ for 30 min and 118.15 MPa at 1600 ℃ for 15 min. • In-situ formation of Ti 3 SiC 2 for pressureless joining of SiC ceramics. • Explain the growth principles of Ti 3 SiC 2 layer through the Ti-Si-C ternary phase diagram and kinetic principles. • Joint shear strength: 127.15 MPa. Explain strength variations using microscopic analysis. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Fuzhou University is the property of Journal of Fuzhou University, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The realization of brazing between the TiZrTaHfNb refractory high-entropy alloy (RHEA) and zirconia (ZrO2) ceramic is of great importance in expanding the application of metal-ceramic composite parts. In this study, reliable brazed joints were achieved using a Ti–28Ni eutectic filler. The typical interfacial microstructure and the effect of brazing temperature on the microstructure and mechanical properties were thoroughly discussed. The results indicated the formation of complex oxides on the ZrO2 ceramic side, including Ti2O, Ni2Ti4O and (Hf, Ta, Zr)O2. Additionally, the RHEA substrate near the brazing seam underwent a transformation from a single BCC phase to double BCC phases, which included a TaNb-rich BCC-1 phase and a Zr-rich BCC-2 phase. The formation of the double BCC phases was caused by the spinodal decomposition. As the brazing temperature rose, the thickness of the oxides layer slightly increased and the double BCC phases formed from the beginning and progressively coarsened. The maximum room shear strength was 124.1 MPa when the joint was obtained at 1040 °C for 10 min. The alternating distribution interlocking structure between MO2 whiskers and Ni2Ti4O by in-situ reaction played a vital role in enhancing the interface strength.

A Sr(II) complex [Sr(L)2 (H2O)4 ]n (1) was synthesized with 1,4,5,8-naphthalene tetracarboxylic acid (H4L1) and strontium chloride hexahydrate under solvothermal conditions. The structure was characterized by elemental analysis (EA), single crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD), infrared spectroscopy (IR) and thermogravimetric analysis (TGA). The single crystal X-ray diffraction results indicate that H2L1 undergoes in-situ reaction to generate 1,3-dioxo-1H,3H-benzo[de]isomere-6,7-dicarboxylic acid (H2L). In complex 1, each Sr(II) atom is located in the geometric configuration of a square antiprism. The L- ligands connect Sr atoms to form a one-dimensional chain structure. 2D supramolecular structure is formed through hydrogen bonding and π ... π stacking interactions. The solid states luminescence behavior of complex 1 was explored. It is found that complex 1 produces a wide emission spectrum band (450-690 nm) at the excitation wavelength of 211 nm, and the maximum emission wavelength appears at 535 nm. Therefore, it can be seen that complex 1 is a potential green light material. [ABSTRACT FROM AUTHOR]

In this study, homogeneous (Ti, Nb)(C, B)/IN625 composite coatings with almost defect-free microstructures were successfully prepared on a 42CrMo steel substrate by coupling ultra-high-speed laser cladding (USLC) with the direct reaction synthesis (DRS) technique to introduce the in-situ exothermic reaction into the cladding materials; these were comparatively analyzed with the pure IN625 coating prepared only by USLC. Our results showed that the interface of the composite coating/substrate was greatly affected by about 670 kJ Joule heat released from the in-situ reaction happening during the cladding process, which was sufficient to remelt the as-deposited materials and significantly increased the coating/substrate interface width to around 24 μm, six times the interface width of pure IN625 coating. Furthermore, the residual stress inside the coating and across the interfacial region was also reduced, alleviating the interface stress mismatch. However, the surface hardness of (Ti, Nb)(C, B)/IN625 composite coating was found to be lower than that of the IN625 coating, and the average wear weight loss was only 10% of that of the IN625 coating, attributable to the in-situ authigenic TiCB, TiC, NbMo3B4 and NbMo2B2 phases providing load transfer from the hard phases to the IN625 composite matrix to achieve abrasion reduction and wear resistance. It was also found that the formation of nano-equiaxial ultrafine grains in the depth range of 250 nm below the wear surface was facilitated by the coupling of the three fields of plastic rheology-heat-force, which dynamically strengthened the wear surface. Based on these findings, it is suggested to promote the strategy of combing USLC and DRS techniques to achieve an additional ability to enhance the coating microstructure and reduce residual stress, to achieve better tribological performance. [ABSTRACT FROM AUTHOR]

Al3Ti/Al-Mg-Mn composites were successfully prepared by in-situ reaction method under ultrasonic and mechanical vibration fields. The effects of reaction temperature and coupling time on microstructure evolution and mechanical properties at room temperature were studied. The results show that the coupling ultrasonic and mechanical vibration fields can promote the in-situ reaction, dispersal and refinement of Al3Ti particles. Compared with Al-Mg-Mn matrix, the room temperature tensile strength, yield strength and elongation of Al3Ti/Al-Mg-Mn composite treated under coupling fields at 760 ℃ for 10 min are 222, 119 MPa and 8.1%, respectively. The tensile strength and yield strength values increase by 17.5% and 25.2%, and the elongation value decreases from 8.7% to 8.1%. The improvement of mechanical properties is mainly attributed to grain refinement strengthening, load transfer strengthening and thermal mismatch strengthening caused by Al3Ti reinforced phase, among which the thermal mismatch strengthening plays a great role in the improvement of the strength of composites.

Compared to other structural alloys, magnesium alloys have a relatively poor corrosion resistance and low mechanical strength, which can be further deteriorated when these alloys are subjected to joining processes using the existing joining methods. Herein, we propose for the first time an additive friction stir-welding (AFSW) using fine Al powder as an additive to improve the mechanical strength as well as corrosion resistance of AZ31B weld joints. AFSW is a solid-state welding method of forming a high-Al AZ31B joint via an in-situ reaction between pure Al powders filled in a machined groove and the AZ31B matrix. To optimize the process parameters, AFSW was performed under different rotational and transverse speeds, and number of passes, using tools with a square or screw pin. In particular, to fabricate a weld zone, where the Al was homogenously dispersed, the effects of the groove shape were investigated using three types of grooves: surface one-line groove, surface-symmetric grooves, and inserted symmetric grooves. The homogenous and defect-less AFS-welded AZ31B joint was successfully fabricated with the following optimal parameters: 1400 rpm, 25 mm/min, four passes, inserted symmetric grooves, and the tool with a square pin. The AFSW fully dissolved the additive Al into α-Mg and in-situ precipitated Mg17Al12 particles, which was confirmed via scanning electron microscopy, transmission electron microscope, and X-ray diffraction analyses. The microhardness, joint efficiency, and elongation at the fracture point of the AFS-welded AZ31B joint were 80 HV, 101%, and 8.9%, respectively. These values are higher than those obtained for the FS-welded AZ31 joint in previous studies. The corrosion resistance of the AFS-welded AZ31B joint, evaluated via hydrogen evolution measurements and potentiodynamic polarization tests, was enhanced to 55% relative to the FS-welded AZ31B joint.

The hardness and adhesion of protective hard coatings to the substrate are the most important parameters that influence the performance of the tool. Herein, we propose an effective strategy, by in-situ hot press sintering, to fabricate a novel niobium carbide coating with high hardness and excellent interfacial bond strength on GCr15. The coating is composed of Nb2C, NbC, and α-Fe phases. The volume fraction of niobium carbide (Nb2C and NbC) phases reaches 93%. Along the direction of coating thickness, the grain morphology of niobium carbide changes from equiaxed (Nb2C) to columnar (NbC), and then to equiaxed (NbC), presenting a gradient microstructure. The coating/substrate interface displays an excellent macro/micro interface. The formation of the gradient microstructure is attributed to the nucleation-growth process controlled by the carbon concentration gradient diffusion. The novel gradient coating can simultaneously achieve superhardness (20.2 ± 0.3 GPa) and excellent bond strength (>210 ± 20 MPa). The excellent bond strength is mainly attributed to the in-situ formation of the coating and the gradient microstructures. The tensile test results show that the fracture mechanism of the niobium carbide coating on GCr15 is mainly a brittle fracture of niobium carbide coating and a small amount of coating debonding.

As a classic in-situ reaction, the Al-TiO2 reaction is expected to prepare aluminum matrix composites with high thermal stability. In this study, it was found that the preparation method of ensuring sufficient reaction using higher temperatures in previous studies was not conducive to acquiring optimized high-temperature strength. With the increase of hot-pressing temperature and the extension of holding time, the in-situ reaction became more thorough, but the strength of the composites first increased and then decreased. Coarsening of the microstructure at high temperatures would lead to degradation of strength and controlling the in-situ reaction process by the hot-pressing parameters could optimize the mechanical properties of the composites. Strengthening mechanisms at room and high temperatures were studied, and it was found that the load-transfer and Orowan strengthening mechanisms are the main strengthening effects at room temperature, while the pinning effect of fine particles became more crucial at elevated temperatures. As a result, the coarsening of the reinforcing phases was more detrimental to the high-temperature strength. Therefore, an insufficient in-situ reaction led to more excellent mechanical properties, and the composite hot-pressed at 605°C and held for 2 h exhibited the highest strength, which was 367 MPa at room temperature and 170 MPa at 350°C. [ABSTRACT FROM AUTHOR]

Lithium (Li) metal anode holds great promise for high-energy-density rechargeable batteries. However, it suffers from the Li dendrites growth and uncontrollable side reactions with electrolyte due to the unstable solid electrolyte interphase (SEI) layer. Herein, we propose a facile strategy for the in-situ fabricate of organic-inorganic composite artificial SEI layers on Li surfaces, which consist of organic fluorinated siloxane and inorganic LiF-rich phases. The hybrid artificial SEI endows high mechanical strength (13.1 GPa) and Li+ transfer number (0.62). Such robust SEI protective layers can not only guide uniform nucleation and deposition of Li metal by facilitating uniform Li-ion distribution, but also prevent unfavourable side reactions. Accordingly, the protected metallic lithium anode (PMTFPS-Li) anode enables stable Li plating/stripping performance in symmetric cells for more than 300 h at 4 mA ·h/cm2 under a high areal capacity of 4 mA/cm2. Moreover, the PMTFPS-Li/S cells could maintain more than 300 stable cycles at 0.5C and the PMTFPS-Li/LFP cells present excellent cycling performance (400 cycles at 1C) and enhanced rate capability (110.4 mA·h/g at 3 C). This work will inspire the design of artificial SEI on Li anodes for advanced Li metal batteries.

x wt.% B4C/Ti6Al4V titanium matrix composites were prepared by selective laser melting (SLM) technology. The microstructure and mechanical properties of the SLM-formed and heat-treated samples were studied in detail. The results indicated that an in-situ reaction occurred during the SLM process, producing acicular TiB, whisker TiB and granular TiC. The microhardness of the selective laser melted sample increased with increasing B4C content. When wt.% (B4C) is 0.05, the mechanical properties, i.e., compressive strength, compressive strain, tensile strength and elongation, of the SLM-formed sample are 2021 MPa, 29.98%, 1225 MPa and 14.17%, respectively. In addition, some of the SLM-formed samples were solution-treated at different temperatures (950 °C, 1000 °C, 1050 °C), and the microstructures were obviously changed, resulting in an increase in grain size and agglomeration of the in-situ reaction products. As the solution temperature increases, the microhardness of the composites decreases, and the tensile strength, compressive strength and strain tend to increase, but they are generally weaker than those of the original samples. When the solution temperature is 1050 °C, the tensile strength and elongation of the composite are 1402 MPa and 13.74%, respectively.

Combining mullite with SiC ceramics is considered to be an effective method to reduce the sintering temperature of ceramics while maintaining excellent performance of the resultant materials. However, traditional heating methods used in this process are still more energy intensive. This work presents a fabrication method for producing mullite-bonded SiC ceramics via microwave heating and an in situ mullite reaction bonding. Via the proposed method, the preparation of samples with a bending strength of 125 ± 6 MPa and a porosity of 36.2% can be achieved at 1200 °C for 15 min. The microwave coupling effect and the impedance matching effect of SiC particles provide the heat source for the rapid sintering of the mullite-bonded SiC ceramics at low temperature. Bridging configuration of mullite between SiC particles occurred due to the unique coupling effects during microwave heating. Moreover, the low sintering temperature and short holding time inhibit the formation of the detrimental cristobalite phase. This work indicates that this rapid and low-temperature preparation method of mullite-bonded SiC ceramics has potential uses in the industrial production of high-performance SiC ceramics. [Display omitted] [ABSTRACT FROM AUTHOR]

The B4C@TiB2 composite powders with core-shell structure were fabricated by in-situ formation of TiB2 on the surface of B4C by chemical coating combined with heat treatment, which the tetrabutyl titanate and B4C powders were used as raw materials. The results showed that the B4C-TiB2 core-shell interface was constructed, which transformed boron carbide from stoichiometric B4C to boron-rich phase B13C2 and caused severe lattice distortion. When the TiB2 content increased from 0 wt % to 20 wt %, the minimum reflection loss value(RLmin) of B4C@TiB2 composite powder increased from-9.76 dB to-19.94 dB. It can be attributed to the improvement of impedance matching of B4C powders. Furthermore, the lattice distortion and core-shell structure enhanced the dipole polarization and the interface polarization, respectively. The synergistic effects improved the dielectric loss capability, which significantly improved the electromagnetic wave absorption performance of B4C powders.  [ABSTRACT FROM AUTHOR]

NbC ceramic surface-reinforced steel matrix composites were prepared by an in-situ reaction method at different temperatures (1,050 °C, 1,100 °C and 1,150 °C) for different times (1 h, 2 h and 3 h). The phase constitution, microstructure and fracture morphology of NbC ceramic surface-reinforced steel matrix composites were analyzed by XRD, SEM and EDS, and the effects of the in-situ reaction temperature and time on the mechanical properties were systematically studied. The results indicate that the NbC reinforcement layer is formed through the reaction between Nb atoms and carbon atoms diffused from the steel matrix to the Nb plate. The thickness of this reinforcement layer increases as the reaction time prolongs. Additionally, an increase in reaction temperature results in a thicker reinforcement layer, although the rate of increase gradually decreases. The relationship among the thickness of the NbC reinforcement layer, the reaction time and temperature was established by data fitting. The optimal tensile performance is achieved at 1,100 °C for 1 h, with a tensile strength of 228 MPa. It is also found that the defects between the reinforcement layer and the steel matrix are related to reaction temperature. At 1,100 °C, these defects are minimal. Fracture mostly occurs in the NbC reinforced layer of the composites, and the fracture mode is characterized by typical intergranular brittle fracture. [ABSTRACT FROM AUTHOR]

Al-Ti-C-(Ce) grain refiners were prepared by combining in-situ reaction, hot extrusion, and adding CeO2. The effects of second phase TiC particle size and distribution, extrusion ratio, and Ce addition on the grain-refining performance of grain refiners were investigated. The results show that about 10 nm TiC particles are dispersed on the surface and inside of 100–200 nm Ti particles by in-situ reaction. The Al-Ti-C grain refiners, which are made, by hot extrusion, of a mixture of in-situ reaction Ti/TiC composite powder and Al powder, increase the effective nucleation phase of α-Al and hinder grain growth due to the fine and dispersed TiC; this results in the average size of pure aluminum grains to decrease from 1912.4 μm to 504.8 μm (adding 1 wt.% Al-Ti-C grain refiner). Additionally, with the increase of the extrusion ratio from 13 to 30, the average size of pure aluminum grains decreases further to 470.8 μm. This is because the micropores in the matrix of grain refiners are reduced, and the nano-TiC aggregates are dispersed with the fragmentation of Ti particles, resulting in a sufficient Al-Ti reaction and an enhanced nucleation effect of nano-TiC. Furthermore, Al-Ti-C-Ce grain refiners were prepared by adding CeO2. Under the conditions of holding for 3–5 min and adding a 5.5 wt.% Al-Ti-C-Ce grain refiner, the average size of pure aluminum grains is reduced to 48.4–48.8 μm. The reason for the excellent grain-refining and good anti-fading performance of the Al-Ti-C-Ce grain refiner is presumedly related to the Ti2Al20Ce rare earth phases and [Ce] atoms, which hinder agglomeration, precipitation, and dissolution of the TiC and TiAl3 particles. [ABSTRACT FROM AUTHOR]

Copyright of Chemistry & Industry of Forest Products is the property of Chemistry & Industry of Forest Products Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• AFSW using fine Al powder was firstly proposed for fabricating the reliable AZ31B joint. • Uniform and defectless AFSWed AZ31B joint was successfully fabricated by using the inserted symmetric grooves. • The AFSW improved mechanical strengths as well as corrosion resistance of AZ31B joint. • Joint efficiency for the AFSWed joint was a superior level to the FSWed AZ31B joints reported previously. • Corrosion resistance of the AFS-welded joint improved by 55% relative to AZ31B joint. Compared to other structural alloys, magnesium alloys have a relatively poor corrosion resistance and low mechanical strength, which can be further deteriorated when these alloys are subjected to joining processes using the existing joining methods. Herein, we propose for the first time an additive friction stir-welding (AFSW) using fine Al powder as an additive to improve the mechanical strength as well as corrosion resistance of AZ31B weld joints. AFSW is a solid-state welding method of forming a high-Al AZ31B joint via an in-situ reaction between pure Al powders filled in a machined groove and the AZ31B matrix. To optimize the process parameters, AFSW was performed under different rotational and transverse speeds, and number of passes, using tools with a square or screw pin. In particular, to fabricate a weld zone, where the Al was homogenously dispersed, the effects of the groove shape were investigated using three types of grooves: surface one-line groove, surface-symmetric grooves, and inserted symmetric grooves. The homogenous and defect-less AFS-welded AZ31B joint was successfully fabricated with the following optimal parameters: 1400 rpm, 25 mm/min, four passes, inserted symmetric grooves, and the tool with a square pin. The AFSW fully dissolved the additive Al into α-Mg and in-situ precipitated Mg 17 Al 12 particles, which was confirmed via scanning electron microscopy, transmission electron microscope, and X-ray diffraction analyses. The microhardness, joint efficiency, and elongation at the fracture point of the AFS-welded AZ31B joint were 80 HV, 101%, and 8.9%, respectively. These values are higher than those obtained for the FS-welded AZ31 joint in previous studies. The corrosion resistance of the AFS-welded AZ31B joint, evaluated via hydrogen evolution measurements and potentiodynamic polarization tests, was enhanced to 55% relative to the FS-welded AZ31B joint. [ABSTRACT FROM AUTHOR]

In the study, Ti fiber (200 μm, 99.8 wt.%) and pure aluminum (99.6 wt.%) were respectively used as the reaction source and matrix to prepare Al-based composites by in-situ synthesis methods. During the stage of preparing the preform, Ti fibers were fixed in the matrix at equal intervals to pre-control the initial position of the product. The preform was heated in an induction heating device finally, at the same time, parameter combinations of different frequencies and currents were applied to promote the in-situ reaction between Al-Ti, thereby the Al matrix composites reinforced by Al3Ti were obtained. The phase composition, microstructure and wear resistance of the composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and wear testers. The results show that when the frequency and current are 5 kHz and 15 A respectively, the Ti fiber is completely reacted, and the product is the isometric Al3Ti with a size of 1 – 2 μm and a particle spacing of about 5 μm, reaching the optimal microstructure under all parameters. Under the condition of a load of 9.8 N, the wear rate of the composites at 5 kHz and 15 A is 2.325 mg/mm2, indicating the best values in this experiment.

The particle-reinforced (ZrB2 + Al3Zr)/AA6016 composites with different contents were prepared by in-situ chemical reaction of the Al-KBF4-K2ZrF6 system. With the (ZrB2 + Al3Zr) particles introduced, the composites exhibit enhanced mechanical properties and plastic instability. The ultimate tensile strength (UTS), yield strength (YS) and elongation of as-cast 6wt.% (ZrB2 + Al3Zr)/AA6016 composites reach 259 MPa, 102 MPa and 21.6%, respectively, which is significantly higher than the matrix with UTS-172 MPa, YS-70 MPa and EL -15.2%. The strain hardening rate curve shows that the presence of particles hinders the dislocation propagation process. According to the dynamical strain aging (DSA), the blocking effect of particles on dislocation motion is further strengthened with the increase of particle density, a larger span of upper and lower yield points appears. The moving range of active dislocations is reduced, which makes the time for fixed dislocations shorter. The existence of reinforcing particles indirectly affects the diffusion of solute atoms and the process of pinning dislocations during heat treatment. After T6 treatment, the type of serration was converted from (A + B) type to type B, and the serration frequency decreased with the increase in stretching rate. [ABSTRACT FROM AUTHOR]

Copper azide with high density was successfully synthesized by in-situ reaction of nanoporous copper (NPC) precursor with HN3 gaseous. NPC with pore size of about 529 nm has been prepared by electroless plating using polystyrene (PS) as templates. The copper shells thickness of NPC was controlled by adjusting the PS loading amount. The effects of copper shell on the morphology, structure and density of copper azide were investigated. The conversion increased from 87.12% to 95.31% when copper shell thickness decrease from 100 to 50 nm. Meanwhile, the density of copper azide prepared by 529 nm NPC for 24 h was up to 2.38 g/cm3. The hollow structure of this NPC was filled by swelling of copper azide which guaranteed enough filling volume for keeping the same shape as well as improving the charge density. Moreover, HNS-IV explosive was successfully initiated by copper azide with minimum charge thickness of 0.55 mm, showing that copper azide prepared has excellent initiation performance, which has more advantages in the application of miniaturized explosive systems.

To refine the dispersive Y2O3 particles and to explore the optimum Y2O3 content, reducing the Y2O3 addition from 1.5 wt% to 0.5 wt% for Cu6Y sourced Cu-Y2O3 was investigated. It was found that reducing the Y2O3 addition had little influence on the number density, while reducing the size of the Y2O3 particles. Compared with the Y2O3 addition, the nucleation point is expected to be more important for the number density of the Y2O3 by the in-situ fabrication method. Moreover, reducing the Y2O3 addition indeed thinned the prior particle boundaries with O enrichment and contamination, thereby improving the mechanical performance and thermal conductivity. It was calculated that dispersion strengthening made great a contribution to the increment of the yield strength for ODS-Cu. While, the large particles with contamination on the prior particle boundaries induced the dimples and the premature micro-cracks, deteriorating the tensile performance. Therefore, the performance of Cu6Y sourced ODS-Cu can be improved once further reduces the introduction of contamination and suppresses the growth of MA powders during MA process.

Full-dense B 4 C-based ceramics with excellent mechanical properties were fabricated using spark plasma sintering with Mg 2 Si as a sintering aid at a low temperature of 1675 °C while applying a uniaxial pressure of 50 MPa. The effect of Mg 2 Si addition on the densification behaviours, mechanical properties and microstructure of as-sintered ceramics were investigated. Not only did the formation of ultra-fine grained SiC using the in-situ reaction effectively inhibit the growth of B 4 C grains, but it also contributed to the strength and toughness of the resultant ceramics. Additionally, microalloying Mg imparted more metal bonding characteristics to the B 4 C matrix, thereby improving their ductility. The results indicate that the composite containing 7 wt% Mg 2 Si had excellent mechanical properties, including a light weight of 2.54 g/cm3, Vickers hardness of 34.3 GPa, fracture toughness of 5.09 MPa m1/2 and flexural strength of 574 MPa. [ABSTRACT FROM AUTHOR]

In the present work, a textured Ti 3 AlC 2 /TiAl 3 /Al composite with anisotropic microstructures and properties was successfully prepared by combining multistep ball-milling, flaky powder self-assembly, spark plasma sintering (SPS), and in-situ reaction. The effects of phase constitution and crystallographic orientation on anisotropic strengthening and fracture mechanisms of the composite were discussed. The results show that the preferred orientation of Ti 3 AlC 2 flakes was achieved during densification with the Lotgering orientation factor of the textured top surface (TTS) of 0.58. The high surface energy of Ti 3 AlC 2 submicron flakes provided the driving force for the low-temperature in-situ formation of TiAl 3. The in-situ formed TiAl 3 further improved the strength of the composite. The// c -axis samples achieved a high flexural strength of 565.9 MPa. The analysis of the flexural fracture surfaces shows that the fracture modes of Ti 3 AlC 2 flakes include basal plane cleavage, delamination, kinking, particle pull-out, and prismatic plane fracture, which in turn affects the toughness of the samples with different loading directions. Particle pull-out of the Ti 3 AlC 2 flakes is the primary mechanism to improve the toughness. This novel technical route provides a new idea for the design of metal matrix composites. [ABSTRACT FROM AUTHOR]

In aerospace applications, the development of high-entropy alloys (HEAs) filler is an effective strategy to obtain reliable C f /SiC nozzles and GH3536 thrust chambers components. Considering the high costs and extended preparation times with HEA fillers, utilizing non-HEA fillers to generate HEAs within brazing seam offers significant advantages. This study successfully joined C f /SiC with GH3536 using a non-HEA Cu–Ti–W composite filler that facilitated the in-situ formation of Fe–W–Ni–Cr–Cu HEA during the brazing process. Furthermore, the formation and accompanying martensite phase transformation were revealed. The microstructure characteristic of W reinforcements/HEA/Cu(s,s) was ultimately formed in the brazing seam. The atomic structure of the HEA, confirmed to be hexagonal close-packed, was elucidated using spherical aberration-corrected transmission electron microscopy. Additionally, a martensite phase transformation was observed in the HEA, involving two adjacent layers of (0 0 0 1) atomic planes that sheared and move a 3 distance alon g [10–10] in opposite directions, resulting in the formation of M-HEA. The inclusion of HEA and M-HEA in the C f /SiC-GH3536 joint, brazed with Cu–Ti–W composite filler, increased its shear strength to 84.8 MPa, which was 2.15 times higher than that of joints without the W reinforcements. This study offers new insights into the design of composite fillers and the application of HEAs. • This work introduced a novel method for incorporating high-entropy alloys in C f /SiC-GH3536 heterostructure joints. • The non-high-entropy alloy composite filler transformed into Fe–W–Ni–Cr–Cu high-entropy alloys within the brazing seam. • Spherical aberration-corrected transmission electron microscopy confirmed the martensite phase transformation of the high-entropy alloys. • The shear strength of the C f /SiC-GH3536 joint increased by 115 % compared to joints without W particles. [ABSTRACT FROM AUTHOR]

Surface modification of CNTs with SiO 2 coating was proposed to fabricate Al matrix composite with high-content intragranular reinforcements. The deposition of SiO 2 nanoparticles on the surface of CNTs improved their compatibility with the Al matrix and thus increased the penetration of CNT@SiO 2 reinforcements into Al grain interiors during powder processing. The intragranular reaction during the sintering process converted the CNT@SiO 2 hybrid reinforcements into Al 4 O 4 C nanoparticles, leading to a remarkable increment in reinforcement content. As a result, incorporating CNT@SiO 2 reinforcements (0.5 wt% CNT coated with 2 wt% SiO 2) into Al resulted in a final composite with 9 vol% nanoreinforcement, of which 85 % were located in the grain interiors. The high-content intragranular reinforcements greatly improved dislocation storage capability and strain hardening rate, resulting in a significant increase in strength while retaining good ductility. The composite's yield strength and tensile strength increased to 370 MPa and 472 MPa, respectively, which were about 66 % and 67 % higher than those of the CNT-Al composite with the same CNT content. [Display omitted] • Deposition of SiO 2 nanoparticles on CNTs increased the homogeneity of reinforcements dispersion. • The deposition of SiO 2 coating improved wettability of CNTs with the Al powders. • The more uniform dispersion of reinforcements and their higher wettability increased their penetration into grain interiors. • The in-situ transformation of CNT@SiO 2 into Al 4 O 4 C nanoparticles increased the reinforcement volume fraction remarkably. • Al 4 O 4 C–Al composite presented superior mechanical properties over CNT-Al and CNT@SiO 2 –Al composites. [ABSTRACT FROM AUTHOR]

Cu-Cr-Nb alloys has become a key material for ITER plasma facing components (PFC) due to its excellent thermal stability. In this study, Cu-3.3Cr-1.6Nb (wt%) alloy was prepared through in-situ casting using Cu Cr and Cr Nb master alloy. The agglomeration and coarsening of Cr 2 Nb particles in Cu-Cr-Nb alloy are improved. The effect of aging temperature on the microstructure and properties of rolled Cu-3.3Cr-1.6Nb alloy. The results show that the aged Cu-3.3Cr-1.6Nb alloy contains multi-scale precipitation phases distribution with micron-level Cr 2 Nb (0.2–2 μm), Cr-rich phase (2.2 μm), nano-level Cr 2 Nb (13.1 nm) and nano-level Cr (9.3 nm). After aging at 450 °C for 0.5 h, the tensile strength and electrical conductivity of the aged alloy were 469 MPa and 78.5% IACS, respectively. According to TEM and EBSD analysis, the Cr 2 Nb particles did not grow during the aging and were pinned the grain boundaries to inhibit the growth of Cu matrix grains, which result in a good thermal stability of Cu-3.3Cr-1.6Nb alloy. This study provides a new method for preparing Cu-Cr-Nb alloy with high-strength, high-conductivity and high heat resistance by casting method. • the microstructure of aged Cu-3.3Cr-1.6Nb alloy contains micro-scale Cr 2 Nb and Cr, nano-scale Cr 2 Nb and Cr precipitates. • The agglomeration and coarsening of Cr 2 Nb particles in Cu-3.3Cr-1.6Nb alloy are improved. • Cu-3.3Cr-1.6Nb alloy has a good thermal stability. [ABSTRACT FROM AUTHOR]

The key problems restricting the wide development of Ti3AlC2 material are the low hardness and strength. In this paper, MAX phase Ti3(Al,Si)C2 solid solutions with different Si doping were successfully synthesized using an in-situ reaction of Ti–Al–C system by powder metallurgy route. The phase structures and microstructures of the as-synthesized Ti3(Al,Si)C2 solid solutions were analyzed, the mechanical properties were tested, and the fracture surface morphologies were characterized. The results show that doping Si can prevent the lath-like structure of MAX phase from coarsening. When doping 0.2 mol Si, the as-synthesized Ti3Al1.0Si0.2C2 sample offers fine microstructure and has excellent performance. Its Vickers hardness, flexural strength and the fracture toughness are 5.52 GPa, 546 MPa, 7.51 MPa m1/2, respectively. The fracture mode is transgranular cleavage fracture. During propagation, the main crack deflects and branches obviously. The crack extends in a zigzag like path, accompanied by transgranular fracture. When suffering external force, the particular layered structure of Ti3(Al,Si)C2 can absorbs and dissipates more energy through hybrid deformation modes such as extrusion, kink, fold, interlaminar separation and tearing. With this complex and mixed fracture mode, the crack propagation were effectively prevented, and its flexural strength and fracture toughness were enhanced.

In the study, Ti fiber (200 µm, 99.8 wt.%) and pure aluminum (99.6 wt.%) were respectively used as the reaction source and matrix to prepare Al-based composites by in-situ synthesis methods. During the stage of preparing the preform, Ti fibers were fixed in the matrix at equal intervals to pre-control the initial position of the product. The preform was heated in an induction heating device finally, at the same time, parameter combinations of different frequencies and currents were applied to promote the in-situ reaction between Al-Ti, thereby the Al matrix composites reinforced by Al3Ti were obtained. The phase composition, microstructure and wear resistance of the composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and wear testers. The results show that when the frequency and current are 5 kHz and 15 A respectively, the Ti fiber is completely reacted, and the product is the isometric Al3Ti with a size of 1 - 2 µm and a particle spacing of about 5 µm, reaching the optimal microstructure under all parameters. Under the condition of a load of 9.8 N, the wear rate of the composites at 5 kHz and 15 A is 2.325 mg/mm2, indicating the best values in this experiment. [ABSTRACT FROM AUTHOR]

In this paper, the in-situ VC reinforced Fe-based composite cladding was experimentally fabricated on 45 steel surface by laser cladding using the mixture of FeV 50 and B 4 C with different contents (10–30 wt%). The formation mechanism of composite cladding and effect of B 4 C content on its wear resistance were investigated through first-principles calculations. The experimental results show that the volume fraction of in-situ formed VC particles increases continuously with increasing B 4 C content. The microhardness of composite cladding increases significantly, and it reaches to 1653.7 HV 0.5 when the B 4 C content is 30 wt%. Meanwhile, the friction coefficient of composite cladding decreases with increasing B 4 C content, and the wear mode gradually changes from adhesive wear to abrasive wear, indicating the enhanced wear resistance of composite cladding. The first-principles calculations results show that the in-situ formed VC and Fe 2 B are both hard and brittle phases, and the VC and Fe 2 B can exist stably in the composite cladding. The interface between VC and Fe matrix is well bonded, and the interfacial separation work is calculated as 5.516 J/m2, which mainly attributes to the bonding characteristics of mixed ion-covalent bonding interactions between Fe and C atoms located at interface. [ABSTRACT FROM AUTHOR]

Al-Ti-C-(Ce) grain refiners were prepared by combining in-situ reaction, hot extrusion, and adding CeO2. The effects of second phase TiC particle size and distribution, extrusion ratio, and Ce addition on the grain-refining performance of grain refiners were investigated. The results show that about 10 nm TiC particles are dispersed on the surface and inside of 100–200 nm Ti particles by in-situ reaction. The Al-Ti-C grain refiners, which are made, by hot extrusion, of a mixture of in-situ reaction Ti/TiC composite powder and Al powder, increase the effective nucleation phase of α-Al and hinder grain growth due to the fine and dispersed TiC; this results in the average size of pure aluminum grains to decrease from 1912.4 μm to 504.8 μm (adding 1 wt.% Al-Ti-C grain refiner). Additionally, with the increase of the extrusion ratio from 13 to 30, the average size of pure aluminum grains decreases further to 470.8 μm. This is because the micropores in the matrix of grain refiners are reduced, and the nano-TiC aggregates are dispersed with the fragmentation of Ti particles, resulting in a sufficient Al-Ti reaction and an enhanced nucleation effect of nano-TiC. Furthermore, Al-Ti-C-Ce grain refiners were prepared by adding CeO2. Under the conditions of holding for 3–5 min and adding a 5.5 wt.% Al-Ti-C-Ce grain refiner, the average size of pure aluminum grains is reduced to 48.4–48.8 μm. The reason for the excellent grain-refining and good anti-fading performance of the Al-Ti-C-Ce grain refiner is presumedly related to the Ti2Al20Ce rare earth phases and [Ce] atoms, which hinder agglomeration, precipitation, and dissolution of the TiC and TiAl3 particles.

Sodium 2,2′-methylene-bis(4,6-di-tertbutylphenyl)-phosphate (NA11) is an α-type nucleating agent for improving the mechanical and crystallization performances of isotactic polypropylene (iPP). However, the limited dispersibility of NA11 inhibits its nucleation. The in-situ nucleation method was used to fabricate well-dispersed NA11. Based on the free energy of the reaction between the two precursors of 2,2′-methylene-bis-(4,6-di-tert-butylphenyl) phosphate (MBP) and sodium stearate (NaSt) obtained via simulations, NA11 may form in situ during the melt processing of iPP. Furthermore, thermogravimetric and Fourier transform infrared spectroscopic results indicated that MBP and NaSt disappeared with the appearance of NA11 and stearic acid (HSt) during heating, providing favorable proofs for the formation of in-situ NA11 [NA11(IS)]. NA11(IS) exhibited better dispersion than NA11 in iPP, thus efficiently improving the mechanical and crystallization performances of iPP. At the NA11(IS) of ~ 0.1 wt%, the tensile strength and flexural modulus of iPP improved by 18.8% and 55.7%, respectively, compared to pure iPP, while equimolar NA11 prepared by traditional method mixed with iPP could not reach such achievement. Moreover, NA11(IS) increased the crystallization peak temperature of iPP by 13.6 °C, with a reduced activation energy of iPP crystallization and the accelerated crystallization rate. Therefore, well-dispersed NA11(IS) may provide more nucleation sites for iPP, resulting in the enhanced nucleation of NA11(IS) and improved performances of iPP. Based on this work, the in-situ nucleation method is potentially applied to a vast area of research, to realize high dispersion of additives in the matrix. [ABSTRACT FROM AUTHOR]

Due to the extremely high hardness and excellent wear resistance of TiB 2 , TiB 2 hard coating has become an irreplaceable common key material in some key fields. In this study, TiB 2 hard coating was designed from the perspective of modulating the microstructure and composition of the material. In-situ TiB 2 nanocomposite coating was deposited by atmospheric plasma spraying technique using Ti and B 4 C as precursor powder. The hardening mechanism of the coating was explored. It was noted that there were fine and dense nanograins in the obtained coating, and the hardness of the coating was high. The microstructure of the coating was characterized by rapid solidification, in which TiB and TiC exhibited a three-dimensional quasi-continuous dendritic network microstructure, and TiB interface and TiC interface were well combined. The TiB 2 and TiC tend to bond with each other, forming near-network microstructure. The interface orientation relationship between TiC phase and TiB 2 phase was [01 1 ̅ ] TiC //[1 2 ̅ 10] TiB2 and (0001) TiB2 //(111) TiC , and the mismatch between TiB 2 and TiC was 0.916 %. The good orientation matching between TiB 2 and TiC indicated that TiB 2 /TiC strong interface was formed. The TiB 2 /TiC strong interface gave the intergrowth ceramic structure a better load-bearing capacity, resulting in a higher hardness of the coating (1530 HV 0.1). Furthermore, dislocations and stacking faults existed at the junction of TiB 2 /TiC grain boundaries, which would hinder the movement of dislocations and greatly increase the hardness of the coating. Therefore, TiB 2 nanocomposite coating with high hardness could be successfully prepared by plasma spraying process through reasonable composition design to meet the application needs of special circumstances. • In-situ TiB 2 nanocomposite coating with high density was prepared by reactive plasma spraying Ti-B 4 C composite powder. • The coherent growth model was designed to explain the growth mechanism. • TiB 2 nanocomposite coating had lower production cost and higher hardness than other single-phase or multiphase coatings. • The hardening mechanism of coating and the contribution of in-situ structure to coating hardness were revealed. [ABSTRACT FROM AUTHOR]

In this experiment, three kinds of hydrous manganese dioxide (HMO) with different Zeta potentials were synthesized, and combined with KMnO4 for deep removal of Pb2+, Cd2+ and Ni2+. The competitive adsorption of three heavy metal ions was also investigated. The results indicated that the stronger the acidity, the higher the Zeta potential (-54.3) of the synthesized HMO. After regenerating HMO with acidic KMnO4 as eluent, the removal rates of Pb2+, Cd2+ and Ni2+ could still reach 79.25%, 80.13% and 60.43% after five cycles of adsorption. The promoting mechanism of KMnO4's effect on HMO was analyzed by SEM, TEM, EDS, FTIR, XRD, XPS, BET, and UV-vis. After absorbing heavy metal ions, HMO will release part of Mn (II), and the released Mn (II) reacts with KMnO4 to form a small amount of highly active in-situ HMO. The ‘HMO + KMnO4’ system can not only improve the removal rate of heavy metal ions by HMO, and reduce the amount of adsorbent, but also remove the released Mn (II). Because of its reproducibility, efficiency and simplicity, the research on water purification materials and technologies is of significance. HIGHLIGHTS A novel mesoporous δ-MnO2 nanoparticle with high Zeta potential, large specific surface area and high hydroxyl content was prepared.; Low cost, simple preparation and high adsorption capacity.; Competitive adsorption of heavy metal ions.; Regeneration and cyclic adsorption of adsorbents.; Adding KMnO4 can greatly improve the removal efficiency of heavy metals and remove the residual Mn (II) in the solution.;

The immiscible bimetallic composites play an important role in civilian industries and aerospace fields owing to their integrated mechanical and physical properties. However, metallic composites of immiscible constituents suffer from one critical drawback of weak interface bonding, which makes the composites particularly vulnerable at elevated service temperatures. Here we proposed a novel strategy to resolve the challenge by creating low-energy phase interfaces in a typical immiscible bimetallic W–Cu composite. This was achieved by in-situ reactions of WO 3 and CuO with WC, which acts in a dual function as the reducing agent for the reactions and an interface forming agent. The sintered W-WC-Cu composite possessed a significant number of low-energy WC/W and WC/Cu interfaces and exhibited a compressive strength of 609 MPa and a compressive ductility of 22.6 % at 600 °C, which ranks among the highest in similar composites. The characteristics of WC/W and WC/Cu interfaces and their effects on the mechanical behavior of the composite were demonstrated by the timely and atomic-resolved high-temperature mechanical investigations. The introduced stable interfaces were also found to induce [ 1 ‾ 11] BCC → [011] FCC phase transformation of W as another mechanism of plastic deformation in addition to dislocation activities in W and Cu. This study provides a new approach to greatly enhance the mechanical properties of the immiscible metallic composites. [Display omitted] • Constructing low-energy and stable interfaces strategy for immiscible bimetal composites. • Superior strength-ductility synergy for the interfacial design of W-WC-Cu composite. • Inserted specific interfaces can induce an allotropic transformation as an additional plastic deformation mechanism. [ABSTRACT FROM AUTHOR]

Multilayer heterogeneous titanium matrix composites (MHTMCs) based on in-situ reaction between Ti6Al4V and TiB 2 were successfully fabricated by selective laser melting (SLM). The microstructure and mechanical properties under various strain rates were characterized by a combination of several methods in detail. Ti6Al4V layers and TMC layers exhibited alternate distribution in MHTMCs, both of which were mainly composed of α′-Ti with high aspect ratio due to the high cooling rate of the molten pool during SLM, and the in-situ TiB effectively refined the α′ laths in the TMC layers. The tensile strength and elongation of the MHTMCs reached 1406 MPa and 6.03 % respectively, and the enhancement of strength of the MHTMCs were mainly attributed to the synergistic effect of grain refinement strengthening, dispersion strengthening and hetero-deformation induced (HDI) strengthening. Under high strain rates, the MHTMCs exhibits significant strain rate hardening effect, and the fragmentation of α′ laths and intensive dislocation pile-up occurred during the dynamic deformation. [ABSTRACT FROM AUTHOR]

A novel lithiophilic artificial interlayer was rationally designed for Li metal anode, i.e., heterostructural Mo 3 N 2 /MoN nanobelt, which not only provides abundant deposition site and fast ion migration kinetics but also mitigates the polarization to suppress the Li dendrite growth. This work provides new insights towards developing metal nitrides for dendrite-free Li metals anodes. [Display omitted] • Heterostructural MoN x nanobelt was firstly used as protective interlayer for Li metal anode. • In-situ formed Li 3 N-rich layer greatly increase ion conductivity and alleviates continuous side reactions. • Mo phase formed by MoN x transformation provides rich Li nucleation site. • Dendritic growth is suppressed significantly according to the post-mortem SEM. • MoN x -Li symmetric cell and MoN x -Li // LPF full cell deliver superior performance. The formation of lithium dendrite and the unstable electrode/electrolyte interface, especially at high rates, are the dominant obstacles impeding the implementation of lithium metal batteries (LMBs). To tackle these fundamental challenges, here we propose a lithiophilic Mo 3 N 2 /MoN heterostructure (designated as MoN x) interlayer for dendrite-free and ultra-stable lithium metal anodes for the first time. The MoN x interlayer presents excellent electrolyte wettability, fast lithium diffusion kinetics and strong mechanical strength, which function synergistically to inhibit lithium dendrite growth. During cycling, an in-situ formation of Li 3 N-rich solid electrolyte interphase layer and metallic Mo phase can regulate the Li-ion conductivity and Li metal deposition, thus indicating uniform and compact Li plating. Above ameliorating features accompany an ultra-long-life of 2000 h at a high current density of 5 mA cm−2 for the MoN x -Li anode. The feasibility of the MoN x -Li anode in LMB is further confirmed in conjunction with LiFePO 4 cathodes. The full cells deliver exceptionally high-capacity retentions of above 82.0% after 500 cycles at 1C and 425 cycles at 3C, which are among the best thus far reported for LMBs. This work provides both new insights towards functional interlayer design and effective transition-metal nitrides for practical LMBs. [ABSTRACT FROM AUTHOR]

The (TiNbTaZrHf)C high entropy carbide(HEC) was successfully synthesized by complete commercial transition metal powders, obtained fine sintered bulks without additives by in-situ reaction element synthesis method. (TiNbTaZrHf)C bulk shows a face centered cubic rock salt structure with homogeneous single-phase FCC structure in composition and structure. The optimum sintering temperature is about 1 900 °C at which the best mechanical properties are obtained. The mechanical properties of (TiNbTaZrHf)C ceramic block are better than those of binary transition metal carbides, and it has obvious high entropy effect. Adding a small amount of Al as sintering additive, the mechanical properties of (TiNbTaZrHf)C ceramics continue to improve, the bending strength of the samples at each temperature is increased by at least 38%, and the highest is 486 MPa. The elastic modulus and hardness of the sample at 1 900 C are also slightly increased by 4% and 14%, respectively. The above conclusions illustrate that the properties of high entropy ceramics are greatly improved by in-situ reaction sintering. [ABSTRACT FROM AUTHOR]

Coordination‐insertion copolymerization of ethylene with polar monomers can directly provide value‐added functionalized polyolefins. Studies on the reactivity of catalysts toward polar monomers can help understand the copolymerization process and then tune the polymerization strategically. In this contribution, the reactivity picture of 2‐diphenylphosphonyl‐8‐phenylnaphthol nickel complex toward fundamental polar monomers was explored by stoichiometric reactions. The insertion rates are in the order of methyl acrylate (MA)>n‐butyl acrylate (BA)>N, N‐dimethylacrylamide (DMAA)>methyl methacrylate (MMA)>vinyl triethoxysilane (VTEoS)>N‐vinyl‐pyrrolidinone (NVP). Acrylic derivatives of MA, BA and DMAA with electron‐withdrawing group favor 2,1‐fashion while non‐acrylic NVP with electron‐donating group prefers 1,2‐fashion. Notably, the 1,1‐disubstituted MMA and bulky VTEoS perform a preferential 1,2‐insertion accompanying by 2,1‐insertion in the percentage of 82 : 18 and 62 : 38, respectively, because of the stronger steric effect. These insights correlate to the copolymerization of polar monomers with ethylene. Linear functional polyethylene with in‐chain and terminal incorporation of BA, DMAA or VTEoS is afforded at a high activity. [ABSTRACT FROM AUTHOR]

The development of porous tetrazolate metal‐organic frameworks (MOFs) and their carbon composites for the efficient adsorption of organic dyes is a highly exciting field for material developments as well as waste water treatment. Herein, we have introduced a copper tetrazole‐based metal organic framework, {(Cu(C2N4H3); CUT1}, synthesized via in‐situ ligand synthesis followed by [2+3] cycloaddition strategy. A set of activated carbon (AC) composites namely as CUT1@1 %AC‐Black and CUT1@5 %AC‐Black have also been prepared by loading of different proportions of activated carbon (AC) in CUT1 via sonication process. Single‐crystal X‐ray data and topological analysis results have been shown that the parent MOF (CUT1) exhibits a three‐dimensional extended structure and formed 43.62.8 ptr net topology. The phase purity and surface area of as‐synthesized MOF and AC composite have been examined through various techniques. The dye adsorption properties have been investigated for present materials by using three anionic dyes and three cationic dyes at room temperature. The results of adsorption studies demonstrated that 5 wt.% AC carbon composite is adequate for promising adsorption activity against all selected organic dyes compared to parent MOF (CUT1). A minor enhancement of surface area in the composite material exhibits the adsorption of both the cationic and anionic dyes rendering the structure and morphology remains unchanged. [ABSTRACT FROM AUTHOR]

In-situ generated (NiCo)Se 2 nanoparticles embedded in MOFs-derived NiCo layered double hydroxide nanoarrays show high energy density in hybrid supercapacitor. [Display omitted] Exploring novel structures consisting of multiple highly active components is a crucial challenge for supercapacitor applications. Using an in-situ self-templated method, we demonstrate the controlled fabrication of a fibrous hierarchical nanocomposite made of carbon microfibers covered with a layer of metal–organic framework (MOF) derived from nickel-cobalt layered double-hydroxide (NiCo-LDH) nanosheets decorated with (NiCo)Se 2 nanoparticles. The (NiCo)Se 2 nanoparticles attached tightly onto the surface of the two-dimensional NiCo-LDH, both of which were generated by the decomposition of the NiCo-based MOF, and exhibited multiple active sites that contributed to improved electrical conductivity, high capacity, and structural stability. Density functional theory calculations revealed that the density of states near the Fermi level was significantly enhanced, favoured OH– adsorption, and promoted the kinetics of the electrochemical reaction. Benefiting from the intrinsic synergetic contributions from the hierarchical nanoscale structure, the electrode made from the nanocomposite delivered an impressive capacity of 1394.2 F g−1 (702.7 C g−1) at 1 A g−1. Furthermore, a hybrid supercapacitor based on the developed nanocomposite demonstrated an energy density of 50.6 W h kg−1 and a power density of 800 W kg−1 with high cyclic stability. Our results suggest that the hierarchical nanocomposite can be a powerful electrode for advanced next-generation supercapacitors. [ABSTRACT FROM AUTHOR]