查看更多>>摘要：The authors regret “Due to our negligence, We need to supplement the following paper as reference, Hu H. J. Simulations of isothermal ECAE for magnesium alloy using FEM software and experimental validations. Journal of Manufacturing Processes, 2012, 14(3):181-187”.
查看更多>>摘要：To improve the catalytic activity and stability of a copper-iron-based Fenton-like system, the element cerium was added to the Cu-Fe-based catalyst via spray drying-calcination method. Polyvinyl alcohol (PVA) was chosen as the target pollutant to evaluate the properties of the ceria-promoted Fe/Cu@γ-Al_2O_3 (Ce-Fe/ Cu@γ-Al_2O_3) microspheres. The experimental results showed that the PVA removal rate reached 99.74% in the Ce-Fe/Cu@γ-Al_2O_3/H_2O_2 system. After 10 consecutive catalytic reactions, the PVA removal rate was still maintained above 96%. Comparative experimental results showed that the addition of Ce signifcantly improved the catalytic activity and stability of the Cu-Fe-based catalyst. In addition, this catalytic system also showed good degradation efciency for Rhodamine-B and Reactive Red X-3B dyes, with removal rates reaching 99.97% and 99.94%, respectively. The mechanism of the synergistic effect of Cu, Fe, and Ce was established, and electron paramagnetic resonance (EPR) experiments revealed that hydroxyl (·OH), super-oxide (O_2-), and singlet oxygen (~1O_2) radicals were involved in the catalytic degradation of PVA. This study demonstrates a novel spray drying-calcination method for the preparation of Ce-Fe/Cu@γ-Al_2O_3 micro-spheres with outstanding catalytic activity and stability in Fenton-like systems. The Ce-Fe/Cu@γ-Al_2O_3 catalyst prepared in this research provides a potential alternative for the efcient removal of organic pollutants in wastewater.
查看更多>>摘要：Li metal is recognized as the most promising anode for Li metal batteries due to its high energy density. However, Li dendritic growth is one of the critical obstacles as the presence of this formation may lead to short circuits which will result in the fatal safety hazards like fre and explosion. Developing electrolytes which stabilize the solid electrolyte interface (SEI) flm on Li/electrolyte interface to inhibit the Li dendritic formation is still challenging. Among the different electrolytes, few are reported based on LiNO_3-carbonated electrolyte because of the low solubility of LiNO_3 in carbonated solution. Here, the new advanced electrolyte based on halogen ions (X=C1~-, Br~-, I~-) dissolved in a mixture of vinyl carbonate, dimethyl carbonate and dimethyl ether (EC:DMC:DME) on inhibiting Li dendrites was investigated systematically. The highly smooth surface of Li metal could be obtained by adopting the LiBr-LiNO_3 electrolytes. The formed stable and homogeneous SEI flm fundamentally decreases the nucleation sites for dendritic Li and establishes ideal matrix for the even Li deposition. The Li metal thus shows improved cycling in LiBr-LiNO_3 mixed electrolyte which may be the crucial for inhibit dendrite growth intrinsically.
查看更多>>摘要：? 2022 Elsevier B.V.Polymer 3D printing has been utilised in aerospace to produce complex lightweight structures, in medical fields to print tissues and organs, and in a number of other industries to combat the rising demand for weight-saving engineering solutions. Pure polymer goods created through 3D printing, on the other hand, lack strength and functionality. Therefore, by combining matrix and reinforcing materials, 3D printing of polymer composites can overcome these problems. Also various researchers have used matrix system either epoxy resin or vinyl ester resin. Despite its wide usage, resins have few drawbacks like microleakage and high curing time which could be eliminated by 3D printing. In this work, we have focused on using 3D printed polymer matrix system. To enhance the property, shape memory alloys (SMAs) are introduced in the structure as a reinforcement. Shape memory alloys are a class of smart material that, when heated over a certain temperature, can recover deformation. SMAs exhibit two main characteristics i.e., shape memory effect (SME) and superelasticity (SE). SMAs are available in a variety of shapes, including wires, springs, sheets, and tubes. The SMA wires can be embedded in the composites for a variety of reasons, such as enhancing mechanical properties, shape morphing of structures and for use as actuators. Damping is one such mechanical property which can enhanced by reinforcing SMA wires. In this research work, the samples were fabricated using 3D printing of PLA and PETG with SMA wires embedded in two different forms i.e., continuous and discontinuous. The samples were then examined under a dynamic mechanical analyzer to study the damping (internal friction) behaviour of the smart composites. It has been found that the incorporation of SMA wires into the matrix had a significant influence on the dynamic mechanical properties. Also, the samples with SMA reinforced in continuous manner had the higher value of tan δ i.e., it had good damping properties in comparison to short fibre reinforced composites.
查看更多>>摘要：? 2022 Elsevier B.V.A half-Heusler (HH) type high entropy alloy (HEA) Ti2NiCoSnSb has been synthesized by a fast powder metallurgy route for the first time. Mechanical alloying (MA) by wet milling produced a powder with a minor fraction of the HH phase. The dry milling route resulted in the desired single-phase HH material. Consolidation of the nanocrystalline mechanically alloyed (MA) powder by spark plasma sintering (SPS) resulted in a majority HH phase. Interestingly, the nanocrystalline alloy exhibited simultaneous enhancement in the Seebeck coefficient and electrical conductivity, with a maximum ZT of 0.13 at 973 K observed for the dry milled alloy. The band structure obtained by density functional theory (DFT) was in good agreement with the ultraviolet-visible-near infrared (UV-Vis-NIR) absorption spectroscopy results. The DFT calculations and microstructural analysis suggest that phase separation strongly influenced the thermoelectric properties. The band structure calculations provided a good rationale for the phase evolution and thermoelectric properties.
查看更多>>摘要：? 2022Multi-element intermetallic energetic structural materials (ESMs) can be applied as reactive fragment, reactive shell and reactive shaped charge. As typical of intermetallics ESMs, Ni-Al ESMs have been heavily studied. However, the low density limits its application. This work proposed to improve the performance of Ni-Al ESMs by adding Ta. The nearly fully dense Ta-Ni-Al ESMs with a molar ratio 4:3:3 was successfully fabricated by explosive consolidation. The density was high up to 10.52 g/cm3 (98.3% theoretical maximum density). The heat treatment was used to further improve the performance of the Ta-Ni-Al ESMs. The microstructure characteristics were analyzed by scanning electron microscopy, X-ray diffraction and transmission electron microscope. The mechanical properties, reaction and impact-induced energy release have been systematically studied. Firstly, quasi-static and dynamic compression tests were conducted to analyze the mechanical properties of the sample before and after heat treatment. Secondly, the reaction characteristics in different atmospheres were discussed by differential scanning calorimetry and thermogravimetric analysis. The effect of the additive Ta was concerned. Furthermore, Impact-induced energy release tests on the Ta-Ni-Al ESMs were performed to understand the energy release properties. Based on these tests, the characterization of Ta-Ni-Al ESMs fabricated by explosive consolidation was obtained. There was no intermetallic formed in explosive consolidated samples. After the heat treatment, Ta-Ni-Al ESMs have good plasticity and strain rate effect. Meanwhile, under high impact velocity, the impact-induced energy release capability of Ta-Ni-Al ESMs was equivalent to Ni-Al ESMs.
查看更多>>摘要：? 2022 The AuthorsFive partial isothermal sections of the Ti–Al–Si system up to 70 at% Al and 40 at% Si have been determined experimentally between 800 and 1200 °C. Seven alloys were heat-treated for 24–1504 h and characterized utilizing scanning electron microscopy, electron probe microanalysis, X-ray diffraction, and differential thermal analysis. No ternary phase was found and αTi, βTi, Ti3Al, TiAl, TiAl(1d-APS), TiAl2, TiAl3 are in equilibrium with Ti5Si3. A partial vertical section at 9 at% Si shows that all determined data are consistent with each other.
查看更多>>摘要：? 2022 Elsevier B.V.Shape Memory Alloys (SMAs) are smart materials that involve a transition from the martensitic phase to the austenitic phase when induced by a change in temperature or stress. SMAs have been proven to possess damping properties, which is caused by the internal friction that occurs in the martensitic phase. This work focuses on exploring the damping properties of some copper-based ternary and quaternary SMAs using Dynamic Mechanical Analysis (DMA) by calculating internal friction. The results show that the peak value of damping lies near to the martensitic start temperature of the respective alloys. The addition of quaternary elements (Ni and Mn) to the existing ternary alloy decreases the transformation temperatures, thereby decreasing the temperature at which the peak damping value occurs. The Ni-Ti alloy attains its peak value of damping at temperatures lower than the temperatures at which peak value is attained for these alloys. Therefore, the results prove that the alloys developed are promising materials for damping applications which can be used over a wide range of temperatures.
查看更多>>摘要：? 2022 Elsevier B.V.This article presents new findings obtained from the study of formation conditions, crystal structure, thermal, spectral, optical properties and electronic band structure of zinc glycolate Zn(OCH2CH2O). This compound was synthesized by heating the solutions of zinc formate Zn(HCOO)2·2H2O in ethylene glycol (A) or in a mixture of ethylene glycol and distilled water (B). The crystal structure of Zn(OCH2CH2O) has been studied using the X-ray powder diffraction method. It is shown that the crystal structure is built via zigzag joining of [Zn4O12C8H16] tetracycles with the tetrahedrally coordinated zinc (ZnO4). Zinc atoms inside the tetracycles and the tetracycles themselves are interconnected with oxygen bridges. Complex anions OCH2CH2O2- are bonded to zinc atoms by chelation. The unit cell parameters of Zn(OCH2CH2O) are as follows: the tetragonal structure, space group I41/a (88?2), Z = 16, a = b = 11.08673(9) ?, c = 11.5902(1) ?, V = 1424.62(2) ?3. The IR and Raman spectra of Zn(OCH2CH2O) correlate fully with the results of structural analysis. Under UV excitation, the luminescence spectra of Zn(OCH2CH2O) samples synthesized following the methods (A) and (B) are characterized by emission maxima at 460 nm (blue luminescence) and 540 nm (yellow-green luminescence), respectively. Yellow-green luminescence is due to the presence of an admixture of zinc oxide nanoparticles of size 10 nm in the sample. The electron density functional method is employed to study the electronic band structure and chemical bonding in Zn(OCH2CH2O). It is shown that the 3dZn orbitals are covalently bonded to 2pO orbitals so that an octagon is formed, where the zinc atoms of four neighboring ZnO4 tetrahedrons are linked through their vertices. The feasibility of synthesizing a layered structure of Zn(OCH2CH2O) is analyzed on the basis of ab initio calculations and Voigt-Reuss-Hill theory.
查看更多>>摘要：? 2022 Elsevier B.V.The facile deposition process for multi-component films is crucial in the development of thin film low-temperature solid oxide fuel cells (LT-SOFCs). Here, we report on the development and optimization of reactive sputtered Ni-SDC(Ni-Sm:CeO2) films for LT-SOFC anodes. The effects of oxygen partial pressure (PO2/PAr of 0 %–50 % at the sputter pressure of 30 mTorr) and deposition temperature on the physical, chemical and electrochemical properties of Ni-SDC films are studied. While the Ni-SDC anodes deposited at high PO2/PAr (>20 %) exhibited higher initial performance, they suffered from crack formation and massive Ni agglomeration upon operation due to NiO-to-Ni reduction and severe volume change. We further show that increasing the deposition temperature to 500 ℃ was effective in suppressing such Ni agglomeration and preserving the performance during operation.
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