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Grain boundary serration and its effect on creep property in LPBF-built Inconel 718 alloy was investigated systematically. By considering the variation of the wavelength and amplitude with processing parameters, this study elucidates the evolution of the serration degree with changes in the intermediate solution treatment and cooling rate. A processing map for the serrated grain boundaries is presented. Three distinct formation mechanisms arise which rely upon grain boundary interaction with δ phase and element segregation: (i) specific direction of δ phase growth induced serration, (ii) the pinning of separated δ phase which hinders the grain boundaries movement, and (iii) lattice distortion resulting from element segregation induced serration. The creep tests under 650 °C/750 N have been performed on samples with different microstructure, one featuring non-serrated and the other with serrated grain boundaries, while keeping other aspects of the microstructure invariant. Compared to non-serrated grain boundary samples, the creep life of serrated grain boundary samples is increased by 56%, the creep strain is increased by 19%, and creep strain rate is decreased by 26%. Grain boundary serration can improve both creep life and creep ductility. The failure modes and accumulated damage were performed using SEM and EBSD technique. It can be found that serrated grain boundaries play a more crucial role in delaying cracks initiation due to it can alleviate the intensity of stress concentration.

Reaction characteristics in pyrometallurgical treatment for aluminum dross were studied qualitatively and quantitatively by thermal analysis. The transformation of aluminum nitride (AlN), volatilization of chlorides and fluorides in two kinds of dross under both argon (Ar) and Ar-Oxygen (O2) atmospheres were in detail analyzed and compared. Gas species including water vapor (H2O(g)), ammonia (NH3), nitrogen (N2), nitric oxide (NO), and carbon dioxide (CO2) were clearly identified. The study indicated that N2 and small amount of NO were produced from AlN–O2 reaction while NH3 from AlN–H2O(g) reaction, and H2O(g) and CO2 were necessarily from thermal decomposition of hydroxides and carbonates. Calculation indicated that the AlN–O2 reaction, AlN–H2O(g) reaction, and volatilization of chlorides or fluorides were remarkably slow, for around 30 mg raw material with taking about 37 min to finish the AlN–O2 reaction in 500–1000°C, 60 min to the AlN–H2O(g) reaction in 130–500 °C, and 30 min to the volatilization of chlorides or fluorides in 760–1000°C. Kinetics study indicated that the Ginstling-Brounshtein's diffusion model and Jander's diffusion model were most appropriate for describing the kinetics, respectively with an apparent activation energy of 273.2 kJ mol−1 and 307.4 kJ mol−1 for the AlN–O2 reaction, and with that of 182.0 kJ mol−1 and 194.0 kJ mol−1 for AlN–H2O(g) reaction. The study will be beneficial for design, optimization of pyrometallurgical routes of aluminum dross treatment and for evaluating its environmental effect.

Microwave heating has the characteristics of simple control and high efficiency, in which electromagnetic force plays an important role. Using the UDF function and energy equation in FLUENT software, the electromagnetic force model in the tube is established. The mixing process of cerium chloride solution under different heating modes, the mixing effect of Lorentz force and the preparation process of cerium oxide under different inlet material velocities were numerically simulated. CFD-Post and MATLAB software are used to post-process the data of the whole fluid area. Through the above analysis, the best process conditions of numerical simulation and experiment are finally determined. The results show that microwave heating has better mixing effect and lower material loss compared with conventional heating, in which electromagnetic force plays a promoting role; Under the condition of microwave heating, the product conversion rate is high, and the concentration of cerium oxide is high and distributed evenly. The more appropriate mixing method of cerium chloride and preparation method of cerium oxide are microwave heating, and the more appropriate inlet velocity of materials is 0.15 m/s.

Pre-aging treatment before cold rolling and final aging was introduced to optimize the mechanical properties and electrical conductivity properties of Cu-0.75Fe-0.35Ti alloy. The alloy was pre-aged at 540 °C for 6 h, then cold rolled with thickness reduction of 80%, followed by aging at 460 °C for 2 h (SARA). Vickers hardness, electronic conductivity and uniaxial tensile tests were conducted to measure the mechanical and electrical conductivity properties. Electron backscatter diffraction and transmission electron microscope were used to characterize the microstructural evolution. The results showed that the hardness, tensile strength and electrical conductivity of SARA were up to 198.2 ± 4.8 HV, 622.6 ± 6.3 MPa and 63.8% IACS, respectively, which were superior to those achieved without pre-aging. The enhanced mechanical properties of SARA were attributed to an increase in low angle boundaries (LABs), geometrically necessary dislocation (GND) density and volume fraction of precipitates, while the favorable electrical conductivity was ascribed to the enhancement of precipitation and resultant matrix purification.

The aluminum dross generated during the aluminum alloy processing and regeneration process contains a large amount of harmful highly reactive aluminum nitride and salts, which can cause environmental pollution. A novel method for preparing calcium aluminate by dry calcification of aluminum dross is proposed in this paper to extract valuable aluminum resources while achieving efficient detoxification. Detection methods such as XRD, XRF, and standard dissolution procedures have been applied to characterize the phase transition and reaction behavior of the aluminum extraction process. The results indicate that calcium additives can react with aluminum components in aluminum dross to generate 12CaO·7Al2O3 (C12A7), which is soluble in sodium carbonate solution, thereby separating it from other impurities. Under the optimal roasting conditions, the leaching rate of alumina is 87.89%, and the removal rate of nitrogen, chlorine, and soluble fluorine elements exceeds 99%.Excessive sodium carbonate is required to ensure that the hydrolysis product of C12A7 is calcium carbonate, avoiding the formation of hydrated calcium aluminate precipitates. The optimal leaching conditions are sodium carbonate concentration of 80 g L−1, caustic soda concentration of 5 g L−1, liquid-solid ratio of 8 mL g−1, and leaching time of 30 min. The leaching reaction of calcium aluminate conforms to the unreacted core model controlled by internal diffusion, and the apparent activation energy of the reaction is 18.05 kJ mol−1.

Unconventional double-peak age strengthening phenomenon has occasionally been observed in some alloys, yet the underlying mechanism responsible for this phenomenon are still unclear. Here, we for the first time report the double-peak age strengthening phenomenon in the Cu–Be–Ni–Co alloys and try to unveil the underlying mechanism. Both the theoretical and experimental analyses demonstrate that the strong coherency strengthening effect of tiny nanoprecipitates (

The black aluminum dross (BAD) from aluminum recycling industry is considered to be a hazardous material due to containing a large amount of AlN and fluoride salt. The potential environmental problems caused by BAD restrict the sustainable development of the aluminum recycling industry. A calcining-leaching process for preparing α-Al2O3 by using BAD is proposed in this paper. The transformation mechanism of toxic substances is discussed in detail based on the analysis of TG-DTG-DSC&MS. The results show that the reaction between AlN and O2 occurs in the range of 500–1000 °C. Most of the gaseous products are N2, and there is also a small amount of NO. The average conversion rate is 0.087 mg/min. The average volatilization rate of chloride salt in BAD under Ar atmosphere is 0.065 mg/min, and the average volatilization rate under Ar + O2 atmosphere is 0.089 mg/min, which is slightly higher than that of pure Ar atmosphere. The BAD processed by calcination-leaching process contain more than 95 % corundum and magnesia-aluminum spinel, which can be used as high-quality raw materials for the preparation of refractory materials.

Objectives: Acute type A aortic dissection (ATAAD) with severe stenosis or occlusion of the true lumen of aortic arch branch vessels often leads to an increased incidence of severe postsurgical neurological complications and mortality rate. In this study, we aimed to introduce our institutional extra-anatomic revascularization and cannulation strategy with improved postoperative outcomes for better management of patients with cerebral malperfusion in the setting of ATAAD. Methods: Twenty-eight patients with ATAAD complicated by severe stenosis or occlusion of the aortic arch branch vessels, as noted on combined computed tomography angiography of the aorta and craniocervical artery, between January 2021 and June 2022 were included in this study. Basic patient characteristics, surgical procedures, hospitalization stays, and early follow-up results were analyzed. Results: The median follow-up duration was 16.5 months (interquartile range: 11.5–20.5), with a 100% completion rate. The 30-day mortality rates was 7.1% (2/28 patients); two patients had multiple cerebral infarctions on preoperative computed tomography and persistent coma. Postoperative transient neurological dysfunction occurred in 10.7% (3/28) of the patients, and no new permanent neurological dysfunction occurred. Of all the patients, 3.6% (1/28) had novel acute renal failure. No other deaths, secondary surgeries, or serious complications occurred during the early follow-up period. Conclusions: Use of extra-anatomic revascularization and a new cannulation strategy before cardiopulmonary bypass is safe and feasible and may reduce the high incidence of postoperative neurological complications in patients with ATAAD and cerebral malperfusion.

Coal gangue is the solid waste from the coal mining process. About 1 billion tons of coal gangue is discharged every year in the world. Coal gangue is usually piled up in the large areas and difficult to be used. Phase transformation and separation of alumina and silica minerals in coal gangue are studied in this paper in order to prompt the resource utilization of coal gangue. The results show that the phase transformation of kaolinite in coal gangue during high-temperature calcination is in the following way: kaolinite → metakaolin → spinel → mullite. Active silica mineral is released during the phase transition process, which can be separated from other minerals by caustic leaching. The optimal calcination temperature of coal gangue is 1050 ± 50 °C while the caustic leaching temperature is 85 °C and the leaching time should be kept between 60 and 80 min. The modulus of the sodium silicate solution can reach 1.0–1.1 and the alumina to silica ratio (A/S) of the desilicated residue can be raised to 1.7.

Resistive random-access memory (RRAM) is a new memory technology that can not only realize high-density storage, but also can simulate the neural synapse for use in artificial intelligence applications. In this study, we propose an RRAM device that shows competitive resistive memory characteristics and can similarly be used as a synapse in simulation of the human visual perception nervous system. First, we demonstrate that the polyvinyl alcohol-graphene oxide (PVA@GO) hybrid material-based RRAM device offers competitive resistive memory characteristics, including long retention capability, high durability, repeatability, and mechanical flexibility. Second, we integrate the RRAM (as the artificial synapse) with a light-sensitive electronic component (a photoreceptor cell) to construct an artificial visual perception system, and realize effective emulation of light perception and conversion of light signals into synaptic signals. Under light irradiation at 532 nm, a range of versatile synaptic functions, including short-term plasticity (STP), long-term plasticity (LTP), and paired pulse facilitation (PPF), was imitated. This work provides valuable insight into the development path for next-generation high-density data storage technology, and also offers a new way to imitate the human visual neural network for multi-functional humanoid robots.

Aluminum dross, a harmful and abundant solid waste generated in aluminum industry, releases toxic ammonia and causes severe environmental pollution and public health disaster. Secondary aluminum dross (SAD) can be effectively treated by the efficient and complete decomposition of aluminum nitride (AlN). The hydrolysis behavior of AlN in SAD was evaluated by thermodynamic analysis and kinetic leaching experiments. Various factors such as temperature, time, liquid-to-solid ratio, additive type, and additive dosage were evaluated to optimize the hydrolysis of AlN. The chemical composition, mineralogical phases, particle size distribution, and morphology of SAD and leaching residue were determined by X-ray diffraction, X-ray fluorescence spectroscopy, laser particle size analysis, and scanning electron microscopy, respectively. The decomposition of AlN reached 96.24% under the following optimum conditions: leaching time of 180 min, leaching temperature of 95 °C, additive of 4 wt% sodium hydroxide, and liquid-to-solid ratio of 6 mL g−1. Meanwhile, the removal efficiency of chlorine and fluorine during leaching reached 95.63% and 69.17%, respectively. The hydrolysis data indicate that the effects of relevant factors on AlN removal are consistent with the shrinking unreacted-core model, where internal layer diffusion is the rate-controlling step. The rate-controlling step was changed to chemical reaction control with the addition of sodium hydroxide, which corrodes bayerite on the surface of AlN. The activation energy of AlN hydrolysis in SAD is 38.64 kJ mol−1.

Staphylococcus aureus infections exert a tremendous burden on the health-care system, and the threat of drug-resistant strains continues to grow. The bacteriolytic enzyme lysostaphin is a potent antistaphylococcal agent with proven efficacy against both drug-sensitive and drug-resistant strains; however, the enzyme's own bacterial origins cause undesirable immunogenicity and pose a barrier to clinical translation. Here, we deimmunized lysostaphin using a computationally guided process that optimizes sets of mutations to delete immunogenic T cell epitopes without disrupting protein function. In vitro analyses showed the methods to be both efficient and effective, producing seven different deimmunized designs exhibiting high function and reduced immunogenic potential. Two deimmunized candidates elicited greatly suppressed proliferative responses in splenocytes from humanized mice, while at the same time the variants maintained wild-type efficacy in a staphylococcal pneumonia model. Overall, the deimmunized enzymes represent promising leads in the battle against S. aureus.