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rapid in situ alloying of CoCrFeMnNi high-entropy alloy from elemental feedstock toward high-throughput synthesis via laser powder bed fusion

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Frontiers of Mechanical Engineering 2023年第1期18卷 131-145页

作者： Bowen WANG Bingheng LU Lijuan ZHANG Jianxun ZHANG Bobo LI Qianyu JI Peng LUO Qian LIU School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of Manufacturing Systems Engineering Xi’an Jiaotong UniversityXi’an 710049China National Innovation Institute of Additive Manufacturing Xi’an 710300China State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China Institute of Materials China Academy of Engineering PhysicsMianyang 621908China

High-entropy alloys(HEAs)are considered alternatives to traditional structural materials because of their superior mechanical,physical,and chemical properties.However,alloy composition combinations are too numerous to explore.Finding a rapid synthesis method to accelerate the development of HEA bulks is imperative.Existing in situ synthesis methods based on additive manufacturing are insufficient for efficiently controlling the uniformity and accuracy of components.In this work,laser powder bed fusion(L-PBF)is adopted for the in situ synthesis of equiatomic CoCrFeMnNi HEA from elemental powder mixtures.High composition accuracy is achieved in parallel with ensuring internal density.The L-PBF-based process parameters are optimized;and two different methods,namely,a multi-melting process and homogenization heat treatment,are adopted to address the problem of incompletely melted Cr particles in the single-melted samples.X-ray diffraction indicates that HEA microstructure can be obtained from elemental powders via L-PBF.In the triple-melted samples,a strong crystallographic texture can be observed through electron backscatter diffraction,with a maximum polar density of 9.92 and a high ultimate tensile strength(UTS)of(735.3±14.1)MPa.The homogenization heat-treated samples appear more like coarse equiaxed grains,with a UTS of(650.8±16.1)MPa and an elongation of(40.2%±1.3%).Cellular substructures are also observed in the triple-melted samples,but not in the homogenization heat-treated samples.The differences in mechanical properties primarily originate from the changes in strengthening mechanism.The even and flat fractographic morphologies of the homogenization heat-treated samples represent a more uniform internal microstructure that is different from the complex morphologies of the triple-melted samples.Relative to the multi-melted samples,the homogenization heat-treated samples exhibit better processability,with a smaller composition deviation,i.e.,≤0.32 at.%.The two methods presented in this study are expected to ha

关键词： laser powder bed fusion(L-PBF) in situ alloying high-entropy alloys heat treatment rapid synthesis

Application of Fengyun-4 Satellite to Flood Disaster Monitoring through a rapid Multi-Temporal synthesis Approach

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Journal of Meteorological Research 2020年第4期34卷 720-731页

作者： Jiali SHAO Hao GAO Xin WANG Qianqian ZHANG National Satellite Meteorological Center China Meteorological AdministrationBeijing 100081

Fengyun-4 A(FY-4 A) belongs to the second generation of geostationary meteorological satellite series in China. Its observations with high frequency and resolution provide a better data basis for monitoring of extreme weather such as sudden flood disasters. In this study, the flood disasters occurred in Bangladesh, India, and some other areas of South Asia in August 2018 were investigated by using a rapid multi-temporal synthesis approach for the first time for removal of thick clouds in FY-4 A images. The maximum between-class variance algorithm(OTSU;developed by Otsu in 2007) and linear spectral unmixing methods are used to extract the water area of flood disasters. The accuracy verification shows that the water area of flood disasters extracted from FY-4 A is highly correlated with that from the high-resolution satellite datasets Gaofen-1(GF-1) and Sentinel-1 A, with the square correlation coefficient R2 reaching 0.9966. The average extraction accuracy of FY-4 A is over 90%. With the rapid multi-temporal synthesis approach used in flood disaster monitoring with FY-4 A satellite data, advantages of the wide coverage, fast acquisition,and strong timeliness with geostationary meteorological satellites are effectively combined. Through the synthesis of multi-temporal images of the flood water body, the influence of clouds is effectively eliminated, which is of great significance for the real-time flood monitoring. This also provides an important service guarantee for the disaster prevention and reduction as well as economic and social development in China and the Asia-Pacific region.

关键词： flood disaster monitoring maximum between-class variance algorithm(OTSU) Fengyun-4A(FY-4A) multi-temporal rapid synthesis

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rapid reactive synthesis of TiAl3 intermetallics by thermal explosion and its oxidation resistance at high temperature

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Progress in Natural Science:Materials International 2019年第4期29卷 447-452页

作者： Xinyang Jiao Xiaoping Cai Gao Niu Xuanru Ren Xueqin Kang Peizhong Feng School of Materials Science and Engineering China University of Mining and Technology School of Chemical Engineering and Technology China University of Mining and Technology Research Center of Laser Fusion China Academy of Engineering Physics

Porous TiAl3intermetallics were synthesized from Ti-75 at.% A1 elemental powder mixtures using an energysaving and rapid reactive method of thermal explosion(TE).The results demonstrated that the actual temperature of the compact climbed rapidly from 673℃to 1036℃within 24 s,indicating that an obvious TE reaction occurred during sintering process.The video graphs suggested that the TE in Ti-Al system behaved instant occurrence and overall heating whether from axial or radial direction.The silver wires and NaCl particles that pressed on the surface of the sample disappeared due to the heavy heat released during TE reaction.Only pure TiAl3phases were synthesized in TE products and the open porosity of 55.4% was easy to obtain.After high-temperature treatment at 1000℃,large amounts of sintering-neck formed and then improved the compressive strength of porous TiAl3materials.Moreover,the mass gain curve of porous TiAl3intermetallics oxidized at 650℃for 120 h exhibited the parabolic oxidation rate law.XPS analysis confirmed that the strong O 1 s peak was 531.4 eV which was the typical binding energy of Al2O3.Therefore,the excellent oxidation resistance of porous TiAl3foams would be considered as good candidate materials for prolonging the service life at high temperatures.

关键词： Porous materials rapid synthesis TiAl3 intermetallics Thermal explosion Oxidation resistance

Noble metal aerogels rapidly synthesized by ultrasound for electrocatalytic reaction

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Chinese Chemical Letters 2022年第4期33卷 2021-2025页

作者： Yueyue Yuan Huan Zhao Wenxia Xv Dan Zhang Zuochao Wang Hongdong Li Yingnan Qin Shaoxiang Li Jianping Lai Lei Wang Key Laboratory of Eco-chemical Engineering Key Laboratory of Optic-electric Sensing and Analytical Chemistry of Life ScienceTaishan Scholar Advantage and Characteristic Discipline Team of Eco Chemical Process and TechnologyCollege of Chemistry and Molecular EngineeringQingdao University of Science and TechnologyQingdao 266042China Shandong Engineering Research Center for Marine Environment Corrosion and Safety Protection College of Environment and Safety EngineeringQingdao University of Science and TechnologyQingdao 266042China

Noble metal aerogels(NMAs), belonging to the porous material, have exhibited excellent catalytic performance. Although the synthesis method continues to improve, it still exists some problems which hindered the experimental process, such as high concentration of noble metal precursors, long synthesis cycle, expensive production cost, and uncontrollable ligament length. In this work, ultrasonic wave and reducing agent Na BH;were simultaneously applied to gelation process. With the cavitation of ultrasound,it can generate huge energy with heating and stirring, thus gelation reaction proceeded quickly, and even completed the process in only a few seconds, that is much faster than the recorded. A wide concentration range was successfully expanded from 0.02 mmol/L to 62.5 mmol/L. Further, we extended this method to a variety of noble metal elements(Au, Ru, Rh, Ag, Pt, Pd), and this method is adaptive for the synthesis of single metal aerogels(Au, Ag, Ru, Rh, Pd), bimetal and trimetal aerogels(Au-Ag, Au-Rh, Au-Ru, Au-Pt,Au-Pd, Au-Pt-Pd). In addition, the ligament size of alloy aerogels are 10 nm or less. Moreover, their brilliant properties were demonstrated in hydrogen evolution reaction(HER) and ethanol oxidation reaction(EOR).

关键词： Ultrasonic Aerogels Noble metals rapid synthesis Electrocatalysis

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High efficiency synthesis of HKUST-1 under mild conditions with high BET surface area and CO2 uptake capacity

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Progress in Natural Science:Materials International 2018年第5期28卷 584-589页

作者： Yipei Chen Xueliang Mu Edward Lester Tao Wu New Materials Institute The University of Nottingham Ningbo China Department of Chemical and Environmental Engineering The University of Nottingham Municipal Key Laboratory of Clean Energy Conversion Technologies The University of Nottingham Ningbo China

This study focuses on the development of a hydrothermal method for the rapid synthesis of good quality copper benzene-1,3,5-tricarboxylate(referred to as HKUST-1)with high yield under mild preparation conditions to address the issues associated with reported methods.Different synthesis conditions and activation methods were studied to understand their influence on the properties of HKUST-1.It was found that mixing the precursors at50°C for 3 h followed by activation via methanol refluxing led to the formation of a product with the highest BET specific surface area of 1615 m~2/g and a high yield of 84.1%.The XRD and SEM data illustrated that the product was highly crystalline.The sample was also tested on its capacity in CO2adsorption.The results showed strong correlation between surface area of the sample and its CO2uptake at 1 bar and 27°C.The HKUST-1 prepared in this study demonstrated a high CO2uptake capacity of 4.2 mmol/g.It is therefore concluded that this novel and efficient method can be used in the rapid preparation of HKUST-1 with high surface area and CO2uptake capacity.

关键词： Metal organic framework HKUST-1 rapid synthesis Green synthesis CO2 adsorption