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Numerical simulation of microstructure and microporosity morphology in directional solidification of aluminum-copper alloys:Effect of copper content and withdrawal rate

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China Foundry 2025年第1期22卷 33-44页

作者： Wei Yuan Hai-dong Zhao Xu Shen Chun Zou Yuan Liu Qing-yan Xu National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510640China Key Laboratory for Advanced Materials Processing Technology(Ministry of Education) Tsinghua UniversityBeijing 100084China

Microporosity formed in the solidification process of Al alloys is detrimental to the alloy properties.A two-dimensional cellular automaton(CA)model was developed to simulate the microstructure and microporosity formation in Al-Cu alloys,considering variations in Cu content and solidification *** results indicate that the Cu content primarily influences the growth of *** validate the model,directional solidification experiments were conducted on Al-Cu alloys with varing Cu contents and withdrawal *** experimental results of dendrites and microporosity characteristics agree well with the predictions from the developed model,thus confirming the validity of the *** alloy’s liquidus temperature,dendrite morphology,and hydrogen saturation solubility arising from different Cu contents have significant effects on microporosity *** withdrawal rate primarily affects the nucleation of hydrogen microporosity by altering cooling rates and dendritic growth rates,resulting in different microporosity characteristics.

关键词： microporosity dendrites cellular automaton Al-Cu alloys directional solidification

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Low-cost dopant-free fluoranthene-based branched hole transporting materials for efficient and stable n-i-p perovskite solar cells

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Chinese Chemical Letters 2024年第10期35卷 187-193页

作者： Xinyu Yu Fei Wu Xianglang Sun Linna Zhu Baoyu Xia Zhong'an Li Key Laboratory for Material Chemistry of Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Energy Faculty of Materials&EnergySouthwest UniversityChongqing 400715China

It has been widely recognized that hole transporting materials(HTMs)play a key role in the rapid progress of perovskite solar cells(PVSCs).However,common organic HTMs such as spiro-OMe TAD not only suffer from high synthetic costs,but also usually require the additional chemical doping process to improve their hole transport ability,which unfortunately induces the terrible stability ***,it is urgent to develop low-cost dopant-free HTMs for efficient and stable *** this work,we have successfully developed a new class of efficient dopant-free fluoranthene-based HTMs(TPF1–5)with quite low lab synthetic costs by combining donor-acceptor and branched structure *** detailed structure-property study revealed that tuning the twisted arms at different substitution sites would regulate the intermolecular interactions and film-forming ability,thereby significantly affecting the performance of the *** applying these HTMs in conventional PVSCs,the dopant-free TPF1-based devices not only achieved the best efficiency of 21.76%,which is comparable to that of the doped spiro-OMeTAD control devices,but also showed much better operational stability,which maintained over 87%of the initial efficiency under maximum power point tracking after 1038 h.

关键词： Perovskite solar cells Holetransporting materials Dopant-free Fluoranthene Low-cost

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Microstructure and mechanical properties of nickel-based wrought superalloys under thermal-mechanical coupling: A review with Inconel 718,625 as main cases

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Progress in Natural Science:materials International 2025年第1期35卷 65-82页

作者： Kai Cao Jiangkun Fan Xudong Liu Jianing Zhang Dian Jiao Yuelin Song Fulong Chen Jun Wang Bin Tang Hongchao Kou Jinshan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical University National & Local Joint Engineering Research Center for Precision Thermoforming Technology of Advanced Metal Materials Chongqing Innovation Center Northwestern Polytechnical University AVIC Manufacturing Technology Institute

The typical processing and in-service behaviors of nickel-based wrought superalloys involve complex thermal-mechanical coupling effects, including elastic and plastic deformations, phase transformations, and other microstructural evolutions, directly impacting the mechanical properties. This review article provides an in-depth discussion on the microstructural evolution of these superalloys under thermal-mechanical coupling, focusing on two key aspects: the thermoplastic deformation behavior, and the phase transformation behavior in temperature/stress coupled field. The dynamic recrystallization(DRX) behavior during hot deformation and its improvement strategies are discussed in detail. The differences in phase precipitation behavior under conventional heat treatment and thermal-mechanical coupling conditions are compared. The mechanisms driving changes in precipitate characteristics are explored, enabling precise control of precipitates. This article further investigates the intricate relationship between the mechanical properties of nickel-based wrought superalloys and the characteristics of their precipitates, offering guidance for current and future optimizations. It also delves into the latest research advancements in precisely tailoring the precipitates through thermal-mechanical coupling methods to optimize these mechanical properties. Finally, it outlines several promising future research directions in this field.

关键词： Dynamic recrystallization

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Research on the Master Plan Scheduling of Casting Workshop Based on Deep Reinforcement Learning 75

Research on the Master Plan Scheduling of Casting Workshop B...

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75th World Foundry Congress, WFC 2024

作者： Zhou, Wenhao Chen, Fayuan Yu, Peng Ji, Xiaoyuan Yin, Yajun Zhou, Jianxin State Key Laboratory of Material Processing and Die & Mould Technology Huazhong University of Science & Technology Wuhan430074 China

With the continuous enhancement of productivity and management levels, many foundry enterprises have begun to adopt multi-workshop distributed production, with each workshop capable of independently completing the full-process machining of castings. Consequently, the complexity of production scheduling tasks has further increased, making the master scheduling of distributed workshops the primary challenge in scheduling. This paper investigates a multi-objective optimization method for distributed workshop scheduling. Initially, a multi-objective optimization model is established, targeting the minimization of the maximum completion time, the minimization of order earliness/tardiness penalties, and the minimization of workshop load imbalance. By employing triangular and trapezoidal fuzzy numbers, the production process of castings is abstracted into a black-box model, upon which master scheduling research is conducted. The production status of workshops is conceptualized as agents, with the state of the workshop agents described by order status, current completion times across workshops, and the total completion time of the task queue. The allocation of tasks and the selection of workshops serve as actions, and a reward mechanism is set based on the objective functions. A dual-network deep reinforcement learning algorithm is utilized to solve the master scheduling model, and the results obtained are compared with those from an in-house improved particle swarm algorithm. The findings indicate that the proposed deep reinforcement learning outperforms the improved particle swarm algorithm in terms of performance for smaller-scale problems. © 2024 75th World Foundry Congress, WFC 2024. All rights reserved.

关键词： Deep reinforcement learning

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Efficient overall photosynthesis of H_(2)O_(2) by the BTz@Mn_(0.2)Cd_(0.8)S S-scheme heterojunction

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Science China Chemistry 2024年第6期67卷 1953-1960页

作者： Zhongyue Chen Sijie Wan Bei Cheng Wang Wang Yao Xiang Jiaguo Yu Shaowen Cao State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China Hubei Technology Innovation Center for Advanced Composites Wuhan University of TechnologyWuhan430070China Hospital of Wuhan University of Technology Wuhan University of TechnologyWuhan430070China Laboratory of Solar Fuel Faculty of Materials Science and ChemistryChina University of GeosciencesWuhan430074China

The photosynthesis of hydrogen peroxide(H_(2)O_(2))through the selective 2e^(-)oxygen reduction reaction(ORR)from O_(2)and H_(2)O stands out as an environmentally sustainable and cost-effective method for generating this essential ***,the widespread application of most photocatalysts is impeded by their reliance on sacrificial *** this context,we present a noteworthy advancement in the form of a step-scheme(S-scheme)heterojunction involving a donor-acceptor(D-A)-conjugated polymer and manganese cadmium sulfide(BTz@MCS).This innovative configuration enables efficient photocatalytic H_(2)O_(2)production within a non-sacrificial system,showcasing an impressive H_(2)O_(2)yield of 5,368μmol g^(-1)h^(-1)and an apparent quantum yield of 4.5%at 420 *** insights gained from in-situ irradiated X-ray photoelectron spectroscopy(ISIXPS),in-situ diffuse reflectance infrared Fourier transformations spectroscopy(DRIFTS),and density function calculations(DFT),it is revealed that the sp^(2)C between thiazole-thiazole rings at the BTz and the concentrated holes at the MCS function as spatially separated redox *** centers catalyze the selective 2e^(-)ORR and 4e^(-)water oxidation reaction(WOR)*** O_(2)generated from the WOR is subsequently utilized by the ORR cycle,enabling the overall photosynthesis of H_(2)O_(2)with accelerated total reaction ***,the high photocatalytic performance of the developed catalyst is attributed to well-designed S-scheme heterojunctions with tuned band *** spatially separated redox centers and effective transfer of photogenerated charge carriers facilitated by the internal electric field significantly enhance reaction *** study introduces a promising avenue for photocatalytic H_(2)O_(2)production without sacrificial agents,providing valuable insights into the underlying mechanisms in S-scheme heterojunctions.

关键词： hydrogen peroxide non-sacrificial redox centers S-scheme heterojunction

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Experimental and theoretical investigations of the photoelectrochemical and photo-Fenton properties of Co-doped FeOCl

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Chinese Physics B 2023年第9期32卷 427-435页

作者：马金环魏智强丁梅杰赵继威路承功 School of Science Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of TechnologyLanzhou 730050China

For the first time,two-dimensional FeOCl(Fe_(1-x)Co_(x)OCl)doped with Co was successfully applied to the photocatalytic and photo-Fenton degradation of Rhodamine B(RhB).The photocatalytic and photo-Fenton experiments showed that the degradation rates of RhB by Fe0.94Co0.06OCl are 82.6%and 98.2%within 50 min under neutral solution,room temperature and visible *** inclusion of Co resulted in lattice imperfections on the surface of Fe OCl,which was advantageous for the photogenerated electron-hole pair separation efficiency(consistent with the density functional theory calculation).Moreover,the RhB removal rate decreased from 98%to 82%during five successive cycles,showing good structural ***,based on the radical capture experiment,a potential mechanism for RhB degradation by Fe_(1-x)Co_(x)OCl catalyst was *** idea of a synergistic mechanism for Fe_(1-x)Co_(x)OCl also offers a fresh concept for catalysts used in doping modification.

关键词： Co doped FeOCl photo-Fenton photocatalytic DFT calculations

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Energy-dispersive X-ray Spectroscopy for the Quantitative Analysis of Pyrite Thin Specimens

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Journal of Wuhan University of technology(materials Science) 2023年第6期38卷 1304-1310页

作者： LUO Tingting GUO Yi DENG Zhao LIU Xiaoqing SUN Zhenya QI Yanyuan YANG Meijun Center for Materials Research and Analysis Testing Wuhan University of Technology Wuhan 430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070Wuhan

To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantitative analysis of pyrite ***,the k factor of pyrite is calculated *** develop an appropriate non-standard quantitative analysis model for pyrite materials,the experimentally calculated k factor is compared with that estimated from the non-standard quantitative analytical model of the instrument *** experimental findings demonstrate that the EDS attached to a TEM can be employed for precise quantitative analysis of micro-and nanoscale regions of pyrite ***,it serves as a reference for improving the results of the EDS quantitative analysis of other sulfides.

关键词： analytical transmission electron microscopy(AEM) energy dispersive X-ray spectroscopy(EDS) pyrite thin specimen quantitative analysis

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Efficient blocked symmetric compressed sparse column method for finite element analysis

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Frontiers of Mechanical Engineering 2025年第1期20卷 87-104页

作者： Yingjun WANG Shijie LUO Jinyu GU Yuanfang ZHANG National Engineering Research Center of Novel Equipment for Polymer Processing The Key Laboratory of Polymer Processing Engineering of the Ministry of EducationGuangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced ManufacturingSouth China University of TechnologyGuangzhou 510641China Shien-Ming Wu School of Intelligent Engineering South China University of TechnologyGuangzhou 511442China

In finite element analysis(FEA),optimizing the storage requirements of the global stiffness matrix and enhancing the computational efficiency of solving finite element equations are pivotal *** address these goals,we present a novel method for compressing the storage of the global stiffness matrix,aimed at minimizing memory consumption and enhancing FEA *** method leverages the block symmetry of the global stiffness matrix,hence named the blocked symmetric compressed sparse column(BSCSC)*** also detail the implementation scheme of the BSCSC method and the corresponding finite element equation solution *** approach optimizes only the global stiffness matrix index,thereby reducing memory requirements without compromising FEA computational *** then demonstrate the efficiency and memory savings of the BSCSC method in FEA using 2D and 3D cantilever beams as *** addition,we employ the BSCSC method to an engine connecting rod model to showcase its superiority in solving complex engineering ***,we extend the BSCSC method to isogeometric analysis and validate its scalability through two examples,achieving up to 66.13%memory reduction and up to 72.06%decrease in total computation time compared to the traditional compressed sparse column method.

关键词： finite element analysis global stiffness matrix blocked symmetric property memory reduction isogeometric analysis

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Effect of Microstructural Characteristics on Fracture Toughness in Direct Energy Deposited Novel Ti-6Al-4V-1Mo Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 119-131页

作者： Chao Xia Kexin Zhao Xin Zhou Yuqi He Panpan Gao Hengxin Zhang Guangrui Gao Fengying Zhang Hua Tan School of Material Science and Engineering Chang’an UniversityXi’an710064China Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi’an710038China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China Surface Material Protection Co. LtdXi’an710018China

Meeting the damage tolerance requirements for engineering-grade titanium alloys pose a significant challenge in achieving high fracture toughness in direct energy deposition(DED)titanium *** work primarily investigated the relationship between the microstructure and the fracture toughness of DED new Ti-6Al-4V-1Mo *** types of microstructures were designed via two process strategies:high-line energy density(HE)and low-line energy density(LE).Relative to LE samples,HE samples possess larger-sized microstructural characteristics(coarser grain boundaryα(α_(GB)),largerαcolonies,and coarserαlaths).Lessα/βphase boundaries were formed by coarserαlaths in the HE samples,increasing the movement of dislocations,resulting in tensile strength decreasing from 1007.1 MPa(LE)to 930.8 MPa(HE)and elongation increasing from 10.8%(LE)to 15.7%(HE).Also,HE samples exhibited an excellent fracture toughness of 114.0 MPa m^(1/2),significantly higher than that of LE samples(76.8 MPa m^(1/2)).An analysis of crack propagation paths was conducted to investigate the factors contributing to *** primary factor enhancing toughness is the frequent obstruction of cracks by coarseαGB and largeαcolonies in HE ***,the pretty large-angle deflections induced by the superposition effect of coarseαGB and largeαcolonies play a vital of significant *** factors induced the long and tortuous high-energy pathways,which resulted in ultimately improved fracture *** discovered microstructural toughening mechanisms can serve as a reference for future studies involving titanium alloys,offering insights on how to enhance fracture toughness by achieving similar characteristics.

关键词： Direct energy deposition Ti-6Al-4V-1Mo Tensile properties Fracture toughness Crack propagation

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Stress-Regulation Design of Lithium Alloy Electrode toward Stable Battery Cycling

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Energy & Environmental materials 2023年第1期6卷 184-191页

作者： Chunhao Li Shuibin Tu Xin Ai Siwei Gui Zihe Chen Wenyu Wang Xiaoxiao Liu Yuchen Tan Hui Yang Yongming Sun Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Material Processing and Die&Mould Technology Department of MechanicsSchool of Aerospace EngineeringHuazhong University of Science and TechnologyWuhan 430074China

Metallic tin(Sn)foil is a promising candidate anode for lithium-ion batteries(LIBs)due to its metallurgical processability and high ***,it suffers low initial Coulombic efficiency and inferior cycling stability due to its uneven alloying/dealloying reactions,large volume change and stress,and fast electrode structural ***,we report an undulating LiSn electrode fabricated by a scalable two-step procedure involving mechanical lithography and chemical prelithiation of Sn *** the combination of experimental measurements and chemo-mechanical simulations,it was revealed the obtained undulating LiSn/Sn electrode could ensure better mechanical stability due to the pre-swelling state from Sn to Li x Sn and undulating structure of lithography in comparison with plane Sn,homogenize the electrochemical alloying/dealloying reactions due to the activated surface materials,and compensate Li loss during cycling due to the introduction of excess Li from Li_(x)Sn,thus enabling enhanced electrochemical *** cells consisting of undulating LiSn/Sn electrode with an active thickness of∼5 um displayed stable cycling over 1000 h at 1 mA cm^(-2) and 1 mAh cm^(-2) with a low average overpotential of<15 *** paired with commercial LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)cathode with high mass loading of 15.8 mg cm^(-2),the full cell demonstrated a high capacity of 2.4 mAh cm^(-2) and outstanding cycling stability with 84.9% capacity retention at 0.5 C after 100 *** work presents an advanced LiSn electrode with stress-regulation design toward high-performance LIBs,and sheds light on the rational electrode design and processing of other high-capacity lithium alloy anodes.

关键词： chemo-mechanical simulation lithium alloy lithium-ion batteries mechanical lithography stress regulation

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