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SSRN 2023年

作者： Zhang, Liang Wang, Songtao Wang, Huixia Wang, Jun Bian, Wenzhuo Hebei Engineering Laboratory of Aviation Lightweight Composite Materials and Processing Technology School of Materials Science and Engineering Hebei University of Science and Technology Hebei050018 China Hebei Key Laboratory of Material Near-net Forming Technology School of Materials Science and Engineering Hebei University of Science and Technology Hebei050018 China Special-shaped Parts Forming Technology of Aviation Composites Laboratory of Hebei Province Hebei050018 China

In this study, a hybrid wire arc additive manufacturing (HWAAM) process that combines low frequency vibration with cold metal transfer (CMT) arc is proposed to address the problems of porosity, coarse grains, and low mechanical performance encountered in WAAM aluminum alloys. The effects of different vibration frequencies on the microstructure and mechanical properties were investigated. The results indicated that as the vibration frequency increases, the grain size refinement reaches a maximum of 19.1% compared with the non-vibrated specimen. Vibration can enhance the fluidity and the cooling rate of the weld pool. The fatigue fracture of dendrite arms is the main mechanism of microstructure grain refinement caused by vibration. The dynamic bending stress induced by vibration on the dendrite arms and the root remelting phenomenon are the dominant factors for the dendrite fragmentation. Increasing the vibration frequency did not result in an obvious improvement in the tensile strength of the specimens, but did significantly increase the elongation. With the increase in vibration frequency, the maximum transverse and longitudinal elongation reached 22.2% and 23.5% respectively, a raise of 15.6% and 38.2% compared with non-vibrated specimen. Vibration reduced the size and distribution density of pores on the fracture surface, and increased the dimpled microstructure, improving the mechanical performance of the aluminum alloy. © 2023, The Authors. All rights reserved.

关键词： 3D printing

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A New Method for Improving Static and High Frequency Magnetic Properties of Fe67Co18Si11B4Amorphous Alloy 10

A New Method for Improving Static and High Frequency Magneti...

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2023 10th International Conference on Advanced Manufacturing technology and materials Engineering, AMTME 2023

作者： Wang, Dongmeng Ding, Yanhong Ma, Xu Li, Yan School of Integrated Circuit Science and Engineering Tianjin Key Laboratory of Film Electronic and Communication Devices Tianjin University of Technology Tianjin300384 China School of Material Science and Engineering Tianjin Engineering Center of Near-Net-Shape Forming Technology for Metallic Materials Tianjin University of Technology Tianjin300384 China Co. Ltd Tianjin300385 China

Rapidly quenched ribbons with a composition of Fe67Co18Si11B4 have been investigated. Surface leveling on the ribbon-free surface leads to the decline of the interior stress of Fe67Co18Si11B4 amorphous alloy, making a decrease of coercivity and a great improvement of static magnetic properties. Free surface leveling treatment can improve the AC magnetic properties of the Fe67Co18Si11B4 amorphous alloy. In high frequency region 106 Hz 3 can be achieved after surface leveling. Free surface leveling is an attractive method to achieve improvements in both static and high frequency magnetic properties. © Published under licence by IOP Publishing Ltd.

关键词： Cobalt alloys

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Development of Nb-Based Alloy Membranes with Improved Resistance to Corrosion by H2s

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SSRN 2023年

作者： Yan, Erhu Zhang, Shuo Liu, Wei Zhang, Kexiang Huang, Guanzhong Jia, Limin Tao, Lizhen Chen, Hongfei Bai, Jinwang Chu, Hailiang Zou, Yongjin Zhang, Huanzhi Xu, Fen Sun, Lixian Guangxi Key Laboratory of Information Materials Guilin University of Electronic Technology Guilin541004 China Hebei Key Laboratory of Material Near-Net Forming Technology Hebei University of Science and Technology Shijiazhuang050018 China Department of Energy Materials and Telecommunications INRS-EMT QuebecJ3X 1S2 Canada

At present, the interest in non-Pd hydrogen permeation membranes mainly focuses on group 5B metals (Nb, V, Ta) and their alloys. To solve the problem of easy oxidation and weak dissociation of hydrogen molecules, a "Pd catalytic layer" needs to be deposited on the membrane surface. Due to its limited stability towards sulfur, issues of irreversible poisoning by sulfur compounds must be addressed. To this end, Pd-, Pd65Ag35-, Pd90Cu10-, Pd80Au20-, and Pd55Ag35Au10-coated Nb30Hf35Co35 membranes were firstly synthesised by magnetron sputtering, and their hydrogen permeation behaviour in pure H2 and/or in different H2/H2S mixtures for up to 1000 ppm at 673 K were evaluated. At these conditions, the permeabilities of the Pd-coated membranes decrease rapidly with increasing the H2S concentration and cannot recover after removal of H2S from the feed mixtures. In comparison, the Pd-Ag-containing membrane greatly increases the pure H2 permeability, whereas the membrane doped with Au can effectively improve the response to H2S. Specifically, the Pd65Ag35-coated membrane shows the highest pure H2 permeability, but it loses maximum permeability value on exposure to H2/H2S feed mixtures. In contrast, Pd80Au20-containing membranes exhibit good tolerance of H2S poisoning and displayed a high fractional recovery (~ 83%) of initial H2 permeability. The degradation of permeability for Pd- or Pd65Ag35-coated membranes after the H2S exposure can be ascribed to the deterioration of the structure caused by the possible formation of bulk Pd4S, which has been corroborated with EDS analysis, XRD, and XPS after testing. Finally, to improve both permeability and chemical tolerance, a Pd55Ag35Au10-coated membrane was successfully fabricated, and it possesses excellent comprehensive performance with respect to the permeability and H2S response. At 120 ppm H2S in the feed, the H2 flux equals ca. 43% of its original value at 673 K and can be stable for at least 166 hours. Bulk sulfides did not fo

关键词： Sulfur compounds

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Atomic Simulations on the Deformation Mechanisms in Nano-Crystalline Ni-Based Superalloy Based on Grain Size, Temperature and Strain Rate

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SSRN 2022年

作者： Dong, Huicong Xu, Tianhao Ning, Tianyang Liu, Meng Wu, Dayong Ma, Haikun Feng, Zhihao Narayanaswamy, Balaji Su, Ru Hebei Key Laboratory of Material Near-net Forming Technology Hebei Engineering Laboratory of Aviation Lightweight Composite Materials and Processing Technology School of Materials Science and Engineering Hebei University of Science and Technology Hebei Shijiazhuang050000 China AVIC Shangda Superalloy Materials Co. Ltd Hebei Xingtai054800 China School of Engineering Deakin University Geelong Australia

Molecular Dynamic (MD) simulations were used to investigate the tensile properties of nanocrystalline Ni-based superalloy at different grain sizes (6.54~20 nm), temperatures (300~1000 K) and strain rates (1×107~1×109 s-1). Results indicate that plastic deformation of nanocrystalline Ni-based superalloy was governed by stacking faults and FCC-to-HCP martensitic phase transformation, which was significantly different from twinning-dominated plastic deformation in nanocrystalline Ni. Nevertheless, the conventional Hall-Petch breakdown occurred at a critical grain size in both nanocrystalline Ni and Ni-based superalloy. Moreover, flow stress and Young’s modulus were both strongly affected by temperature and strain rate. Furthermore, an increase in temperature can accelerate GB diffusion and GB migration. And, GB diffusion and GB migration were the main plastic deformation mechanisms at higher strain rates. The current study provides an atomic perspective on the deformation process and mechanisms in nanocrystalline Ni-based superalloy, as well as new perspectives on designing novel superalloys with excellent mechanical properties. © 2022, The Authors. All rights reserved.

关键词： Strain rate

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Investigation on Fatigue Failure of Split-Sleeve Cold Expansion Holes of 7075-T651 Aluminum Alloy

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SSRN 2023年

作者： Su, Ru Li, Jinyu Liu, Weiguang Xu, Changzhou Gao, Lijie Liang, Xueze Wu, Dayong Huang, Xin Dong, Huicong Ma, Haikun Hebei Key Laboratory of Material Near-net Forming Technology School of Materials Science and Engineering Hebei University of Science and Technology Shijiazhuang050018 China Shijiazhuang Haishan Industrial Development Corporation Shijiazhuang050208 China Oriental Bluesky Titanium Technology Co. LTD Yantai264670 China

7075-T6 is widely used in the fabrication of aircraft structural components, the majority of which are joined and assembled through hole structures. However, the geometric discontinuity near the fastener holes facilitates stress concentration and makes the joints susceptible to crack initiation and fatigue failure. It is essential to enhance the hole structure's fatigue resistance. In this work, the factors affecting the split-sleeve cold expansion on the fatigue behavior of fastener holes of 7075-T651 are studied based on the compressive residual stress, microstructure, surface roughness, and fatigue fracture. Results revealed that the residual stress curve along the hole axis shows a 'hook' shape while the tangential residual stress distribution around the hole is nonaxisymmetric, which is the main reason for the improved fatigue life of the specimens. The cold expansion causes sub-grain refinement near the hole wall, increasing the surface micro-hardness and improving the fatigue life. The main origin of the fatigue for cold expansion specimens is initiated at the corner of the hole on the mandrel inlet side. The constituent particles and microstructure after expansion are important factors affecting fatigue performance, and the presence of iron-bearing particles has a significant impact on service life reduction. © 2023, The Authors. All rights reserved.

关键词： Residual stresses

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Preparation of Nano Al 3 Ti-Tib 2 -Aln-Tin/Al Inoculant Ribbons And its Effect On Microstructures and Properties Of Alznmgcu Alloys

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SSRN 2023年

作者： Wang, Qian Zhao, Jinman Cui, Chunxiang Wu, Dayong He, Peng Ma, Haikun Kang, Jie Dong, Huicong Su, Ru Hebei Key Laboratory of Material Near-Net Forming Technology School of Materials Science and Engineering Hebei University of Science and Technology Shijiazhuang050018 China Key Lab. for New Type of Functional Materials in Hebei Province School of Materials science and Engineering Hebei University of Technology Tianjin300130 China China International Engineering Consulting Corporation Beijing100048 China

The nano Al3Ti-TiB2-AlN-TiN/Al inoculant ribbons which contain a large number of evenly distributed nano particles, such as Al3Ti (size about 300 nm),TiB2 (size about 100 nm), AlN (size about 150 nm) and TiN (size about 200 nm) were prepared by vacuum rapid quenching furnace to refine the AlZnMgCu alloys. The nano Al3Ti-TiB2-AlN-TiN/Al inoculant ribbons showed excellent inoculant effect, which modified the dendrite crystals to equiaxed crystals and refined the grains from 122 ± 4 μm to 36 ± 5 μm by addition of 0.3 wt% nano Al3Ti-TiB2-AlN-TiN/Al inoculant ribbons. In addition to nano Al3Ti and TiB2 particles, nano AlN and TiN particles also have a certain orientation relationship with α-Al, which suggest that these particles possess nucleation potency to α-Al. After inoculated by 0.3% nano Al3Ti-TiB2-AlN-TiN/Al inoculant ribbons, the ultimate tensile strength, yield strength, and microhardnessof the AlZnMgCu alloys increased from 246 MPa, 79 MPa, and 112 HV to 319 MPa, 100 MPa, and 136 HV, increased by 29.7%, 26.6% and 21.4%, respectively. © 2023, The Authors. All rights reserved.

关键词： Nanoparticles

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Atomic Simulations of Crack Propagation in Ni-Al Binary Single Crystal Superalloy with a Central Crack

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SSRN 2024年

作者： Yang, Liu Dong, Huicong Wu, Dayong Ma, Haikun Feng, Zhihao He, Peng Narayanaswamy, Balaji You, Baocai Wang, Qian Su, Ru Hebei Key Laboratory of Material Near-net Forming Technology Hebei Engineering Laboratory of Aviation Lightweight Composite Materials and Processing Technology School of Materials Science and Engineering Hebei University of Science and Technology Hebei Shijiazhuang050000 China China International Engineering Consulting Corporation Beijing100000 China Deakin University Australia Shenyang Aircraft Design Institute Shenyang110000 China

Nickel (Ni)-based single-crystal superalloys are of great importance in the aircraft industry due to their excellent mechanical properties, and cracks as unavoidable defects may affect the mechanical performances of materials dramatically. In this paper, large scale molecular dynamics (MD) simulations are carried out to understand the deformation mechanisms of Ni-based single crystal with a central crack under tension. Here, the effects of matrixes (g, g′ and g/g′), strain rates (1×109 s-1 ~ 3×109 s-1) and temperatures (300 K~ 900 K) on the role of crack propagation are considered. It is observed that dislocations and slip systems in the γ′ model are concentrated near the crack, resulting in the rapid expansion of dislocation, which leads to the fastest crack growth speed and early fracture. While the crack propagation rate of γ and γ/γ′ models are relatively slow,due to the combined action of the Lomer-Cottrell lock and stacking fault tetrahedron structure and Stair-rod dislocation, which hinders crack propagation. In addition, deformation at increased strain rates and/or reduced temperatures, lead to superior yield stress and Young′s modulus for models with a central crack at g/g′ interface. On the other hand, high temperature and high strain rate will promote crack propagation in the r phase, and the higher the strain rate and/or temperature, the faster the crack propagation speed will be. These results will enrich our understanding on the crack propagation and evolution mechanisms in Ni-based single crystal superalloy. © 2024, The Authors. All rights reserved.

关键词： Molecular dynamics

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Effect of Single and Double Stage Homogenization Treatments on Microstructure and Properties of Wire + Arc Additively Manufactured 2319 Al Alloy

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SSRN 2024年

作者： Cao, Fenglei Gu, Yunfei Wang, Liwei Liu, Ying Chen, Shaohui Tian, Changjiang Liang, Zhimin Narayanaswamy, Balaji Hebei Key Laboratory of Material Near-Net Forming Technology School of Materials Science and Engineering Hebei University of Science and Technology Shijiazhuang050018 China Beijing Aeronautical Technology Research Center Beijing100076 China Shijiazhuang Haishan Industrial Development Co. Ltd. Shijiazhuang050208 China University of Sydney NSW2006 Australia

In this study, the effect of homogenization treatments (single and double stages) on the wire + arc additively manufactured (WAAM) 2319 Al alloy was analyzed. This involved an in-depth study on the diffusion and dissolution of eutectic phases using advanced characterization techniques (DSC, XRD, optical and electron microscopy). Homogenization treatment parameters (temperature and time) were determined based on DSC analyses. These parameters were later confirmed using homogenization kinetics calculations. A single-stage homogenization at 530℃/24h facilitated a full diffusion of the Al2Cu phase, but some eutectic phases remain undissolved at the grain boundaries. There is resulted in reduction of hardness, ultimate tensile strength and yield strength reduced by 26.0%, 28.5 and 28.8, respectively. A double-stage homogenization at 480℃/8h + 530℃/24h facilitated a full diffusion and dissolution of Al2Cu, resulting in an improvement of elongation (by 2.8%), while the hardness, ultimate tensile strength and yield strength was reduced by 28.7%, 28.3 and 26.2, respectively. Al2Cu phase at the grain boundaries was almost disappeared, with several Al2Cu particles being precipitated within the grain. The homogenization treatments eliminated the eutectic phase segregation formed during the additive manufacturing (AM) process, improved the homogeneity of the WAAM 2319 Al alloy microstructures at a compromise in the mechanical properties. © 2024, The Authors. All rights reserved.

关键词： Diffusion

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Modulation of Catalyst Interfacial Electric Field and Charge Transfer Promotes Nis-Modified Cowo4/Znin2s4 S-Scheme Heterojunction for Efficient Photocatalytic Hydrogen Evolution

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SSRN 2024年

作者： Dou, Jianmin Liu, Xiaojie Dou, Mingyu Yang, Guang Liu, Erkang Li, Zeming Han, Baochen Yang, Hua Li, Dacheng Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology School of Chemistry and Chemical Engineering Liaocheng University Liaocheng252059 China Hebei Key Laboratory of Material Near-Net Forming Technology School of Material Science and Engineering Hebei University of Science and Technology 26 Yuxiang Street Shijiazhuang050018 China Institute of Powder Metallurgy and Advanced Ceramics School of Materials Science and Engineering University of Science and Technology Beijing Beijing100083 China

The strategic post-synthetic modification of engineered S-scheme heterojunctions represents a potent and manipulable approach to significantly enhance photocatalytic activity. This study details the synthesis of innovative photocatalysts via the deposition of NiS nanoparticles onto S-scheme heterojunctions of CoWO4/ZnIn2S4 (CWO/ZIS-NiS), facilitated by solvothermal and photochemical methodologies. Under visible light irradiation, the hydrogen production rate of CWO/ZIS-NiS was 22.398 mmol·g−1·h−1, which 15 times higher than that of the ZnIn2S4. XPS, EPR, SPV and DFT calculations were used to analyze the charge transfer path and the reasons for the performance improvement of the catalyst. The construction of theS-scheme CoWO4/ZnIn2S4 heterojunction, along with NiS modification to enhance the interfacial electric field (IEF) and act as a reaction center, was identified as the primary reason for the enhanced hydrogen production activity. This work provides guidance for the design of efficient photocatalytic systems using the synergistic effect between cocatalysts and S-scheme heterojunctions. © 2024, The Authors. All rights reserved.

关键词： Heterojunctions

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Microstructural Evolution and Carbides Precipitation Behavior and Their Effects on Mechanical Property of Nb-Ti Microalloyed Fb590 Steel

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SSRN 2024年

作者： Zheng, Yaxu Chu, Shaokang Yang, Qin Lin, Yu Zhu, Liguang Li, Yongliang Guo, Zhihong Zhang, Di Cao, Ruifang Feng, Jie Wang, Bo School of Material Science and Engineering Hebei Short Process Steel Making Technology Innovation Center Hebei Key Laboratory of Material Near-Net Forming Technology Hebei University of Science and Technology Shijiazhuang050018 China QuesTek Innovations EvanstonIL United States College of Materials Science and Engineering Chongqing University Chongqing400045 China Rolling operation department Beijing Shougang Co. LTD. Tangshan064404 China Hebei University of Science and Technology China

Ferrite-bainite dual phase steels have been widely used in automobile manufacturing industry due to their high strength and excellent hole expansion performance. In this study, the effects of coiling temperature on mechanical properties and hole expansion performance of low carbon Nb-Ti micro-alloyed FB590 ferrite-bainite steel have been studied. Additionally,, the microstructure evolution and carbide precipitation behavior during hot rolling and coiling processes have been investigated. The influence mechanism of microstructures and carbides on both mechanical properties and hole expansion performance has also been discussed. The results suggest that the fraction of the retained austenite and the martensite decreases gradually with increasing coiling temperatures from 450℃ to 500℃. The main reason for the formation of martensite and retained austenite in steel 1# coiled at 450℃ is that the coiling temperature is in the martensitic transformation range. Increasing the coiling temperature to 500℃ which is above the Ms leads to ferritic and bainitic structure. The carbides precipitation behavior has been studied by TEM, thermodynamic and kinetics calculation. The results show that the size of the carbides increases with increasing coiling temperatures from 450°C to 500°C. Most of the large size carbides above 100 nm with high percent of Ti are the undissolved particles in austenite during slab heating. The medium size particles between 10 nm and 100 nm precipitate during hot rolling. The small size carbides below 10 nm with high percent of Nb precipitate during coiling. The strength of the steel is effectively increased by the fine carbides and martensite formed at low coiling temperature of 450°C. However, the fine carbides, martensite and residual austenite are bad for plasticity and hole expansion performance. Raising the coiling temperature of FB590 steel from 450℃ to 500°C can effectively reduce the content of martensite and retained austenite in the steel. Altho

关键词： Microalloying

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