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Strengthening low-angle grain boundaries by twinning grids: Improving the ability of γ phase to store and block dislocations in TiAl alloy

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Journal of Alloys and Compounds 2025年 1034卷

作者： Xiaokang Yang Hongze Fang Lingyan Zhou Xianfei Ding Yong Zhang Ruirun Chen National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Harbin Heilongjiang 150001 PR China Zhengzhou Research Institute Harbin Institute of Technology Zhenzhou Henan 450000 PR China Cast Titanium Alloy R&D Center Beijing Institute of Aeronautical Materials Beijing 100095 PR China Heilongjiang Province Key Laboratory of Advanced Mg&Al Alloys Casting and Engineering Application Harbin Heilongjiang 150066 PR China

The twin grid structure enhances low-angle grain boundaries (LAGBs) in the γ phase, effectively storing and hindering dislocations to improve the high-temperature properties of TiAl alloys. Hf was added to Ti-47Al-6Nb-0.1C-1.6Ta alloy and related mechanisms were studied. The results indicate that the addition of Hf promotes the formation of a Hf-enriched γ phase (with an L 10 structure, defined as the γ Hf phase) in the TiAl alloy. The γ Hf phase is surrounded by a γ phase containing twin grids (with an L 10 structure, defined as the γ n phase). The γ Hf and γ n phases exhibit close orientations with LAGBs at their interfaces. The Hf and Al-rich regions in the α phase preferentially transform into the γ Hf phase, with α grain boundary migration making γ Hf either within the α parent phase or at its boundaries. The residual α phase around γ Hf undergoes multiple twinning on {111} and {100} planes, ultimately resulting in the formation of the γ n phase with twin grids. The 900 ℃ tensile strength and elongation of the Hf-added TiAl alloy reach 620.8 ± 23.1 MPa and 7.27 ± 0.6 %, respectively. The twin grids in the γ n phases uniformly accommodate dislocations, while the substantial lattice distortion and strong atomic bonding in γ Hf impede dislocation activation, resulting in the absence of dislocations within γ Hf . Consequently, the LAGB between γ n and γ Hf effectively hinders dislocations originating from the twin grids, thereby enhancing the alloy's high-temperature strength.

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Effect of Iron on Crystallization and Flow Properties of Coal Ash Slag: A Combined Computational-Experimental Study

SSRN

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SSRN 2022年

作者： Zhang, Linmin Song, Xudong Wei, Juntao Yang, Jianrong Bai, Yonghui Wang, Jiaofei Yang, Huijun Yu, Guangsuo State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering School of Chemistry and Chemical Engineering Ningxia University Yinchuan750021 China Co-Innovation Center of Efficient Processing Utilization of Forest Resources School of Materials Science and Engineering Nanjing Forestry University Nanjing210037 China CHN Energy Ningxia Coal Industry Co. Ltd. Yinchuan750000 China Institute of Clean Coal Technology East China University of Science and Technology Shanghai200237 China

The crystallization and viscosity behavior of coal ash slag play a decisive role in the stable slagging of industrial gasifiers. However, the influence of iron on the crystallization and flow properties of slag is still poorly understood for its heterovalent component. Therefore, the influence of iron on the melting and crystallinity of slag was studied by preparing synthetic ashes with different iron contents, in this work. The results demonstrated that the ash fusion temperature (AFTs) could be significantly lowered with the increase of Fe content. This was because of the low-temperature eutectic reaction in slag caused by the increased iron content, which caused the sub-liquid phase in slag to change from high-melting mullite to low-melting anorthite and spinel. At high temperature, iron was mainly presented in slag as Fe2+. At the same time, Fe2+ as an alkaline component could terminate the interconnection between [SiO4]4- and [AlO4]5- tetrahedral by replacing Si4+ and Al3+ in slag. This consequence destroyed the slag network structure and lowered the degree of polymerization. Slag with lower polymerization degree exhibited lower viscosity and stronger ionic transport capacity, which was favorable for crystal growth. Meanwhile, thermodynamic and quantum chemical calculations revealed that anorthite was a crystalline mineral during slag cooling. © 2022, The Authors. All rights reserved.

关键词： Slags

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Proactively introducing defects and forming twinning and low angle grain boundaries in the γ phase to particularly improve the 900 °C tensile strengths of theTi-47Al-6Nb-0.1C-1.6Ta alloy

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materials Science and Engineering: A 2025年 940卷

作者： Xiaokang Yang Hongze Fang Lingyan Zhou Kexuan Li Xianfei Ding Yong Zhang Ruirun Chen National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Harbin Heilongjiang 150001 PR China Zhengzhou Research Institute Harbin Institute of Technology Zhenzhou Henan 450000 PR China Cast Titanium Alloy R&D Center Beijing Institute of Aeronautical Materials Beijing 100095 PR China Heilongjiang Province Key Laboratory of Advanced Mg&Al Alloys Casting and Engineering Application Harbin Heilongjiang 150066 PR China

Actively introducing different types of defects into γ phase with lower formation energy is an effective method to improve the mechanical properties of TiAl alloys at room and high temperatures. Ta was added in Ti-47Al-6Nb-0.1C alloy (TiAl-0Ta alloy), and defect types, microstructure, mechanical properties at room and 900 °C, and related mechanisms were studied. Results show that four kinds of surface defects are formed in the γ phase between lamellar colonies after adding Ta, including stacking faults (SFs), twin boundaries (TB), low angle grain boundaries (LAGB) and 120° rotation boundaries (RB). Ta promotes SFs generating by reducing the stacking fault energy. Insertion of extrinsic SF changes the stacking order to generate twin. The continuous generation of SFs leads to the widening of twins. Ta substitute Al will form lattice distortion and vacancies. Vacancies are filled by Al atoms to form edge dislocations, resulting in LAGB. The substitution also reduces the formation energy of the RB to form that. Compressive strength and strain of Ti-47Al-6Nb-0.1C-1.6Ta alloy (TiAl-1.6Ta alloy) reached 2606 MPa and 40.6 %, and the 900 °C tensile strength and elongation of alloy reached 550.2 MPa and 10.8 %. The edge dislocation at LAGB, elastic stress field at TB and RB increase the critical resolved shear stress of dislocation and hinder dislocation slip. The SFs decompose the dislocation into partial dislocations to consume its energy.

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Observation of the out-of-plane polarized spin current from CVD grown WTe2

arXiv

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arXiv 2021年

作者： Shi, Shuyuan Li, Jie Hsu, Chuang-Han Lee, Kyusup Wang, Yi Yang, Li Wang, Junyong Wang, Qisheng Wu, Hao Zhang, Wenfeng Eda, Goki Liang, Gengchiau Chang, Haixin Yang, Hyunsoo Department of Electrical and Computer Engineering National University of Singapore 117576 Singapore Quantum-Nano Matter and Device Lab State Key Laboratory of Material Processing and Die & Mould Technology School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan430074 China Institute of Physics Academia Sinica Taipei11529 Taiwan Key Laboratory of Materials Modification by Laser Ion and Electron Beams Ministry of Education Dalian University of Technology Dalian116024 China Centre for Advanced 2D Materials National University of Singapore 6 Science Drive 2 117546 Singapore Department of Physics National University of Singapore 117542 Singapore

Weyl semimetal Td-phase WTe2 possesses the spin-resolved band structure with strong spin-orbit coupling, holding promises as a useful spin source material. The noncentrosymmetric crystalline structure of Td-WTe2 endows the generation of the out-of-plane polarized spin, which is of great interest in magnetic memory applications. Previously, WTe2 was explored in spin devices based on mechanically exfoliated single crystal flakes with a size of micrometers. For practical spintronics applications, it is highly desirable to implement wafer-scale thin films. In this work, we utilize centimeter-scale chemical vapor deposition (CVD)-grown Td-WTe2 thin films and study the spin current generation by the spin torque ferromagnetic resonance technique. We find the in-plane and out-of-plane spin conductivities of 7.36 × 103 (ħ/2e) (Ωm)–1 and 1.76 × 103 (ħ/2e) (Ωm)–1, respectively, in CVD-growth 5 nm-WTe2. We further demonstrate the current induced magnetization switching in WTe2/NiFe at room temperature in the domain wall motion regime, which may invigorate potential spintronic device innovations based on Weyl semimetals. Copyright © 2021, The Authors. All rights reserved.

关键词： Thin films

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Functional Group-Driven Competing Mechanism in Electrochemical Reaction and Adsorption/Desorption Processes toward High-Capacity Aluminum-Porphyrin Batteries

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Angewandte Chemie 2024年第39期136卷

作者： Prof. Dr. Shuqiang Jiao Dr. Xue Han Prof. Dr. Li-Li Jiang Prof. Dr. Xueyan Du Dr. Zheng Huang Dr. Shijie Li Prof. Dr. Wei Wang Prof. Dr. Mingyong Wang Prof. Dr. Yunpeng Liu Prof. Dr. Wei-Li Song State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metal Lanzhou University of Technology Lanzhou 730050 P.R. China State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing 100083 P. R. China State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200240 P. R. China School of Materials Science and Engineering Xi'an Jiao Tong University Xi'an 710049 P. R. China Beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 P. R. China Institute of Advanced Structure Technology Beijing Institute of Technology Beijing 100081 P. R. China

Nonaqueous organic aluminum batteries are considered as promising high-safety energy storage devices due to stable ionic liquid electrolytes and Al metals. However, the stability and capacity of organic positive electrodes are limited by their inherent high solubility and low active organic molecules. To address such issues, here porphyrin compounds with rigid molecular structures present stable and reversible capability in electrochemically storing AlCl 2 + . Comparison between the porphyrin molecules with electron-donating groups (TPP-EDG) and with electron-withdrawing groups (TPP-EWG) suggests that EDG is responsible for increasing both highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, resulting in decreased redox potentials. On the other hand, EWG is associated with decreasing both HOMO and LUMO energy levels, leading to promoted redox potentials. EDG and EWG play critical roles in regulating electron density of porphyrin π bond and electrochemical energy storage kinetics behavior. The competitive mechanism between electrochemical redox reaction and de/adsorption processes suggests that TPP-OCH 3 delivers the highest specific capacity ~171.8 mAh g −1 , approaching a record in the organic Al batteries.

关键词： Porphyrin electron-donating group electron-withdrawing group redox potential Faradaic/Non-Faradaic process

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Verifying the Charge-Transfer Mechanism in S-Scheme Heterojunctions Using Femtosecond Transient Absorption Spectroscopy

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Angewandte Chemie 2022年第8期135卷

作者： Chang Cheng Dr. Jianjun Zhang Dr. Bicheng Zhu Prof. Guijie Liang Prof. Liuyang Zhang Prof. Jiaguo Yu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology 430070 Wuhan P. R. China Laboratory of Solar Fuel Faculty of Materials Science and Chemistry China University of Geosciences 68 Jincheng Street 430078 Wuhan P. R. China Hubei Key Laboratory of Low Dimensional Arts and Science Hubei University of Arts and Science 441053 Xiangyang P. R. China

The S-scheme heterojunction is flourishing in photocatalysis because it concurrently realizes separated charge carriers and sufficient redox ability. Steady-state charge transfer has been confirmed by other methods. However, an essential part, the transfer dynamics in S-scheme heterojunctions, is still missing. To compensate, a series of cadmium sulfide/pyrene- alt -difluorinated benzothiadiazole heterojunctions were constructed and the photophysical processes were investigated with femtosecond transient absorption spectroscopy. Encouragingly, an interfacial charge-transfer signal was detected in the spectra of the heterojunction, which provides solid evidence for S-scheme charge transfer to complement the results from well-established methods. Furthermore, the lifetime for interfacial charge transfer was calculated to be ca. 78.6 ps. Moreover, the S-scheme heterojunction photocatalysts exhibit higher photocatalytic conversion of 1,2-diols and H 2 production rates than bare cadmium sulfide.

关键词： 1,2-Diols Oxidation Hydrogen Production Photocatalysis S-Scheme Transient Absorption

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Preparation and Gas Separation Performance of Polysulfone Mixed Matrix Membrane

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Journal of Nanomaterials 2021年第1期2021卷

作者： Jiang, Lili Meng, Yimin Xu, Su Yu, Haitao Hou, Xingang State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of Technology Gansu Lanzhou730050 China Wenzhou Engineering Institute of Pump and Valve Lanzhou University of Technology Zhejiang Wenzhou325000 China School of Material Science and Technology Lanzhou University of Technology Langongping Road Gansu Province Lanzhou730050 China Department of Medical Laboratory First Hospital of Lanzhou University No. 1 Donggang Road Chengguan District Gansu Province Lanzhou730000 China

As an economical, environmentally friendly, and highly efficient separation technology, membrane separation is a popular research topic in the field of separation. Organic polymer materials have attracted considerable attention in membrane separation because of their controllable preparation processes, simple modification method, and high toughness. Taking polysulfone (PSF) as the substrate of gas separation membrane, we prepared the mixed matrix membrane jointly by using the solution casting method and by adding graphene oxide (GO) and carbon nanotubes (CNTs). On this basis, the permeability of the membrane for CO2 and N2 and the permeability coefficient of the mixed gas were studied. With the addition of CNTs and GO, the permeability of gas was significantly improved. At 0.2 MPa, permeability of CO2 increased from 553 Barrer to 975 Barrer, and permeability of N2 increased from 536 Barrer to 745 Barrer. The max ideal separation coefficient of CO2 and N2 is 1.94 at 0.1 MPa. Increasing of the content of carbon nanotubes can significantly improve the permeability coefficient of CO2, while the change of inlet side pressure has a great impact on the permeability coefficient of N2. At 0.1 MPa, when the ratio of CNTs to GO was 5: 1, the ideal permeability coefficient of CO2/N2 was 1.94, whereas the ideal permeability coefficient of PSF membrane was 1.46. The above results of PSF/GO/CNT mixed matrix membrane lay a theoretical foundation for industrial application. © 2021 Lili Jiang et al.

关键词： Carbon dioxide

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Corrigendum to “Effects of energy input during friction stir processing on microstructures and mechanical properties of aluminum/carbon nanotubes nanocomposites” [J. Alloy. Comp. 798 (2019) 523–530]

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Journal of Alloys and Compounds 2019年 800卷 550-551页

作者： Shuai Zhang Gaoqiang Chen Jinquan Wei Yijun Liu Ruishan Xie Qu Liu Shenbo Zeng Gong Zhang Qingyu Shi State Key Laboratory of Tribology Key Laboratory for Advanced Materials Processing Technology Ministry of Education of China Department of Mechanical Engineering Tsinghua University Beijing 100084 China Key Lab for Advanced Materials Processing Technology of Education Ministry School of Materials Science and Engineering Tsinghua University Beijing 100084 China

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Frontispiece: Hybrid Hydrogen-Bonded Organic Frameworks: Structures and Functional Applications

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Chemistry – A European Journal 2023年第14期29卷

作者： Ying Liu Prof. Ganggang Chang Dr. Fang Zheng Dr. Lihang Chen Prof. Qiwei Yang Prof. Qilong Ren Prof. Zongbi Bao Key Laboratory of Biomass Chemical Engineering of Ministry of Education College of Chemical and Biological Engineering Zhejiang University 38 Zheda Road Hangzhou Zhejiang Province 310027 P.R. China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Chemistry Chemical Engineering and Life Science Wuhan University of Technology 122 Luoshi Road Wuhan Hubei Province 430070 P.R. China Institute of Zhejiang University-Quzhou 99 Zheda Road Quzhou Zhejiang Province 324000 P.R. China

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Influence of substrate plate heating on the fabrication of Al-12Si produced by selective laser melting

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Transactions of the Indian National Academy of Engineering 2021年第4期6卷 1027-1036页

作者： Xi, L. X. Ma, P. Jia, Y. D. Chaubey, A. K. Wang, Z. Prashanth, K. G. College of Materials Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing China Jiangsu Provincial Engineering Laboratory for Laser Additive Manufacturing of High-Performance Metallic Components Nanjing University of Aeronautics and Astronautics Nanjing China School of Materials Engineering Shanghai University of Engineering Science Shanghai China School of Materials Science and Engineering Shanghai University Shanghai China CSIR–Institute of Minerals and Materials Technology (IMMT) Bhubaneshwar India Guangdong Key Laboratory for Processing and Forming of Advanced Metallic Materials South China University of Technology Guangzhou China School of Mechanical and Automotive Engineering South China University of Technology Guangzhou China Department of Mechanical and Industrial Engineering Tallinn University of Technology Tallinn Estonia Erich Schmid Institute of Materials Science Austrian Academy of Sciences Leoben Austria CBCMT School of Mechanical Engineering Vellore Institute of Technology Vellore India

Substrate plate heating is one of the methodology followed during the selective laser melting (SLM) process, to reduce the cooling rate of the process, to reduce the internal stresses in the SLM-fabricated material, to reduce the cracking tendency in some alloys. However, employing substrate plate heating with larger samples may introduce anisotropy and inhomogeneity in both microstructure and properties. To study this effect, Al-12Si samples were fabricated using the SLM process. The samples were produced with (473 K and 673 K) and without substrate plate heating. The sample was also subjected to external treatment at 473 K and 673 K to compare the microstructural effects with the substrate plate-heated samples. The microstructural investigation was carried out using optical and scanning electron microscopy and the structural characterization using X-ray diffraction. The mechanical properties of the samples were tested using room temperature tensile test and hardness maps. The results suggest that the samples fabricated using substrate plate heating lead to anisotropy along the length scale, which is not desirable.

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