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Functionalities of frozen domain walls in helical antiferromagnets

Physical Review B 2025年第9期111卷 094423-094423页

作者： A. Sedda E. Lähderanta M. Comas M.-L. Corró X. Wang J. Frenzel G. Eggeler D. Salazar E. K. H. Salje Universitat de les Illes Balears cra. Valldemossa km. 7.5 07122 Palma Spain Lappeenranta-Lahti University of Technology LUT School of Engineering Science Yliopistonkatu 34 53850 Lappeenranta Finland Department of Physics Politecnico di Milano Via Anzani 42 22100 Como Italy State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jingshi Road 17923 Jinan 250061 People's Republic of China Ruhr-Universität Bochum Universitätsstraße 150 D-44801 Bochum Germany BCMaterials Basque Center for Materials Applications and Nanostructures UPV/EHU Science Park 48940 Leioa Spain Department of Earth Sciences University of Cambridge Cambridge CB2 3EQ United Kingdom

Principles behind antiferromagnetic spintronics often claim that an antiferromagnet (AF) cannot be manipulated by external magnetic fields and that domain walls (DWs) are highly mobile and do not suffer strong pinning while maintaining robustness during thermal fluctuations. Using dysprosium (Dy) as an example, we take the opposite view. The functionality of a helical AF in Dy uses two intrinsic properties of chiral DWs: their intrinsic magnetization and their freezing just below the Néel temperature. Experiments with Dy single crystal show that field cooling through the fluctuation regime converts a helical AF into a domain wall–dominated system with striking properties related with robustness of frozen chiral DWs. On the other hand, chiral DWs are easily controlled by external fields throughout the fluctuation regime.

关键词： Dysprosium

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Understanding the Oxidation Behavior and Failure Mechanisms of an In-Situ Composite Alcocrfeni2.1 Eutectic High-Entropy Alloy at 1300 °C

SSRN

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SSRN 2023年

作者： Lu, Jie Zhang, Han Ren, Guoliang Chen, Ying Luo, Lirong Cai, Huangyue Shan, Xiao Zhang, Xiancheng Zhao, Xiaofeng Shanghai Key Laboratory of Advanced High-Temperature Materials and Precision Forming School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai200240 China Department of Materials The Henry Royce Institute The University of Manchester ManchesterM13 9PL United Kingdom Engineering Research Center of Nano-Geo Materials of Ministry of Education Faculty of Materials Science and Chemistry China University of Geosciences Wuhan430074 China Key Laboratory of Pressure Systems and Safety Ministry of Education School of Mechanical and Power Engineering East China University of Science and Technology Shanghai200237 China

We present a detail study on oxidation behavior and failure mechanisms of an in-situ composite AlCoCrFeNi2.1 eutectic high-entropy alloy (ISC-EHEA) doped with Y and Hf at 1300 °C. We demonstrate that the ISC-EHEA has much stronger resistance to surface rumpling and oxide spallation than two conventional NiCoCrAlYHf alloys (CNAs). Hybrid molecular dynamics (MD) and Monte Carlo (MC) simulations show that the diffusion coefficients of the metal elements in the Al-depletion layer of the ISC-EHEA are 50% lower than those of the CNAs. The low diffusion coefficients lead to low growth stress in the thermally grown Al2O3 scale on the ISC-EHEA and improve the creep resistance of the metal in contact with the scale, thus preventing the occurrence of rumpling. The oxidation rate constant of the ISC-EHEA is ~32% lower in comparison to those of the CNAs, which is attributed to the coarser columnar Al2O3 grains that effectively mitigate grain boundary diffusion. The rumpling-free metal/oxide interface, the low residual stress and the low oxide growth rate for the ISC-EHEA result in strong resistance to scale spallation. Owing to the strong scale/alloy bonding at the interface and the build-up of strain energy during prolonged oxidation, damage in the Al2O3 scale on the ISC-EHEA is initiated as surface cracks rather than interface decohesion. When re-oxidized at 1300 °C, the ingress of oxygen along the surface cracks results in fast growth of new oxides at the metal/oxide interface, which causes local stress concentration, interface crack propagation and scale spallation. © 2023, The Authors. All rights reserved.

关键词： Molecular dynamics

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Cover Picture: Materials and Corrosion. 5/2025

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Materials and Corrosion 2025年第5期76卷 613-613页

作者： Yiqi Zhou Xiaochang Xu Shuoyang Wang Decheng Kong Fan Zhang Lili Li Tingting Liu Xiaogang Li Xuanhui Qu Yu Yan Chaofang Dong Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing China Shunde Innovation School University of Science and Technology Beijing Shunde China State Key Laboratory of Nuclear Power Safety Technology and Equipment University of Science and Technology Beijing Beijing China Shanghai Key Laboratory of Advanced High-Temperature Materials and Precision Forming School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai China School of Mathematics and Physics University of Science and Technology Beijing Beijing China

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Near-α Ti60 alloy dwell fatigue basal slip-induced cracking: faceted crack initiation and local strain evolution

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Journal of Materials Science & technology 2025年

作者： Boning Wang Weidong Zeng Zibo Zhao Runchen Jia Jianwei Xu Qingjiang Wang Heng Li State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University Xi’an 710072 China Defense Technologies Innovation Center of precision forging and ring rolling School of Materials Science and Engineering Northwestern Polytechnical University Xi’an 710072 China Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment Northwestern Polytechnical University Xi’an 710072 China Shi Changxu Innovation Center for Advanced Materials Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

Basal fracture due to dwell fatigue (DF) is primary cause of core material failure during aero-engine service, which highlights the importance of understanding the crack initiation mechanism. In this study, the relationship between activation of plastic slip within the [0001] basal plane orientation, local strain and crack initiation in near-α Ti60 alloys was investigated using coupled in situ and high-resolution digital image correlation (HR-DIC) methods. The results show that basal slip is preferentially activated resulting into a higher shear strain in DF compared to [10 1 ¯ 0] prismatic orientation grains. Two types of cracking induced by strong basal slip were identified in grains with medium to high basal Schmidt factor (SF): slip transgranular cracking and basal twist grain boundary (BTGB) cracking. The slip deformation and strain evolution of the two types of cracks before and after their initiation were observed for the first time on the sample surface by in-situ dwell, which provides experimental and theoretical support for their formation mechanism. In order to constitute potential locations for crack nucleation, these regions have high local and shear strains during the basal slip stage prior to crack initiation. The higher local strain in the former is attributed to the intrusion and extrusion mechanism of the slip bands, while the latter is attributed to the inconsistency of the slip deformation of the microscopic dislocations on both sides of the BTGB making the GB slip-shear. Additionally, the incoordination on both sides of the GB, coupled with the inherently low cleavage energy, makes the BTGB more susceptible to cracking compared to slip transgranular cracking. No elemental segregation or β-phase influence was observed at the grain boundary interface. This study provides new insights into the mechanisms involved basal slip-induced cracking in Ti alloys subjected to dwell loadings.

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Microstructures and joining characteristics of TiAl/TiAl joints brazed with Ti-Mn-Fe-Ni-Nb system medium-entropy alloy filler metal

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Journal of Materials Science & technology 2025年

作者： Zhiliang Zhai Xinyu Ren Haishui Ren Binbin Liu Cong Zhang Huaping Xiong Haiqing Yin Bo Chen Yaoyong Cheng Welding and Plastic Forming Division Beijing Institute of Aeronautical Materials Beijing 100095 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China Collaborative Innovation Center of Steel Technology University of Science and Technology Beijing Beijing 100083 China

Based on the design combination of Ni-Nb binary alloy and Ti-Mn-Fe ternary alloy, and the calculated results of liquidus temperature for the quinary system alloys, the optimum composition of Ti-Mn-Fe-Ni-Nb system medium-entropy alloy brazing filler metal was proposed for TiAl joining. The filler alloy consisted of Ti-based solid solutions, TiFe and TiMn phases with Nb and Ni dissolved, showing a liquidus temperature of 1084.2°C. As the dynamic wettability test result, the filler alloy exhibited an equilibrium contact angle of 24.5° on the TiAl substrate after being held at 1150°C for 5 min. The TiAl/TiAl joint brazed with the brazing filler powder was mainly composed of B2, γ-TiAl, and α 2 -Ti 3 Al as well as residual brazing filler metal reaction phase with a hexagonal close-packed structure. The presence of nanotwins, dislocations, and their interactions within the γ phase, as well as 6H and 18R type long periodic stacking ordered structures within the brazing seam, had a beneficial effect on joint strength. A transition region with a thickness of approximately 10 nm was observed at the B2/α 2 interface by means of a three-dimensional atom probe. Increasing brazing temperature or prolonging dwell time led to a gradual increase in both the joint thickness and the volume fraction of the γ-TiAl phase within the joint, yet it was accompanied by a remarkable decrease in the thickness of the residual brazing filler metal reaction layer. Under the brazing condition of 1180°C/45 min, the joints offered a volume fraction of γ-TiAl phase of 31.6%, a joint thickness of 244 μm and a maximum tensile strength of 463 MPa at ambient temperature, representing 78.5% of the base alloy strength. The brazed joints exhibited tensile strength of 497 MPa at 750°C and 469 MPa at 800°C, corresponding to the joint strength coefficient of 88.3% and 90.7%, respectively. In this case, the fracture occurred in the brazing seam with a flexural pathway but still presented typical brittle characte

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Microstructural Investigation and High-Temperature Oxidation Performance of K417G Alloy Prepared by Wide-Gap Brazing

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Crystals 2025年第5期15卷 434-434页

作者： Zhun Cheng Xin Lai Jing He Xiaoqiang Li Jiafeng Fan Fuqiang Lai Guangdong Polytechnic of Industry and Commerce Guangzhou 510510 China Guangdong Key Laboratory for Advanced Metallic Materials Fabrication and Forming National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials South China University of Technology Guangzhou 510640 China School of Mechanical Engineering and Automation Fuzhou University Fuzhou 350116 China

K417G superalloy is widely applied in gas turbine components such as blades, vanes, and nozzles. In this work, the oxidation behavior and mechanism of K417G alloy prepared by wide-gap brazing were investigated in air at 800, 900, 1000, and 1100 °C. Microstructures of the bonded joints differ in the wide-gap braze region (WGBR) and base metal (BM). The surface and cross-sectional morphology, composition, and structure of specimens were analyzed by XRD, SEM, and EDS after oxidation tests. The experimental data demonstrate that the WGBR (wide-gap brazed region) exhibits markedly superior oxidation resistance compared to the BM (base material) under elevated-temperature conditions exceeding 1000 °C. This performance disparity is quantitatively validated by oxidation kinetics analysis, where the weight gain curve of the WGBR demonstrates parabolic oxidation kinetics, as evidenced by its significantly lower parabolic rate constant relative to the BM. The oxide layers of the BM and WGBR are similar after oxidation at high temperatures of 800–900 °C, and they consist of an outermost layer of NiO, a middle mixed layer of Cr2O3, and an innermost layer of dendritic Al2O3. However, when the temperature is between 1000 and 1100 °C, the NiO on the surface of the BM spalls of due to thermal expansion coefficient mismatch in coarse-grained regions, resulting in oxidation mainly divided into outer layer Cr2O3 and inner layer Al2O3 and TiO2. Under high-temperature oxidation conditions (1000–1100 °C), a structural transition occurs in the oxide scale of the BM, with the underlying mechanism attributable to grain-coarsening-induced oxide scale destabilization. Specifically, the coarse-grained structure of the BM (characteristic grain size exceeding 50 μm) is exhibited. Therefore, the WGBR demonstrates outstanding oxidation resistance, as evidenced by the formation of a continuous Al2O3 scale with parabolic rate constants of about 1.38 × 10−3 mg2·cm−4·min−1 at 1100 °C.

关键词： K417G alloy oxidation resistance microstructures oxidation layer

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Corrigendum to “Research on the influence of differential speed ratio on the microstructure and properties of 316L/Ni/EH40 composite plate by asymmetrical rolling” [Mater. Today Commun. 37 (2023) 107431]

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Materials Today Communications 2024年 38卷

作者： Kangkang Feng Biao Zhang Xiaolong Shen Yali Yi Herong Jin School of Mechanical Engineering Yanshan University Qinhuangdao 066004 China Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao 066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of National Education Yanshan University Qinhuangdao 066004 China

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Microstructure and strengthening mechanism of Mg-5.88Zn-0.53Cu-0.16Zr alloy solidified under high pressure

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Transactions of Nonferrous Metals Society of China 2020年第1期30卷 99-109页

作者： Kun-yu GUO Chang XU Xiao-ping LIN Jie YE Chong ZHANG Duo HUANG School of Resources and Materials Northeastern University at QinhuangdaoQinhuangdao 066004China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China Key Laboratory of Advanced Metal Materials and Forming Technology in Qinhuangdao Northeastern University at QinhuangdaoQinhuangdao 066004China

Mg-5.88 Zn-0.53 Cu-0.16 Zr(wt.%)alloy was solidified at 2-6 GPa using high-pressure solidification *** microstructure,strengthening mechanism and compressive properties at room temperature were studied using SEM and *** results showed that the microstructure was refined and the secondary dendrite spacing changed from 35μm at atmospheric pressure to 10μm at 6 GPa ***,Mg(Zn,Cu)2 and Mg Zn Cu eutectic phases were distributed in the shape of network,while under high pressures the second phases(Mg(Zn,Cu)2 and Mg7 Zn3)were mainly granular or *** solid solubility of Zn and Cu in the matrix built up over increasing solidification pressure and reached 4.12%and 0.32%respectively at 6 *** hardness value was HV 90 and the maximum compression resistance was 430 ***,the grain refinement strengthening,the second phase strengthening and the solid solution strengthening are the principal strengthening mechanisms.

关键词： high pressure solidification Mg-Zn-Cu-Zr alloy strengthening mechanism eutectic transformation

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Effect of Si and Ti addition on the tribological behavior of aged Cu–15Ni–8Sn alloys

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Tribology International 2025年 211卷

作者： Daoxi Li Chao Zhao Rui Zhong Haokai Dong Zhi Wang Zongqiang Luo Weiwen Zhang College of Mechanical and Energy Engineering Shaoyang University Shaoyang 422000 China School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China Guangdong Key Laboratory for Processing and Forming of Advanced Metallic Materials South China University of Technology Guangzhou 510640 China School of Mechanical and Automotive Engineering South China University of Technology Guangzhou 510640 China State Key Laboratory of Advanced Marine Materials Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo 315201 China

A comparative study was conducted to evaluate the tribological properties of base alloy (Cu–15Ni–8Sn, wt.%) and Si–Ti-modified alloy (Cu–15Ni–8Sn–0.3Si–0.1Ti, wt.%). Both alloys were tested against 100Cr6 steel under dry sliding conditions at various loads using a block-on-ring tester. Scanning electron microscopy and transmission electron microscopy revealed that the Si–Ti-modified alloy exhibits a refined grain structure with reduced discontinuous precipitation, significantly enhancing plasticity while improving tribological performance. The addition of trace amounts of Si and Ti stabilizes key sub-tribo-layers (oxide layer and mechanically mixed layer) and promotes a transition from abrasive/adhesive wear to oxidative wear. Consequently, the modified alloy shows lower friction coefficients and specific wear rates compared to the base alloy, demonstrating superior anti-friction and wear-resistance properties under these conditions.

关键词： Cu–15Ni–8Sn alloy Dry sliding wear Tribo-layers Wear mechanism

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Study on the Distribution of Frictional Forces on Z-Yarn Continuous Implanted Preforms and Its Application

Research Square

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Research Square 2021年

作者： Guo, Zitong Shan, Zhongde Huang, JiHua Xue, Debo School of Materials Science and Engineering University of Science and Technology Beijing Beijing100083 China State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and Technology Group Co. ltd Beijing100083 China School of Mechanical Engineering Shandong University of Technology Zibo255000 China

In order to improve the quality and efficiency of the Z-directional 3D preform forming, the Z-yarn friction force distribution model of the preform and its wear mechanism were investigated. Designed the tensile force measuring device of the replacement guide sleeves,the measured tensile force is equivalent to the Z-yarn friction force. Found that the frictional force was proportional to the number of preform layers, the frictional force applied to the one preform decreased from the corner, edge, sub-edge and middle in order. Established BP neural network model to predict the friction at different positions of preform with different layers, the error is within1.9%. The wear of Z-yarn was studied at different frictional positions and after different times of successive implantation into the preform, showed that with the increase of the number of Z-yarn implantation and the friction force, the amount of carbon fiber bundle hairiness gradually increase, and the tensile fracture strength damage of the fiber is increasingly affected by the friction force,and in the corner position of the preform, when the number of implantation is 25 times, the fiber fracture strength will occur non-linearly and substantially decreased, in order to avoid fiber fracture in the implantation process, the Z-yarn needs to be replaced in time after 20~25 times of continuous implantation. © 2021, CC BY.

关键词： Wear of materials

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