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Mining of lattice distortion, strength, and intrinsic ductility of refractory high entropy alloys

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npj Computational Materials 2023年第1期9卷 1814-1825页

作者： Christopher Tandoc yong-Jie Hu Liang Qi Peter k.Liaw Department of Materials Science and Engineering Drexel UniversityPhiladelphiaPA 19104USA Department of Materials Science and Engineering University of MichiganAnn ArborMI 48109USA Department of Materials Science and Engineering University of TennesseeKnoxvilleTN 37996USA

Severe lattice distortion is a prominent feature of high-entropy alloys(HEAs)considered a reason for many of those alloys’***,accurate characterizations of lattice distortion are still scarce to only cover a tiny fraction of HEA’s giant composition space due to the expensive experimental or computational *** we present a physics-informed statistical model to efficiently produce high-throughput lattice distortion predictions for refractory non-dilute/high-entropy alloys(RHEAs)in a 10-element composition *** model offers improved accuracy over conventional methods for fast estimates of lattice distortion by making predictions based on physical properties of interatomic bonding rather than atomic size mismatch of pure *** modeling of lattice distortion also implements a predictive model for yield strengths of RHEAs validated by various sets of experimental *** our previous model on intrinsic ductility,a data mining design framework is demonstrated for efficient exploration of strong and ductile single-phase RHEAs.

关键词： alloys ductility strength

Formation mechanism of titanium and niobium carbides in hardfacing alloy

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Rare Metals 2017年第8期36卷 640-644页

作者： ke Yang kèYang Ye-Feng Bao yong-Feng Jiang College of Mechanical and Electrical Engineering Hohai UniversityChangzhou 213022China

The most effective carbide-forming elements titanium and niobium were added into hardfacing *** and composition of carbides in the hardfacing alloy were investigated by means of optical microscope（OM）,scanning electron microscope（SEM）,X-ray diffraction（XRD）and energy-dispersive spectrometer（EDS）.Hardness and impact toughness of the hardfacing alloy were *** thermodynamics and formation mechanism of carbides were also *** is found that the carbides consist of TiC and NbC which are able to form directly from welding pool during the welding *** formation mechanism of carbides involves nucleation of TiC followed by epitaxial precipitation of NbC on the surface of *** formation of titanium and niobium carbides can obviously refine the microstructure and deplete the carbon in the *** micros tructure transforms to well-distributed carbides and a tough martensite matrix,contributing to a good combination of high hardness and high toughness in the hardfacing alloy.

关键词： Titanium Niobium Hardfacing alloy Carbides Microstructure

Achieving high carrier mobility and low lattice thermal conductivity in GeTe-based alloys by cationic/anionic co-doping

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Rare Metals 2024年第6期43卷 2784-2795页

作者： Xiao-Qiang Wang Xiao-Quan Hu Jun-Yan Lin Chu-Bin Li Xiao-Tong Yu Qi-yong Chen Li-Li Xi Qi-Shuo Yang Han Li Ji-Ye Zhang Shuan-kui Li kai Guo School of Physics and Materials Science Guangzhou UniversityGuangzhou 510006China Research Center for Advanced Information Materials(CAIM) Huangpu Research&Graduate School of Guangzhou UniversitySino-Singapore Guangzhou Knowledge CityGuangzhou510555China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Materials Genome Institute Shanghai UniversityShanghai 200444China School of Mechanical and Mining Engineering University of QueenslandBrisbaneQLD 4072Australia key Laboratory of Si-Based Information Materials&Devices and Integrated Circuits Design Department of Education of Guangdong ProvinceGuangzhou 510006China

TheⅣ-Ⅵcompound GeTe is considered as a promising alternative to the toxic PbTe for high-efficiency mid-temperature thermoelectric ***,pristine GeTe suffers from a high concentration of Ge vacancies,resulting in an excessively high hole concentration(>1×10^(21)cm^(-3)),which greatly limits its thermoelectric *** address this issue,CuBiTe_(2)alloying is introduced to increase the formation energy of Ge vacancies in GeTe,thereby inhibiting the high carrier *** carrier scattering caused by the electronegativity difference between different elements is suppressed due to the similar electronegativity of Cu and Ge atoms.A relatively high hole mobility is obtained,which ultimately leads to a high power ***,by introducing Se as an alloying element at the anionic site in GeTe,dense point defects with mass/strainfield fluctuations are *** contributes to the strengthening of phonon scattering,thereby reducing the lattice thermal conductivity from 1.44 W·m^(-1)·k^(-1)for pristine GeTe to 0.28 W·m^(-1)·k^(-1)for Ge_(0.95)Cu_(0.05)Bi_(0.05)Te_(0.9)Se_(0.15)compound at 623 k.

关键词： GeTe Carrier mobility CuBiTe_(2)alloying Lattice thermal conductivity Thermoelectric properties

Preternatural Hexagonal High-Entropy Alloys: A Review

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Acta Metallurgica Sinica(English Letters) 2020年第8期33卷 1033-1045页

作者： Rui-Xuan Li Jun-Wei Qiao Peter k. Liaw yong Zhang Beijing Advanced Innovation Center of Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology Beijing30 Xueyuan RoadBeijing 100083China Research Center for High-Entropy Alloys College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan 030024China Department of Materials Science and Engineering The University of TennesseeKnoxvilleTN 37996USA

Recently,various topics on high-entropy alloys have been reported and great amounts of excellent properties have been investigated,including high strength,great corrosion resistance,great thermal stability,good fatigue and fracture properties,*** all these research activities,high-entropy alloys tend to form face-centered-cubic(FCC)or body-centeredcubic(BCC)solid solutions due to their high-entropy stabilization effect,while the hexagonal structures are rarely *** to now,the reported hexagonal high-entropy alloys are mainly composed of rare-earth elements and transitional *** phase transformation and magnetic properties have also aroused wide *** study summarizes the above results and provides the forecast to the future.

关键词： High-entropy alloys Hexagonal close-packed structure Phase formation rules Rare-earth elements Multiple-based-element(MBE)alloys

Processing effects on the magnetic and mechanical properties of FeCoNiAl_(0.2)Si_(0.2) high entropy alloy

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International Journal of Minerals,Metallurgy and Materials 2013年第6期20卷 549-555页

作者： Ting-ting Zuo Song-bo Ren Peter k. Liaw yong Zhang State key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing Hangke Engine Control System Science & Technology Co. Ltd. Department of Materials Science and Engineering The University of Tennessee

High entropy alloys with the composition of FeCoNiA10.2Si0.2 were prepared by arc melting and induction melting, denoted by A1 and A2, respectively. The samples prepared by these two techniques have a face-centered cubic （FCC） phase structure and a typical dendrite morphology. The tensile yield strength and maximum strength of A2 samples are about 280 and 632 MPa, respectively. Moreover~ the elongation can reach 41.7%. These two alloys prepared by the different methods possess the similar magnetic properties. The saturation magnetization and coercivity can reach 1.151 T and 1400 A/m for A1 samples and 1.015 T and 1431 A/m for A2 samples, respectively. Phases in A2 samples do not change, which are heat treated at different temperatures, then quenched in water. Only the sample, which is heat treated at 600~C for 3 h and then furnace cooled, has a new phase precipitated. Besides, the coercivity decreases obviously at this temperature. Cold rolling and the subsequent heat treatment cannot improve the magnetic properties effectively. However, cold rolling plays an important role in improving the strength.

关键词： high entropy alloys magnetic properties mechanical properties heat treatment

Numerical and Experimental Research on Modular Oscillating Fin

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Journal of Bionic Engineering 2008年第1期5卷 13-23页

作者： yong-hua Zhang Yan Song Jie Yang k. H. Low Department of Precision Machinery and Precision Instrumentation University of Science and Technology of China Hefei 230026 P. R. China School of Mechanical and Aerospace Engineering Nanyang Technological University 639798 Singapore

Fishes are famous for their ability to position themselves accurately even in turbulent flows. This ability is the result of the coordinated movement of fins which extend from the body. We have embarked on a research program designed to develop an agile and high efficient biologically inspired robotic fish based on the performance of hybrid mechanical fms. To accomplish this goal, a mechanical ray-like fin actuated by Shape Memory Alloy （SMA） is developed, which can realize both oscillatory locomotion and undulatory locomotion. We first give a brief introduction on the mechanical structure of our fin and then carry out theoretic analysis on force generation. Detailed information of these theoretical results is later revealed by Computational Huid Dynamic （CFD）, and is final validated by experiments. This robotic fin has potential application as a propulsor for future underwater vehicles in addition to being a valuable scientific instrument.

关键词： oscillating fin Shape Memory Alloy (SMA) Computational Huid Dynamics (CFD) modular design

Quantitative Evaluation of Pain with Pain Index Extractecl from Electroencephalogram

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Chinese Medical Journal 2017年第16期130卷 1926-1931页

作者： Jian-Xiong An yong Wang Doris k Cope John P Williams Department of Anesthesiology Pain Medicine and Critical Care Medicine Aviation General Hospital of China Medical University & Beijing Institute of Translational Medicine Chinese Academy of Sciences Beijing 100012 China Department of Anesthesiology University of Pittsburgh School of Medicine Pittsburg 15213 PA USA

Background： The current pain assessment methods are strongly subjective and easily affected by outside influences, and there is an urgent need to develop a reliable objective and quantitative pain-monitoring indicator. The aim of this study was to evaluate the feasibility of using Pain index （Pi） to assess pain symptoms in pain patients. Methods： Subjects were enrolled from patients seeking treatment at Pain Medicine Center of China Medical University Aviation General Hospital from October 2015 to December 2016, such as postherpetic neuralgia, spinal cord injury, femoral head necrosis, lumbar disc herniation, trigeminal neuralgia, complex regional pain syndrome, pefineal pain, phantom limb pain, etc., （pain group, n = 111）, as well as healthy volunteers without subjective pain （control group, n = 100）. The subjective pain symptoms in pain patients were evaluated by Pi and visual analogue scale/numerical rating scales （VAS/NRS）, respectively, and the relationship between them was analyzed using single factor correlation analysis and multiple factor regression analysis. Results： Pi levels in the pain group were significantly higher than those of the control group （t= 6.273, P 〈 0.001 ）, the correlation analysis of Pi and VAS/NRS score in the pain group showed that the Pearson correlation coefficient was 0.797 （P 〈 0.001）; After adjusted for types of pain, pain sites, medication, gender, and age, Pi was found to be independently correlated to VAS/NRS score （P 〈 0.001）. Conclusions： Pi significantly correlates with VAS/NRS score, might be used to evaluate the subjective pain symptoms in patients and has good research and application value as an objective pain assessment tool.

关键词： Electroencephalogram Pain Wavelet Algorithm

Hyperbolic hierarchical graph attention network for knowledge graph completion

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High Technology Letters 2024年第3期 271-279页

作者：许浩 CHEN Shudong QI Donglin TONG Da YU yong CHEN Shuai Institute of Microelectronics of Chinese Academy of Sciences University of Chinese Academy of Sciences

Utilizing graph neural networks for knowledge embedding to accomplish the task of knowledge graph completion(kGC) has become an important research area in knowledge graph ***,the number of nodes in the knowledge graph increases exponentially with the depth of the tree,whereas the distances of nodes in Euclidean space are second-order polynomial distances,whereby knowledge embedding using graph neural networks in Euclidean space will not represent the distances between nodes *** paper introduces a novel approach called hyperbolic hierarchical graph attention network(H2GAT) to rectify this ***,the paper conducts knowledge representation in the hyperbolic space,effectively mitigating the issue of exponential growth of nodes with tree depth and consequent information ***,it introduces a hierarchical graph attention mechanism specifically designed for the hyperbolic space,allowing for enhanced capture of the network structure inherent in the knowledge ***,the efficacy of the proposed H2GAT model is evaluated on benchmark datasets,namely WN18RR and FB15k-237,thereby validating its *** H2GAT model achieved 0.445,0.515,and 0.586 in the Hits@1,Hits@3 and Hits@10 metrics respectively on the WN18RR dataset and 0.243,0.367 and 0.518 on the FB15k-237 *** incorporating hyperbolic space embedding and hierarchical graph attention,the H2GAT model successfully addresses the limitations of existing hyperbolic knowledge embedding models,exhibiting its competence in knowledge graph completion tasks.

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Tailoring-compensated ferrimagnetic state and anomalous Hall effect in quaternary Mn–Ru–V–Ga Heusler compounds

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Chinese Physics B 2024年第7期33卷 595-603页

作者：梁瑾静郗学奎王文洪刘永昌 Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Tiangong University Tianjin 300387China

Cubic Mn_(2)Ru_(x)Ga Heusler compound is a typical example of compensated ferrimagnet with attractive potential for high-density,ultrafast,and low-power spintronic *** the form of epitaxial thin films,Mn_(2)Ru_(x)Ga exhibits high spin polarization and high tunability of compensation temperature by freely changing the Ru content x in a broad range(0.3k buttons prepared by arc melting are systematically studied and it is found that in equilibrium bulk form,the cubic structure is unstable when xk which is confirmed by both the magnetic measurement and anomalous Hall effect *** analyses of the anomalous Hall effect scaling in quaternary Mn-Ru-V-Ga alloy reveal the dominant role of skew scattering,notably that contributed caused by the thermally excited phonons,in contrast to the dominant intrinsic mechanism found in many other 3d ferromagnets and Heusler *** is further shown that the Ga antisites and V content can simultaneously control the residual resistivity ratio(RRR)as well as the relative contribution of phonon and defect to the anomalous Hall effect a"/a0'in Mn-Ru-V-Ga,resulting in a scaling relation a"/a0'∝RRR^(1.8).

关键词： compensated ferrimagnet anomalous Hall effect residual resistivity ratio