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Observation and computer simulation of multicomponent chemical short-range order (MCSRO) for the bulk metallic glasses

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Journal of University of Science and Technology Beijing 2005年第2期12卷 143-150页

作者： GuoliangChen XidongHui KefuYao HuaiyuHou XiongjunLiu MeilingWang GuangChen StateKeyLaboratoryforAdvancedMetalsandMaterials UniversityofScienceandTechnologyBeijingBeijing100083China／／DepartmentofMaterialScienceandEngineeringNanjingUniversityofScienceandTechnologyNanjing210094China StateKeyLaboratoryforAdvancedMetalsandMaterials UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofMechanicalEngineering TsinghuaUniversityBeijing100084China. DepartmentofMaterialScienceandEngineering NanjingUniversityofScienceandTechnologyNanjing210094China

The atomic configuration of chemical short-range order (CSRO) for the Zr-base metallic glasses was investigated by using nano-diffraction and high resolution transmission electronic microscopy (HRTEM) technology with a beam size of 0.5 nm. It is il- lustrated that the pattern of atomic configuration of CSRO might have various compound counterparts because of the chemical inter- action of bonding atoms. Some atomic configuration of MCSRO is similar to the icosahedral structure with 10-fold symmetry of very weak spots. In deed, the nano-beam technology could clearly detect the evolution of atomic configuration in nanometer scale during the transformation from the metallic melt to the primary crystallization. The local atomic configuration of CSRO is also investigated by molecular dynamics simulation (MD) for the Zr2Ni compound in a wider temperature range. The CSRO in the melt could be pic- torially demonstrated as distorted coordination polyhedron of the compound structure and/or the structure similar to cubo-octahedron analogs. The MD simulation illustrates that the atomic packing of long-range order disappears just above the melting point, but the chemical interaction of bonding atoms still exists that leads to form the various CSRO with the atomic configuration similar to stable or metastable unit cell of Zr2Ni compound. The icosahedral polyhedron became more abundance as the overheating temperature was raised.

关键词： bulk metallic glasses short-range order nano-diffraction and HRTEM technology molecular dynamic simulation

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Generalization properties of restricted Boltzmann machine for short-range order

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Chinese Physics B 2023年第6期32卷 556-562页

作者： M A Timirgazin A K Arzhnikov Udmurt Federal Research Center Ural Branch of RASIzhevsk 426067Russia

A biased sampling algorithm for the restricted Boltzmann machine(RBM) is proposed, which allows generating configurations with a conserved quantity. To validate the method, a study of the short-range order in binary alloys with positive and negative exchange interactions is carried out. The network is trained on the data collected by Monte–Carlo simulations for a simple Ising-like binary alloy model and used to calculate the Warren–Cowley short-range order parameter and other thermodynamic properties. We demonstrate that the proposed method allows us not only to correctly reproduce the order parameters for the alloy concentration at which the network was trained, but can also predict them for any other concentrations.

关键词： machine learning short-range order Ising model restricted Boltzmann machine

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Mssbauer Studies of the Atomic short-range order (SRO) and the Electron Transfer in Amorphous TM-M Alloys

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苏州大学学报(自然科学版) 1988年第4期 543-554页

作者：许裕生 Physics Department

The Mossbauer spectra of amorphous alloys FeB-M(M=P, C, Si, Ge) at room temperature and at 4.2 K have been measured. It is found that the mean values of the hyperfine field and the isomer shift vary linearly when M substitutes for B. According to these results and those of their crystalline counterparts, it is shown that there does not exist a microcrystalline short-range order in the amorphous alloys investigated and that thc 4s electrons of iron take part in lhe charge transfer.

关键词： amorphous alloys short-range order electron transfer M(?)ssbaucr spectroscopy hyperfine field isomer shift.

Anomalies in the short-range local environment and atomic diffusion in single crystalline equiatomic CrMnFeCoNi highentropy alloy

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Nano Research 2024年第6期17卷 5336-5348页

作者： Alevtina Smekhova Daniel Gaertner Alexei Kuzmin Ana Guilherme Buzanich Goetz Schuck Ivo Zizak Gerhard Wilde Kirill V.Yusenko Sergiy Divinski Helmholtz-Zentrum Berlin für Materialien und Energie(HZB) D-12489 BerlinGermany Institute of Materials Physics University of MünsterD-48149 MünsterGermany Institute of Solid State Physics University of LatviaLV-1063 RigaLatvia Bundesanstalt für Materialforschung und–prüfung(BAM) D-12489 BerlinGermany

Multi-edge extended X-ray absorption fine structure(EXAFS)spectroscopy combined with reverse Monte Carlo(RMC)simulations was used to probe the details of element-specific local coordinations and component-dependent structure relaxations in single crystalline equiatomic CrMnFeCoNi high-entropy alloy as a function of the annealing *** representative states,namely a high-temperature state,created by annealing at 1373 K,and a low-temperature state,produced by long-term annealing at 993 K,were compared in *** features identified in atomic configurations of particular principal components indicate variations in the local environment distortions connected to different degrees of compositional disorder at the chosen representative *** detected changes provide new atomistic insights and correlate with the existence of kinks previously observed in the Arrhenius dependencies of component diffusion rates in the CrMnFeCoNi high-entropy alloy.

关键词： high-entropy alloys diffusion short-range order extended X-ray absorption fine structure(EXAFS) reverse Monte Carlo

Structure and dynamical properties during solidification of liquid aluminum induced by cooling and compression

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Chinese Physics B 2024年第7期33卷 476-481页

作者：吴旻杨永琪王垚 College of Materials Science and Engineering Zhejiang University of TechnologyHangzhou 310014China Shaoxing Research Institute Zhejiang University of TechnologyShaoxing 312000China

The structural transformation from a liquid into a crystalline solid is an important subject in condensed matter physics and materials science. In the present study, first-principles molecular dynamics calculations are performed to investigate the structure and properties of aluminum during the solidification which is induced by cooling and compression. In the cooling process and compression process, it is found that the icosahedral short-range order is initially enhanced and then begin to decay, the face-centered cubic short-range order eventually becomes dominant before it transforms into a crystalline solid.

关键词： first-principles method molecular dynamics short-range order liquid aluminum

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Influence of carbon addition on mechanical properties of Fe-Mn-C twinning-induced plasticity steels

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Journal of Iron and Steel Research International 2022年第9期29卷 1446-1454页

作者： Peng Fu Zhi-bing Zheng Wei-ping Yang Hao-kun Yang School of Engineering Jiangxi Agricultural UniversityNanchang 330045JiangxiChina Institute of New Materials GuangdongAcademy of SciencesGuangdong Provincial iron Matrix Composite Engineering Research CenterGuangzhou 510650GuangdongChina Smart Manufacturing Division Hong Kong Productivity CouncilHong Kong 999077.China

Mechanical properties and microstructural evolution of Fe-22Mn-0.6C and Fe-22Mn-1.0C(wt.%)twinning-induced plasticity(TwIP)steels were investigated by monotonic,stress-relaxation and unloading-reloading tensile *** dynamic strain aging(DSA)effect,resulting from pinning of dislocations,effectively improved the dislocation activation volume of the two TWIP *** the meanwhile,DSA-facilitated twinning nucleation mechanism kept similar twinning capabilities of the two TWIP *** strain increasing,the formation of high-density deformation twins restricted the dislocation motion and reduced the activation volume with increasing ***,C addition simultaneously improved the ultimate tensile strength and uniform elongation,and significantly enhanced the friction stress,rather than back *** stronger short-range order effect,brought by friction stress,promotes the planar dislocation slipping,thus improving the work-hardening *** a result,the additional work-hardening capacity can be achieved in Fe-Mn-C with higher C addition.

关键词： Twinning induced plasticity steel Work-hardening rate Dynamic strain aging short-range order Deformation twin

Temperature-driven phase transformation and element segregation in Pd-Ru immiscible alloy nanoparticles:Spatial resolving of elements and insights for electrocatalysis

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Nano Research 2023年第7期16卷 9968-9976页

作者： Hui Li Zheng Hu Yu Zhang Wenbo Zhao Yuyao Zeng Wei Zhou Shi Hu Department of Chemistry School of ScienceTianjin Key Laboratory of Molecular Optoelectronic ScienceTianjin UniversityTianjin 300072China Institute of Energy Hefei Comprehensive National Science CenterHefei 230031China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin 300071China Department of Physics School of ScienceTianjin Key Laboratory of Molecular Optoelectronic ScienceTianjin UniversityTianjin 300072China

Bimetallic alloys could form three typical structures including solid solution,heterostructure,and intermetallic compound,depending on the interactions between identical and different *** the trend can be predicted by the types of binary phase diagram,different synthetic protocols will trap the system in various kinetic intermediates among the three typical ***,we studied the phase evolution and elemental segregation in the alloy nanoparticles of immiscible Pd-Ru before and after thermal *** developing an analysis method of local element segregation(LES)based on the energy dispersive spectroscopy(EDS)mapping signals,we were able to quantify the mixing of Pd and Ru atoms during the gradual phase transition from face-centered cubic(fcc)to hexagonal close packed(hcp).Density functional theory was also applied to calculate the energies of all possible PdRu4 structures(93 fcc models and 267 hcp models),which helps to rationalize the phase transition and element *** annealing process also leads to the change of the electronic structure,which further influences the performance in the electrocatalytic hydrogen evolution *** highest activity of PdRu4-400 was largely attributed to the proper interface between the Pd-rich fcc phase and Ru-rich hcp phase,as revolved by the above methods.

关键词： Pd-Ru alloy short-range order local element segregation hydrogen evolution reaction

Raman Scattering Study on Vibrational Modes and .Structure of Lanthanum Tellurite Glasses

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Chinese Journal of Chemical Physics 2012年第5期25卷 519-525,I0003页

作者： Angelos G Kalampounias Department of Chemical Engineering University of Patras and Institute of Chemical Engineering andHigh Temperature Chemical Processes FORTH/ICE-HT P.O. Box 1414 Patras GR-26 504 Greece

Raman spectra of xLa203-（1-x）TeO2 （x=0, 0.05, 0.10, 0.15, 0.20, and 0.25） lanthanum tellurite glasses were measured and analyzed over the entire glass-forming region in an effort to quantitatively follow the structural changes caused by lanthanum oxide variation. For the first time, systematic intensity measurements have been performed to elucidate the composition induced structural changes in tile high-frequency stretching vibration region and a possible mechanism was proposed. The network structure of the glasses is formed by mixing TeO4 trigonal bipyramid and Te03 trigonal pyramid units. The change of the lanthanum oxide content results in conversion of the TeO4 units to TeO3 units with a varying number of non-bridging oxygen atoms. Analysis of the Raman band contours in terms of vibrations due to different oxygen bridged trigonal bipyramid and trigonal pyramid tellurite structural units, allowed to calculate the relative amounts of the species involved in the structural changes with composition. The fraction of the terminal oxygen atoms has been estimated from the Raman intensities with the aid of a structural model concerning the structure of tellurite network systems. The simulation of the experimental density of lanthanum tellurite glasses with modifier content up to 25% revealed that the short range order building units assumed here are sufficient to account for the overall structure in these glasses.

关键词： Tellurite glass Raman spectroscopy short-range order Density model

Band Gaps of an Amorphous Photonic Materials

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Chinese Physics Letters 2004年第2期21卷 324-325页

作者：王义全冯志芳胡小永程丙英张道中 OpticalPhysicsLaboratory InstituteofPhysicsandCenterforCondensedMatterPhysicsChineseAcademyofSciencesBeijing100080

A new kind of amorphous photonic materials is presented. Both the simulated and experimental results show that although the disorder of the whole dielectric structure is strong, the amorphous photonic materials have two photonic gaps. This confirms that the short-range order is an essential factor for the formation of the photonic gaps.

关键词： Band gap photonic materials simulating photonic short-range order noncrystalline