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Excellent dynamic yield and spall strength of single crystal NiAlCo alloy under shock compression

materials science and engineering: A 2025年 939卷

作者： Pan, X.T. Dong, J.L. Chen, X.M. Luo, B.Q. Shui, R.J. Xu, C. Wu, G. Wang, G.J. Wu, H.A. Tan, F.L. Zhao, J.H. Sun, C.W. CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics CAS Center for Excellence in Complex System Mechanics University of Science and Technology of China Hefei230027 China Institute of Fluid Physics China Academy of Engineering Physics Mianyang621999 China Institute of Applied Electronics China Academy of Engineering Physics Mianyang621999 China

A fundamental understanding of the mechanical behaviors and deformation mechanism of materials subjected to dynamic loading is critical for developing outstanding structural materials. This work focuses on the experimental investigation into the dynamic mechanical behaviors, deformation mechanisms, and damage characteristics of single-crystal NiAlCo which was regarded as a potential structure material at high pressure and strain rate. The shock responses of the single-crystal NiAlCo alloy were tested over a range of shock pressure from 10 to 50 GPa at a strain rate of 105/s utilizing the technique of magnetically driven high-velocity flyer plates on high pulsed power generator CQ-4. Based on the analyses of free surface velocity profiles, a linear Hugoniot relationship between shock wave speed and particle velocity was obtained, and the spall strength gradually increased from 2.61 GPa to 6.98 GPa with increasing shock pressure. The yield strength was calculated from the Hugoniot elastic limit, and it reaches 1.80 GPa over the wide range of shock pressure. Further, the relationship between dynamic strength and strain rate was depicted by empirical formulas in power exponential form. Finally, the detailed transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) microscopic characterization results of recovered samples disclose that single-crystal NiAlCo have abundant micro-deformation mechanisms under high pressure and high strain rate, including dislocation tangle, high-density stacking faults, and Lomer-Cottrell locks. The results show that both spall and yield strength are significantly higher than those of most alloys, exhibiting superior mechanical properties, which may be attributed to the coupling of multiple deformation mechanisms. © 2025 Elsevier B.V.

关键词： Strain rate

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Performance analysis of steel W18CR4V grinding using RSM, DNN-GA, KNN, LM, DT, SVM models, and optimization via desirability function and MOGWO

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Heliyon 2025年第4期11卷 e42640页

作者： Touati, Sofiane Boumediri, Haithem Karmi, Yacine Chitour, Mourad Boumediri, Khaled Zemmouri, Amina Moussa, Athmani Fernandes, Filipe Mechanical Engineering Department University Abbes Laghrour BP. 1252 Khenchela 40004 Algeria Mechanical Department Institute of Applied Science and Technology University of Constantine 1 Constantine Algeria Electromechanical Department Institute of Applied Science and Technology University of Constantine 1 Constantine Algeria Laboratoire de Recherche en Électromécanique et Sûreté de Fonctionnement LRESF Laboratory University of Souk Ahras P.O. Box 1553 Souk Ahras 41000 Algeria Mechanical Engineering Department Badji Mokhtar Annaba University Mechanics of Materials and Plant Maintenance Research Laboratory (LR3MI) Algeria Laboratory of Physics of Thin Films and Applications University of Mohamed Khider BP 145 RP Biskra 07000 Algeria CIDEM ISEP - Polytechnic of Porto Rua Dr. António Bernardino de Almeida Porto 4249-015 Portugal University of Coimbra CEMMPRE ARISE Department of Mechanical Engineering Rua Luís Reis Santos Coimbra 3030-788 Portugal

This study presents an innovative approach to optimizing the grinding process of W18CR4V steel, a high-performance material used in reamer manufacturing, using advanced machine learning models and multi-objective optimization techniques. The novel combination of Deep Neural Networks with Genetic Algorithm (DNN-GA), K-Nearest Neighbors (KNN), Levenberg-Marquardt (LM), Decision Trees (DT), and Support Vector Machines (SVM) was employed to predict key process outcomes, such as surface roughness (Ra), maximum roughness height (Rz), and production time. The results reveal significant improvements, with Ra values ranging from 0.231 μm to 1.250 μm (up to 81.5 % reduction) and Rz from 1.519 μm to 6.833 μm (up to 77.7 % reduction). The hybrid DNN-GA model achieved R² > 0.99, reducing prediction errors by 23–45 % compared to traditional models. Optimization via the Desirability Function achieved Ra values around 0.341 μm and Rz around 2.3 μm, with production times ranging from 1181 to 1426 s. The innovative Multi-Objective Grey Wolf Optimization (MOGWO) provided Pareto-optimal solutions, minimizing Ra to 0.3 μm, Rz to 1.5 μm, and production times between 2000 and 3000 s, offering better balance between surface quality and machining efficiency. This work highlights the unique integration of machine learning models with optimization techniques to significantly enhance grinding performance and manufacturing efficiency in high-precision industries. © 2025 The Authors

关键词： Desirability function Grinding process Machine learning models Multi-objective grey wolf optimization (MOGWO) Surface roughness W18CR4V steel

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Spin Seebeck effect at low temperatures in the nominally paramagnetic insulating state of vanadium dioxide

arXiv

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arXiv 2022年

作者： Luo, Renjie Zhao, Xuanhan Chen, Liyang Legvold, Tanner J. Navarro, Henry Schuller, Ivan K. Natelson, Douglas Department of Physics and Astronomy Rice University HoustonTX77005 United States Applied Physics Graduate Program Rice University HoustonTX77005 United States Department of Physics Center for Advanced Nanoscience University of California-San Diego La Jolla CA92093 United States Department of Electrical and Computer Engineering Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States

The low temperature monoclinic, insulating phase of vanadium dioxide is ordinarily considered nonmagnetic, with dimerized vanadium atoms forming spin singlets, though paramagnetic response is seen at low temperatures. We find a nonlocal spin Seebeck signal in VO2 films that appears below 30 K and which increases with decreasing temperature. The spin Seebeck response has a non-hysteretic dependence on in-plane external magnetic field. This paramagnetic spin Seebeck response is discussed in terms of prior findings on paramagnetic spin Seebeck effects and expected magnetic excitations of the monoclinic ground state. Copyright © 2022, The Authors. All rights reserved.

关键词： Vanadium dioxide

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Ultrafast switchable polar and magnetic orders by nonlinear light-matter interaction

arXiv

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arXiv 2025年

作者： Wei, Haoyu Kaplan, Daniel Xu, Haowei Li, Ju Department of Materials Science and Engineering Massachusetts Institute of Technology CambridgeMA02139 United States Tsien Excellence in Engineering Program Tsinghua University Beijing100084 China Department of Applied Physics Yale University New HavenCT06520 United States Center for Materials Theory Department of Physics and Astronomy Rutgers University PiscatawayNJ08854 United States Department of Nuclear Science and Engineering Massachusetts Institute of Technology CambridgeMA02139 United States

An outstanding challenge in materials science and physics is the harnessing of light for switching charge order in e.g., ferroelectrics. Here we propose a mechanism through which electrons in ferroelectric bilayers excited with light cause ionic structural transitions. Using perturbation theory within a many-body formalism, we show that the ionic coupling is mediated by a resonant change in electronic occupation functions, ultimately governed by the quantum geometric tensor (QGT) of the ground state. Furthermore, we show that such transitions are generally accompanied by multiferroic order switching. We demonstrate two examples of light-induced structural and polarization switching under this mechanism using first-principle calculations on bilayer CrI3 and MoTe2 . We show that the two materials can switch between atomic stackings with a light intensity threshold of only 101-102GW/cm2, a value 1-3 orders of magnitude lower than that required by direct light-ion coupling thanks to the superior efficiency of resonant light-electron coupling. Since such switching is fast, highly controllable, contactless, and reversible, it is promising for use in optically controlled nonvolatile memory, nanophotonics and electronic devices. Copyright © 2025, The Authors. All rights reserved.

关键词： Perturbation techniques

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Room-temperature quantum sensing with photoexcited triplet electrons in organic crystals

arXiv

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arXiv 2024年

作者： Singh, Harpreet D’Souza, Noella Zhong, Keyuan Druga, Emanuel Oshiro, Julianne Blankenship, Brian Montis, Riccardo Reimer, Jeffrey A. Breeze, Jonathan D. Ajoy, Ashok Department of Chemistry University of California Berkeley BerkeleyCA94720 United States Department of Physics Guru Nanak Dev University Punjab Amritsar143005 India Chemical Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Department of Chemical and Biomolecular Engineering University of California BerkeleyCA94720 United States Department of Pure and Applied Science University of Urbino Carlo Bo UrbinoI-61029 Italy Materials Science Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Department of Physics & Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom CIFAR Azrieli Global Scholars Program 661 University Ave TorontoONM5G 1M1 Canada

Quantum sensors have notably advanced high-sensitivity magnetic field detection. Here, we report quantum sensors constructed from polarized spin-triplet electrons in photoexcited organic chromophores, specifically focusing on pentacene-doped para-terphenyl (≈0.1%). We demonstrate essential quantum sensing properties at room temperature (RT): optically-generated electronic polarization and state-dependent fluorescence contrast, by leveraging differential pumping and relaxation rates between triplet and ground states. We measure high optically-detected magnetic resonance (ODMR) contrast ≈16.8% of the triplet states at RT, along with long coherence times under spin echo and CPMG sequences, T2=2.7μs and T2DD=18.4μs, respectively, limited only by the triplet lifetimes. The material offers several advantages for quantum sensing, including the ability to grow large (cm-scale) crystals at low cost, absence of paramagnetic impurities, and electronic diamagnetism when not optically illuminated. Utilizing pentacene as a representative of a broader class of spin triplet- polarizable organic molecules, this study highlights new potential for quantum sensing in chemical systems. © 2024, CC BY.

关键词： Crystal impurities

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Pinning of extended dislocations in atomically disordered crystals

arXiv

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arXiv 2021年

作者： Vaid, Aviral Wei, De'an Bitzek, Erik Nasiri, Samaneh Zaiser, Michael Department of Materials Science WW1-General Materials Properties Friedrich-Alexander Universität Erlangen-Nürnberg Martensstr. 5 Erlangen91058 Germany Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and Engineering Southwest Jiaotong University Chengdu610031 China Department of Materials Science WW8-Materials Simulation Friedrich-Alexander Universität Erlangen-Nürnberg Dr.-Mack-str. 77 Fürth90762 Germany

In recent years there has been renewed interest in the behavior of dislocations in crystals that exhibit strong atomic scale disorder, as typical of compositionally complex single phase alloys. The behavior of dislocations in such crystals has been often studied in the framework of elastic manifold pinning in disordered systems. Here we discuss modifications of this framework that may need to be adapted when dealing with extended dislocations that split into widely separated partials. We demonstrate that the presence of a stacking fault gives rise to an additional stress scale that needs to be compared with the pinning stress of elastic manifold theory to decide whether the partials are pinned individually or the dislocation is pinned as a whole. For the case of weakly interacting partial dislocations, we demonstrate the existence of multiple metastable states at stresses below the depinning threshold and analyze the stress evolution of the stacking fault width during loading. In addition we investigate how geometrical constraints can modulate the dislocation-solute interaction and enhance the pinning stress. We compare our theoretical arguments with results of atomistic and discrete (partial) dislocation dynamics (D(P)DD) simulations. © 2021, CC BY.

关键词： Shear stress

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Delocalization Transition in Colloidal Crystals

arXiv

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arXiv 2020年

作者： Lopez-Rios, Hector Ehlen, Ali de la Cruz, Monica Olvera Department of Materials Science and Engineering Northwestern University United States Applied Physics Program Northwestern University United States

Sublattice melting is the loss of order of one lattice component in binary or ternary ionic crystals upon increase in temperature. A related transition has been predicted in colloidal crystals. To understand the nature of this transition, we study delocalization in self-assembled, size asymmetric binary colloidal crystals using a generalized molecular dynamics model. Focusing on BCC lattices, we observe a smooth change from localized-to-delocalized interstitial particles for a variety of interaction strengths. Thermodynamic arguments, mainly the absence of a discontinuity in the heat capacity, suggest that the passage from localization-to-delocalization is continuous and not a phase transition. This change is enhanced by lattice vibrations, and the temperature of the onset of delocalization can be tuned by the strength of the interaction between the colloid species. Therefore, the localized and delocalized regimes of the sublattice are dominated by enthalpic and entropic driving forces, respectively. This work sets the stage for future studies of sublattice melting in colloidal systems with different stoichiometries and lattice types, and it provides insights into superionic materials, which have potential for application in energy storage technologies. Copyright © 2020, The Authors. All rights reserved.

关键词： Melting

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ML-Enabled Single Image Magnetic Phase Reconstruction for Lorentz Transmission Electron Microscopy

引用

Microscopy and Microanalysis 2024年第SUPPLEMENT_1期30卷

作者： McCray, Arthur R C Zhou, Tao Li, Yue Kandel, Saugat Petford-Long, Amanda Cherukara, Mathew J Phatak, Charudatta Materials Science Division Argonne National Laboratory Lemont IL USA Applied Physics Program Northwestern University Evanston IL USA Center for Nanoscale Materials Argonne National Laboratory Lemont IL USA Advanced Photon Source Argonne National Laboratory Lemont IL USA Department of Materials Science and Engineering Northwestern University Evanston IL USA

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Helium Nano-Bubbles in Copper Thin Films Slows Down Creep Under Ion Irradiation

SSRN

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SSRN 2024年

作者： Khiara, Nargisse Coulombier, Michaël Raskin, Jean-Pierre Bréchet, Yves Pardoen, Thomas Onimus, Fabien Université Paris-Saclay CEA Service de Recherche en Matériaux et procédés Avancés Gifsur-Yvette91191 France Materials science department Monash University Clayton Campus Wellington Road ClaytonVIC3800 Australia Institute of Mechanics Materials and Civil Engineering UCLouvain Place Sainte Barbe 2 L5.02.02 Louvain-la-Neuve1348 Belgium Institute of Information and Communication Technologies Electronics and Applied Mathematics UCLouvain Place du Levant 2 L5.04.04 Louvain-la-Neuve1348 Belgium WEL Research Institute Avenue Pasteur 6 Wavre1300 Belgium

Neutron irradiation of structural materials in nuclear applications is accompanied by a variety of microstructural changes including generation of helium nano-voids at high doses. When operating under stress, irradiation creep is taking place, leading to change of dimensions of components, relaxation of springs or screw torques. These distortions may have important implications on the performance of the nuclear reactor. Irradiation creep is particularly complicated to investigate and the link between creep rate and microstructure remains partly elusive. Ultra-miniaturized testing of thin films allows using ion irradiation and implantation methods to emulate the effect of in-reactor neutron irradiation. Here, on-chip tests on freestanding copper films reveal much slower irradiation creep of helium implanted copper layers compared with non-implanted copper, with or without ion irradiation hardening prior testing. This effect is due to the presence of the high density of helium bubbles, as evidenced by transmission electron microscopy, that impede dislocation glide and climb, thus limiting irradiation creep. A unified elementary model for moderate to high stress creep under irradiation is proposed showing that the creep law for this range of stress primarily depends on the yield strength which is increased by the presence of helium bubbles. © 2024, The Authors. All rights reserved.

关键词： Ion bombardment

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The dimension split element-free Galerkin method for three-dimensional potential problems

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Acta Mechanica Sinica 2018年第3期34卷 462-474页

作者： Z.J.Meng H.Cheng L.D.Ma Y.M.Cheng Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University School of Applied Science Taiyuan University of Science and Technology Department of Civil Engineering Shanghai University School of Materials Science and Engineering Taiyuan University of Science and Technology

This paper presents the dimension split element-free Galerkin （DSEFG） method for three-dimensional potential problems, and the corresponding formulae are obtained. The main idea of the DSEFG method is that a three-dimensional potential problem can be transformed into a series of two-dimensional problems. For these two-dimensional problems, the improved moving least-squares （IMLS） approximation is applied to construct the shape function, which uses an orthogonal function system with a weight function as the basis functions. The Galerkin weak form is applied to obtain a discretized system equation, and the penalty method is employed to impose the essential boundary condition. The finite difference method is selected in the splitting direction. For the purposes of demonstration, some selected numerical examples are solved using the DSEFG method. The convergence study and error analysis of the DSEFG method are presented. The numerical examples show that the DSEFG method has greater computational precision and computational efficiency than the IEFG method.

关键词： Dimension split method Improved moving least-squares （IMLS） approximation Improved element-free Galerkin （IEFG） method Finite difference method （FDM） Dimension split element-free Galerkin （DSEFG） method Potential problem

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