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Zhou J, Yang Y, Yu Y. Revealing mechanical property–strengthening micro-mechanism of Ni/Ni3Al-based alloys by molecular dynamics simulation. J Mol Model 2022; 28:371. [DOI: 10.1007/s00894-022-05350-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 10/05/2022] [Indexed: 11/11/2022]
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2
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Bhowmik BP, Hentschel HGE, Procaccia I. Creep failure of amorphous solids under tensile stress. Phys Rev E 2022; 106:034906. [PMID: 36266831 DOI: 10.1103/physreve.106.034906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
Applying constant tensile stress to a piece of amorphous solid results in a slow extension, followed by an eventual rapid mechanical collapse. This "creep" process is of paramount engineering concern, and as such was the subject of study in a variety of materials, for more than a century. Predictive theories for τ_{w}, the expected time of collapse, are incomplete, mainly due to its dependence on a bewildering variety of parameters, including temperature, system size, tensile force, but also the detailed microscopic interactions between constituents. The complex dependence of the collapse time on all the parameters is discussed below, using simulations of strip of amorphous material. Different scenarios are observed for ductile and brittle materials, resulting in serious difficulties in creating an all-encompassing theory that could offer safety measures for given conditions. A central aim of this paper is to employ scaling concepts, to achieve data collapse for the probability distribution function (pdf) of lnτ_{w}. The scaling ideas result in a universal function which provides a prediction of the pdf of lnτ_{w} for out-of-sample systems, from measurements at other values of these parameters. The predictive power of the scaling theory is demonstrated for both ductile and brittle systems. Finally, we present a derivation of universal scaling function for brittle materials. The ductile case appears to be due to a plastic necking instability and is left for future research.
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Affiliation(s)
- Bhanu Prasad Bhowmik
- Department of Chemical Physics, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - H G E Hentschel
- Department of Chemical Physics, The Weizmann Institute of Science, Rehovot 76100, Israel
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| | - Itamar Procaccia
- Department of Chemical Physics, The Weizmann Institute of Science, Rehovot 76100, Israel
- Center for OPTical IMagery Analysis and Learning, Northwestern Polytechnical University, Xi'an 710072, China
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3
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Zhang Y, Li J, Hu Y, Ding S, Du F, Xia R. Characterization of the deformation behaviors under uniaxial stress for bicontinuous nanoporous amorphous alloys. Phys Chem Chem Phys 2022; 24:1099-1112. [PMID: 34927647 DOI: 10.1039/d1cp04970d] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In this paper, the deformation behaviors of Cu50Zr50 bicontinuous nanoporous amorphous alloys (BNAMs) under uniaxial tension/compression are explored by molecular dynamics simulations. Scaling laws between mechanical properties and relative density are investigated. The results demonstrate that the bending deformation of the ligament is the main elastic deformation mechanism under tension. Necking and subsequent fracture of ligaments are the primary failure mechanism under tension. Under tensile loading, shear bands emerge near the plastic hinges for the BNAMs with large porosities. The typical compressive behaviors of porous structure are observed in the BNAMs with large porosities. However, for small porosity, no distinguished plateau and densification are captured under compression. The tension-compression asymmetry of modulus increases with increasing porosity, whereas the BNAMs can be seen as tension-compression symmetry of yield strength. The modulus and yield strength are negatively correlated with temperature, but a positive relationship between the tensile ductility and temperature is shown. This work will help to provide a useful understanding of the mechanical behaviors of the BNAMs.
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Affiliation(s)
- Yuhang Zhang
- Key Laboratory of Hydraulic Machinery Transients (Wuhan University), Ministry of Education, Wuhan 430072, China.
| | - Jiejie Li
- Key Laboratory of Hydraulic Machinery Transients (Wuhan University), Ministry of Education, Wuhan 430072, China. .,College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China
| | - Yiqun Hu
- Key Laboratory of Hydraulic Machinery Transients (Wuhan University), Ministry of Education, Wuhan 430072, China.
| | - Suhang Ding
- Key Laboratory of Hydraulic Machinery Transients (Wuhan University), Ministry of Education, Wuhan 430072, China.
| | - Fuying Du
- Key Laboratory of Hydraulic Machinery Transients (Wuhan University), Ministry of Education, Wuhan 430072, China.
| | - Re Xia
- Key Laboratory of Hydraulic Machinery Transients (Wuhan University), Ministry of Education, Wuhan 430072, China. .,Hubei Key Laboratory of Waterjet Theory and New Technology, Wuhan University, Wuhan 430072, China.
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4
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Wang X, Zhang H, Douglas JF. The initiation of shear band formation in deformed metallic glasses from soft localized domains. J Chem Phys 2021; 155:204504. [PMID: 34852471 DOI: 10.1063/5.0069729] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
It has long been thought that shear band (SB) formation in amorphous solids initiates from relatively "soft" regions in the material in which large-scale non-affine deformations become localized. The test of this hypothesis requires an effective means of identifying "soft" regions and their evolution as the material is deformed to varying degrees, where the metric of "softness" must also account for the effect of temperature on local material stiffness. We show that the mean square atomic displacement on a caging timescale ⟨u2⟩, the "Debye-Waller factor," provides a useful method for estimating the shear modulus of the entire material and, by extension, the material stiffness at an atomic scale. Based on this "softness" metrology, we observe that SB formation indeed occurs through the strain-induced formation of localized soft regions in our deformed metallic glass free-standing films. Unexpectedly, the critical strain condition for SB formation occurs when the softness (⟨u2⟩) distribution within the emerging soft regions approaches that of the interfacial region in its undeformed state, initiating an instability with similarities to the transition to turbulence. Correspondingly, no SBs arise when the material is so thin that the entire material can be approximately described as being "interfacial" in nature. We also quantify relaxation in the glass and the nature and origin of highly non-Gaussian particle displacements in the dynamically heterogeneous SB regions at times longer than the caging time.
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Affiliation(s)
- Xinyi Wang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Hao Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Jack F Douglas
- Material Measurement Laboratory, Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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5
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Yang Q, Pei CQ, Yu HB, Feng T. Metallic Nanoglasses with Promoted β-Relaxation and Tensile Plasticity. NANO LETTERS 2021; 21:6051-6056. [PMID: 34240612 DOI: 10.1021/acs.nanolett.1c01283] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The secondary (β) relaxation is an intrinsic feature of glassy systems and is crucial for the mechanical properties of metallic glasses. However, it remains puzzling what structural features control the β-relaxation fundamentally. Here, we use the recently developed nanoglasses exhibiting well-defined structural features at the nanometer scale to interrogate such structure-dynamics relations. We show that an electrodeposited Ni77.5P22.5 nanoglass exhibits promoted β-relaxation and enhanced microscale tensile plasticity over the most rapidly melt-quenched metallic glass with the same composition. Structurally, the β-relaxation is sensitive to the interfacial regions among grains in the nanoglasses. Our results reveal a clear correlation between the amorphous nanostructures and the β-relaxation. It seems that the nanostructuring represents a novel route to obtain high-energy glassy states, that is, the inverse problem of the ultrastable glass.
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Affiliation(s)
- Qun Yang
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, Hubei China
| | - Chao-Qun Pei
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Hai-Bin Yu
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, Hubei China
| | - Tao Feng
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
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6
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Yan W, Richard I, Kurtuldu G, James ND, Schiavone G, Squair JW, Nguyen-Dang T, Das Gupta T, Qu Y, Cao JD, Ignatans R, Lacour SP, Tileli V, Courtine G, Löffler JF, Sorin F. Structured nanoscale metallic glass fibres with extreme aspect ratios. NATURE NANOTECHNOLOGY 2020; 15:875-882. [PMID: 32747740 DOI: 10.1038/s41565-020-0747-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
Micro- and nanoscale metallic glasses offer exciting opportunities for both fundamental research and applications in healthcare, micro-engineering, optics and electronics. The scientific and technological challenges associated with the fabrication and utilization of nanoscale metallic glasses, however, remain unresolved. Here, we present a simple and scalable approach for the fabrication of metallic glass fibres with nanoscale architectures based on their thermal co-drawing within a polymer matrix with matched rheological properties. Our method yields well-ordered and uniform metallic glasses with controllable feature sizes down to a few tens of nanometres, and aspect ratios greater than 1010. We combine fluid dynamics and advanced in situ transmission electron microscopy analysis to elucidate the interplay between fluid instability and crystallization kinetics that determines the achievable feature sizes. Our approach yields complex fibre architectures that, combined with other functional materials, enable new advanced all-in-fibre devices. We demonstrate in particular an implantable metallic glass-based fibre probe tested in vivo for a stable brain-machine interface that paves the way towards innovative high-performance and multifunctional neuro-probes.
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Affiliation(s)
- Wei Yan
- Laboratory of Photonic Materials and Fibre Devices (FIMAP), Institute of Materials, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Inès Richard
- Laboratory of Photonic Materials and Fibre Devices (FIMAP), Institute of Materials, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Güven Kurtuldu
- Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Nicholas D James
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Defitech Center for Interventional Neurotherapies (NeuroRestore), University Hospital Lausanne (CHUV), University of Lausanne (UNIL) and École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Giuseppe Schiavone
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Institute of Microengineering, Institute of Bioengineering, Centre for Neuroprosthetics, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Jordan W Squair
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Defitech Center for Interventional Neurotherapies (NeuroRestore), University Hospital Lausanne (CHUV), University of Lausanne (UNIL) and École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Tung Nguyen-Dang
- Laboratory of Photonic Materials and Fibre Devices (FIMAP), Institute of Materials, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Tapajyoti Das Gupta
- Laboratory of Photonic Materials and Fibre Devices (FIMAP), Institute of Materials, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Yunpeng Qu
- Laboratory of Photonic Materials and Fibre Devices (FIMAP), Institute of Materials, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Jake D Cao
- Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Reinis Ignatans
- Institute of Materials, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Stéphanie P Lacour
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Institute of Microengineering, Institute of Bioengineering, Centre for Neuroprosthetics, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Vasiliki Tileli
- Institute of Materials, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Grégoire Courtine
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Defitech Center for Interventional Neurotherapies (NeuroRestore), University Hospital Lausanne (CHUV), University of Lausanne (UNIL) and École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Jörg F Löffler
- Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Fabien Sorin
- Laboratory of Photonic Materials and Fibre Devices (FIMAP), Institute of Materials, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
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7
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Mahmud G, Zhang H, Douglas JF. Localization model description of the interfacial dynamics of crystalline Cu and Cu 64Zr 36 metallic glass films. J Chem Phys 2020; 153:124508. [PMID: 33003746 DOI: 10.1063/5.0022937] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Recent studies of structural relaxation in Cu-Zr metallic glass materials having a range of compositions and over a wide range of temperatures and in crystalline UO2 under superionic conditions have indicated that the localization model (LM) can predict the structural relaxation time τα of these materials from the intermediate scattering function without any free parameters from the particle mean square displacement ⟨r2⟩ at a caging time on the order of ps, i.e., the "Debye-Waller factor" (DWF). In the present work, we test whether this remarkable relation between the "fast" picosecond dynamics and the rate of structural relaxation τα in these model amorphous and crystalline materials can be extended to the prediction of the local interfacial dynamics of model amorphous and crystalline films. Specifically, we simulate the free-standing amorphous Cu64Zr36 and crystalline Cu films and find that the LM provides an excellent parameter-free prediction for τα of the interfacial region. We also show that the Tammann temperature, defining the initial formation of a mobile interfacial layer, can be estimated precisely for both crystalline and glass-forming solid materials from the condition that the DWFs of the interfacial region and the material interior coincide.
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Affiliation(s)
- Gazi Mahmud
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Hao Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Jack F Douglas
- Material Measurement Laboratory, Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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8
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Kiani MT, Barr CM, Xu S, Doan D, Wang Z, Parakh A, Hattar K, Gu XW. Ductile Metallic Glass Nanoparticles via Colloidal Synthesis. NANO LETTERS 2020; 20:6481-6487. [PMID: 32786936 DOI: 10.1021/acs.nanolett.0c02177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The design of ductile metallic glasses has been a longstanding challenge. Here, we use colloidal synthesis to fabricate nickel-boron metallic glass nanoparticles that exhibit homogeneous deformation at room temperature and moderate strain rates. In situ compression testing is used to characterize the mechanical behavior of 90-260 nm diameter nanoparticles. The force-displacement curves consist of two regimes separated by a slowly propagating shear band in small, 90 nm particles. The propensity for shear banding decreases with increasing particle size, such that large particles are more likely to deform homogeneously through gradual shape change. We relate this behavior to differences in composition and atomic bonding between particles of different size using mass spectroscopy and XPS. We propose that the ductility of the nanoparticles is related to their internal structure, which consists of atomic clusters made of a metalloid core and a metallic shell that are connected to neighboring clusters by metal-metal bonds.
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Affiliation(s)
- Mehrdad T Kiani
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Christopher Michael Barr
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185-1056, United States
| | - Shicheng Xu
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - David Doan
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Zhaoxuan Wang
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Abhinav Parakh
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Khalid Hattar
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185-1056, United States
| | - X Wendy Gu
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
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9
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Kiani MT, Hattar K, Gu XW. In Situ TEM Study of Radiation Resistance of Metallic Glass-Metal Core-Shell Nanocubes. ACS APPLIED MATERIALS & INTERFACES 2020; 12:40910-40916. [PMID: 32805810 DOI: 10.1021/acsami.0c10664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Radiation damage can cause significantly more surface damage in metallic nanostructures than bulk materials. Structural changes from displacement damage compromise the performance of nanostructures in radiation environments such as nuclear reactors and outer space, or used in radiation therapy for biomedical treatments. As such, it is important to develop strategies to prevent this from occurring if nanostructures are to be incorporated into these applications. Here, in situ transmission electron microscope ion irradiation was used to investigate whether a metallic glass (MG) coating mitigates sputtering and morphological changes in metallic nanostructures. Dislocation-free Au nanocubes and Au nanocubes coated with a Ni-B MG were bombarded with 2.8 MeV Au4+ ions. The formation of internal defects in bare Au nanocubes was observed at a fluence of 7.5 × 1011 ions/cm2 (0.008 dpa), and morphological changes such as surface roughening, rounding of corners, and formation of nanofilaments began at 4 × 1012 ions/cm2 (0.04 dpa). In contrast, the Ni-B MG-coated Au nanocubes (Au@NiB) showed minimal morphological changes at a fluence of 1.9 × 1013 ions/cm2 (0.2 dpa). The MG coating maintains its amorphous nature under all irradiation conditions investigated.
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Affiliation(s)
- Mehrdad T Kiani
- Department of Materials Science & Engineering, Stanford University, Stanford 94305, California, United States
| | - Khalid Hattar
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque 87123, New Mexico, United States
| | - X Wendy Gu
- Department of Mechanical Engineering, Stanford University, Stanford 94305, California, United States
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10
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Zhang X, Wang Y, Ding B, Li X. Design, Fabrication, and Mechanics of 3D Micro-/Nanolattices. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1902842. [PMID: 31483576 DOI: 10.1002/smll.201902842] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/21/2019] [Indexed: 06/10/2023]
Abstract
Over the past several decades, lattice materials have been developed and used as engineering materials for lightweight and stiff industrial structures. Recent advances in additive manufacturing techniques have prompted the emergence of architected materials with minimum characteristic sizes ranging from several micrometers to hundreds of nanometers. Taking advantage of the topological design, structural optimization, and size effects of nanomaterials, various 3D micro-/nanolattice materials composed of different materials exhibit combinations of superior mechanical properties, such as low density, high strength (even approaching the theoretical limits), large deformability, good recoverability, and flaw tolerance. As a result, some micro-/nanolattices occupy an unprecedented area in Ashby charts with a combination of different material properties. Here, recent advances in the fabrication and mechanics of micro-/nanolattices are described. First, various design principles and advanced techniques used for the fabrication of micro-/nanolattices are summarized. Then, the mechanical behaviors and properties of micro-/nanolattices are further described, including the compressive Young's modulus, strength, energy absorption, recoverability, and tensile behavior, with an emphasis on mechanistic insights and origins. Finally, the main challenges in the fabrication and mechanics of micro-/nanolattices are addressed and an outlook for further investigations and potential applications of micro-/nanolattices in the future is provided.
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Affiliation(s)
- Xuan Zhang
- Centre for Advanced Mechanics and Materials, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Yujia Wang
- Centre for Advanced Mechanics and Materials, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Bin Ding
- Centre for Advanced Mechanics and Materials, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
| | - Xiaoyan Li
- Centre for Advanced Mechanics and Materials, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
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11
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Zhang Q, Li QK, Zhao SF, Wang WH, Li M. Structural characteristics in deformation mechanism transformation in nanoscale metallic glasses. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:455401. [PMID: 31342932 DOI: 10.1088/1361-648x/ab3529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Deformation of metallic glasses is closely related to their microstructures which depend on the composition, processing method, and the size of the materials. This subtle structure-property relation is fairly complex and remains to be explored. Here, we scrutinize the microstructural evolution in relation to the mechanical properties in metallic glass nanowires with the same composition and size but subtle microstructural differences by controlling the preparing process using molecular dynamics simulations. The results suggest that a structural threshold exists for the transformation of deformation mechanisms in metallic glasses: when the structural feature exceeds the threshold, the deformation changes from homogeneous flow to shear localized deformation.
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Affiliation(s)
- Qi Zhang
- Qian Xuesen laboratory of Space Technology, NO. 104 Youyi Road, Haidian district, Beijing 100094, People's Republic of China
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12
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Chen Z, Liu H, Li W, Mo J, Wang M, Zhang Y, Li J, Jiang Q, Yang W, Tang C. Chiral metallic glass nanolattices with combined lower density and improved auxeticity. Phys Chem Chem Phys 2019; 21:20588-20594. [PMID: 31237283 DOI: 10.1039/c9cp02545f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Auxetic materials are promising structural and functional candidates due to their unique lateral expansion when stretched, however, bulk metallic glasses (MGs) could not show any auxeticity because of their intrinsic isotropic nature. Here we construct chiral Cu50Zr50 metallic glass nanolattices with cavities, and investigate their auxeticity and underlying mechanism with molecular dynamics simulations. It is found that, compared to monolithic MGs, all the chiral metallic glass nanolattices (CMGNs) exhibit improved auxeticity and lower density. For CMGNs with cavities, the negative Poisson's ratio and ultimate tensile strength (UTS) increase first and then decrease with increasing cavity radius, with the cavity radius of 2.5 nm being the most favorable for auxeticity and enhanced UTS. The auxetic mechanism is attributed to the competition between rotation behavior and non-affine deformation under tension. Our study not only reveals the mechanism of auxeticity in CMGNs having cavities but also provides a feasible method to optimize their auxetic performance and density by structure designing of MGs.
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Affiliation(s)
- Zhe Chen
- School of Physical Science and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China.
| | - Haishun Liu
- School of Physical Science and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China.
| | - Wenyu Li
- State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, University of Mining and Technology, Xuzhou 221116, People's Republic of China.
| | - Jinyong Mo
- School of Physical Science and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China.
| | - Mingzi Wang
- School of Physical Science and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China.
| | - Yue Zhang
- School of Physical Science and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China.
| | - Jingyan Li
- School of Physical Science and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China.
| | - Qi Jiang
- School of Physical Science and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China.
| | - Weiming Yang
- State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, University of Mining and Technology, Xuzhou 221116, People's Republic of China.
| | - Chunguang Tang
- Research School of Chemistry, Energy Change Institute, Australian National University, Canberra ACT, 2601, Australia.
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13
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Exceptional fracture resistance of ultrathin metallic glass films due to an intrinsic size effect. Sci Rep 2019; 9:8281. [PMID: 31164663 PMCID: PMC6547732 DOI: 10.1038/s41598-019-44384-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 05/14/2019] [Indexed: 11/25/2022] Open
Abstract
Metallic glasses typically fail in a brittle manner through shear band propagation but can exhibit significant ductility when the sample size is reduced below a few hundreds of nanometers. To date the size effect was mainly demonstrated for free-standing samples and the role of extrinsic setup parameters on the observed behavior is still under debate. Therefore, in the present work we investigated the mechanical properties of polymer-supported sputtered amorphous Pd82Si18 thin films with various thicknesses. We show that the films exhibit brittle fracture for thicknesses far below 100 nm. A pronounced size effect resulting in extended crack-free deformation up to 6% strain was observed only in films as thin as 7 nm – a thickness which is lower than the typical shear band thickness. This size effect results in exceptional cyclic reliability of ultrathin metallic glass films which can sustain cyclic strains of 3% up to at least 30,000 cycles without any indication of fatigue damage or electrical conductivity degradation. Since the enhancement of mechanical properties is observed at ambient conditions using inexpensive substrates and an industrially scalable sputter deposition technique, a new research avenue for utilization of ultrathin metallic glasses in microelectronics, flexible electronics or nanoelectromechanical devices is opened up.
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14
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Vashisth A, Khatri S, Hahn SH, Zhang W, van Duin ACT, Naraghi M. Mechanical size effects of amorphous polymer-derived ceramics at the nanoscale: experiments and ReaxFF simulations. NANOSCALE 2019; 11:7447-7456. [PMID: 30938750 DOI: 10.1039/c9nr00958b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Here we report an unprecedented mechanical size effect at the nanoscale in polymer-derived ceramic (PDC) nanofibers. Silicon oxycarbide (SiOC) PDCs were fabricated as micro- and nanofibers without the aid of fillers. By decreasing the size of SiOC ceramic fibers from 1.1 μm to 630 nm (reduction of 74%), the strength of nanofibers nearly tripled, going from ∼1 GPa to ∼3.3 GPa. This increase in strength exceeds the predictions of the Griffith theorem, which relies on the length-scale dependence of energy release rate during crack propagation, suggesting a reduction in flaw size more than proportional to sample size. Given the crosslinked and amorphous nature of SiOC PDCs, flaws are likely microcracks and voids, which form during polymer degassing as it is pyrolyzed to PDC nanofibers. A reduction in sample size may favor degassing via diffusion, preceding bubble and void formation. We developed a new reactive force field (ReaxFF) with parameters for Si/O/C/H/N to study the mechanics of PDCs in extreme cases where no void is present. The models and experiments compare favorably in terms of the elastic modulus. The simulations suggest a strength of ∼8.5 GPa for a "flawless" structure, which is in line with extrapolated experimental results, with C-C breakage as the root cause of failure. This work clearly shows the benefits of utilizing nanoscale components as building blocks of superstrong PDC structures.
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Affiliation(s)
- Aniruddh Vashisth
- Aerospace Engineering, Texas A&M University, College Station, TX 77845, USA.
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15
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Bonfanti S, Ferrero EE, Sellerio AL, Guerra R, Zapperi S. Damage Accumulation in Silica Glass Nanofibers. NANO LETTERS 2018; 18:4100-4106. [PMID: 29856226 DOI: 10.1021/acs.nanolett.8b00469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The origin of the brittle-to-ductile transition, experimentally observed in amorphous silica nanofibers as the sample size is reduced, is still debated. Here we investigate the issue by extensive molecular dynamics simulations at low and room temperatures for a broad range of sample sizes, with open and periodic boundary conditions. Our results show that small sample-size enhanced ductility is primarily due to diffuse damage accumulation, that for larger samples leads to brittle catastrophic failure. Surface effects such as boundary fluidization contribute to ductility at room temperature by promoting necking, but are not the main driver of the transition. Our results suggest that the experimentally observed size-induced ductility of silica nanofibers is a manifestation of finite-size criticality, as expected in general for quasi-brittle disordered networks.
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Affiliation(s)
- Silvia Bonfanti
- Center for Complexity and Biosystems, Department of Physics , University of Milano , via Celoria 16 , 20133 Milano , Italy
| | - Ezequiel E Ferrero
- Center for Complexity and Biosystems, Department of Physics , University of Milano , via Celoria 16 , 20133 Milano , Italy
- CONICET, Centro Atómico Bariloche , Av. Bustillo 9500 , 8400 S. C. de Bariloche , Río Negro Argentina
| | - Alessandro L Sellerio
- Center for Complexity and Biosystems, Department of Physics , University of Milano , via Celoria 16 , 20133 Milano , Italy
| | - Roberto Guerra
- Center for Complexity and Biosystems, Department of Physics , University of Milano , via Celoria 16 , 20133 Milano , Italy
| | - Stefano Zapperi
- Center for Complexity and Biosystems, Department of Physics , University of Milano , via Celoria 16 , 20133 Milano , Italy
- Consiglio Nazionale delle Ricerche , Istituto di Chimica della Materia Condensata e di Tecnologie per l'Energia , Via R. Cozzi 53 , 20125 Milano , Italy
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16
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Greer JR, Park J. Additive Manufacturing of Nano- and Microarchitected Materials. NANO LETTERS 2018; 18:2187-2188. [PMID: 29635920 DOI: 10.1021/acs.nanolett.8b00724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
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17
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Jafary-Zadeh M, Praveen Kumar G, Branicio PS, Seifi M, Lewandowski JJ, Cui F. A Critical Review on Metallic Glasses as Structural Materials for Cardiovascular Stent Applications. J Funct Biomater 2018; 9:E19. [PMID: 29495521 PMCID: PMC5872105 DOI: 10.3390/jfb9010019] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 02/05/2018] [Accepted: 02/22/2018] [Indexed: 01/20/2023] Open
Abstract
Functional and mechanical properties of novel biomaterials must be carefully evaluated to guarantee long-term biocompatibility and structural integrity of implantable medical devices. Owing to the combination of metallic bonding and amorphous structure, metallic glasses (MGs) exhibit extraordinary properties superior to conventional crystalline metallic alloys, placing them at the frontier of biomaterials research. MGs have potential to improve corrosion resistance, biocompatibility, strength, and longevity of biomedical implants, and hence are promising materials for cardiovascular stent applications. Nevertheless, while functional properties and biocompatibility of MGs have been widely investigated and validated, a solid understanding of their mechanical performance during different stages in stent applications is still scarce. In this review, we provide a brief, yet comprehensive account on the general aspects of MGs regarding their formation, processing, structure, mechanical, and chemical properties. More specifically, we focus on the additive manufacturing (AM) of MGs, their outstanding high strength and resilience, and their fatigue properties. The interconnection between processing, structure and mechanical behaviour of MGs is highlighted. We further review the main categories of cardiovascular stents, the required mechanical properties of each category, and the conventional materials have been using to address these requirements. Then, we bridge between the mechanical requirements of stents, structural properties of MGs, and the corresponding stent design caveats. In particular, we discuss our recent findings on the feasibility of using MGs in self-expandable stents where our results show that a metallic glass based aortic stent can be crimped without mechanical failure. We further justify the safe deployment of this stent in human descending aorta. It is our intent with this review to inspire biodevice developers toward the realization of MG-based stents.
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Affiliation(s)
- Mehdi Jafary-Zadeh
- Institute of High Performance Computing, A*STAR, Singapore 138632, Singapore.
| | | | - Paulo Sergio Branicio
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-0241, USA.
| | - Mohsen Seifi
- Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - John J Lewandowski
- Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Fangsen Cui
- Institute of High Performance Computing, A*STAR, Singapore 138632, Singapore.
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18
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Effect of surface and internal defects on the mechanical properties of metallic glasses. Sci Rep 2017; 7:13472. [PMID: 29044193 PMCID: PMC5647394 DOI: 10.1038/s41598-017-13410-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 09/21/2017] [Indexed: 11/20/2022] Open
Abstract
Despite the significance of surface effects on the deformation behaviours of small-scale metallic glasses, systematic investigations on surface states are lacking. In this work, by employing atomistic simulations, we characterise the distributions of local inhomogeneity near surfaces created by casting and cutting, along with internal distributions in pristine and irradiated bulk specimens, and investigate the effects of inhomogeneity on the mechanical properties. The cast surface shows enhanced yield strength and degrees of shear localisation, while the cut surface shows the opposite effects, although the fraction of vibrational soft spots, known to indicate low-energy barriers for local rearrangement, is high near both surfaces. Correspondingly, plastic deformation is initiated near the cut surface, but far from the cast surface. We reveal that improved local orientational symmetry promotes strengthening in cast surfaces and originates from the effectively lower quenching rate due to faster diffusion near the surface. However, a significant correlation among vibrational soft spots, local symmetries, and the degree of shear localisation is found for the pristine and irradiated bulk materials. Our findings reveal the sensitivity of the surface state to the surface preparation methods, and indicate that particular care must be taken when studying metallic glasses containing free surfaces.
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Bauer J, Meza LR, Schaedler TA, Schwaiger R, Zheng X, Valdevit L. Nanolattices: An Emerging Class of Mechanical Metamaterials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29. [PMID: 28873250 DOI: 10.1002/adma.201701850] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/23/2017] [Indexed: 05/12/2023]
Abstract
In 1903, Alexander Graham Bell developed a design principle to generate lightweight, mechanically robust lattice structures based on triangular cells; this has since found broad application in lightweight design. Over one hundred years later, the same principle is being used in the fabrication of nanolattice materials, namely lattice structures composed of nanoscale constituents. Taking advantage of the size-dependent properties typical of nanoparticles, nanowires, and thin films, nanolattices redefine the limits of the accessible material-property space throughout different disciplines. Herein, the exceptional mechanical performance of nanolattices, including their ultrahigh strength, damage tolerance, and stiffness, are reviewed, and their potential for multifunctional applications beyond mechanics is examined. The efficient integration of architecture and size-affected properties is key to further develop nanolattices. The introduction of a hierarchical architecture is an effective tool in enhancing mechanical properties, and the eventual goal of nanolattice design may be to replicate the intricate hierarchies and functionalities observed in biological materials. Additive manufacturing and self-assembly techniques enable lattice design at the nanoscale; the scaling-up of nanolattice fabrication is currently the major challenge to their widespread use in technological applications.
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Affiliation(s)
- Jens Bauer
- Department of Mechanical and Aerospace Engineering, University of California Irvine, CA, 92697, USA
- Institute for Applied Materials, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, 76344, Germany
| | - Lucas R Meza
- Engineering Department, Trumpington Street, Cambridge, CB2 1PZ, UK
| | | | - Ruth Schwaiger
- Institute for Applied Materials, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, 76344, Germany
| | - Xiaoyu Zheng
- Department of Mechanical Engineering, Virginia Tech, 635 Prices Fork Road, Blacksburg, VA, 24061, USA
| | - Lorenzo Valdevit
- Department of Mechanical and Aerospace Engineering, University of California Irvine, CA, 92697, USA
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20
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Zhang WB, Liu J, Lu SH, Zhang H, Wang H, Wang XD, Cao QP, Zhang DX, Jiang JZ. Size effect on atomic structure in low-dimensional Cu-Zr amorphous systems. Sci Rep 2017; 7:7291. [PMID: 28779092 PMCID: PMC5544703 DOI: 10.1038/s41598-017-07708-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 07/03/2017] [Indexed: 11/28/2022] Open
Abstract
The size effect on atomic structure of a Cu64Zr36 amorphous system, including zero-dimensional small-size amorphous particles (SSAPs) and two-dimensional small-size amorphous films (SSAFs) together with bulk sample was investigated by molecular dynamics simulations. We revealed that sample size strongly affects local atomic structure in both Cu64Zr36 SSAPs and SSAFs, which are composed of core and shell (surface) components. Compared with core component, the shell component of SSAPs has lower average coordination number and average bond length, higher degree of ordering, and lower packing density due to the segregation of Cu atoms on the shell of Cu64Zr36 SSAPs. These atomic structure differences in SSAPs with various sizes result in different glass transition temperatures, in which the glass transition temperature for the shell component is found to be 577 K, which is much lower than 910 K for the core component. We further extended the size effect on the structure and glasses transition temperature to Cu64Zr36 SSAFs, and revealed that the Tg decreases when SSAFs becomes thinner due to the following factors: different dynamic motion (mean square displacement), different density of core and surface and Cu segregation on the surface of SSAFs. The obtained results here are different from the results for the size effect on atomic structure of nanometer-sized crystalline metallic alloys.
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Affiliation(s)
- W B Zhang
- International Center for New-Structured Materials (ICNSM), Laboratory of New-Structured Materials, State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, People's Republic of China
| | - J Liu
- International Center for New-Structured Materials (ICNSM), Laboratory of New-Structured Materials, State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, People's Republic of China
| | - S H Lu
- School of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - H Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4, Canada
| | - H Wang
- Institute of Nanosurface Science and Engineering, Shenzhen University, Shenzhen, 518060, People's Republic of China
| | - X D Wang
- International Center for New-Structured Materials (ICNSM), Laboratory of New-Structured Materials, State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, People's Republic of China
| | - Q P Cao
- International Center for New-Structured Materials (ICNSM), Laboratory of New-Structured Materials, State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, People's Republic of China
| | - D X Zhang
- State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, 310027, People's Republic of China
| | - J Z Jiang
- International Center for New-Structured Materials (ICNSM), Laboratory of New-Structured Materials, State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, People's Republic of China.
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21
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Dual-phase nanostructuring as a route to high-strength magnesium alloys. Nature 2017; 545:80-83. [PMID: 28379942 DOI: 10.1038/nature21691] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 02/03/2017] [Indexed: 11/08/2022]
Abstract
It is not easy to fabricate materials that exhibit their theoretical 'ideal' strength. Most methods of producing stronger materials are based on controlling defects to impede the motion of dislocations, but such methods have their limitations. For example, industrial single-phase nanocrystalline alloys and single-phase metallic glasses can be very strong, but they typically soften at relatively low strains (less than two per cent) because of, respectively, the reverse Hall-Petch effect and shear-band formation. Here we describe an approach that combines the strengthening benefits of nanocrystallinity with those of amorphization to produce a dual-phase material that exhibits near-ideal strength at room temperature and without sample size effects. Our magnesium-alloy system consists of nanocrystalline cores embedded in amorphous glassy shells, and the strength of the resulting dual-phase material is a near-ideal 3.3 gigapascals-making this the strongest magnesium-alloy thin film yet achieved. We propose a mechanism, supported by constitutive modelling, in which the crystalline phase (consisting of almost-dislocation-free grains of around six nanometres in diameter) blocks the propagation of localized shear bands when under strain; moreover, within any shear bands that do appear, embedded crystalline grains divide and rotate, contributing to hardening and countering the softening effect of the shear band.
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22
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Zhang Q, Li QK, Li M. Key factors affecting mechanical behavior of metallic glass nanowires. Sci Rep 2017; 7:41365. [PMID: 28134292 PMCID: PMC5278411 DOI: 10.1038/srep41365] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 12/20/2016] [Indexed: 11/09/2022] Open
Abstract
Both strengthening and weakening trends with decreasing diameter have been observed for metallic glass nanowires, sometimes even in the samples with the same chemical composition. How to reconcile the results has reminded a puzzle. Since the detailed stress state and microstructure of metallic glass nanowires may differ from each other significantly depending on preparation, to discover the intrinsic size effect it is necessary to study metallic glass nanowires fabricated differently. Here we show the complex size effects from one such class of metallic glass nanowires prepared by casting using molecular dynamics simulations. As compared with the nanowires of the same composition prepared by other methods, the cast nanowires deform nearly homogeneously with much lower strength but better ductility; and also show strengthening in tension but weakening in compression with decreasing wire diameter. The subtle size dependence is shown to be related to the key factors including internal and surface stress state, atomic structure variation, and presence of various gradients. The complex interplay of these factors at decreasing size leads to the different deformation behaviors.
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Affiliation(s)
- Qi Zhang
- Nanophotonics and Optoelectronics Research Center, Qian Xuesen laboratory of Space Technology, China Academy of Space Technology, Beijing, 100094, China.,School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Qi-Kai Li
- State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China
| | - Mo Li
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.,State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China
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23
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Structural evolution of nanoscale metallic glasses during high-pressure torsion: A molecular dynamics analysis. Sci Rep 2016; 6:36627. [PMID: 27819352 PMCID: PMC5098210 DOI: 10.1038/srep36627] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/17/2016] [Indexed: 11/08/2022] Open
Abstract
Structural evolution in nanoscale Cu50Zr50 metallic glasses during high-pressure torsion is investigated using molecular dynamics simulations. Results show that the strong cooperation of shear transformations can be realized by high-pressure torsion in nanoscale Cu50Zr50 metallic glasses at room temperature. It is further shown that high-pressure torsion could prompt atoms to possess lower five-fold symmetries and higher potential energies, making them more likely to participate in shear transformations. Meanwhile, a higher torsion period leads to a greater degree of forced cooperative flow. And the pronounced forced cooperative flow at room temperature under high-pressure torsion permits the study of the shear transformation, its activation and characteristics, and its relationship to the deformations behaviors. This research not only provides an important platform for probing the atomic-level understanding of the fundamental mechanisms of high-pressure torsion in metallic glasses, but also leads to higher stresses and homogeneous flow near lower temperatures which is impossible previously.
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24
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Ordered fragmentation of oxide thin films at submicron scale. Nat Commun 2016; 7:13148. [PMID: 27748456 PMCID: PMC5071645 DOI: 10.1038/ncomms13148] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 09/07/2016] [Indexed: 11/08/2022] Open
Abstract
Crack formation is typically undesirable as it represents mechanical failure that compromises strength and integrity. Recently, there have also been numerous attempts to control crack formation in materials with the aim to prevent or isolate crack propagation. In this work, we utilize fragmentation, at submicron and nanometre scales, to create ordered metal oxide film coatings. We introduce a simple method to create modified films using electroplating on a prepatterned substrate. The modified films undergo preferential fragmentation at locations defined by the initial structures on the substrate, yielding ordered structures. In thicker films, some randomness in the characteristic sizes of the fragments is introduced due to competition between crack propagation and crack creation. The method presented allows patterning of metal oxide films over relatively large areas by controlling the fragmentation process. We demonstrate use of the method to fabricate high-performance electrochromic structures, yielding good coloration contrast and high coloration efficiency. Fracture and related processes are typically considered detrimental, but have also attracted interest in more constructive roles. Here authors demonstrate ordered fragmentation at submicron scales of a metal oxide/hydroxide thin film by introducing preferential sites for fracture on the underlying substrate.
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25
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Nanoscale Structure, Dynamics, and Aging Behavior of Metallic Glass Thin Films. Sci Rep 2016; 6:30973. [PMID: 27498698 PMCID: PMC4976322 DOI: 10.1038/srep30973] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 07/12/2016] [Indexed: 11/24/2022] Open
Abstract
Scanning tunnelling microscopy observations resolve the structure and dynamics of metallic glass Cu100−xHfx films and demonstrate scanning tunnelling microscopy control of aging at a metallic glass surface. Surface clusters exhibit heterogeneous hopping dynamics. Low Hf concentration films feature an aged surface of larger, slower clusters. Argon ion-sputtering destroys the aged configuration, yielding a surface in constant fluctuation. Scanning tunnelling microscopy can locally restore the relaxed state, allowing for nanoscale lithographic definition of aged sections.
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26
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Şopu D, Foroughi A, Stoica M, Eckert J. Brittle-to-Ductile Transition in Metallic Glass Nanowires. NANO LETTERS 2016; 16:4467-4471. [PMID: 27248329 DOI: 10.1021/acs.nanolett.6b01636] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
When reducing the size of metallic glass samples down to the nanoscale regime, experimental studies on the plasticity under uniaxial tension show a wide range of failure modes ranging from brittle to ductile ones. Simulations on the deformation behavior of nanoscaled metallic glasses report an unusual extended strain softening and are not able to reproduce the brittle-like fracture deformation as found in experiments. Using large-scale molecular dynamics simulations we provide an atomistic understanding of the deformation mechanisms of metallic glass nanowires and differentiate the extrinsic size effects and aspect ratio contribution to plasticity. A model for predicting the critical nanowire aspect ratio for the ductile-to-brittle transition is developed. Furthermore, the structure of brittle nanowires can be tuned to a softer phase characterized by a defective short-range order and an excess free volume upon systematic structural rejuvenation, leading to enhanced tensile ductility. The presented results shed light on the fundamental deformation mechanisms of nanoscaled metallic glasses and demarcate ductile and catastrophic failure.
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Affiliation(s)
- D Şopu
- IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden, Germany
| | - A Foroughi
- IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden, Germany
| | - M Stoica
- IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden, Germany
- Politehnica University of Timisoara , P-ta Victoriei 2, RO-300006 Timisoara, Romania
| | - J Eckert
- Erich Schmid Institute of Materials Science, Austrian Academy of Sciences , Jahnstrasse 12, A-8700 Leoben, Austria
- Department Materials Physics, Mountanuniversität Leoben , Jahnstrasse 12, A-8700 Leoben, Austria
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27
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Thermomechanical Behavior of Molded Metallic Glass Nanowires. Sci Rep 2016; 6:19530. [PMID: 26787400 PMCID: PMC4726219 DOI: 10.1038/srep19530] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 12/15/2015] [Indexed: 11/23/2022] Open
Abstract
Metallic glasses are disordered materials that offer the unique ability to perform thermoplastic forming operations at low thermal budget while preserving excellent mechanical properties such as high strength, large elastic strain limits, and wear resistance owing to the metallic nature of bonding and lack of internal defects. Interest in molding micro- and nanoscale metallic glass objects is driven by the promise of robust and high performance micro- and nanoelectromechanical systems and miniature energy conversion devices. Yet accurate and efficient processing of these materials hinges on a robust understanding of their thermomechanical behavior. Here, we combine large-scale thermoplastic tensile deformation of collections of Pt-based amorphous nanowires with quantitative thermomechanical studies of individual nanowires in creep-like conditions to demonstrate that superplastic-like flow persists to small length scales. Systematic studies as a function of temperature, strain-rate, and applied stress reveal the transition from Newtonian to non-Newtonian flow to be ubiquitous across the investigated length scales. However, we provide evidence that nanoscale specimens sustain greater free volume generation at elevated temperatures resulting in a flow transition at higher strain-rates than their bulk counterparts. Our results provide guidance for the design of thermoplastic processing methods and methods for verifying the flow response at the nanoscale.
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28
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Abstract
Fracture toughness of transition metals can be correlated to the electron work function. Within the range where the electron work function is smaller than 4.6 eV, the fracture toughness increases with the electron work function. However, if the electron work function exceeds 4.6 eV, the fracture toughness decreases with an increase in electron work function.
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Affiliation(s)
- Guomin Hua
- Department of Chemical and Materials Engineering
- University of Alberta
- Edmonton
- Canada
| | - Dongyang Li
- Department of Chemical and Materials Engineering
- University of Alberta
- Edmonton
- Canada
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29
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Adibi S, Branicio PS, Joshi SP. Suppression of Shear Banding and Transition to Necking and Homogeneous Flow in Nanoglass Nanopillars. Sci Rep 2015; 5:15611. [PMID: 26503114 PMCID: PMC4621512 DOI: 10.1038/srep15611] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 09/28/2015] [Indexed: 11/18/2022] Open
Abstract
In order to improve the properties of metallic glasses (MG) a new type of MG structure, composed of nanoscale grains, referred to as nanoglass (NG), has been recently proposed. Here, we use large-scale molecular dynamics (MD) simulations of tensile loading to investigate the deformation and failure mechanisms of Cu64Zr36 NG nanopillars with large, experimentally accessible, 50 nm diameter. Our results reveal NG ductility and failure by necking below the average glassy grain size of 20 nm, in contrast to brittle failure by shear band propagation in MG nanopillars. Moreover, the results predict substantially larger ductility in NG nanopillars compared with previous predictions of MD simulations of bulk NG models with columnar grains. The results, in excellent agreement with experimental data, highlight the substantial enhancement of plasticity induced in experimentally relevant MG samples by the use of nanoglass architectures and point out to exciting novel applications of these materials.
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Affiliation(s)
- Sara Adibi
- Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632
- Department of Mechanical Engineering, National University of Singapore, 117576, Singapore
| | - Paulo S. Branicio
- Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632
| | - Shailendra P. Joshi
- Department of Mechanical Engineering, National University of Singapore, 117576, Singapore
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30
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Lee SW, Jafary-Zadeh M, Chen DZ, Zhang YW, Greer JR. Size Effect Suppresses Brittle Failure in Hollow Cu60Zr40 Metallic Glass Nanolattices Deformed at Cryogenic Temperatures. NANO LETTERS 2015; 15:5673-5681. [PMID: 26262592 DOI: 10.1021/acs.nanolett.5b01034] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
To harness "smaller is more ductile" behavior emergent at nanoscale and to proliferate it onto materials with macroscale dimensions, we produced hollow-tube Cu60Zr40 metallic glass nanolattices with the layer thicknesses of 120, 60, and 20 nm. They exhibit unique transitions in deformation mode with tube-wall thickness and temperature. Molecular dynamics simulations and analytical models were used to interpret these unique transitions in terms of size effects on the plasticity of metallic glasses and elastic instability.
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Affiliation(s)
- Seok-Woo Lee
- Division of Engineering and Applied Science, California Institute of Technology , 1200 E California Blvd, Pasadena, California 91125, United States
- Department of Materials Science and Engineering, Institute of Materials Science, University of Connecticut , Unit 3136, 97 North Eagleville Road, Storrs, Connecticut 06269-3136, United States
| | - Mehdi Jafary-Zadeh
- Institute of High Performance Computing, A*STAR, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore
| | - David Z Chen
- Division of Engineering and Applied Science, California Institute of Technology , 1200 E California Blvd, Pasadena, California 91125, United States
| | - Yong-Wei Zhang
- Institute of High Performance Computing, A*STAR, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore
| | - Julia R Greer
- Division of Engineering and Applied Science, California Institute of Technology , 1200 E California Blvd, Pasadena, California 91125, United States
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31
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Sussman DM, Goodrich CP, Liu AJ, Nagel SR. Disordered surface vibrations in jammed sphere packings. SOFT MATTER 2015; 11:2745-2751. [PMID: 25690151 DOI: 10.1039/c4sm02905d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We study the vibrational properties near a free surface of disordered spring networks derived from jammed sphere packings. In bulk systems, without surfaces, it is well understood that such systems have a plateau in the density of vibrational modes extending down to a frequency scale ω*. This frequency is controlled by ΔZ = 〈Z〉 - 2d, the difference between the average coordination of the spheres and twice the spatial dimension, d, of the system, which vanishes at the jamming transition. In the presence of a free surface we find that there is a density of disordered vibrational modes associated with the surface that extends far below ω*. The total number of these low-frequency surface modes is controlled by ΔZ, and the profile of their decay into the bulk has two characteristic length scales, which diverge as ΔZ(-1/2) and ΔZ(-1) as the jamming transition is approached.
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Affiliation(s)
- Daniel M Sussman
- Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104, USA.
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Abstract
Bulk metallic glasses (BMGs) are ideal for nanomoulding as they possess desirable strength for molds as well as for moldable materials and furthermore lack intrinsic size limitations. Despite their attractiveness, only recently Pt-based BMGs have been successfully molded into pores ranging 10-100 nm (Kumar et al 2009 Nature 457 868-72). Here, we introduce a quantitative theory, which reveals previous challenges in filling nanosized pores. This theory considers, in addition to a viscous and a capillary term, also oxidation, which becomes increasingly more important on smaller length scales. Based on this theory we construct a nanomoulding processing map for BMG, which reveals the limiting factors for BMG nanomoulding. Based on the quantitative prediction of the processing map, we introduce a strategy to reduce the capillary effect through a wetting layer, which allows us to mold non-noble BMGs below 1 μm in air. An additional benefit of this strategy is that it drastically facilitates demoulding, one of the main challenges of nanomoulding in general.
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Affiliation(s)
- Ze Liu
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520, USA. Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06511, USA
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33
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Direct in situ observation of metallic glass deformation by real-time nano-scale indentation. Sci Rep 2015; 5:9122. [PMID: 25773051 PMCID: PMC4360469 DOI: 10.1038/srep09122] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 02/18/2015] [Indexed: 11/08/2022] Open
Abstract
A common understanding of plastic deformation of metallic glasses (MGs) at room temperature is that such deformation occurs via the formation of runaway shear bands that usually lead to catastrophic failure of MGs. Here we demonstrate that inhomogeneous plastic flow at nanoscale can evolve in a well-controlled manner without further developing of shear bands. It is suggested that the sample undergoes an elasto-plastic transition in terms of quasi steady-state localized shearing. During this transition, embryonic shear localization (ESL) propagates with a very slow velocity of order of ~1 nm/s without the formation of a hot matured shear band. This finding further advances our understanding of the microscopic deformation process associated with the elasto-plastic transition and may shed light on the theoretical development of shear deformation in MGs.
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Sun C, Zheng S, Wei CC, Wu Y, Shao L, Yang Y, Hartwig KT, Maloy SA, Zinkle SJ, Allen TR, Wang H, Zhang X. Superior radiation-resistant nanoengineered austenitic 304L stainless steel for applications in extreme radiation environments. Sci Rep 2015; 5:7801. [PMID: 25588326 PMCID: PMC4295098 DOI: 10.1038/srep07801] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 11/28/2014] [Indexed: 11/17/2022] Open
Abstract
Nuclear energy provides more than 10% of electrical power internationally, and the increasing engagement of nuclear energy is essential to meet the rapid worldwide increase in energy demand. A paramount challenge in the development of advanced nuclear reactors is the discovery of advanced structural materials that can endure extreme environments, such as severe neutron irradiation damage at high temperatures. It has been known for decades that high dose radiation can introduce significant void swelling accompanied by precipitation in austenitic stainless steel (SS). Here we report, however, that through nanoengineering, ultra-fine grained (UFG) 304L SS with an average grain size of ~100 nm, can withstand Fe ion irradiation at 500°C to 80 displacements-per-atom (dpa) with moderate grain coarsening. Compared to coarse grained (CG) counterparts, swelling resistance of UFG SS is improved by nearly an order of magnitude and swelling rate is reduced by a factor of 5. M23C6 precipitates, abundant in irradiated CG SS, are largely absent in UFG SS. This study provides a nanoengineering approach to design and discover radiation tolerant metallic materials for applications in extreme radiation environments.
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Affiliation(s)
- C Sun
- 1] Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843 [2] Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - S Zheng
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - C C Wei
- Department of Nuclear Engineering, Texas A&M University, College Station, TX 77843
| | - Y Wu
- Department of Materials Science and Engineering, Nuclear Engineering Program, University of Florida, Gainesville, FL 32611
| | - L Shao
- Department of Nuclear Engineering, Texas A&M University, College Station, TX 77843
| | - Y Yang
- Department of Materials Science and Engineering, Nuclear Engineering Program, University of Florida, Gainesville, FL 32611
| | - K T Hartwig
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843
| | - S A Maloy
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - S J Zinkle
- Department of Nuclear Engineering, The University of Tennessee, Knoxville, TN, 37996, USA
| | - T R Allen
- Department of Engineering Physics, University of Wisconsin, Madison, WI 53706, USA
| | - H Wang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843
| | - X Zhang
- 1] Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843 [2] Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843
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Gu XW, Jafary-Zadeh M, Chen DZ, Wu Z, Zhang YW, Srolovitz DJ, Greer JR. Mechanisms of failure in nanoscale metallic glass. NANO LETTERS 2014; 14:5858-5864. [PMID: 25198652 DOI: 10.1021/nl5027869] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The emergence of size-dependent mechanical strength in nanosized materials is now well-established, but no fundamental understanding of fracture toughness or flaw sensitivity in nanostructures exists. We report the fabrication and in situ fracture testing of ∼70 nm diameter Ni-P metallic glass samples with a structural flaw. Failure occurs at the structural flaw in all cases, and the failure strength of flawed samples was reduced by 40% compared to unflawed samples. We explore deformation and failure mechanisms in a similar nanometallic glass via molecular dynamics simulations, which corroborate sensitivity to flaws and reveal that the structural flaw shifts the failure mechanism from shear banding to cavitation. We find that failure strength and deformation in amorphous nanosolids depend critically on the presence of flaws.
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Affiliation(s)
- X Wendy Gu
- Division of Chemistry and Chemical Engineering and ‡Division of Engineering and Applied Science, California Institute of Technology , 1200 E. California Blvd., Pasadena, California 91125, United States
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Meza LR, Das S, Greer JR. Strong, lightweight, and recoverable three-dimensional ceramic nanolattices. Science 2014; 345:1322-6. [DOI: 10.1126/science.1255908] [Citation(s) in RCA: 836] [Impact Index Per Article: 83.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Liontas R, Gu XW, Fu E, Wang Y, Li N, Mara N, Greer JR. Effects of helium implantation on the tensile properties and microstructure of Ni73P27 metallic glass nanostructures. NANO LETTERS 2014; 14:5176-5183. [PMID: 25084487 DOI: 10.1021/nl502074d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report fabrication and nanomechanical tension experiments on as-fabricated and helium-implanted ∼130 nm diameter Ni73P27 metallic glass nanocylinders. The nanocylinders were fabricated by a templated electroplating process and implanted with He(+) at energies of 50, 100, 150, and 200 keV to create a uniform helium concentration of ∼3 atom % throughout the nanocylinders. Transmission electron microscopy imaging and through-focus analysis reveal that the specimens contained ∼2 nm helium bubbles distributed uniformly throughout the nanocylinder volume. In situ tensile experiments indicate that helium-implanted specimens exhibit enhanced ductility as evidenced by a 2-fold increase in plastic strain over as-fabricated specimens with no sacrifice in yield and ultimate tensile strengths. This improvement in mechanical properties suggests that metallic glasses may actually exhibit a favorable response to high levels of helium implantation.
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Affiliation(s)
- Rachel Liontas
- Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
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38
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Liu L, Hasan M, Kumar G. Metallic glass nanostructures: fabrication, properties, and applications. NANOSCALE 2014; 6:2027-2036. [PMID: 24384932 DOI: 10.1039/c3nr05645g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Remarkable progress has been made in fabrication and characterization of metal nanostructures because of their crucial role in energy conversion, nanophotonics, nanoelectronics, and biodiagnostics. Less emphasis has been placed on the synthesis of nanostructures from metallic alloys, which are better suited than elemental metals for certain applications such as fuel-cell catalysts. The main challenges in fabrication of alloy nanostructures are controlling their chemical stoichiometry, crystal structures, and shapes because of anisotropic nucleation and growth rates. These limitations can be overcome by using metallic glasses (amorphous metal alloys) which are isotropic and provide additional control handles through their tunable compositions and degree of crystallinity. Here, we review the recent developments in fabrication and characterization of metallic glass (MG) nanostructures. The focus is on sub-micron structures synthesized by unconventional thermoplastic techniques. A concept of self-assembly is introduced for fashioning functional structures using MG nanostructures as building blocks. The article concludes with a brief discussion about unique properties and prospective applications of MG nanostructures.
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Affiliation(s)
- Lianci Liu
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409-3121, USA.
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