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Zhuo F, Zhou X, Dietrich F, Soleimany M, Breckner P, Groszewicz PB, Xu BX, Buntkowsky G, Rödel J. Dislocation Density-Mediated Functionality in Single-Crystal BaTiO 3. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2403550. [PMID: 38885353 DOI: 10.1002/advs.202403550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 05/12/2024] [Indexed: 06/20/2024]
Abstract
Unlike metals where dislocations carry strain singularity but no charge, dislocations in oxide ceramics are characterized by both a strain field and a local charge with a compensating charge envelope. Oxide ceramics with their deliberate engineering and manipulation are pivotal in numerous modern technologies such as semiconductors, superconductors, solar cells, and ferroics. Dislocations facilitate plastic deformation in metals and lead to a monotonous increase in the strength of metallic materials in accordance with the widely recognized Taylor hardening law. However, achieving the objective of tailoring the functionality of oxide ceramics by dislocation density still remains elusive. Here a strategy to imprint dislocations with {100}<100> slip systems and a tenfold change in dislocation density of BaTiO3 single crystals using high-temperature uniaxial compression are reported. Through a dislocation density-based approach, dielectric permittivity, converse piezoelectric coefficient, and alternating current conductivity are tailored, exhibiting a peak at medium dislocation density. Combined with phase-field simulations and domain wall potential energy analyses, the dislocation-density-based design in bulk ferroelectrics is mechanistically rationalized. These findings may provide a new dimension for employing plastic strain engineering to tune the electrical properties of ferroics, potentially paving the way for advancing dislocation technology in functional ceramics.
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Affiliation(s)
- Fangping Zhuo
- Department of Materials and Earth Sciences, Technical University of Darmstadt, 64287, Darmstadt, Germany
| | - Xiandong Zhou
- Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province, College of Architecture and Environment, MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Felix Dietrich
- Institute of Physical Chemistry, Technical University of Darmstadt, 64287, Darmstadt, Germany
| | - Mehrzad Soleimany
- Department of Materials and Earth Sciences, Technical University of Darmstadt, 64287, Darmstadt, Germany
| | - Patrick Breckner
- Department of Materials and Earth Sciences, Technical University of Darmstadt, 64287, Darmstadt, Germany
| | - Pedro B Groszewicz
- Department of Radiation Science and Technology, Delft University of Technology, Delft, 2629JB, Netherlands
| | - Bai-Xiang Xu
- Department of Materials and Earth Sciences, Technical University of Darmstadt, 64287, Darmstadt, Germany
| | - Gerd Buntkowsky
- Institute of Physical Chemistry, Technical University of Darmstadt, 64287, Darmstadt, Germany
| | - Jürgen Rödel
- Department of Materials and Earth Sciences, Technical University of Darmstadt, 64287, Darmstadt, Germany
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2
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Trifunctional nanoprecipitates ductilize and toughen a strong laminated metastable titanium alloy. Nat Commun 2023; 14:1397. [PMID: 36914678 PMCID: PMC10011607 DOI: 10.1038/s41467-023-37155-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 03/03/2023] [Indexed: 03/14/2023] Open
Abstract
Metastability-engineering, e.g., transformation-induced plasticity (TRIP), can enhance the ductility of alloys, however it often comes at the expense of relatively low yield strength. Here, using a metastable Ti-1Al-8.5Mo-2.8Cr-2.7Zr (wt.%) alloy as a model material, we fabricate a heterogeneous laminated structure decorated by multiple-morphological α-nanoprecipitates. The hard α nanoprecipitate in our alloy acts not only as a strengthener to the material, but also as a local stress raiser to activate TRIP in the soft matrix for great uniform elongation and as a promoter to trigger interfacial delamination toughening for superior fracture resistance. By elaborately manipulating the activation sequence of lamellar-thickness-dependent deformation mechanisms in Ti-1Al-8.5Mo-2.8Cr-2.7Zr alloys, the yield strength of the present submicron-laminated alloy is twice that of equiaxed-coarse grained alloys with the same composition, yet without sacrificing the large uniform elongation. The desired mechanical properties enabled by this strategy combining the laminated metastable structure and trifunctional nanoprecipitates provide new insights into designing ultra-strong and ductile materials with great toughness.
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3
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Ali S, Sikdar S, Basak S, Roy D, Das D, Haydar MS, Ghosh NN, Roy K, Mandal P, Roy MN. Intrinsic Light-Activated Oxidase Mimicking Activity of Conductive Polyaniline Nanofibers: A Class of Metal-Free Nanozyme. ACS APPLIED BIO MATERIALS 2022; 5:5518-5531. [PMID: 36367462 DOI: 10.1021/acsabm.2c00491] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In recent decades, studies have focused on inorganic nanozymes to overcome the intrinsic drawbacks of bioenzymes due to the demands of improving the reaction conditions and lack of robustness to harsh environmental factors. Many biochemical reactions catalyzed by enzymes require light activation. Light-activated nanozymes have distinct advantages, including being regulated by light stimuli, activating the molecular oxygen to produce reactive oxygen species (ROS) without interfering supplementary oxidants, and often showing a synergistic effect to catalyze some challenging reactions. Only a few studies have been done on this connection. Therefore, it is still a big challenge to develop a nanozyme regulated by light activation. Herein, we uncovered the light-activated oxidase mimicking activity of a conducting polymer polyaniline nanofibers (PANI-NFs). PANI-NFs exhibit intrinsic light-activated brilliant oxidase-like activity, can catalyze the colorless tetramethyl benzidine (TMB) to produce a blue product TMBox, and have a distinct Km = 0.087 mM and a high Vmax = 2.32 μM min-1 value, measured by using Hanes-Woolf kinetics. We also report the light-activated oxidase activity of some other renowned carbocatalysts graphene oxide and graphitic carbon nitride and compare them with PANI-NFs. This type of property shown by the conductive polymer is amazing. The density functional theory is used to verify the stability and the mode of adsorption of the PANI NFs-TMB composite, which corroborates the experimental results. Furthermore, the current nanozyme demonstrated a significant ability to kill both Gram-negative and Gram-positive bacteria as well as effectively destroy biofilms under physiological conditions. We believe that this work provides the motivation to create a link between optoelectronics and biological activity in the near future.
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Affiliation(s)
- Salim Ali
- Department of Chemistry, University of North Bengal, Darjeeling734013, India
| | - Suranjan Sikdar
- Department of Chemistry, Government General Degree College at Kushmandi, Dakshin Dinajpur733121, India
| | - Shatarupa Basak
- Department of Chemistry, University of North Bengal, Darjeeling734013, India
| | - Debadrita Roy
- Department of Chemistry, University of North Bengal, Darjeeling734013, India
| | - Dipayan Das
- Nanobiology and Phytotherapy Laboratory, Department of Botany, University of North Bengal, Siliguri734013, West Bengal, India
| | - Md Salman Haydar
- Nanobiology and Phytotherapy Laboratory, Department of Botany, University of North Bengal, Siliguri734013, West Bengal, India
| | | | - Kanak Roy
- Department of Chemistry, Alipurduar University, Alipurduar736122, India
| | - Palash Mandal
- Nanobiology and Phytotherapy Laboratory, Department of Botany, University of North Bengal, Siliguri734013, West Bengal, India
| | - Mahendra Nath Roy
- Department of Chemistry, University of North Bengal, Darjeeling734013, India.,Department of Chemistry, Alipurduar University, Alipurduar736122, India
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4
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Exploring the origins of the indentation size effect at submicron scales. Proc Natl Acad Sci U S A 2021; 118:2025657118. [PMID: 34301887 DOI: 10.1073/pnas.2025657118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The origin of the indentation size effect has been extensively researched over the last three decades, following the establishment of nanoindentation as a broadly used small-scale mechanical testing technique that enables hardness measurements at submicrometer scales. However, a mechanistic understanding of the indentation size effect based on direct experimental observations at the dislocation level remains limited due to difficulties in observing and quantifying the dislocation structures that form underneath indents using conventional microscopy techniques. Here, we employ precession electron beam diffraction microscopy to "look beneath the surface," revealing the dislocation characteristics (e.g., distribution and total length) as a function of indentation depth for a single crystal of nickel. At smaller depths, individual dislocation lines can be resolved, and the dislocation distribution is quite diffuse. The indentation size effect deviates from the Nix-Gao model and is controlled by dislocation source starvation, as the dislocations are very mobile and glide away from the indented zone, leaving behind a relatively low dislocation density in the plastically deformed volume. At larger depths, dislocations become highly entangled and self-arrange to form subgrain boundaries. In this depth range, the Nix-Gao model provides a rational description because the entanglements and subgrain boundaries effectively confine dislocation movement to a small hemispherical volume beneath the contact impression, leading to dislocation interaction hardening. The work highlights the critical role of dislocation structural development in the small-scale mechanistic transition in indentation size effect and its importance in understanding the plastic deformation of materials at the submicron scale.
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Superelastic oxide micropillars enabled by surface tension-modulated 90° domain switching with excellent fatigue resistance. Proc Natl Acad Sci U S A 2021; 118:2025255118. [PMID: 34117121 DOI: 10.1073/pnas.2025255118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Superelastic materials capable of recovering large nonlinear strains are ideal for a variety of applications in morphing structures, reconfigurable systems, and robots. However, making oxide materials superelastic has been a long-standing challenge due to their intrinsic brittleness. Here, we fabricate ferroelectric BaTiO3 (BTO) micropillars that not only are superelastic but also possess excellent fatigue resistance, lasting over 1 million cycles without accumulating residual strains or noticeable variation in stress-strain curves. Phase field simulations reveal that the large recoverable strains of BTO micropillars arise from surface tension-modulated 90° domain switching and thus are size dependent, while the small energy barrier and ultralow energy dissipation are responsible for their unprecedented cyclic stability among superelastic materials. This work demonstrates a general strategy to realize superelastic and fatigue-resistant domain switching in ferroelectric oxides for many potential applications.
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6
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Wang Y, Shi F, Gasc J, Ohfuji H, Wen B, Yu T, Officer T, Nishiyama N, Shinmei T, Irifune T. Plastic Deformation and Strengthening Mechanisms of Nanopolycrystalline Diamond. ACS NANO 2021; 15:8283-8294. [PMID: 33929826 DOI: 10.1021/acsnano.0c08737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Bulk nanopolycrystalline diamond (NPD) samples were deformed plastically within the diamond stability field up to 14 GPa and above 1473 K. Macroscopic differential stress Δσ was determined on the basis of the distortion of the 111 Debye ring using synchrotron X-ray diffraction. Up to ∼5(2)% strain, Debye ring distortion can be satisfactorily described by lattice strain theories as an ellipse. Beyond ∼5(2)% strain, lattice spacing d111 along the Δσ direction becomes saturated and remains constant with further deformation. Transmission electron microscopy on as-synthesized NPD shows well-bonded grain boundaries with no free dislocations within the grains. Deformed samples also contain very few free dislocations, while density of {111} twins increases with plastic strain. Individual grains display complex contrast, exhibiting increasing misorientation with deformation according electron diffraction. Thus, NPD does not deform by dislocation slip, which is the dominated mechanism in conventional polycrystalline diamond composites (PCDCs, grain size >1 μm). The nonelliptical Debye ring distortion is modeled by nucleating 12⟨110⟩ dislocations or their dissociated 16⟨112⟩ partials gliding in the {111} planes to produce deformation twinning. With increasing strain up to ∼5(2)%, strength increases rapidly to ∼20(1) GPa, where d111 reaches saturation. Strength beyond the saturation shows a weak dependence on strain, reaching ∼22(1) GPa at >10% strain. Overall, the strength is ∼2-3 times that of conventional PCDCs. Combined with molecular dynamics simulations and lattice rotation theory, we conclude that the rapid rise of strength with strain is due to defect-source strengthening, whereas further deformation is dominated by nanotwinning and lattice rotation.
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Affiliation(s)
- Yanbin Wang
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
| | - Feng Shi
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
| | - Julien Gasc
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
| | - Hiroaki Ohfuji
- Geodynamics Research Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Bin Wen
- State Key Laboratory of Metastable Materials and Technology, Yanshan University, Qinhuangdao, Hebei 066004, China
| | - Tony Yu
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
| | - Timothy Officer
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
| | - Norimasa Nishiyama
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
| | - Toru Shinmei
- Geodynamics Research Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Tetsuo Irifune
- Geodynamics Research Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
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7
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Porz L, Klomp AJ, Fang X, Li N, Yildirim C, Detlefs C, Bruder E, Höfling M, Rheinheimer W, Patterson EA, Gao P, Durst K, Nakamura A, Albe K, Simons H, Rödel J. Dislocation-toughened ceramics. MATERIALS HORIZONS 2021; 8:1528-1537. [PMID: 34846461 DOI: 10.1039/d0mh02033h] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Functional and structural ceramics have become irreplaceable in countless high-tech applications. However, their inherent brittleness tremendously limits the application range and, despite extensive research efforts, particularly short cracks are hard to combat. While local plasticity carried by mobile dislocations allows desirable toughness in metals, high bond strength is widely believed to hinder dislocation-based toughening of ceramics. Here, we demonstrate the possibility to induce and engineer a dislocation microstructure in ceramics that improves the crack tip toughness even though such toughening does not occur naturally after conventional processing. With modern microscopy and simulation techniques, we reveal key ingredients for successful engineering of dislocation-based toughness at ambient temperature. For many ceramics a dislocation-based plastic zone is not impossible due to some intrinsic property (e.g. bond strength) but limited by an engineerable quantity, i.e. the dislocation density. The impact of dislocation density is demonstrated in a surface near region and suggested to be transferrable to bulk ceramics. Unexpected potential in improving mechanical performance of ceramics could be realized with novel synthesis strategies.
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Affiliation(s)
- Lukas Porz
- Technical University of Darmstadt, Department of Materials and Earth Science, Darmstadt, Germany.
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8
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Takeuchi S, Edagawa K, Kamimura Y. Theoretical Justification of Single-Ended Dislocation-Source-Controlled Deformation of Micropillar fcc Crystals. PHYSICAL REVIEW LETTERS 2021; 126:155501. [PMID: 33929229 DOI: 10.1103/physrevlett.126.155501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/13/2021] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
It was established at the beginning of the 21st century that the critical resolved shear stress of small-sized (diameter from 50 nm to 10 μm) metallic crystals fabricated from bulk crystals increases drastically with decreasing specimen diameter. Dou and Derby [Scr. Mater. 61, 524 (2009)SCMAF71359-646210.1016/j.scriptamat.2009.05.012] showed that, the critical shear stresses of small-sized single crystals of various fcc metals obeyed a universal power law of specimen size with an exponent of -0.66. In this study, we succeeded in reproducing almost perfectly the above universal relation without any adjustable parameters, based on a deformation process controlled by the operation of single-ended dislocation sources.
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Affiliation(s)
- Shin Takeuchi
- Professor Emeritus of Tokyo University of Science, Shinjuku-ku, Tokyo 162-8601, Japan
| | - Keiichi Edagawa
- Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
| | - Yasushi Kamimura
- Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
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9
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Zhang X, Li W, Tian H, Liu J, Li C, Dong H, Chen J, Song M, Chen B, Sheng H, Wang S, Zhang D, Zhang H. Ultra-incompressible High-Entropy Diborides. J Phys Chem Lett 2021; 12:3106-3113. [PMID: 33754740 DOI: 10.1021/acs.jpclett.1c00399] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Transition metal borides are commonly hard and incompressible, offering great opportunities for advanced applications under extreme conditions. Recent studies show that the hardness of high-entropy borides may exceed that of their constituent simple borides due to the "cocktail effect". However, how high-entropy borides deform elastically remains largely unknown. Here, we show that two newly synthesized high-entropy diborides are ultra-incompressible, attaining ∼90% of the incompressibility of single-crystalline diamond and exhibiting a 50-60% enhancement over the density functional theory predictions. This unusual behavior is attributed to a Hall-Petch-like effect resulting from nanosizing under high pressure, which increases the bulk moduli through dynamic dislocation interactions and creation of stacking faults. The exceptionally low compressibility, together with their high phase stabilities, high hardness, and high electric conductance, renders them promising candidates for electromechanics and microelectronic devices that demand strong resistance to environmental impacts, in addition to traditional grinding and abrading.
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Affiliation(s)
- Xiaoliang Zhang
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Weiwei Li
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Hua Tian
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Junxiu Liu
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Cong Li
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Hongliang Dong
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201899, China
| | - Jian Chen
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Meng Song
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Bin Chen
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Hongwei Sheng
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Shanmin Wang
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Dongzhou Zhang
- Partnership for Extreme Crystallography Program, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Hengzhong Zhang
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
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10
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Negative Strain Rate Sensitivity Induced by Structure Heterogeneity in Zr64.13Cu15.75Ni10.12Al10 Bulk Metallic Glass. METALS 2021. [DOI: 10.3390/met11020339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The negative strain rate sensitivity (SRS) of metallic glasses is frequently observed. However, the physical essence involved is still not well understood. In the present work, small-angle X-ray scattering (SAXS) and high-resolution transmission electron microscopy (HRTEM) reveal the strong structure heterogeneity at nanometer and tens of nanometer scales, respectively, in bulk metallic glass (BMG) Zr64.13Cu15.75Ni10.12Al10 subjected to fully confined compression processing. A transition of SRS of stress, from 0.012 in the as-cast specimen to −0.005 in compression processed specimen, was observed through nanoindentation. A qualitative formulation clarifies the critical role of internal stress induced by structural heterogeneity in this transition. It reveals the physical origin of this negative SRS frequently reported in structurally heterogeneous BMG alloys and its composites.
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Prospects of Using Small Scale Testing to Examine Different Deformation Mechanisms in Nanoscale Single Crystals—A Case Study in Mg. CRYSTALS 2021. [DOI: 10.3390/cryst11010061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The advent of miniaturised testing techniques led to excessive studies on size effects in materials. Concomitantly, these techniques also offer the capability to thoroughly examine deformation mechanisms operative in small volumes, in particular when performed in-situ in electron microscopes. This opens the feasibility of a comprehensive assessment of plasticity by spatially arranging samples specifically with respect to the crystal unit cell of interest. In the present manuscript, we will showcase this less commonly utilised aspect of small-scale testing on the case of the hexagonal metal Mg, where, besides dislocation slip on different slip planes, twinning also exists as a possible deformation mechanism. While it is close to impossible to examine individual deformation mechanisms in macroscale tests, where local multiaxial stress states in polycrystalline structures will always favour multiple mechanisms of plasticity, we demonstrate that miniaturised uniaxial experiments conducted in-situ in the scanning electron microscope are ideally suited for a detailed assessment of specific processes.
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12
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Statistics of dislocation avalanches in FCC and BCC metals: dislocation mechanisms and mean swept distances across microsample sizes and temperatures. Sci Rep 2020; 10:19024. [PMID: 33149199 PMCID: PMC7642400 DOI: 10.1038/s41598-020-75934-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 10/19/2020] [Indexed: 11/23/2022] Open
Abstract
Plastic deformation in crystalline materials consists of an ensemble of collective dislocation glide processes, which lead to strain burst emissions in micro-scale samples. To unravel the combined role of crystalline structure, sample size and temperature on these processes, we performed a comprehensive set of strict displacement-controlled micropillar compression experiments in conjunction with large-scale molecular dynamics and physics-based discrete dislocation dynamics simulations. The results indicate that plastic strain bursts consist of numerous individual dislocation glide events, which span over minuscule time intervals. The size distributions of these events exhibit a gradual transition from an incipient power-law slip regime (spanning \documentclass[12pt]{minimal}
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\begin{document}$$\approx$$\end{document}≈ 2.5 decades of slip sizes) to a large avalanche domain (spanning \documentclass[12pt]{minimal}
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\begin{document}$$\approx$$\end{document}≈ 4 decades of emission probability) at a cut-off slip magnitude \documentclass[12pt]{minimal}
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\begin{document}$${s}_{\mathrm{c}}$$\end{document}sc. This cut-off slip provides a statistical measure to the characteristic mean dislocation swept distance, which allows for the scaling of the avalanche distributions vis-à-vis the archetypal dislocation mechanisms in face-centered cubic (FCC) and body-centered cubic (BCC) metals. Our statistical findings provide a new pathway to characterizing metal plasticity and towards comprehension of the sample size effects that limit the mechanical reliability in small-scale structures.
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Liu W, Liu Y, Cheng Y, Chen L, Yu L, Yi X, Duan H. Unified Model for Size-Dependent to Size-Independent Transition in Yield Strength of Crystalline Metallic Materials. PHYSICAL REVIEW LETTERS 2020; 124:235501. [PMID: 32603175 DOI: 10.1103/physrevlett.124.235501] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 05/14/2020] [Accepted: 05/18/2020] [Indexed: 06/11/2023]
Abstract
Size-dependent yield strength is a common feature observed in miniaturized crystalline metallic samples, and plenty of studies have been conducted in experiments and numerical simulations to explore the underlying mechanism. However, the transition in yield strength from bulklike to size-affected behavior has received less attention. Here a unified theoretical model is proposed to probe the yield strength of crystalline metallic materials with sample size from nanoscale to macroscale. We show that the transition in yield strength versus size can be fully explained by the competition between the stresses required for dislocation source activation and dislocation motion, which is regulated by dislocation density, irradiation defect, grain boundary, and so on. Based on various grain boundary densities, the extended Hall-Petch relation, incorporated into the unified model, captures the reverse size effect for polycrystalline samples. The proposed model predictions agree well with reported experimental measurements of various specimens, including the prestrained nickel, irradiated copper, ultrafine grain tungsten, and so on.
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Affiliation(s)
- Wenbin Liu
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Ying Liu
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Yangyang Cheng
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Lirong Chen
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Long Yu
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Xin Yi
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Huiling Duan
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
- CAPT, HEDPS, and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, People's Republic of China
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14
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Papanikolaou S, Po G. Λ-Invariant and Topological Pathways to Influence the Strength of Submicron Crystals. PHYSICAL REVIEW LETTERS 2020; 124:205502. [PMID: 32501064 DOI: 10.1103/physrevlett.124.205502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 12/24/2019] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
In small volumes, sample dimensions are known to strongly influence mechanical behavior: especially strength and crystal plasticity. This correlation fades away at the so-called "mesoscale," loosely defined at several micrometers in both experiments and simulations. However, this picture depends on the "entanglement" of the initial defect configuration. In this Letter, we study the effect of dislocation topology through the use of a novel observable for dislocation ensembles (the Λ invariant) that depends only on mutual dislocation linking: It is built on the natural vortex character of dislocations, and it has a continuum-discrete correspondence that may assist multiscale modeling descriptions. We investigate arbitrarily complex initial dislocation microstructures in sub-micron-sized pillars using three-dimensional discrete dislocation dynamics simulations for finite volumes. We demonstrate how to engineer nanoscale dislocation ensembles that are independent from sample dimensions, either by biased-random dislocation loop deposition or by sequential mechanical loads of compression and torsion.
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Affiliation(s)
- Stefanos Papanikolaou
- Department of Mechanical and Aerospace Engineering, West Virginia University, 395 Evansdale Drive, Morgantown, West Virginia 26506-6070, USA
- Department of Physics and Astronomy, West Virginia University, 135 Willey Street, Morgantown, West Virginia 26506-6070, USA
| | - Giacomo Po
- Department of Mechanical and Aerospace Engineering, University of Miami, 1251 Memorial Drive, Coral Gables, Florida 33146, USA
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15
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Learning to Predict Crystal Plasticity at the Nanoscale: Deep Residual Networks and Size Effects in Uniaxial Compression Discrete Dislocation Simulations. Sci Rep 2020; 10:8262. [PMID: 32427971 PMCID: PMC7237459 DOI: 10.1038/s41598-020-65157-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/22/2020] [Indexed: 01/26/2023] Open
Abstract
The density and configurational changes of crystal dislocations during plastic deformation influence the mechanical properties of materials. These influences have become clearest in nanoscale experiments, in terms of strength, hardness and work hardening size effects in small volumes. The mechanical characterization of a model crystal may be cast as an inverse problem of deducing the defect population characteristics (density, correlations) in small volumes from the mechanical behavior. In this work, we demonstrate how a deep residual network can be used to deduce the dislocation characteristics of a sample of interest using only its surface strain profiles at small deformations, and then statistically predict the mechanical response of size-affected samples at larger deformations. As a testbed of our approach, we utilize high-throughput discrete dislocation simulations for systems of widths that range from nano- to micro- meters. We show that the proposed deep learning model significantly outperforms a traditional machine learning model, as well as accurately produces statistical predictions of the size effects in samples of various widths. By visualizing the filters in convolutional layers and saliency maps, we find that the proposed model is able to learn the significant features of sample strain profiles.
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16
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Li Q, Xue S, Price P, Sun X, Ding J, Shang Z, Fan Z, Wang H, Zhang Y, Chen Y, Wang H, Hattar K, Zhang X. Hierarchical nanotwins in single-crystal-like nickel with high strength and corrosion resistance produced via a hybrid technique. NANOSCALE 2020; 12:1356-1365. [PMID: 31854411 DOI: 10.1039/c9nr07472d] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
High-density growth nanotwins enable high-strength and good ductility in metallic materials. However, twinning propensity is greatly reduced in metals with high stacking fault energy. Here we adopted a hybrid technique coupled with template-directed heteroepitaxial growth method to fabricate single-crystal-like, nanotwinned (nt) Ni. The nt Ni primarily contains hierarchical twin structures that consist of coherent and incoherent twin boundary segments with few conventional grain boundaries. In situ compression studies show the nt Ni has a high flow strength of ∼2 GPa and good deformability. Moreover, the nt Ni has superb corrosion behavior due to the unique twin structure in comparison to coarse grained and nanocrystalline counterparts. The hybrid technique opens the door for the fabrication of a wide variety of single-crystal-like nt metals with unique mechanical and chemical properties.
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Affiliation(s)
- Qiang Li
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA
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17
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Predicting the flow stress and dominant yielding mechanisms: analytical models based on discrete dislocation plasticity. Sci Rep 2019; 9:20422. [PMID: 31892696 PMCID: PMC6938519 DOI: 10.1038/s41598-019-56252-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 12/03/2019] [Indexed: 11/08/2022] Open
Abstract
Dislocations are the carriers of plasticity in crystalline materials. Their collective interaction behavior is dependent on the strain rate and sample size. In small specimens, details of the nucleation process are of particular importance. In the present work, discrete dislocation dynamics (DDD) simulations are performed to investigate the dominant yielding mechanisms in single crystalline copper pillars with diameters ranging from 100 to 800 nm. Based on our simulations with different strain rates and sample size, we observe a transition of the relevant nucleation mechanism from "dislocation multiplication" to "surface nucleation". Two physics-based analytical models are established to quantitatively predict this transition, showing a good agreement for different strain rates with our DDD simulation data and with available experimental data. Therefore, the proposed analytical models help to understand the interplay between different physical parameters and nucleation mechanisms and are well suitable to estimate the material strength for different material properties and under given loading conditions.
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18
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Abstract
We present a high-throughput nanoindentation study of in situ bending effects on incipient plastic deformation behavior of polycrystalline and single-crystalline pure aluminum and pure copper at ultranano depths (< 200 nm). We find that hardness displays a statistically inverse dependence on in-plane stress for indentation depths smaller than 10 nm, and the dependence disappears for larger indentation depths. In contrast, plastic noise in the nanoindentation force and displacement displays statistically robust noise features, independently of applied stresses. Our experimental results suggest the existence of a regime in Face Centered Cubic (FCC) crystals where ultranano hardness is sensitive to residual applied stresses, but plasticity pop-in noise is insensitive to it.
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19
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Amin W, Ali MA, Vajragupta N, Hartmaier A. Studying Grain Boundary Strengthening by Dislocation-Based Strain Gradient Crystal Plasticity Coupled with a Multi-Phase-Field Model. MATERIALS 2019; 12:ma12182977. [PMID: 31540092 PMCID: PMC6766182 DOI: 10.3390/ma12182977] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 11/16/2022]
Abstract
One ambitious objective of Integrated Computational Materials Engineering (ICME) is to shorten the materials development cycle by using computational materials simulation techniques at different length scales. In this regard, the most important aspects are the prediction of the microstructural evolution during material processing and the understanding of the contributions of microstructural features to the mechanical response of the materials. One possible solution to such a challenge is to apply the Phase Field (PF) method because it can predict the microstructural evolution under the influence of different internal or external stimuli, including deformation. To accomplish this, it is necessary to take into account plasticity or, specifically, non-homogeneous plastic deformation, which is particularly important for investigating the size effects in materials emerging at the micron length scale. In this work, we present quasi-2D simulations of plastic deformation in a face centred cubic system using a finite strain formulation. Our model consists of dislocation-based strain gradient crystal plasticity implemented into a PF code. We apply this model to study the influence of grain size on the mechanical behavior of polycrystals, which includes dislocation storage and annihilation. Furthermore, the initial state of the material before deformation is also considered. The results show that a dislocation-based strain gradient crystal plasticity model can capture the Hall-Petch effect in many aspects. The model reproduced the correct functional dependence of the flow stress of the polycrystal on grain size without assigning any special properties to the grain boundaries. However, the predicted Hall-Petch coefficients are significantly smaller than those found typically in experiments. In any case, we found a good qualitative agreement between our findings and experimental results.
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Affiliation(s)
- Waseem Amin
- Interdisciplinary Center for Advanced Materials Simulation (ICAMS), Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
- Department of Metallurgy and Materials Engineering, University of Engineering and Technology, Taxila 47050, Pakistan.
| | - Muhammad Adil Ali
- Interdisciplinary Center for Advanced Materials Simulation (ICAMS), Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
| | - Napat Vajragupta
- Interdisciplinary Center for Advanced Materials Simulation (ICAMS), Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
| | - Alexander Hartmaier
- Interdisciplinary Center for Advanced Materials Simulation (ICAMS), Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
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20
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Weiss J. Ice: the paradigm of wild plasticity. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2019; 377:20180260. [PMID: 30982451 DOI: 10.1098/rsta.2018.0260] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
Ice plasticity has been thoroughly studied, owing to its importance in glaciers and ice sheets dynamics. In particular, its anisotropy (easy basal slip) has been suspected for a long time, then fully characterized 40 years ago. More recently emerged the interest of ice as a model material to study some fundamental aspects of crystalline plasticity. An example is the nature of plastic fluctuations and collective dislocation dynamics. Twenty years ago, acoustic emission measurements performed during the deformation of ice single crystals revealed that plastic 'flow' proceeds through intermittent dislocation avalanches, power law distributed in size and energy. This means that most of ice plasticity takes place through few, very large avalanches, thus qualifying associated plastic fluctuations as 'wild'. This launched an intense research activity on plastic intermittency in the Material Science community. The interest of ice in this debate is reviewed, from a comparison with other crystalline materials. In this context, ice appears as an extreme case of plastic intermittency, characterized by scale-free fluctuations, complex space and time correlations as well as avalanche triggering. In other words, ice can be considered as the paradigm of wild plasticity. This article is part of the theme issue 'The physics and chemistry of ice: scaffolding across scales, from the viability of life to the formation of planets'.
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Affiliation(s)
- Jérôme Weiss
- Institut des Sciences de la Terre (ISTerre), University Grenoble Alpes, CNRS, ISTerre , 38000 Grenoble , France
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21
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Liu Z. Investigation of Temperature and Feature Size Effects on Deformation of Metals by Superplastic Nanomolding. PHYSICAL REVIEW LETTERS 2019; 122:016101. [PMID: 31012722 DOI: 10.1103/physrevlett.122.016101] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/25/2018] [Indexed: 06/09/2023]
Abstract
We report a novel method to introduce feature size into the prevalent deformation-mechanism map by the superplastic nanomolding technique. This new map enables various deformation mechanisms to be decoupled and allows for experimentally identifying the boundary between dislocation and diffusion dominated deformation regimes. Moreover, the proposed method provides a practical way to investigate the temperature effect on the mechanical properties of materials at small scales. As an example, the size-temperature-deformation mechanism map of gold is first determined by the proposed method. We found that the well-known Hall-Petch effect significantly weakens as the temperature increases. Besides, a transition from dislocation to diffusion dominated deformation regimes as the temperature increases is unambiguously revealed in the map, and the transition temperature is determined to be ∼0.54T_{m} for gold.
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Affiliation(s)
- Ze Liu
- Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan, Hubei 430072, China
- State Key Laboratory of Water Resources & Hydropower Engineering Science, Wuhan University, Wuhan 430072, China
- Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province, School of Civil Engineering, Wuhan University, Wuhan, 430072, China
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22
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Mordehai D, David O, Kositski R. Nucleation-Controlled Plasticity of Metallic Nanowires and Nanoparticles. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1706710. [PMID: 29962014 DOI: 10.1002/adma.201706710] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/16/2018] [Indexed: 06/08/2023]
Abstract
Nanowires and nanoparticles are envisioned as important elements of future technology and devices, owing to their unique mechanical properties. Metallic nanowires and nanoparticles demonstrate outstanding size-dependent strength since their deformation is dislocation nucleation-controlled. In this context, the recent experimental and computational studies of nucleation-controlled plasticity are reviewed. The underlying microstructural mechanisms that govern the strength of nanowires and the origin of their stochastic nature are also discussed. Nanoparticles, in which the stress state under compression is nonuniform, exhibit a shape-dependent strength. Perspectives on improved methods to study nucleation-controlled plasticity are discussed, as well the insights gained for microstructural-based design of mechanical properties at the nanoscale.
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Affiliation(s)
- Dan Mordehai
- Department of Mechanical Engineering, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Omer David
- Department of Mechanical Engineering, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Roman Kositski
- Department of Mechanical Engineering, Technion-Israel Institute of Technology, 32000, Haifa, Israel
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23
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Plastic Deformation Induced by Nanoindentation Test Applied on ZrN/Si3N4 Multilayer Coatings. COATINGS 2017. [DOI: 10.3390/coatings8010011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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24
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Hegyi ÁI, Ispánovity PD, Knapek M, Tüzes D, Máthis K, Chmelík F, Dankházi Z, Varga G, Groma I. Micron-Scale Deformation: A Coupled In Situ Study of Strain Bursts and Acoustic Emission. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2017; 23:1076-1081. [PMID: 29037270 DOI: 10.1017/s1431927617012594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Plastic deformation of micron-scale crystalline materials differs considerably from bulk samples as it is characterized by stochastic strain bursts. To obtain a detailed picture of the intermittent deformation phenomena, numerous micron-sized specimens must be fabricated and tested. An improved focused ion beam fabrication method is proposed to prepare non-tapered micropillars with excellent control over their shape. Moreover, the fabrication time is less compared with other methods. The in situ compression device developed in our laboratory allows high-accuracy sample positioning and force/displacement measurements with high data sampling rates. The collective avalanche-like motion of the dislocations is observed as stress decreases on the stress-strain curves. An acoustic emission (AE) technique was employed for the first time to study the deformation behavior of micropillars. The AE technique provides important additional in situ information about the underlying processes during plastic deformation and is especially sensitive to the collective avalanche-like motion of the dislocations observed as the stress decreases on the deformation curves.
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Affiliation(s)
- Ádám István Hegyi
- 1Department of Materials Physics,Eötvös Loránd University,Pázmány Péter sétány 1/a,H-1117 Budapest,Hungary
| | - Péter Dusán Ispánovity
- 1Department of Materials Physics,Eötvös Loránd University,Pázmány Péter sétány 1/a,H-1117 Budapest,Hungary
| | - Michal Knapek
- 2Faculty of Mathematics and Physics,Department of Physics of Materials,Charles University in Prague,Ke Karlovu 5,121 16 Prague 2,Czech Republic
| | - Dániel Tüzes
- 1Department of Materials Physics,Eötvös Loránd University,Pázmány Péter sétány 1/a,H-1117 Budapest,Hungary
| | - Kristián Máthis
- 2Faculty of Mathematics and Physics,Department of Physics of Materials,Charles University in Prague,Ke Karlovu 5,121 16 Prague 2,Czech Republic
| | - František Chmelík
- 2Faculty of Mathematics and Physics,Department of Physics of Materials,Charles University in Prague,Ke Karlovu 5,121 16 Prague 2,Czech Republic
| | - Zoltán Dankházi
- 1Department of Materials Physics,Eötvös Loránd University,Pázmány Péter sétány 1/a,H-1117 Budapest,Hungary
| | - Gábor Varga
- 1Department of Materials Physics,Eötvös Loránd University,Pázmány Péter sétány 1/a,H-1117 Budapest,Hungary
| | - István Groma
- 1Department of Materials Physics,Eötvös Loránd University,Pázmány Péter sétány 1/a,H-1117 Budapest,Hungary
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25
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Dupraz M, Beutier G, Cornelius TW, Parry G, Ren Z, Labat S, Richard MI, Chahine GA, Kovalenko O, De Boissieu M, Rabkin E, Verdier M, Thomas O. 3D Imaging of a Dislocation Loop at the Onset of Plasticity in an Indented Nanocrystal. NANO LETTERS 2017; 17:6696-6701. [PMID: 29052998 DOI: 10.1021/acs.nanolett.7b02680] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Structural quality and stability of nanocrystals are fundamental problems that bear important consequences for the performances of small-scale devices. Indeed, at the nanoscale, their functional properties are largely influenced by elastic strain and depend critically on the presence of crystal defects. It is thus of prime importance to be able to monitor, by noninvasive means, the stability of the microstructure of nano-objects against external stimuli such as mechanical load. Here we demonstrate the potential of Bragg coherent diffraction imaging for such measurements, by imaging in 3D the evolution of the microstructure of a nanocrystal exposed to in situ mechanical loading. Not only could we observe the evolution of the internal strain field after successive loadings, but we also evidenced a transient microstructure hosting a stable dislocation loop. The latter is fully characterized from its characteristic displacement field. The mechanical behavior of this small crystal is clearly at odds with what happens in bulk materials where many dislocations interact. Moreover, this original in situ experiment opens interesting possibilities for the investigation of plastic deformation at the nanoscale.
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Affiliation(s)
- M Dupraz
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP , F-38000 Grenoble, France
| | - G Beutier
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP , F-38000 Grenoble, France
| | - T W Cornelius
- Aix Marseille Université, Université de Toulon, CNRS , IM2NP UMR 7334, F-13397 Marseille Cedex 20, France
| | - G Parry
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP , F-38000 Grenoble, France
| | - Z Ren
- Aix Marseille Université, Université de Toulon, CNRS , IM2NP UMR 7334, F-13397 Marseille Cedex 20, France
| | - S Labat
- Aix Marseille Université, Université de Toulon, CNRS , IM2NP UMR 7334, F-13397 Marseille Cedex 20, France
| | - M-I Richard
- Aix Marseille Université, Université de Toulon, CNRS , IM2NP UMR 7334, F-13397 Marseille Cedex 20, France
- ID01/ESRF , 71 Avenue des Martyrs, CS40220, F-38043 Grenoble Cedex 9, France
| | - G A Chahine
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP , F-38000 Grenoble, France
| | - O Kovalenko
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology , 32000 Haifa, Israel
| | - M De Boissieu
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP , F-38000 Grenoble, France
| | - E Rabkin
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology , 32000 Haifa, Israel
| | - M Verdier
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP , F-38000 Grenoble, France
| | - O Thomas
- Aix Marseille Université, Université de Toulon, CNRS , IM2NP UMR 7334, F-13397 Marseille Cedex 20, France
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26
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Alekseeva S, Fanta ABDS, Iandolo B, Antosiewicz TJ, Nugroho FAA, Wagner JB, Burrows A, Zhdanov VP, Langhammer C. Grain boundary mediated hydriding phase transformations in individual polycrystalline metal nanoparticles. Nat Commun 2017; 8:1084. [PMID: 29057929 PMCID: PMC5651804 DOI: 10.1038/s41467-017-00879-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/02/2017] [Indexed: 11/09/2022] Open
Abstract
Grain boundaries separate crystallites in solids and influence material properties, as widely documented for bulk materials. In nanomaterials, however, investigations of grain boundaries are very challenging and just beginning. Here, we report the systematic mapping of the role of grain boundaries in the hydrogenation phase transformation in individual Pd nanoparticles. Employing multichannel single-particle plasmonic nanospectroscopy, we observe large variation in particle-specific hydride-formation pressure, which is absent in hydride decomposition. Transmission Kikuchi diffraction suggests direct correlation between length and type of grain boundaries and hydride-formation pressure. This correlation is consistent with tensile lattice strain induced by hydrogen localized near grain boundaries as the dominant factor controlling the phase transition during hydrogen absorption. In contrast, such correlation is absent for hydride decomposition, suggesting a different phase-transition pathway. In a wider context, our experimental setup represents a powerful platform to unravel microstructure-function correlations at the individual-nanoparticle level.
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Affiliation(s)
- Svetlana Alekseeva
- Department of Physics, Chalmers University of Technology, Göteborg, 412 96, Sweden
| | | | - Beniamino Iandolo
- Center for Electron Nanoscopy, Technical University of Denmark, Fysikvej, 2800 Kgs, Lyngby, Denmark.,Department of Microtechnology and Nanotechnology, Technical University of Denmark, Ørsteds Pl., 2800 Kgs, Lyngby, Denmark
| | - Tomasz J Antosiewicz
- Department of Physics, Chalmers University of Technology, Göteborg, 412 96, Sweden.,Centre of New Technologies, University of Warsaw, Banacha 2c, Warsaw, 02-097, Poland
| | | | - Jakob B Wagner
- Center for Electron Nanoscopy, Technical University of Denmark, Fysikvej, 2800 Kgs, Lyngby, Denmark
| | - Andrew Burrows
- Center for Electron Nanoscopy, Technical University of Denmark, Fysikvej, 2800 Kgs, Lyngby, Denmark
| | - Vladimir P Zhdanov
- Department of Physics, Chalmers University of Technology, Göteborg, 412 96, Sweden.,Boreskov Institute of Catalysis, Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Christoph Langhammer
- Department of Physics, Chalmers University of Technology, Göteborg, 412 96, Sweden.
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27
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The Role of Geometrically Necessary Dislocations in Cantilever Beam Bending Experiments of Single Crystals. MATERIALS 2017; 10:ma10030289. [PMID: 28772657 PMCID: PMC5503410 DOI: 10.3390/ma10030289] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/01/2017] [Accepted: 03/03/2017] [Indexed: 11/17/2022]
Abstract
The mechanical behavior of single crystalline, micro-sized copper is investigated in the context of cantilever beam bending experiments. Particular focus is on the role of geometrically necessary dislocations (GNDs) during bending-dominated load conditions and their impact on the characteristic bending size effect. Three different sample sizes are considered in this work with main variation in thickness. A gradient extended crystal plasticity model is presented and applied in a three-dimensional finite-element (FE) framework considering slip system-based edge and screw components of the dislocation density vector. The underlying mathematical model contains non-standard evolution equations for GNDs, crystal-specific interaction relations, and higher-order boundary conditions. Moreover, two element formulations are examined and compared with respect to size-independent as well as size-dependent bending behavior. The first formulation is based on a linear interpolation of the displacement and the GND density field together with a full integration scheme whereas the second is based on a mixed interpolation scheme. While the GND density fields are treated equivalently, the displacement field is interpolated quadratically in combination with a reduced integration scheme. Computational results indicate that GND storage in small cantilever beams strongly influences the evolution of statistically stored dislocations (SSDs) and, hence, the distribution of the total dislocation density. As a particular example, the mechanical bending behavior in the case of a physically motivated limitation of GND storage is studied. The resulting impact on the mechanical bending response as well as on the predicted size effect is analyzed. Obtained results are discussed and related to experimental findings from the literature.
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28
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Origin of sample size effect: Stochastic dislocation formation in crystalline metals at small scales. Sci Rep 2016; 6:39242. [PMID: 27976740 PMCID: PMC5157047 DOI: 10.1038/srep39242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 11/21/2016] [Indexed: 11/28/2022] Open
Abstract
In crystalline metals at small scales, the dislocation density will be increased by stochastic events of dislocation network, leading to a universal power law for various material structures. In this work, we develop a model obeyed by a probability distribution of dislocation density to describe the dislocation formation in terms of a chain reaction. The leading order terms of steady-state of probability distribution gives physical and quantitative insight to the scaling exponent n values in the power law of sample size effect. This approach is found to be consistent with experimental n values in a wide range.
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29
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Wheeler JM, Kirchlechner C, Micha JS, Michler J, Kiener D. The effect of size on the strength of FCC metals at elevated temperatures: annealed copper. PHILOSOPHICAL MAGAZINE (ABINGDON, ENGLAND) 2016; 96:3379-3395. [PMID: 28003795 PMCID: PMC5125415 DOI: 10.1080/14786435.2016.1224945] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 08/11/2016] [Indexed: 06/06/2023]
Abstract
As the length scale of sample dimensions is reduced to the micron and sub-micron scales, the strength of various materials has been observed to increase with decreasing size, a fact commonly referred to as the 'sample size effect'. In this work, the influence of temperature on the sample size effect in copper is investigated using in situ microcompression testing at 25, 200 and 400 °C in the SEM on vacuum-annealed copper structures, and the resulting deformed structures were analysed using X-ray μLaue diffraction and scanning electron microscopy. For pillars with sizes between 0.4 and 4 μm, the size effect was measured to be constant with temperature, within the measurement precision, up to half of the melting point of copper. It is expected that the size effect will remain constant with temperature until diffusion-controlled dislocation motion becomes significant at higher temperatures and/or lower strain rates. Furthermore, the annealing treatment of the copper micropillars produced structures which yielded at stresses three times greater than their un-annealed, FIB-machined counterparts.
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Affiliation(s)
- Jeffrey M. Wheeler
- Laboratory for Nanometallurgy, ETH Zürich, Zurich, Switzerland
- Laboratory for Mechanics of Materials and Nanostructures, Empa, Swiss Federal Laboratories for Materials Science and Technology, Thun, Switzerland
| | - Christoph Kirchlechner
- Structure and Nano-/Micromechanics of Materials, Max-Planck-Institut fur Eisenforschung GmbH, Dusseldorf, Germany
- Department of Materials Physics, Montanuniversität Leoben, Leoben, Austria
| | - Jean-Sébastien Micha
- UMR CNRS-CEA SPrAM, Institute Nanosciences and Cryogenics, Université Grenoble Alpes, Grenoble, France
- CRG-IF BM32 Beamline at the European Synchrotron (ESRF), Grenoble, France
| | - Johann Michler
- Laboratory for Mechanics of Materials and Nanostructures, Empa, Swiss Federal Laboratories for Materials Science and Technology, Thun, Switzerland
| | - Daniel Kiener
- Department of Materials Physics, Montanuniversität Leoben, Leoben, Austria
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30
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Derlet PM, Maaß R. Critical stress statistics and a fold catastrophe in intermittent crystal plasticity. Phys Rev E 2016; 94:033001. [PMID: 27739777 DOI: 10.1103/physreve.94.033001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Indexed: 11/07/2022]
Abstract
The statistics and origin of the first discrete plastic event in a one-dimensional dislocation dynamics simulation are studied. This is done via a linear stability analysis of the evolving dislocation configuration up to the onset of irreversible plasticity. It is found that, via a fold catastrophe, the dislocation configuration prior to loading directly determines the stress at which the plastic event occurs and that between one and two trigger dislocations are involved. The resulting irreversible plastic strain arising from the instability is found to be highly correlated with these triggering dislocations.
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Affiliation(s)
- P M Derlet
- Condensed Matter Theory Group, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - R Maaß
- Department of Materials Science and Engineering, University of Illinois at Urbana Champaign, 1304 West Green Street, Urbana, Illinois 61801, USA
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Cui Y, Po G, Ghoniem N. Controlling Strain Bursts and Avalanches at the Nano- to Micrometer Scale. PHYSICAL REVIEW LETTERS 2016; 117:155502. [PMID: 27768336 DOI: 10.1103/physrevlett.117.155502] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Indexed: 06/06/2023]
Abstract
We demonstrate, through three-dimensional discrete dislocation dynamics simulations, that the complex dynamical response of nano- and microcrystals to external constraints can be tuned. Under load rate control, strain bursts are shown to exhibit scale-free avalanche statistics, similar to critical phenomena in many physical systems. For the other extreme of displacement rate control, strain burst response transitions to quasiperiodic oscillations, similar to stick-slip earthquakes. External load mode control is shown to enable a qualitative transition in the complex collective dynamics of dislocations from self-organized criticality to quasiperiodic oscillations.
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Affiliation(s)
- Yinan Cui
- Mechanical and Aerospace Engineering Department, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, California 90095, USA
| | - Giacomo Po
- Mechanical and Aerospace Engineering Department, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, California 90095, USA
| | - Nasr Ghoniem
- Mechanical and Aerospace Engineering Department, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, California 90095, USA
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Li J, An Z, Wang Z, Toda M, Ono T. Pulse-Reverse Electrodeposition and Micromachining of Graphene-Nickel Composite: An Efficient Strategy toward High-Performance Microsystem Application. ACS APPLIED MATERIALS & INTERFACES 2016; 8:3969-76. [PMID: 26812267 DOI: 10.1021/acsami.5b11164] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Graphene reinforced nickel (Ni) is an intriguing nanocomposite with tremendous potential for microelectromechanical system (MEMS) applications by remedying mechanical drawbacks of the metal matrix for device optimization, though very few related works have been reported. In this paper, we developed a pulse-reverse electrodeposition method for synthesizing graphene-Ni (G-Ni) composite microcomponents with high content and homogeneously dispersed graphene filler. While the Vickers hardness is largely enhanced by 2.7-fold after adding graphene, the Young's modulus of composite under dynamic condition shows ∼1.4-fold increase based on the raised resonant frequency of a composite microcantilever array. For the first time, we also demonstrate the application of G-Ni composite in microsystems by fabricating a Si micromirror with the composite supporting beams as well as investigate the long-term stability of the mirror at resonant vibration. Compared with the pure Ni counterpart, the composite mirror shows an apparently lessened fluctuations of resonant frequency and scanning angle due to a suppressed plastic deformation even under the sustaining periodic loading. This can be ascribed to the reduced grain size of Ni matrix and dislocation hindering in the presence of graphene by taking into account the crystalline refinement strengthen mechanism. The rational discussions also imply that the strong interface and efficient load transfer between graphene layers and metal matrix play an important role for improving stiffness in composite. It is believed that a proper design of graphene-metal composite makes it a promising structural material candidate for advanced micromechanical devices.
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Affiliation(s)
| | | | - Zhuqing Wang
- Research Institute for Engineering and Technology, Tohoku Gakuin University , Sendai, 985-8537, Japan
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Recovery of strain-hardening rate in Ni-Si alloys. Sci Rep 2015; 5:15532. [PMID: 26487419 PMCID: PMC4614450 DOI: 10.1038/srep15532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/28/2015] [Indexed: 11/19/2022] Open
Abstract
In this study, the recovery of strain-hardening rate (RSHR) was discovered for the first time in polycrystalline materials (Ni-Si alloys) that have only dislocation activities during tensile test. Detailed microstructure characterizations show that the activation of dislocations in the secondary slip systems during tensile deformation is the major reason for this RSHR. By taking into account other metals that also exhibit RSHR during tension, a more general mechanism for the RSHR was proposed, i.e. the occurrence of a sharp decrease of dislocation mean free path (Λ) during plastic deformation, caused by either planar defects or linear defects.
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