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Sun K, Chen J, Wu B, Wang L, Fang L. Size-Dependent Mechanical Properties of Amorphous SiO 2 Nanowires: A Molecular Dynamics Study. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E5110. [PMID: 33198310 PMCID: PMC7696835 DOI: 10.3390/ma13225110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 11/06/2020] [Accepted: 11/10/2020] [Indexed: 06/11/2023]
Abstract
Uniaxial tension tests were performed for amorphous SiO2 nanowires using molecular dynamics simulation to probe the size effect on the mechanical properties and plastic deformation by varying the length of nanowires. The simulation results showed that the Young's modulus of SiO2 nanowires increased with the decrease of nanowires length due to its higher surface stress. The corresponding deformation of SiO2 nanowires during tension exhibited two periods: atomic arrangement at small strain and plastic deformation at large strain. During the atomic arrangement period, the percentage variations of atom number of 2-coordinated silicon and 3-coordinated silicon (PCN2 and PCN3) decreased, while the percentage variations of atom number of 4-coordinated silicon, 5-coordinated silicon (PCN4 and PCN5) and the Si-O bond number (PCB) rose slightly with increasing strain, as the strain was less than 22%. The situation reversed at the plastic deformation period, owing to the numerous breakage of Si-O bonds as the strain grew beyond 22%. The size effect of nanowires radius was considered, finding that the Young's modulus and fracture stress were higher for the larger nanowire because of fewer dangling bonds and coordinate defeats in the surface area. The elastic deformation occurred at a small strain for the larger nanowire, followed by the massive plastic deformation during tension. A brittle mechanism covers the fracture characteristics, irrespective of the nanowire size.
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Affiliation(s)
- Kun Sun
- State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China
| | - Juan Chen
- School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China;
| | - Bingjie Wu
- Nuclear Power Institute of China, Chengdu 610014, China; (B.W.); (L.W.)
| | - Liubing Wang
- Nuclear Power Institute of China, Chengdu 610014, China; (B.W.); (L.W.)
| | - Liang Fang
- State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China
- School of Mechanical & Electrical Engineering, Xiamen University Tan Kah Kee College, Zhangzhou 363105, China
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Reveal the Deformation Mechanism of (110) Silicon from Cryogenic Temperature to Elevated Temperature by Molecular Dynamics Simulation. NANOMATERIALS 2019; 9:nano9111632. [PMID: 31752128 PMCID: PMC6915669 DOI: 10.3390/nano9111632] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 11/17/2022]
Abstract
Silicon undergoes a brittle-to-ductile transition as its characteristic dimension reduces from macroscale to nanoscale. The thorough understanding of the plastic deformation mechanism of silicon at the nanoscale is still challenging, although it is essential for developing Si-based micro/nanoelectromechanical systems (MEMS/NEMS). Given the wide application of silicon in extreme conditions, it is, therefore, highly desirable to reveal the nanomechanical behavior of silicon from cryogenic temperature to elevated temperature. In this paper, large-scale molecular dynamics (MD) simulations were performed to reveal the spherical nanoindentation response and plastic deformation mechanism of (110)Si at the temperature range of 0.5 K to 573 K. Special attention was paid to the effect of temperature. Multiple pop-ins detected in load/pressure-indentation strain curves are impacted by temperature. Four featured structures induced by nanoindentation, including high-pressure phases, extrusion of α-Si, dislocations, and crack, are observed at all temperatures, consistent with experiment results. The detailed structure evolution of silicon was revealed at the atomic scale and its dependence on temperature was analyzed. Furthermore, structure changes were correlated with pop-ins in load/pressure-indentation strain curves. These results may advance our understanding of the mechanical properties of silicon.
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Lah NAC, Trigueros S. Synthesis and modelling of the mechanical properties of Ag, Au and Cu nanowires. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2019; 20:225-261. [PMID: 30956731 PMCID: PMC6442207 DOI: 10.1080/14686996.2019.1585145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 02/16/2019] [Accepted: 02/16/2019] [Indexed: 05/04/2023]
Abstract
The recent interest to nanotechnology aims not only at device miniaturisation, but also at understanding the effects of quantised structure in materials of reduced dimensions, which exhibit different properties from their bulk counterparts. In particular, quantised metal nanowires made of silver, gold or copper have attracted much attention owing to their unique intrinsic and extrinsic length-dependent mechanical properties. Here we review the current state of art and developments in these nanowires from synthesis to mechanical properties, which make them leading contenders for next-generation nanoelectromechanical systems. We also present theories of interatomic interaction in metallic nanowires, as well as challenges in their synthesis and simulation.
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Affiliation(s)
- Nurul Akmal Che Lah
- Innovative Manufacturing, Mechatronics and Sports Lab (iMAMS), Faculty of Manufacturing Engineering, Universiti Malaysia Pahang, Pekan, Malaysia
- CONTACT Nurul Akmal Che Lah
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Rebuilding the Strain Hardening at a Large Strain in Twinned Au Nanowires. NANOMATERIALS 2018; 8:nano8100848. [PMID: 30340344 PMCID: PMC6215313 DOI: 10.3390/nano8100848] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 10/14/2018] [Accepted: 10/17/2018] [Indexed: 11/23/2022]
Abstract
Metallic nanowires usually exhibit ultrahigh strength but low tensile ductility, owing to their limited strain hardening capability. Here, our larger scale molecular dynamics simulations demonstrated that we could rebuild the highly desirable strain hardening behavior at a large strain (0.21 to 0.31) in twinned Au nanowires by changing twin orientation, which strongly contrasts with the strain hardening at the incipient plastic deformation in low stacking-fault energy metals nanowires. Because of this strain hardening, an improved ductility is achieved. With the change of twin orientation, a competing effect between partial dislocation propagation and twin migration is observed in nanowires with slant twin boundaries. When twin migration gains the upper hand, the strain hardening occurs. Otherwise, the strain softening occurs. As the twin orientation increases from 0° to 90°, the dominating deformation mechanism shifts from slip-twin boundary interaction to dislocation slip, twin migration, and slip transmission in sequence. Our work could not only deepen our understanding of the mechanical behavior and deformation mechanism of twinned Au nanowires, but also provide new insights into enhancing the strength and ductility of nanowires by engineering the nanoscale twins.
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Chen J, Shi J, Wang Y, Sun J, Han J, Sun K, Fang L. Nanoindentation and deformation behaviors of silicon covered with amorphous SiO2: a molecular dynamic study. RSC Adv 2018; 8:12597-12607. [PMID: 35541277 PMCID: PMC9079387 DOI: 10.1039/c7ra13638b] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Accepted: 03/26/2018] [Indexed: 12/02/2022] Open
Abstract
A fundamental understanding of the mechanical properties and deformation behaviors of surface modified silicon during chemical mechanical polishing (CMP) processes is difficult to obtain at the nanometer scale. In this research, MD simulations of monocrystalline silicon covered with an amorphous SiO2 film with different thickness are implemented by nanoindentation, and it is found that both the indentation modulus and hardness increase with the growing indentation depth owning to the strongly silicon substrate effect. At the same indentation depth, the indentation modulus decreases shapely with the increase of film thickness because of less substrate influence, while the hardness agrees well with the trend of modulus at shallow depth but mismatches at larger indentation depth. The observed SiO2 film deformation consists of densification and thinning along indentation direction and extension in the deformed area due to the rotation and deformation of massive SiO4 tetrahedra. The SiO2 film plays an important role in the onset and development of silicon phase transformation. The thinner the SiO2 film is, the earlier the silicon phase transformation takes place. So the numbers of phase transformation atoms increase with the decrease of SiO2 film thickness at the same indentation depth. It is suggested that the thicker film should be better during CMP process for higher material removal rate and less defects within silicon substrate. Force–indentation depth curves and cross-section snapshots of phase transformation evolution of silicon under various film thickness (H).![]()
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Affiliation(s)
- Juan Chen
- State Key Laboratory for Mechanical Behavior of Materials
- Xi'an Jiaotong University
- Xi'an 710049
- China
| | - Junqin Shi
- State Key Laboratory for Mechanical Behavior of Materials
- Xi'an Jiaotong University
- Xi'an 710049
- China
| | - Yunpeng Wang
- State Key Laboratory for Mechanical Behavior of Materials
- Xi'an Jiaotong University
- Xi'an 710049
- China
| | - Jiapeng Sun
- College of Mechanics and Materials
- Hohai University
- Nanjing 210098
- China
| | - Jing Han
- School of Mechanical and Electrical Engineering
- China University of Mining and Technology
- Xuzhou 221116
- China
| | - Kun Sun
- State Key Laboratory for Mechanical Behavior of Materials
- Xi'an Jiaotong University
- Xi'an 710049
- China
| | - Liang Fang
- State Key Laboratory for Mechanical Behavior of Materials
- Xi'an Jiaotong University
- Xi'an 710049
- China
- School of Mechanical & Electrical Engineering
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Li M, Lin L, Guo R, Bhalla A, Zeng X. Numerical investigation of size effects on mechanical behaviors of Fe nanoparticles through an atomistic field theory. ACTA ACUST UNITED AC 2017. [DOI: 10.1142/s2424913017500102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
At nanoscale, the mechanical response of nanoparticles is largely affected by the particle size. To assess the effects of nanoparticle size (e.g., nanoparticle’s volume, cross-sectional area and length) on mechanical behaviors of bcc Fe nanoparticles under compressive loading, an atomistic field theory was introduced in current study. In the theory, atomistic definitions and continuous local density functions of fundamental physical quantities were derived. Through the atomistic potential-based method, the mechanical responses of bcc Fe nanoparticles were analyzed in different sizes. The simulation results reveal that the ultimate stress decreases as Fe nanoparticle’s volume, cross-sectional area or length increases under compressive loading. Nonetheless, the Young’s modulus increases as nanoparticle size increases. In addition, for a fixed finite volume nanoparticle, this study indicates that the ultimate stress will increase as strain rate increases, but Young’s modulus will decrease with increasing strain rate. A loading–unloading study illustrates the energy dissipation due to irreversible structure changes in Fe nanoparticles.
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Affiliation(s)
- Meng Li
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, TX 78249, USA
| | - Liqiang Lin
- Department of Mechanical Engineering, University of Texas at San Antonio, TX 78249, USA
| | - Ruyan Guo
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, TX 78249, USA
| | - Amar Bhalla
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, TX 78249, USA
| | - Xiaowei Zeng
- Department of Mechanical Engineering, University of Texas at San Antonio, TX 78249, USA
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French WR, Pervaje AK, Santos AP, Iacovella CR, Cummings PT. Probing the Statistical Validity of the Ductile-to-Brittle Transition in Metallic Nanowires Using GPU Computing. J Chem Theory Comput 2013; 9:5558-66. [PMID: 26592289 DOI: 10.1021/ct400885z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We perform a large-scale statistical analysis (>2000 independent simulations) of the elongation and rupture of gold nanowires, probing the validity and scope of the recently proposed ductile-to-brittle transition that occurs with increasing nanowire length [Wu et al. Nano Lett. 2012, 12, 910-914]. To facilitate a high-throughput simulation approach, we implement the second-moment approximation to the tight-binding (TB-SMA) potential within HOOMD-Blue, a molecular dynamics package which runs on massively parallel graphics processing units (GPUs). In a statistical sense, we find that the nanowires obey the ductile-to-brittle model quite well; however, we observe several unexpected features from the simulations that build on our understanding of the ductile-to-brittle transition. First, occasional failure behavior is observed that qualitatively differs from that predicted by the model prediction; this is attributed to stochastic thermal motion of the Au atoms and occurs at temperatures as low as 10 K. In addition, we also find that the ductile-to-brittle model, which was developed using classical dislocation theory, holds for nanowires as small as 3 nm in diameter. Finally, we demonstrate that the nanowire critical length is higher at 298 K relative to 10 K, a result that is not predicted by the ductile-to-brittle model. These results offer practical design strategies for adjusting nanowire failure and structure and also demonstrate that GPU computing is an excellent tool for studies requiring a large number of independent trajectories in order to fully characterize a system's behavior.
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Affiliation(s)
- William R French
- Department of Chemical and Biomolecular Engineering, Vanderbilt University , Nashville, Tennessee, United States
| | - Amulya K Pervaje
- Department of Chemical and Biomolecular Engineering, Vanderbilt University , Nashville, Tennessee, United States
| | - Andrew P Santos
- Department of Chemical and Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina, United States
| | - Christopher R Iacovella
- Department of Chemical and Biomolecular Engineering, Vanderbilt University , Nashville, Tennessee, United States
| | - Peter T Cummings
- Department of Chemical and Biomolecular Engineering, Vanderbilt University , Nashville, Tennessee, United States.,Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee, United States
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