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Dynamic probing of structural evolution for Co50Ni50 metallic glass during pressurized cooling using atomistic simulation. J Mol Model 2020; 26:208. [DOI: 10.1007/s00894-020-04468-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 07/08/2020] [Indexed: 11/26/2022]
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Zhang Y, Liu H, Mo J, Wang M, Chen Z, He Y, Yang W, Tang C. Atomic-level crystallization in selective laser melting fabricated Zr-based metallic glasses. Phys Chem Chem Phys 2019; 21:12406-12413. [PMID: 31140496 DOI: 10.1039/c9cp02181g] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
As a promising additive manufacturing technique, selective laser melting (SLM) provides the possibility of fabricating metallic glassy components free of the constraints of geometrical complexity and dimensions. However, unexpected crystallization greatly affects the microstructure and degrades the mechanical performance of SLM-fabricated metallic glasses (MGs). To clarify the crystallization mechanism and the effect of laser processing on the crystallization, we investigate the atomic-level crystallization in the SLM Zr90Cu10 MG by using molecular dynamics simulations. The results show that crystallization highly related to scan speed lies in the atomic-level cluster changes. Lower scan speed leads to a dramatically increased fraction of the BCC crystal phase, accompanied by the nucleation of a few HCP and FCC crystal phases. As scan speed increases, more icosahedron-like clusters are formed, leading to the formation of the MG, while the nucleation of the crystal phase is suppressed. The suppression of crystallization is further attributed to a higher average temperature variation rate induced by higher scan speed, which reduces the relaxation time, preventing the nucleation and growth of crystal phases. This work contributes to the understanding of the crystallization in MGs during the SLM process at the atomic level, providing guidance to suppress the crystallization in the SLM process of desired metallic glassy components.
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Affiliation(s)
- Yue Zhang
- 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.
| | - 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.
| | - Zhe Chen
- School of Physical Science and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China.
| | - Yezeng He
- Institute of Massive Amorphous Metal Science, School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou 221116, People's Republic of China
| | - Weiming Yang
- Institute of Massive Amorphous Metal Science, School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou 221116, People's Republic of China and State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, China 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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Feng SD, Chan KKC, Zhao L, Wang LM, Liu RP. Molecular Dynamics Simulation of Structural Signals of Shear-Band Formation in Zr 46Cu 46Al₈ Metallic Glasses. MATERIALS (BASEL, SWITZERLAND) 2018; 11:E2564. [PMID: 30562968 PMCID: PMC6316119 DOI: 10.3390/ma11122564] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 11/22/2022]
Abstract
The evolution from initiation to formation of a shear band in Zr46Cu46Al₈ metallic glasses is presented via molecular dynamics simulation. The increase in number and the decrease in average size of clusters with the quasi-nearest atoms being 0 correspond to the shear-band evolution from initiation to formation. When the shear band is completely formed, the distribution of the bond orientational order q₆ reaches a minimum. The maximum of the number of the polyhedral loss of Cu-centered <0, 0, 12, 0> and the minimum of the number of the polyhedral loss of Zr-centered <0, 2, 8, 5> correspond to the shear-band formation. These findings provide a strong foundation for characterizing the evolution from initiation to formation of shear bands.
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Affiliation(s)
- Shi-Dong Feng
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China.
- Advanced Manufacturing Technology Research Centre, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom 999077, Hong Kong.
| | - Keith K C Chan
- Advanced Manufacturing Technology Research Centre, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom 999077, Hong Kong.
| | - Lei Zhao
- Advanced Manufacturing Technology Research Centre, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom 999077, Hong Kong.
| | - Li-Min Wang
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China.
| | - Ri-Ping Liu
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China.
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Icosahedra clustering and short range order in Ni-Nb-Zr amorphous membranes. Sci Rep 2018; 8:6084. [PMID: 29666391 PMCID: PMC5904141 DOI: 10.1038/s41598-018-24433-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/28/2018] [Indexed: 11/08/2022] Open
Abstract
Crystalline Pd/Pd-Ag membranes are widely used for hydrogen separation from CO2 and other gases in power generation applications. To substitute these high cost noble metal alloy membranes, the Ni-Nb-Zr amorphous alloys are being developed that exhibit relatively high permeability of hydrogen between 200–400 °C. Atom probe tomography (APT) experiments performed on these ribbons revealed nm-scale Nb-rich and Zr-rich regions (clusters) embedded in a ternary matrix, indicating phase separation within the Ni-Nb-Zr amorphous alloy. Density functional theory (DFT) simulations have predicted that these clusters are composed of icosahedral coordination polyhedra. The interatomic distances and correlation lengths of the short range order of these alloys were determined by neutron total scattering which match well with our DFT based molecular dynamics (DFT-MD) simulations.
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Niu X, Feng S, Pan S. Related Structure Characters and Stability of Structural Defects in a Metallic Glass. MATERIALS 2018; 11:ma11040468. [PMID: 29565298 PMCID: PMC5951314 DOI: 10.3390/ma11040468] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 03/16/2018] [Accepted: 03/20/2018] [Indexed: 11/16/2022]
Abstract
Structural defects were investigated by a recently proposed structural parameter, quasi-nearest atom (QNA), in a modeled Zr50Cu50 metallic glass through molecular dynamics simulations. More QNAs around an atom usually means that more defects are located near the atom. Structural analysis reveals that the spatial distribution of the numbers of QNAs displays to be clearly heterogeneous. Furthermore, QNA is closely correlated with cluster connections, especially four-atom cluster connections. Atoms with larger coordination numbers usually have less QNAs. When two atoms have the same coordination number, the atom with larger five-fold symmetry has less QNAs. The number of QNAs around an atom changes rather frequently and the change of QNAs might be correlated with the fast relaxation metallic glasses.
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Affiliation(s)
- Xiaofeng Niu
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
- Shanxi Key Laboratory of Advanced Magnesium-Based Materials, Taiyuan University of Technology, Taiyuan 030024, China.
| | - Shidong Feng
- Advanced Manufacturing Technology Research Centre, Department of Industrial and Systems Engineering, Hong Kong Polytechnic University, Hong Kong 999077, China.
| | - Shaopeng Pan
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
- Shanxi Key Laboratory of Advanced Magnesium-Based Materials, Taiyuan University of Technology, Taiyuan 030024, China.
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Free Volume Contributing to the Different Yield Behaviors between Tension and Compression Deformations in Metallic Glasses. METALS 2017. [DOI: 10.3390/met7100444] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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