skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Mechanical and dynamical behaviors of ZrSi and ZrSi{sub 2} bulk metallic glasses: A molecular dynamics study

Abstract

The mechanical and dynamical properties of ZrSi and ZrSi{sub 2} bulk metallic glasses (BMGs) have been investigated by molecular dynamics simulation. The Honeycutt-Anderson (HA) index analysis indicates that the major indexes in ZrSi and ZrSi{sub 2} bulk metallic glasses are 1551, 1541, and 1431, which refers to the liquid structure. For uniaxial tension, the results show that the ZrSi and ZrSi{sub 2} BMGs are more ductile than their crystal counterparts. The evolution of the distribution of atomic local shear strain clearly shows the initialization of shear transformation zones (STZs), the extension of STZs, and the formation of shear bands along a direction 45° from the tensile direction when the tensile strain gradually increases. The self-diffusion coefficients of ZrSi and ZrSi{sub 2} BMGs at temperatures near their melting points were calculated by the Einstein equation according to the slopes of the MSD profiles at the long-time limit. Because the HA fraction summation of icosahedral-like structures of ZrSi BMG is higher than that of ZrSi{sub 2} BMG, and these local structures are more dense, the self-diffusion coefficients of the total, Zr, and Si atoms of ZrSi{sub 2} BMG are larger than those of ZrSi BMG. This can be attributed to the cagemore » effect, where a denser local structure has a higher possibility of atoms jumping back to form a backflow and then suppress atomic diffusivity. For ZrSi{sub 2} BMG, the self-diffusion coefficient of Si increases with temperature more significantly than does that of Zr, because more open packing rhombohedra structures are formed by the Si-Si pair.« less

Authors:
 [1];  [2]; ;  [1]
  1. Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-sen University, Kaohsiung 804, Taiwan (China)
  2. (China)
Publication Date:
OSTI Identifier:
22399268
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 10; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ATOMS; COMPUTERIZED SIMULATION; EINSTEIN-MAXWELL EQUATIONS; INDEXES; LIQUIDS; MELTING POINTS; METALLIC GLASSES; MOLECULAR DYNAMICS METHOD; SELF-DIFFUSION; SHEAR; STRAINS; TRANSFORMATIONS; ZIRCONIUM SILICIDES

Citation Formats

Ju, Shin-Pon, E-mail: jushin-pon@mail.nsysu.edu.tw, Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan, Wu, Tsang-Yu, and Liu, Shih-Hao. Mechanical and dynamical behaviors of ZrSi and ZrSi{sub 2} bulk metallic glasses: A molecular dynamics study. United States: N. p., 2015. Web. doi:10.1063/1.4913707.
Ju, Shin-Pon, E-mail: jushin-pon@mail.nsysu.edu.tw, Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan, Wu, Tsang-Yu, & Liu, Shih-Hao. Mechanical and dynamical behaviors of ZrSi and ZrSi{sub 2} bulk metallic glasses: A molecular dynamics study. United States. doi:10.1063/1.4913707.
Ju, Shin-Pon, E-mail: jushin-pon@mail.nsysu.edu.tw, Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan, Wu, Tsang-Yu, and Liu, Shih-Hao. Sat . "Mechanical and dynamical behaviors of ZrSi and ZrSi{sub 2} bulk metallic glasses: A molecular dynamics study". United States. doi:10.1063/1.4913707.
@article{osti_22399268,
title = {Mechanical and dynamical behaviors of ZrSi and ZrSi{sub 2} bulk metallic glasses: A molecular dynamics study},
author = {Ju, Shin-Pon, E-mail: jushin-pon@mail.nsysu.edu.tw and Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan and Wu, Tsang-Yu and Liu, Shih-Hao},
abstractNote = {The mechanical and dynamical properties of ZrSi and ZrSi{sub 2} bulk metallic glasses (BMGs) have been investigated by molecular dynamics simulation. The Honeycutt-Anderson (HA) index analysis indicates that the major indexes in ZrSi and ZrSi{sub 2} bulk metallic glasses are 1551, 1541, and 1431, which refers to the liquid structure. For uniaxial tension, the results show that the ZrSi and ZrSi{sub 2} BMGs are more ductile than their crystal counterparts. The evolution of the distribution of atomic local shear strain clearly shows the initialization of shear transformation zones (STZs), the extension of STZs, and the formation of shear bands along a direction 45° from the tensile direction when the tensile strain gradually increases. The self-diffusion coefficients of ZrSi and ZrSi{sub 2} BMGs at temperatures near their melting points were calculated by the Einstein equation according to the slopes of the MSD profiles at the long-time limit. Because the HA fraction summation of icosahedral-like structures of ZrSi BMG is higher than that of ZrSi{sub 2} BMG, and these local structures are more dense, the self-diffusion coefficients of the total, Zr, and Si atoms of ZrSi{sub 2} BMG are larger than those of ZrSi BMG. This can be attributed to the cage effect, where a denser local structure has a higher possibility of atoms jumping back to form a backflow and then suppress atomic diffusivity. For ZrSi{sub 2} BMG, the self-diffusion coefficient of Si increases with temperature more significantly than does that of Zr, because more open packing rhombohedra structures are formed by the Si-Si pair.},
doi = {10.1063/1.4913707},
journal = {Journal of Applied Physics},
number = 10,
volume = 117,
place = {United States},
year = {Sat Mar 14 00:00:00 EDT 2015},
month = {Sat Mar 14 00:00:00 EDT 2015}
}
  • Bulk metallic glasses La{sub 62}Al{sub 14}Ni{sub 12}Cu{sub 12} and Cu{sub 46}Zr{sub 44}Al{sub 7}Y{sub 3} were prepared by copper mold suction casting. The thermal-physical behaviors of bulk metallic glasses were investigated by means of x-ray diffraction, differential scanning calorimetry, ultrasonic techniques, and dilatometry. By calculating the Mie potential function from experimental data, the values of potential function powers (m and n) and related physical parameters such as the mean binding energy, etc., are obtained. Thus, unlike what some people have done by assuming values of m-n (7-14), the values of average nearest-neighbor separation r{sub 0} and effective depth of pair potentialmore » {phi}{sub 0} can be obtained from calculated values of m and n from Mie potential functions and they agree very well with the results in the literature. The calculations can be well consistent with the thermophysical behaviors by comparing the two amorphous alloys. In addition, it was enhanced that the effective depth of pair potential correlated with the glass-forming ability of bulk metallic glass.« less
  • The dynamics of the Johari–Goldstein (JG) β relaxation and the α relaxation in bulk metallic glasses (MGs) has been investigated by using mechanical spectroscopy combined with the Coupling Model. The β relaxations of MGs exhibit different behaviors such as peaks, humps, and excess wings due to the different fluctuations of the chemical interactions among the constituting atoms. A universal correlation between the β relaxation and the α relaxation is generally found by their activation energies and relaxation times as well as the non-exponentiality parameter of the α relaxation, which can be predicted quantitatively from the Coupling Model. Based on themore » quasi-point defects theory, a correlation factor χ shows a broad peak along with the β relaxation, suggesting that the concentration and the correlation degree of the string-like configurations involved in the β relaxation vary with increasing temperature, which challenges the previous view that the system is in an iso-configuration state below T{sub g} and may shed new light on the nature of the JG β relaxation in metallic glasses.« less
  • Comparative analysis between Zr-rich Zr 50Cu 45Al 5 and Cu-rich Cu 50Zr 45Al 5 metallic glasses (MGs) is extensively performed to locate the key structural motifs accounting for their difference of glass forming ability. Here we adopt ab initio molecular dynamics simulations to investigate the local atomic structures of Zr 50Cu 45Al 5 and Cu 50Zr 45Al 5 MGs. A high content of icosahedral-related (full and distorted) orders was found in both samples, while in the Zr-rich MG full icosahedrons < 0,0,12,0 > is dominant, and in the Cu-rich one the distorted icosahedral orders, especially < 0,2,8,2 > and <more » 0,2,8,1 >, are prominent. And the < 0,2,8,2 > polyhedra in Cu 50Zr 45Al 5 MG mainly originate from Al-centered clusters, while the < 0,0,12,0 > in Zr 50Cu 45Al 5 derives from both Cu-centered clusters and Al-centered clusters. These difference may be ascribed to the atomic size difference and chemical property between Cu and Zr atoms. Lastly, the relatively large size of Zr and large negative heat of mixing between Zr and Al atoms, enhancing the packing density and stability of metallic glass system, may be responsible for the higher glass forming ability of Zr 50Cu 45Al 5.« less
  • In this study, we characterize the mechanical properties of Cu{sub 64}Zr{sub 36} nanoglasses under tensile load by means of large-scale molecular dynamics simulations and compare the deformation behavior to the case of a homogeneous bulk glass. The simulations reveal that interfaces act as precursors for the formation of multiple shear bands. In contrast, a bulk metallic glass under uniaxial tension shows inhomogeneous plastic flow confined in one dominant shear band. The results suggest that controlling the microstructure of a nanoglass can pave the way for tuning the mechanical properties of glassy materials.