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Microstructure formation of metallic nanoglasses: Insights from molecular dynamics simulations

Adjaoud, Omar and Albe, Karsten (2017):
Microstructure formation of metallic nanoglasses: Insights from molecular dynamics simulations.
In: Acta Materialia, pp. 322-330, 145, ISSN 13596454, DOI: 10.1016/j.actamat.2017.12.014, [Online-Edition: https://doi.org/10.1016/j.actamat.2017.12.014],
[Article]

Abstract

We investigate the microstructure formation of Pd_80Si_20 and Cu_64Zr_36 nanoglasses by molecular dynamics simulations of the consolidation process of nanometer-sized metallic glassy spheres. Our results reveal that during cold compaction most of the glassy spheres deform by homogeneous plastic flow and in some glassy spheres strain localization occurs in a shear band which traverses the whole glassy sphere. Moreover, the porosity is closed if hydrostatic pressures exceed 4 GPa. The resulting nanoglasses are composed of glassy regions connected by glass-glass interfaces. The results reveal that the width of these interfaces is significantly larger than estimated in previous atomistic models based on planar interfaces. Moreover, structural changes occur not only in the interfaces but also in the glassy regions. In addition, thermodynamics analysis show that surface segregation is favorable in the primary glassy spheres but not always in the nanoglass. The present findings shed light on the process of the microstructure formation of metallic nanoglasses and can serve to interpret the experimental results.

Item Type: Article
Erschienen: 2017
Creators: Adjaoud, Omar and Albe, Karsten
Title: Microstructure formation of metallic nanoglasses: Insights from molecular dynamics simulations
Language: English
Abstract:

We investigate the microstructure formation of Pd_80Si_20 and Cu_64Zr_36 nanoglasses by molecular dynamics simulations of the consolidation process of nanometer-sized metallic glassy spheres. Our results reveal that during cold compaction most of the glassy spheres deform by homogeneous plastic flow and in some glassy spheres strain localization occurs in a shear band which traverses the whole glassy sphere. Moreover, the porosity is closed if hydrostatic pressures exceed 4 GPa. The resulting nanoglasses are composed of glassy regions connected by glass-glass interfaces. The results reveal that the width of these interfaces is significantly larger than estimated in previous atomistic models based on planar interfaces. Moreover, structural changes occur not only in the interfaces but also in the glassy regions. In addition, thermodynamics analysis show that surface segregation is favorable in the primary glassy spheres but not always in the nanoglass. The present findings shed light on the process of the microstructure formation of metallic nanoglasses and can serve to interpret the experimental results.

Journal or Publication Title: Acta Materialia
Volume: 145
Uncontrolled Keywords: Nanoglass, Metallic glass, Glass-glass interface, Microstructure, Molecular dynamics simulation
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Materials Modelling
Zentrale Einrichtungen > University IT-Service and Computing Centre (HRZ) > Hochleistungsrechner
11 Department of Materials and Earth Sciences > Material Science
Zentrale Einrichtungen > University IT-Service and Computing Centre (HRZ)
11 Department of Materials and Earth Sciences
Zentrale Einrichtungen
Date Deposited: 30 Jan 2018 09:42
DOI: 10.1016/j.actamat.2017.12.014
Official URL: https://doi.org/10.1016/j.actamat.2017.12.014
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