TU Darmstadt / ULB / TUbiblio

Influence of topological structure and chemical segregation on the thermal and mechanical properties of Pd-Si nanoglasses

Nandam, Sree Harsha and Adjaoud, Omar and Schwaiger, Ruth and Ivanisenko, Yulia and Chellali, Mohammed Reda and Wang, Di and Albe, Karsten and Hahn, Horst (2020):
Influence of topological structure and chemical segregation on the thermal and mechanical properties of Pd-Si nanoglasses.
In: Acta Materialia, Elsevier Ltd., ISSN 13596454,
DOI: 10.1016/j.actamat.2020.03.021,
[Online-Edition: https://doi.org/10.1016/j.actamat.2020.03.021],
[Article]

Abstract

Metallic nanoglasses are non-crystalline solids with interfacial regions, typically characterized by a modified short-range order and compositional gradients. These interfaces can act as nucleation sites for the formation of shear transformation zones during mechanical deformation, which gives rise to a deformation behavior distinct from the bulk glass counterpart. While various studies have investigated nanoglasses experimentally (mostly Fe-Sc) and in computer simulations (typically Cu-Zr), there is hitherto no study comparing compositionally identical nanoglasses and conventional metallic glasses by experiments and simulations. In this contribution, we investigate Pd-Si as a model system and compare nanoglasses produced by inert gas condensation with melt-spun ribbons. Molecular dynamics simulations and atom probe tomography provide evidence that glass-glass interfaces are primarily topological and chemical defects in this particular system. Differential scanning calorimetry shows a decrease in the glass transition and crystallization temperature of the nanoglasses compared to melt-spun ribbons. Nanoindentation and micropillar tests on Pd-Si metallic nanoglasses, however, provide evidence for shear band formation in both sample types, the melt-spun ribbons and nanoglass. Shear bands in the nanoglass samples appear more diffuse as compared to melt-spun ribbons. This is also evident from the reduced strain localization in the nanoglass. It is concluded that the topological inhomogenieties induced by forming glass-glass interfaces significantly affect the mechanical properties of nanoglasses.

Item Type: Article
Erschienen: 2020
Creators: Nandam, Sree Harsha and Adjaoud, Omar and Schwaiger, Ruth and Ivanisenko, Yulia and Chellali, Mohammed Reda and Wang, Di and Albe, Karsten and Hahn, Horst
Title: Influence of topological structure and chemical segregation on the thermal and mechanical properties of Pd-Si nanoglasses
Language: English
Abstract:

Metallic nanoglasses are non-crystalline solids with interfacial regions, typically characterized by a modified short-range order and compositional gradients. These interfaces can act as nucleation sites for the formation of shear transformation zones during mechanical deformation, which gives rise to a deformation behavior distinct from the bulk glass counterpart. While various studies have investigated nanoglasses experimentally (mostly Fe-Sc) and in computer simulations (typically Cu-Zr), there is hitherto no study comparing compositionally identical nanoglasses and conventional metallic glasses by experiments and simulations. In this contribution, we investigate Pd-Si as a model system and compare nanoglasses produced by inert gas condensation with melt-spun ribbons. Molecular dynamics simulations and atom probe tomography provide evidence that glass-glass interfaces are primarily topological and chemical defects in this particular system. Differential scanning calorimetry shows a decrease in the glass transition and crystallization temperature of the nanoglasses compared to melt-spun ribbons. Nanoindentation and micropillar tests on Pd-Si metallic nanoglasses, however, provide evidence for shear band formation in both sample types, the melt-spun ribbons and nanoglass. Shear bands in the nanoglass samples appear more diffuse as compared to melt-spun ribbons. This is also evident from the reduced strain localization in the nanoglass. It is concluded that the topological inhomogenieties induced by forming glass-glass interfaces significantly affect the mechanical properties of nanoglasses.

Journal or Publication Title: Acta Materialia
Publisher: Elsevier Ltd.
Uncontrolled Keywords: Nanoglass, Micro-compression, MD simulations, Nanoindentation, Differential scanning calorimetry
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Materials Modelling
Zentrale Einrichtungen
Zentrale Einrichtungen > University IT-Service and Computing Centre (HRZ)
Zentrale Einrichtungen > University IT-Service and Computing Centre (HRZ) > Hochleistungsrechner
Date Deposited: 21 Apr 2020 05:44
DOI: 10.1016/j.actamat.2020.03.021
Official URL: https://doi.org/10.1016/j.actamat.2020.03.021
Projects: DFG/SPP 1594
Export:
Suche nach Titel in: TUfind oder in Google
Send an inquiry Send an inquiry

Options (only for editors)
Show editorial Details Show editorial Details