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Cohesive strength of zirconia/molybdenum interfaces and grain boundaries in molybdenum: A comparative study

Lenchuk, Olena and Rohrer, Jochen and Albe, Karsten (2017):
Cohesive strength of zirconia/molybdenum interfaces and grain boundaries in molybdenum: A comparative study.
In: Acta Materialia, ISSN 13596454,
[Online-Edition: http://doi.org/10.1016/j.actamat.2017.05.070],
[Article]

Abstract

We present calculations within density functional theory on the thermodynamic stability and mechanical properties of t-ZrO_2(001)/Mo(001) interfaces. The interfacial strength is evaluated by applying energy-based (work of separation) and stress-based (theoretical strength) criteria for different cleavage planes. The lowest energy for crack propagation is obtained for a cut creating a stoichiometric ZrO_2(001) surface. Our results reveal that molybdenum grain boundaries contaminated with oxygen are less stable against brittle fracture than pure Mo GBs. Addition of Zr to Mo-based alloys, however, can strengthen Mo grain boundaries that contain oxygen by forming an ultrathin zirconia film between Mo grains. The stress required to cleave an ultrathin zirconia film is equal to that required for a pure Mo GB.

Item Type: Article
Erschienen: 2017
Creators: Lenchuk, Olena and Rohrer, Jochen and Albe, Karsten
Title: Cohesive strength of zirconia/molybdenum interfaces and grain boundaries in molybdenum: A comparative study
Language: English
Abstract:

We present calculations within density functional theory on the thermodynamic stability and mechanical properties of t-ZrO_2(001)/Mo(001) interfaces. The interfacial strength is evaluated by applying energy-based (work of separation) and stress-based (theoretical strength) criteria for different cleavage planes. The lowest energy for crack propagation is obtained for a cut creating a stoichiometric ZrO_2(001) surface. Our results reveal that molybdenum grain boundaries contaminated with oxygen are less stable against brittle fracture than pure Mo GBs. Addition of Zr to Mo-based alloys, however, can strengthen Mo grain boundaries that contain oxygen by forming an ultrathin zirconia film between Mo grains. The stress required to cleave an ultrathin zirconia film is equal to that required for a pure Mo GB.

Journal or Publication Title: Acta Materialia
Uncontrolled Keywords: Density functional theory (DFT); Thermodynamic stability; Adhesion; Brittle fracture
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: 09 Jun 2017 09:48
Official URL: http://doi.org/10.1016/j.actamat.2017.05.070
Identification Number: doi:10.1016/j.actamat.2017.05.070
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