Dislocation reactions, plastic anisotropy and forest strengthening in MgO at high temperature

Published Date
Mechanics of Materials
April 2014, Vol.71:62–73, doi:10.1016/j.mechmat.2014.01.001

• Author 

• J. Amodeo ^a,,
• B. Devincre ^b
• Ph. Carrez ^a
• P. Cordier ^a

• aUnité Matériaux et Transformations, UMR CNRS 8207, Université de Lille 1, Cité Scientifique, 59655 Villeneuve d’Ascq, France
• bLaboratoire d’Etude des Microstructures, UMR 104, CNRS-ONERA, 29 avenue de la Division Leclerc, 92322 Chatillon, France

Received 6 November 2013. Revised 21 December 2013. Available online 18 January 2014. 

Highlights

• •
  We model reactions between dislocations in MgO using DD simulation.
• •
  The role of forest reactions on plastic deformation is studied at high temperature.
• •
  Strengthening coefficients are calculated.
• •
  Massive DD simulation provides information on frequent experimental observations.

Abstract

The collective properties of dislocations in MgO are investigated in the high temperature regime and at constant strain rate with 3D Dislocation Dynamics simulations. Intersections between slip systems 1/2〈1 1 0〉{1 1 0} and 1/2〈1 1 0〉{1 0 0} allow essentially two types of junction reactions. These junctions are energetically stable and are expected to promote strong forest strengthening at high temperature. Large-scale DD simulations show that MgO strain hardening at high temperature may be dominated by forest reactions. Important parameters for dislocation density based modeling of MgO plasticity are finally calculated and verified to be consistent with experimental observations.

Keywords

MgO

Plasticity

Dislocation Dynamics simulation

Forest strengthening

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• ⁎ 
  Corresponding author. Present address: INSA Lyon, Laboratoire MATEIS, UMR CNRS 5510, 25 avenue Jean Capelle, 69621 Villeurbanne Cedex, France. Tel.: +33 472 438235; fax: +33 472 438539.

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