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Effect of Misorientation on the Compression of Highly Anisotropic Single-Crystal Micropillars

Authors

  • Rafael Soler,

    1. IMDEA Materials Institute, c/Eric Kandel 2, 28906 Getafe, Madrid, Spain
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  • Jon Mikel Molina-Aldareguia,

    Corresponding author
    1. IMDEA Materials Institute, c/Eric Kandel 2, 28906 Getafe, Madrid, Spain
    • IMDEA Materials Institute, c/Eric Kandel 2, 28906 Getafe, Madrid, Spain.

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  • Javier Segurado,

    1. IMDEA Materials Institute, c/Eric Kandel 2, 28906 Getafe, Madrid, Spain
    2. Department of Materials Science, Polytechnic University of Madrid, E. T. S. de Ingenieros de Caminos 28040 Madrid, Spain
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  • Javier LLorca

    1. IMDEA Materials Institute, c/Eric Kandel 2, 28906 Getafe, Madrid, Spain
    2. Department of Materials Science, Polytechnic University of Madrid, E. T. S. de Ingenieros de Caminos 28040 Madrid, Spain
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  • The authors acknowledge the financial support of the Spanish Ministry of Science and Innovation (MAT2009-14396) and the Comunidad de Madrid through the program ESTRUMAT (S2009/MAT-1585).

Abstract

The effect of crystal misorientation, geometrical tilt, and contact misalignment on the compression of highly anisotropic single crystal micropillars was assessed by means of crystal plasticity finite element simulations. The investigation was focused in single crystals with the NaCl structure, like MgO or LiF, which present a marked plastic anisotropy as a result of the large difference in the critical resolved shear stress between the “soft” {110}〈110〉 and the “hard” {100}〈110〉 active slip systems. It was found that contact misalignment led to a large reduction in the initial stiffness of the micropillar in crystals oriented in the soft and hard direction. The crystallographic tilt did not modify, however, the initial crystal stiffness. From the viewpoint of the plastic response, none of the effects analyzed led to significant differences in the flow stress when the single crystals were oriented along the “soft” [100] direction. Large differences were found, however, if the single crystal was oriented in the “hard” [111] direction as a result of the activation of the soft slip system. Numerical simulations were in very good agreement with experimental literature data.

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