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Size effect on deformation twinning in face-centred cubic single crystals: Experiments and modelling

Liang, Z. Y., De Hosson, J. T. M. & Huang, M. X., 1-May-2017, In : Acta Materialia. 129, p. 1-10 10 p.

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  • Size effect on deformation twinning in face-centred cubic single crystals

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DOI

In addition to slip by dislocation glide, deformation twinning in small-sized metallic crystals also exhibits size effect, namely the twinning stress increases with decreasing sample size. In order to understand the underpinning mechanisms responsible for such effect, systematic experiments were carried out on the small-sized single-crystalline pillars of a twinning-induced plasticity steel with a face-centred cubic structure. The flow stress increases considerably with decreasing pillar diameter from 3 to 0.5 mu m, demonstrating a substantial size effect with a power exponent of 0.43. Detailed microstructural characterization reveals that the plastic deformation of the present pillars is dominant by twinning, primarily via twin growth, indicating that the size effect should be related to deformation twinning instead of slip by dislocation glide. Subsequent modelling works indicate that twinning can be accomplished by the dissociation of the ion-radiation-induced vacancy Frank loops in the damaged subsurface layer of the pillars, and the size effect is attributed to the ion-radiation-induced compressive stress in the subsurface layer, which decreases with pillar diameter. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)1-10
Number of pages10
JournalActa Materialia
Volume129
Publication statusPublished - 1-May-2017

    Keywords

  • Deformation twinning, Size effect, Radiation, TWIP steel, Pillar, STACKING-FAULT TETRAHEDRA, SURFACE DISLOCATION NUCLEATION, INDUCED PLASTICITY STEEL, HIGH-ENTROPY ALLOY, MEDIATED DEFORMATION, ATOMISTIC SIMULATION, ULTRAHIGH STRENGTH, STRAIN GRADIENTS, MICRO-PILLARS, NANOWIRES

ID: 97448490