Yielding and irreversible deformation below the microscale: Surface effects and non-mean-field plastic avalanches

Abstract

Nanoindentation techniques recently developed to measure the mechanical response of crystals under external loading conditions reveal new phenomena upon decreasing sample size below the microscale. At small length scales, material resistance to irreversible deformation depends on sample morphology. Here we study the mechanisms of yield and plastic flow in inherently small crystals under uniaxial compression. Discrete structural rearrangements emerge as series of abrupt discontinuities in stress-strain curves. We obtain the theoretical dependence of the yield stress on system size and geometry and elucidate the statistical properties of plastic deformation at such scales. Our results show that the absence of dislocation storage leads to crucial effects on the statistics of plastic events, ultimately affecting the universal scaling behavior observed at larger scales.

Supporting Videos available at http://dx.plos.org/10.1371/journal.pone.0020418

References in corpus (3)

• Strain bursts in plastically deforming Molybdenum micro- and nanopillars
• Scale-free statistics of plasticity-induced surface steps on KCl single crystals
• From Brittle to Ductile Fracture in Disordered Materials

Cited by in corpus (6)

• Landau theory of crystal plasticity
• Atomistic mechanisms of intermittent plasticity in metals: Dislocation avalanches and defect cluster pinning
• Dynamic hysteresis in cyclic deformation of crystalline solids
• Barrier effect of grain boundaries on the avalanche propagation of polycrystalline plasticity
• Avalanches, Plasticity, and Ordering in Colloidal Crystals Under Compression
• Compressive deformation of Fe nanopillar : Modalities of dislocation dynamics