Plastic strain is a mixture of avalanches and quasi-reversible deformations: Study of various sizes

Abstract

Size-dependence of plastic flow is studied by discrete dislocation dynamical simulation of systems with various numbers of interacting linear edge dislocations while the stress is slowly increased. Regions between avalanches in the individual stress curves as functions of the plastic strain were found nearly linear and reversible, where the plastic deformation obeys an effective equation of motion with a nearly linear force. For small plastic deformation, the means of the stress-strain curves are power law over two decades. Here and for somewhat larger plastic deformations, the mean stress-strain curves converge for larger sizes, while their variances shrink, both indicating the existence of a thermodynamical limit. The converging averages decrease with increasing size, in accordance with size-effects from experiments. For large plastic deformations, where steady flow sets in, thermodynamical limit was not realized in this model system.

5 pages, 5 figures

References in corpus (4)

• Submicron plasticity: yield stress, dislocation avalanches, and velocity distribution
• Fluctuations and scaling in creep deformation
• Slip avalanches in crystal plasticity: scaling of the avalanche cutoff
• Role of density fluctuations in the relaxation of random dislocation systems

Cited by in corpus (6)

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• Bayesian optimization of discrete dislocation plasticity of two-dimensional precipitation hardened crystals
• Avalanche Dynamics and the Effect of Straining in Dislocation Systems with Quenched Disorder