Effect of loading condition on statistics of intermittent plasticity in metallic crystals

Abstract

Intermittent crystalline plasticity with power-law behaviors, which is reminiscent of self-organized criticality, has been reported in recent experimental and numerical studies. In this study, we show that the compressive loading condition can provide different statistical features of intermittent plasticity in metals from those under tensile loading. Employing an embedded atom method potential for aluminum we performed molecular dynamics simulations for uniaxial tensile and compressive deformation. It is shown that the power spectra of tensile stress have power-law decay region. Powerlaw distribution of stress drop and waiting time of plastic deformation events are also observed. However, under the compressive loading large-scale deformation events which result in a plateau and larger cutoff on the stress drop distribution are observed. This difference is originated from the geometrical feature of slip systems that dominate interaction between dislocations in crystals.