Molecular dynamics simulation of tension-compression asymmetry in plasticity of fivefold twinned Ag nanopillars

Tension-compression asymmetry in plasticity is a notable feature in small-sized single crystals. Here we present results from molecular dynamics simulations of fivefold twinned Ag nanopillars in tension and compression. The fivefold twinned Ag nanopillar shows completely different deformation behaviors in each case. While surface nucleation of stacking fault decahedrons and subsequent formation of necking at region with high density of stacking fault decahedrons is the primary deformation mechanism in tension, generation of {001}〈110〉 Lomer dislocations and their subsequent cross-slip are observed in compression. The reason for the difference is simply discussed by considering the conditions of activation of trailing partials.