Realistic time-scale fully atomistic simulations of surface nucleation of dislocations in pristine nanopillars

摘要: We use our recently proposed accelerated dynamics algorithm (Tiwary and van de Walle, 2011) to calculate temperature stress dependence of activation free energy for surface nucleation dislocations in pristine Gold nanopillars under realistic loads. While maintaining fully atomistic resolution, we achieve the fraction a second time-scale regime. find that depends significantly non-linearly on driving force (stress or strain) temperature, leading very high entropies. also perform compression tests strain-rates varying between 7 orders magnitudes, reaching as low 10^3/s. Our calculations bring out perils strain-rate Molecular Dynamics calculations: while failure mechanism remains same across entire range, elastic limit (defined first dislocation) strain-rate. propose new methodology overcomes some limits original scheme (and methods general). lay sufficient details so be used understanding predicting deformation forces various problems.