Atomistic simulation of the deformation of nanocrystalline palladium: The effect of voids

Atomistic simulations of uniaxial deformation of porous nanocrystalline palladium were performed at room temperature. The porosity was varied from 1% to 3%. The diameter of the pores was varied from 1 to 4 nm. It is found that a significant part of the void volume fraction is lost during sample preparation at high temperature. During deformation, the presence of voids does not lead to an earlier onset of dislocation activity compared to the void-free sample. Poisson's ratio is found to be almost insensitive to porosity, while Young's modulus and the stress for the initiation of grain boundary mediated plastic flow moderately decrease with increasing porosity. The total strain for the onset of plastic deformation, however, is unaffected by the porosity.