Nucleation of dislocations in aluminum alloys with copper

The influence of copper impurities on the nucleation of dislocations in aluminum has been investigated using the method for determining the average lifetime of the metastable state. The primary data have been obtained using the molecular dynamics method. The obtained dependences of the dislocation nucleation rate on the shear stress in pure aluminum and aluminum solid solutions with copper have been plotted in the Arrhenius form. It has been found that, with an increase in the copper concentration, the activation parameters for these dependences decrease. It has been shown that an increase in the temperature leads to an increase in the sensitivity of the dislocation nucleation rate to stresses in aluminum solid solutions with 0.1-3.0 at % Cu, in contrast to pure aluminum in which the sensitivity is almost independent of the temperature. The dependences of the dislocation nucleation rate on the copper concentration and temperature over the entire range of stresses have been discussed based on the obtained approximations.