Computer simulation of dislocation-solute interaction in dilute Fe-Cu alloys

The effects of the substitutional element copper in solution in α-iron on glide of a 〈111〉 { 110 } edge dislocation are investigated by atomic-scale computer simulation. Under static conditions (temperature T ≤ 0 K), single copper atoms and nearest-neighbour pairs in the first atomic plane below the dislocation slip plane provide the strongest barrier to slip, in partial agreement with continuum theory. This contrasts with recent simulation results for the Ni-Al fcc alloy (Rodary et al 2004 Phys. Rev. B 70 054111), where Al atoms displaced into nearest-neighbour coordination across the slip plane form the strongest obstacles. The dynamics of dislocation glide in Fe-Cu solid solution at T > 0 K are determined as a function of solute concentration. Parameters such as velocity, critical stress and drag coefficient are analysed. Again, there are differences from the Ni-Al system. The results are discussed in terms of the static strength of solute configurations and the different crystal structure of iron and nickel.