Comment on 'Constant intermittent flow of dislocations: central problems in plasticity' by L. M. Brown

Brown′s recent impressive review on crystal plasticity is discussed, in particular with respect to the results obtained on stage II work hardening in face-centred cubic crystals. An important issue is the modelling of slip bands as ellipsoids which allows Brown to derive in analytical form many properties of slip bands, in agreement with observation. Nonetheless, some questions are raised as to whether the representation of slip bands as ellipsoids conforms to reality or whether it should be viewed as a convenient approximation for the purpose of an analytical description of a complex situation.