A study was carried out on model systems deformed under plane-strain. Finite element analysis was used to examine continuously and discontinuously layered models, in which the reinforcement to matrix flow stress ratio, r(s), was varied within the range 1.5 < r(s) < 10. It was found that, for homogeneous refinement of continuously reinforced laminates, the critical value of r(s) is approximately 2. This value, valid for the ideal plastic case, can be increased to a maximum value of r(s) approximate to5 with work hardening. For discontinuously layered systems, similar results were found. It is therefore concluded that macrostructural control is possible in metal/ metal svstems either in the form of homogeneous refinement of the continuous structures or in the form of structures with thin, long, closely spaced reinforcements, provided that the flow strength of the reinforcement is not more than five times that of the matrix. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.