Metal composite materials are heterogeneous materials consisting of two or more different components bonded together internally. Special kinds of metal composites are produced by simultaneous plastic deformation of different metals. Process variables and characteristics of materials deformed simultaneously have an effect on the amount of deformation in each material, plastic zone, influencing the results of simultaneous plastic deformation. The present paper investigates the ability of dissimilar powder metallurgical (P/M) preforms to undergo simultaneous deformation using a special laboratory test. The influence of density ratio, thickness or volume ratio, type of deformation and total plastic strain on the strain experienced by individual metals are studied to establish the conditions of sound flow during simultaneous deformation. The results indicate that the simultaneous plastic deformation of dissimilar P/M preforms with different properties makes the deformation heterogeneous. The difference in the plastic strain experienced by each material increases with increase in the total plastic strain, volume or thickness ratio and deviation from the unit density ratio. The consolidation and metal matrix hardening mechanisms associated with the P/M the deformation behavior of each metal and the onset of steady state deformation, during simultaneous deformation. Parameters such as volume ratio and type of deformation also strongly influence the simultaneous deformation results. (C) 2004 Elsevier B.V. All rights reserved.