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The search for the development of metals with high mechanical strength has raised intense interest in severe plastic deformation (SPD) methods. [1,2] These involve the application of intense straining to ultimately produce ultrafine-grained (UFG) materials. Among the available SPD techniques, multidirectional forging (MDF) [3-5] is one of the simplest procedures and can be readily applied in industry. During MDF processing, a cuboid workpiece is successively submitted to the same compression strain along its three orthogonal axes, so that after each three compressions (a so-called MDF cycle) the dimensions of the sample return to the unprocessed state. [4,6] MDF processing allows the determination of the material in situ stressstrain curves for every compression step and can be performed with or without the use of dies confining the plastic flow. [3,7] Although the grain refinement mechanisms associated with SPD are still not fully understood, it is generally accepted that it is caused by the fragmentation of the original grains in the material by boundaries formed from dislocation arrangements created during straining. [8] Sakai et al. [3] have emphasized the importance of the development of micro shear bands (MSBs), which are localized planar sheared regions within the initial grains, in the development of UFG structures in metals processed by different SPD procedures [3,7,9-18] This microstructural evolution is also referred to in the literature as continuous dynamic recrystallization [3,7,9,12,19] and the successive deformation at mutually orthogonal