Severe deformation processes, such as equal channel angular extrusion, accumulative roll bonding and asymmetric rolling, have been identified as having potential for producing bulk ultrafine-grained materials on an industrial scale. The relative merits of these processes are discussed with reference to their effectiveness at producing ultrafine-grain structures and their commercial viability. Key features of the grain refinement mechanisms, operating in simple, model, aluminium alloys, are illustrated using quantitative EBSD analysis of the deformed microstructures. The influence of second phase particles, and the role of the texture evolution are also discussed.