Severe plastic deformation (SPD) processing is widely used to control and refine the grain size of monolithic metals and alloys, with grain sizes of less than 100 nm produced in recent years. One particular SPD technique, severe plastic torsional straining, has been found to effectively consolidate both micrometre and nanometre sized metallic powders and metalceramic powder mixtures, with resultant grains refined to submicrometre or nanometre size.