Equal Channel Angular Extrusion (ECAE) processing was used to produce ultra-fine grained microstructures in several classes of materials; multiphase aluminum alloys, intermetallics, titanium alloys and high strength steels. The effect of ECAE processing on the room temperature strength, ductility, fatigue performance and toughness, and the high temperature workability and superplasticity was studied. Severe Plastic Deformation (SPD) via ECAE processing is a viable method for producing ultra-fine grain structures in bulk intermetallics and holds promise for improving the room temperature ductility and toughness and high temperature superplasticity of intermetallics. Significant strength and toughness improvements without loss of ductility were observed in aluminum and magnesium alloys. A reduction in grain size from 20 to 2 mm resulted in an improvement of fatigue life by three orders of magnitude and 30 % increase in fatigue strength in Ti-6Al-4V alloy. In titanium aluminides, grain refinement down to 1mm by utilizing ECAE processing resulted in a 25-50 % increase in yield strength and 50-90 % increase in ductility, 20-40 % increase in fracture toughness. An increase in strength of up to 100 % without loss in ductility was observed in steels.