Consolidation of partially amorphous aluminium-alloy powders by severe plastic deformation

The microstructures and properties of Al-based alloys produced by severe plastic deformation under high pressure torsion straining were compared with alloys of the same compositions consolidated by hot extrusion and spray-forming processing. Partially amorphous alloy powders of two systems were studied; Al90Fe7Z3 alloy powders were prepared by high-energy ball milling and Al84Y3Ni8Co4Zr1+SiC composite powder was prepared by gas atomisation. The alloy powders have been cold consolidated by high-pressure torsion straining under a stress of 5 GPa resulting in refined and uniform microstructures, with hardness values well above the measured values for the hot-extruded Al90Fe7Z3 alloy and for the spray-deposited Al84Y3Ni8Co4Zr1+SiC composite alloy.