Microstructure and properties of high strength aluminium alloys subjected to rapid solidification processing

High strength aluminium alloys of 7075 type, modified by the addition of 1.0 wt% Fe, Mn, or Ni were rapidly solidified (RS) by centrifugal atomization and substrate quenching. The product was in the form of circular platelets of 3-5 mm diameter and 20-50 mu m thick and solidified at a cooling rate of greater than or equal to 10(4)degrees C/s. Mictostructural study of the RS alloys revealed some novel features like bimodal morphology and spiral morphology. The RS platelets were consolidated by compacting, vacuum heat treatment and hot extrusion. The consolidated alloys had good surface finish and exhibited moderate improvement in properties.