Recycling of aluminium alloy and aluminium matrix composite chips by pressing and hot extrusion

A method for recycling aluminium alloy chips by cold and hot pressing followed by hot extrusion was studied as well as the possibility of using this method to recycle aluminium matrix composite chips. Hot extrusion of cold or hot pressed samples could satisfactorily promote the consolidation of the chips. Hot extrusion of hot pressed samples proved to be the best route, from the point of view of mechanical properties, but, on the other hand, hot extrusion of cold pressed samples route has higher cost profit. Aluminium AA6061 matrix composite reinforced with Al2O3 recycled by cold pressing and hot extrusion was compared with the primary material produced by conventional casting process from which the chips were obtained. Due to the refinement of the microstructure and the dispersion of the aluminium oxide caused by the extrusion process, the ultimate tensile strength (UTS) and the hardness were higher for the recycled material than for the former composite. (C) 2003 Published by Elsevier Science B.V.