Solid state recycling of aluminium sheet scrap by means of spark plasma sintering

Various solid state or ‘meltless’ recycling techniques have recently been developed for light metal scrap in form of chips. Main objective of all approaches is to bypass the need for remelting in order to reduce the overall required energy, and to avoid the material losses that occur during this step. Within this paper, the use of Spark Plasma Sintering (SPS) is proposed as a novel solid state recycling/welding technique for sheet metal scrap. Aluminium 5182 alloy scrap, derived from sheet metal, was successfully consolidated into a fully dense billet via SPS. The use of pulsed electric current heating, in temperatures well below the alloy melting point, combined with mechanical pressure, enchased the densification process resulting into a void-less material. The recycled SPS sample was fully densified and microstructural investigation has been performed in order to confirm effective oxide film breakage. The results illustrate the effectiveness of SPS in aluminium scrap consolidation, also in form of sheet scrap, providing additional means in solid state recycling. The involved mechanisms that contribute to oxide film fracture and scrap consolidation in SPS are being discussed.status: publishe