Applications of screw extrusion for pure aluminium and aluminium foils

Abstract

This thesis has assessed the effect of the screw extrusion process on a super pure aluminium Ø 3mm wire. This thesis also determined that commercial quality aluminium foil can be screw extruded using the prototype found at Department of Materials Science and Engineering, NTNU. The foil was screw extruded into a Ø 3mm wire and a Ø 10mm round profile. \par The electrical conductivity of screw extruded Ø 3mm wires were tested and showed a minimal decrease in conductivity for the super pure aluminium (SP-Al) compared to values found in literature (64.60\%IACS for SP-Al versus 64.95\% found in literature). The conductivity for the aluminium foil based wire varied around 57\%IACS due to the high iron content (1.24wt\%). The mechanical properties for the best performing super pure aluminium measured a hardness of 21.4HV and an Ulitmate Tensile Strength (UTS) of 43MPa. The mechanical properties for the screw extruded aluminium foil based Ø 3mm wire showed a hardness of 35$\pm$4HV varying with extrusion temperature with a stable UTS of 110MPa. The screw extruded aluminium foil based Ø 10mm profile had similar results with low deviation. The screw extruded aluminium foil based profiles both fractured in a ductile manner, with one out of eight samples deviating from a ductile fracture.