Novel method of screw extrusion for fabricating Al/Mg (macro-) composites from aluminum alloy 6063 and magnesium granules
(1. Department of Materials Science and Engineering, Norwegian University of Science and Technology,
Trondheim N-7491, Norway;
2. R&D Materials Technology, Hydro Aluminium AS, Sunndalsora 6600, Norway;
3. Center for Advanced Materials, Qatar University, Doha 2713, Qatar)
Trondheim N-7491, Norway;
2. R&D Materials Technology, Hydro Aluminium AS, Sunndalsora 6600, Norway;
3. Center for Advanced Materials, Qatar University, Doha 2713, Qatar)
Abstract: A novel method of screw extrusion was used for producing a bimetal composite Al/Mg from granules containing aluminium alloy 6063 (AA6063) and commercial pure magnesium. Up to 12.5% (mass fraction) pure magnesium was added to the aluminium alloy. In general, the material consisted of a fine grained microstructure. In addition to the phases originating from the input materials, intermetallic phases were observed as islands consisting of the Al2Mg3 phase surrounded by γ-Mg17Al12, throughout the microstructure. The mechanical properties of the extruded material showed a gradual increase in strength with increasing the addition of Mg. The highest registered UTS, well above 350 MPa, was observed for the material containing 10% Mg. Examinations of the fracture surfaces indicated that increasing the magnesium content led to a higher degree of brittle fracture and a gradual change of the fracture micro-mechanisms. The optimization of the post-extrusion processing conditions is still ongoing.
Key words: Al/Mg composites; extrusion; microstructure; mechanical properties