Abstract
The tensile properties and blow forming characteristics of 5083 Al alloy recycled by solid-state recycling were investigated from the viewpoint of oxide contamination. Three types of machined chip with different volumes were recycled by hot extrusion and hot rolling in air. Oxide layers, which were contaminants from the machined chip surface, were distributed in the extrusion direction for the recycled specimens. Oxygen concentration in the recycled specimens increased with the total surface area of the machined chips per unit volume. From the result of the tensile tests performed at 773 K, the elongation to failure of the specimen made of smaller machined chips was lower, than that of the specimens made of larger machined chips, in spite of their same strain rate sensitivity of 0.5. Similarly, in the blow-forming tests at 773 K, the specimen made of smaller machined chips exhibited a lower formability. The low elongation to failure and formability of the recycled specimens made of smaller machined chips are likely to be attributed to a greater contamination of oxide. Thus, oxide contamination has a detrimental effect on the superplastic properties of recycled Al alloy.
