An Investigation of Sc Addition on the Extrudability, Recrystallisation Resistance and Mechanical Properties of a 6082- and a 7108-Alloy

摘要

In the present work the effect of scandium as a dispersoid former in a 6082 and a 7108 alloy is explored, both by adding Sc alone and in combination with other dispersoid forming elements (Zr, Mn,Cr). In extrusion the breakthrough pressure is in general highest when Sc is added in combination with other dispersoid forming elements. The maximum extrusion speed before tearing decreases somewhat when Sc is added to the 6082 alloys, while taking Mn out of 6082 gives a dramatic decrease in maximum speed due to a change in the melting reaction that takes place. In 7108 with Zr the maximum speed was slightly reduced with increasing Sc content. As for the recrystallisation resistance, it is clear that Sc does not have a strong effect in 6082 under the present conditions. For the 7108 alloy, adding both Sc and Zr lead to a much higher recrystallisation resistance than by adding only Sc or only Zr. Additions of Sc had some influence on the mechanical properties which for the 6082 alloys can be related to differences in the degree of recrystallisation.