Yield strength of twin-belt cast Al-Mg-Sc-Zr alloy after annealing

AA5xxx aluminium alloys are used in the automotive and packaging industries owing to their high strength and ductility. The addition of Sc and Zr to these alloys has shown promise for improving high temperature stability and therefore broadening the range of applications. This high temperature stability is due to the formation of fine Al-3(Sc, Zr) precipitates during aging. In this work, two twin-belt cast Al-3% Mg alloys, one with 0.4% Sc and the other without Sc, were annealed at 300 and 400 degrees C. Hardness, tensile yield stress and electrical resistivity measurements were used to examine the evolution of microstructure and strength of the alloys. These results were then utilised to develop a yield stress-precipitation model to describe simultaneous precipitation hardening and recovery.