Structure and strength properties of the cold-deformed Al–Mg2Si-based alloys with additives of transition metals

Abstract

Using methods of hardness measurements, determination of the tensile strength properties, and microstructure observation, the effect of annealing at various temperatures on structure and change in the strength properties of the cold-deformed Al–Mg₂Si alloys alloyed with joint additives of scandium and zirconium is studied. It is shown that the hardness decreases with increasing annealing temperature to minimal values in the interval of 300–500°C and then increases up to 600°C. Such a change in hardness is explained by the recovery process (hardness decrease) and enrichment of the aluminum solid solution in magnesium and silicon followed by its natural aging (hardness increase). Addition of scandium and zirconium to the colddeformed Al–Mg₂Si alloys promotes an increase in their strength properties both after aging of these alloys at 170°C for 16 h and after softening annealing at 400°C for 1 h.