Effect of the Annealing Temperature on the Aging-Induced Recovery in Magnesium Alloys with Rare-Earth Metals

The possibility of recovery in binary magnesium alloys with the yttrium group rare-earth metals (Y, Gd, Tb, Dy, Ho), in which the decomposition of a supersaturated magnesium solid solution at 200°C is accompanied by substantial hardening, is studied at an annealing temperature of 300°C. Annealing at 300°C of the alloys aged at 200°C to the state with the highest hardness results in significant recovery, which is much higher than the established recovery of these alloys at an annealing temperature of 250°C. The recovery regularly changes as a function of the atomic number of a rare-earth metal. Structural analysis of the alloys suggests that the phases formed in them during hardening aging are partly retained during the subsequent recovery, and no new phases form.