Effect of heating conditions on structural changes in ingots of alloy AMg5

Conclusions

• 1. Schedules for preparing ingots of alloy AMg5 affect the distribution of alloying elements in α-solid solution based on aluminum and insoluble phases; with an increase in melt temperature the content of magnesium in solid solution probably becomes greater than in excess phases; after casting at increased rates the basic amount of magnesium remains in excess phases.

• 2. During annealing of alloy AMg5 castings there is decomposition of solid solution whose character is affected by the original cast structure; a more supersaturated solid solution decomposes more intensely. An increase in annealing duration from 3 to 10 h provides more uniform distribution of alloying elements in the alloy.

• 3. The nature of solid solution decomposition during annealing has a marked effect on the corrosion resistance of alloy AMg5 ingots; a reduction in the degree of the dispersion of precipitating particles and the uniformity of their distribution leads to a reduction in resistance of this alloy to corrosion.

• 4. The corrosion resistance of alloy AMg5 is also reduced with an increase in cooling rate after annealing at 320°C.