Homogenization conditions and mechanical properties of ingots of calcium-doped AV alloy

Abstract

The influence of calcium microalloying on the homogenization temperature of ingots of AV grade alloys of the Al–Mg–Si–Cu system is studied. It is shown that, to provide the maximum dissolution of excess phases, the homogenization temperature of ingots should be chosen in a range of 560–575°C. The microstructure of ingots of the calcium-doped AV alloy has two types of phase components over boundaries of dendrite cells: light skeleton-like and dark compact round shapes. The calcium microalloying additive results in the formation of dispersed particles of excess intermetallide phases in the AV alloy with variable composition of Al_xSi_yCa and Al_xSi_yMg_zCa, which promote nucleation of new grains. It is likely that calcium as the surfaceactive element changes the contribution of grain-boundary energy. This is the constraint for collective recrystallization.