Crystallization and dissolution studies of iron intermetallics in aluminum-silicon alloys

The crystallization behaviour of iron intermetallics during solidification and the dissolution behaviour of iron intermetallics during heat treatment and their subsequent effect on mechanical properties have been studied.;Addition of iron decreases DAS and affects eutectic silicon particle size as nucleation and growth of silicon crystals takes place on the ;In the absence of manganese, the iron intermetallics crystallize in the ;When the melt is superheated to a high temperature (about 200 to 300 degrees above the liquidus temperature), the iron intermetallic crystallizes in the ;Investigation of the dissolution behaviour of the iron intermetallics on non-equilibrium heat treatment indicates that the ;The 0.15% Fe alloy exhibits the highest tensile strength and percent elongation compared to 1.0% Fe and 1.0% Fe + 0.5% Mn alloys under as-cast and equilibrium heat treated conditions. However, under non-equilibrium heat treatment conditions, ie., 30 degrees above the T4 equilibrium solution temperature, the strength properties of 1.0% Fe alloy exceed, or at least equal, that of the equilibrium heat treated 0.15% Fe alloy.;An attempt is made to correlate the iron intermetallics present in the microstructure and mechanical properties with the associated fracture mode in this alloy.