Abstract: Methods for in-situ solution heat treating an additively manufactured metallic component in order to increase the mechanical properties thereof and systems to perform the same. The method can include depositing filler material on a substrate forming a deposition layer, measuring the temperature of a heat affected zone corresponding to the deposition layer, and solution heat treating the deposition layer subsequent to the depositing and proximate to the deposition head. The solution heat treating can include heating the deposition layer to a solution temperature so as to achieve solution heat treatment and controlling the cooling rate of the deposition layer to at or above the critical cooling rate of the filler material until a target temperature is reached. Optionally, the method can include inducing an electron flow in the deposition layer to electromagnetically stir molten filler material in the heat affected zone.