Additive metal casting system and method

An additive metal casting method for producing a metallic object by generating a stack of production layers having mold regions and object regions, the mold regions constituting a mold-in-progress and the object regions constituting a cast-in-progress withheld in the mold-in-progress, the method comprising, for each production layer:

• iteratively constructing a mold region of a current production layer on top of said stack of production layers;
• and
• processing an object region of the current production layer, wherein processing the object region of the current production layer comprises
• melting a first volume of previously-solidified metal in the cast-in-progress and dropping a second volume of molten metal into the first volume, wherein said first volume and said second volume accumulate into a melt zone of at least a minimum volume of molten material required for cast-property modification processes;
• and
• providing an allocated amount of at least one cast-property modifying powder to the melt zone;
• and
• maintaining the melt zone under inert environment while in the melt state.