Secondarily applied cold side features for cast heat exchanger

A heat exchanger comprising:

• a primary one-piece unitary cast plate including a first surface, a second surface, a leading edge, a trailing edge and a plurality of internal passages extending between an inlet and an outlet;
• and
• a secondary one-piece unitary cast plate that includes a flat joint side attached to at least one of the first surface and second surface of the primary plate, and a first side with heat transfer structures, wherein the heat transfer structures include a plurality of fin portions disposed between open channels, wherein the heat transfer structures of the secondary plate include augmentation structures;
• wherein the augmentation structures extend from the channel bottom up a side of at least one of the plurality of fin portions bordering the channel bottom.