Gas turbine engine fan blade, design, and fabrication

A fan blade comprising:

• a metallic pressure sidewall and a metallic suction sidewall, each sidewall extending in span from a base to a tip, and extending in chord from a leading edge to a trailing edge;
• an interior region defined by a total volume between the pressure and suction sidewalls, the interior region of the fan blade comprising:
• a first fully dense metallic portion having a volume occupying at least 10% of the total volume of the interior region, spaced from the pressure and suction sidewalls, the fully dense metallic portion having substantially no porosity;
• and
• a first porous metallic portion integrally joined to the fully dense metallic portion, the first porous metallic portion selected from a structured lattice, an unstructured foam, and combinations thereof;
• wherein the structured lattice includes a first plurality of lattice unit cells defined by a first plurality of ligaments connected at a first plurality of nodes;
• wherein the first plurality of ligaments includes first ligaments have a first diameter and second ligaments have a second diameter different from the first diameter.