Gas turbine engine fan blade, design, and fabrication

1. 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.

2. The fan blade of claim 1 , wherein the first porous metallic portion has continuously variable density in at least one of a spanwise, chordwise, or thickness direction.

3. The fan blade of claim 1 , wherein the first plurality of nodes are distributed in all of the spanwise, chordwise, and thickness directions of the fan blade.

4. The fan blade of claim 1 , wherein the first plurality of nodes define a first plurality of open unit cells) each node having lattice material occupying a first volume and each unit cell having porosity occupying a first unit cell volume.

5. The fan blade of claim 1 , wherein a ligament diameter varies along a length of a primary blade axis A or a primary build axis B.

6. The fan blade of claim 1 , wherein a ligament diameter varies in a plane normal to a primary blade axis A or a primary build axis B.

7. The fan blade of claim 1 , wherein a pair of the first plurality of ligaments converge at a node at an angle of no more than 90°.

8. The fan blade of claim 1 , further comprising:

a skin metallurgically deposited onto at least the first porous portion without adhesive, the skin forming at least a portion of the suction sidewall, the pressure sidewall, or a combination thereof.

9. The fan blade of claim 1 , wherein the structured lattice includes of at least one individual ligament having a diameter varying along its length.

10. The fan blade of claim 1 , wherein the structured lattice comprises a fully three-dimensional (3D) lattice, a quasi-3D lattice based on a two-dimensional (2D) cross-section, or a combination thereof.

11. A method comprising:

forming a metallic pressure sidewall or a metallic suction sidewall, the sidewall extending in span from a base to a tip, and extending in chord from a leading edge to a trailing edge, together defining a total volume of an interior airfoil region;

depositing a first fully dense metallic portion having substantially no porosity;

depositing and integrally joined a first porous metallic portion to the fully dense metallic portion, the first porous metallic portion selected from a structured lattice, an unstructured foam, and combinations thereof; and

metallurgically securing the integrally joined first fully dense metallic portion and the first porous metallic portion to at least one part of the interior airfoil region;

wherein depositing the structured lattice includes forming 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.

12. The method of claim 11 , wherein the fully dense metallic portion has a volume occupying at least 10% of the total volume of the interior region.

13. The method of claim 11 , wherein the first porous metallic portion is formed to have continuously variable porosity in at least one of a spanwise, chordwise, or thickness direction of the interior airfoil region.

14. The method of claim 11 , wherein forming the first plurality of lattice unit cells includes distributing the first plurality of lattice unit cells in all of the spanwise, chordwise, and thickness directions of the airfoil.

15. The method of claim 11 , wherein depositing the structured lattice includes varying a volume of the first plurality of nodes to include nodes having at least a first volume and nodes having a second volume different from the first volume.

16. The method of claim 11 , wherein depositing the structured lattice includes varying diameter of adjacent ligaments along at least one of a primary build axis and a plane normal to a primary build axis.

17. The method of claim 11 , wherein depositing the structured lattice includes varying a diameter of at least one individual ligament along its length.

18. The method of claim 11 , further comprising metallurgically depositing a skin onto at least the first porous portion without adhesive, the skin forming at least a portion of the suction sidewall, the pressure sidewall, or a combination thereof.

19. The method of claim 11 , wherein depositing the first fully dense metallic portion and the integrally joined first porous metallic portion is performed by one or more of: a laser powder bed fusion process, a directed energy powder deposition process, a wire-based electron beam additive manufacturing process, a wire arc additive manufacturing process, an ultrasonic additive manufacturing process, and an investment casting process.

20. The method of claim 18 , wherein a cellular structure of the first porous metallic portion is produced by one or more of: a laser powder bed fusion process, a directed energy powder deposition process, a wire arc additive manufacturing process, an ultrasonic additive manufacturing process, and a wire-based electron beam additive manufacturing process; and wherein the structured lattice is aligned with a build direction of the airfoil.

21. The method of claim 20 , wherein a cellular structure of the first porous metallic portion includes ligaments of at least 4 mm and lattice unit cells with up to 45° orientation of all ligaments to the build direction such that a pair of the first plurality of ligaments converge at a node at an angle of no more than 90°.