Infiltration methods for forming drill bits

1. An infiltration method of forming an article comprising:

providing a working mold including a solid binder member extending through an interior of the working mold wall, wherein the solid binder member comprises a binder material;

providing a layer of powder matrix material within a molding void of the working mold; and

heating the working mold to form a molten binder pathway from the solid binder member to infiltrate the layer of powder matrix material.

2. The method of claim 1 , further comprising forming the solid binder member.

3. The method of claim 2 , wherein forming the solid binder member comprises casting the solid binder member.

4. The method of claim 1 , further comprising forming a master mold.

5. The method of claim 4 , further comprising placing the solid binder member at a surface of the master mold.

6. The method of claim 5 , wherein placing the solid binder member comprises affixing the solid binder member to a surface of the master mold.

7. The method of claim 5 , further comprising forming the working mold from the master mold.

8. The method of claim 7 , wherein forming the working mold comprises casting a working mold around the master mold and solid binder member to form a working mold having the solid binder member contained within the interior of the working mold.

9. The method of claim 1 , wherein the solid binder member extends from the interior of the working mold and through a thickness of the layer of powder matrix material.

10. The method of claim 1 , wherein the binder material comprises a copper-based alloy.

11. The method of claim 1 , further comprising providing a layer of powder binder material over the powder matrix material.

12. The method of claim 1 , wherein the powder matrix material comprises a metal or metal alloy.

13. The method of claim 12 , wherein the powder matrix material comprises a metal selected from the group of metals consisting of iron, tungsten, nickel, and a combination thereof.

14. The method of claim 1 , wherein the powder matrix material comprises a steel-based alloy.

15. An infiltration method of forming an article comprising:

providing a working mold comprising a wall defining a molding void for formation of an article therein, wherein the molding void comprises a molding void height (h mv ) between a bottom surface and a top surface, the working mold further comprising a cavity within an interior portion of the wall in fluid communication with a bottom half of the working void;

positioning a solid binder member within the cavity;

providing a layer of powder matrix material within the molding void; and

heating the working mold to melt the solid binder member and infiltrating a bottom region of the layer of powder matrix material with molten binder material flowing from the cavity into the molding void.

16. The method of claim 15 , wherein the cavity is in fluid communication with a bottom third of the working void.

17. The method of claim 15 , wherein the molten binder material is generated from a secondary solid binder material contained within the cavity.

18. The method of claim 17 , wherein the secondary solid binder material comprises a solid, polycrystalline binder member.

19. The method of claim 15 , wherein infiltrating is completed via a gravity-fed infiltration process.

20. An infiltration method of forming an article comprising:

providing a layer of powder matrix material within a molding void of a working mold, wherein the molding void is defined by a working mold wall; and

heating the working mold and forming a molten binder pathway from a solid binder member extending through an interior of the working mold wall of the working mold, the molten binder pathway flowing into the molding void to infiltrate the powder matrix material, wherein the molten binder pathway within the working mold wall has an average diameter significantly greater than an average interparticle porosity of the powder matrix material.