Polycrystalline diamond compacts, and related methods and applications

1. A method of fabricating a polycrystalline diamond compact, comprising:

positioning an at least partially leached polycrystalline diamond table adjacent to a substrate to form an assembly, wherein the at least partially leached polycrystalline diamond table includes a proximal region adjacent to the substrate and a distal region spaced from the substrate; and

subjecting the assembly to a high-pressure/high-temperature process to infiltrate the proximal region of the at least partially leached polycrystalline diamond table with an infiltrant from the substrate to no further than an intermediate location within the at least partially leached polycrystalline diamond table, while the distal region of the at least partially leached polycrystalline diamond table is not infiltrated with any infiltrant during the high-pressure/high-temperature process.

2. The method of claim 1 wherein subjecting the assembly to a high-pressure/high-temperature process to infiltrate the proximal region of the at least partially leached polycrystalline diamond table with an infiltrant from the substrate to no further than an intermediate location within the at least partially leached polycrystalline diamond table comprises selecting pressure and temperature conditions of the high-pressure/high-temperature process to be sufficiently low so that the infiltrant does not completely infiltrate the at least partially leached polycrystalline diamond table.

3. A method of fabricating a polycrystalline diamond compact, comprising:

forming an at least partially leached polycrystalline diamond table including a first surface and an opposing second surface, the at least partially leached polycrystalline diamond table including bonded diamond grains defining interstitial regions, the at least partially leached polycrystalline diamond table including a first region extending from the first surface to an intermediate location therein having tungsten, tungsten carbide, or combinations thereof disposed in at least some of the interstitial regions thereof and a second region extending inwardly from the second surface that is substantially free of tungsten;

positioning the second region at least proximate to a substrate to form an assembly; and

subjecting the assembly to a high-pressure/high-temperature process to form the polycrystalline diamond compact.

4. The method of claim 3 wherein forming an least partially leached polycrystalline diamond table comprises:

sintering diamond particles positioned adjacent to a cemented tungsten carbide substrate to form a polycrystalline diamond table bonded to the cemented tungsten carbide substrate, the polycrystalline diamond table including bonded diamond grains having metal-solvent catalyst disposed interstitially therebetween, the polycrystalline diamond table further including a portion adjacent to the cemented tungsten carbide substrate having the tungsten, the tungsten carbide, or the combinations thereof; and

separating the polycrystalline diamond table from the cemented tungsten carbide substrate; and

leaching at least a portion of the metal-solvent catalyst from the separated polycrystalline diamond table.

5. The method of claim 3 wherein the first region of the at least partially leached polycrystalline diamond table exhibits a thickness substantially less than that of the second region.

6. The method of claim 3 wherein:

the assembly comprises a silicon-cobalt containing layer between the at least partially leached polycrystalline diamond table and the substrate; and

subjecting the assembly to a high-pressure/high-temperature process to form the polycrystalline diamond compact comprises infiltrating the at least partially leached polycrystalline diamond table with a liquid comprising silicon and cobalt so that at least a portion of the interstitial regions include at least one material formed therein selected from the group consisting of silicon carbide, cobalt carbide, and a mixed carbide of silicon and cobalt.

7. The method of claim 3 wherein subjecting the assembly to a high-pressure/high-temperature process to form the polycrystalline diamond compact comprises infiltrating the at least partially leached polycrystalline diamond table with an infiltrant from the substrate to no further than an intermediate location within the at least partially leached polycrystalline diamond table.

8. The method of claim 3 wherein the tungsten is in the form of substantially pure tungsten, an alloy including the tungsten, or combinations thereof.

9. The method of claim 1 wherein the intermediate location is at a depth, from an upper working surface of the at least partially leached polycrystalline diamond table, of at least about 50 μm.

10. The method of claim 1 wherein the intermediate location is at a depth, from an upper working surface of the at least partially leached polycrystalline diamond table, of about 50 μm to about 2000 μm.

11. The method of claim 1 , further comprising not leaching the partially infiltrated polycrystalline diamond table.

12. The method of claim 1 wherein the substrate comprises a cemented carbide substrate including the infiltrant therein.

13. The method of claim 1 wherein the infiltrant comprises a metallic infiltrant.

14. The method of claim 4 wherein separating the polycrystalline diamond table from the cemented tungsten carbide substrate comprises grinding the cemented carbide substrate.

15. The method of claim 3 wherein:

the assembly comprises a metallic-infiltrant-containing layer disposed between the at least partially leached polycrystalline diamond table and the substrate; and

subjecting the assembly to a high-pressure/high-temperature process to form the polycrystalline diamond compact comprises infiltrating the at least partially leached polycrystalline diamond table metallic infiltrant from the metallic-infiltrant-containing layer.