Polycrystalline diamond compacts

1. A polycrystalline diamond compact, comprising:

a substrate; and

a polycrystalline diamond table bonded to the substrate and including an upper exterior working surface, at least one lateral surface, and a chamfer extending between the upper exterior working surface and the at least one lateral surface, the polycrystalline diamond table including a plurality of bonded diamond grains defining a plurality of interstitial regions, the plurality of bonded diamond grains exhibiting an average grain size of about 40 μm or less, the polycrystalline diamond table further including:

a first region adjacent to the substrate, at least a portion of the interstitial regions of the first region including cobalt disposed therein; and

a second leached region adjacent to the first region and extending inwardly from the upper exterior working surface to a selected depth of at least about 700 μm, the interstitial regions of the second leached region being substantially free of metal-solvent catalyst, the second leached region being partially defined by a boundary that terminates at the at least one lateral surface at a location that is spaced from the chamfer, wherein the boundary partially defining the second leached region is generally horizontal and terminates at the at least one lateral surface;

wherein a cross-section of the second leached region exhibits:

a first depth measured from and substantially perpendicularly to the upper exterior working surface at an intersection of the chamfer and the upper exterior working surface; and

a second depth measured from and substantially perpendicularly to the upper exterior working surface at a generally central location on the upper exterior working surface;

wherein the first depth and the second depth are substantially equal.

2. The polycrystalline diamond compact of claim 1 wherein the average grain size of the polycrystalline diamond table is about 30 μm or less.

3. The polycrystalline diamond compact of claim 1 wherein the interstitial regions the second region are substantially void of material.

4. The polycrystalline diamond compact of claim 1 wherein the selected depth is about 750 μm to about 2100 μm.

5. The polycrystalline diamond compact of claim 1 wherein the selected depth is about 1000 μm to about 2000 μm.

6. The polycrystalline diamond compact of claim 1 wherein the average grain size of the polycrystalline diamond table is about 30 μm or less, a thickness of the polycrystalline diamond table is about 0.065 inch to about 0.080 inch, the second leached region of the polycrystalline diamond table is essentially free of silicon, nickel, or combinations thereof.

7. A rotary drill bit, comprising:

a bit body configured to engage a subterranean formation; and

a plurality of polycrystalline diamond cutting elements affixed to the bit body, at least one of the polycrystalline diamond cutting elements including:

a substrate; and

a polycrystalline diamond table bonded to the substrate and including an upper exterior working surface, at least one lateral surface, and a chamfer extending between the upper exterior working surface and the at least one lateral surface, the polycrystalline diamond table including a plurality of bonded diamond grains defining a plurality of interstitial regions, the plurality of bonded diamond grains exhibiting an average grain size of about 40 μm or less, the polycrystalline diamond table further including:

a first region adjacent to the substrate, at least a portion of the interstitial regions of the first region including cobalt disposed therein; and

a second leached region adjacent to the first region and extending inwardly from the upper exterior working surface to a selected depth of at least about 700 μm, the interstitial regions of the second leached region being substantially free of metal-solvent catalyst, the second leached region being partially defined by a boundary that terminates at the at least one lateral surface at a location that is spaced from the chamfer;

wherein a cross-section of the second leached region exhibits:

a first depth measured from and substantially perpendicularly to the upper exterior working surface at an intersection of the chamfer and the upper exterior working surface; and

a second depth measured from and substantially perpendicularly to the upper exterior working surface at a generally central location on the upper exterior working surface;

wherein the first depth and the second depth are substantially equal.

8. A rotary drill bit, comprising:

a bit body configured to engage a subterranean formation; and

a plurality of polycrystalline diamond cutting elements affixed to the bit body, at least one of the polycrystalline diamond cutting elements including:

a substrate; and

a polycrystalline diamond table bonded to the substrate and including an upper exterior working surface, at least one lateral surface, and a chamfer extending between the upper exterior working surface and the at least one lateral surface, the polycrystalline diamond table including a plurality of bonded diamond grains defining a plurality of interstitial regions, the polycrystalline diamond table further including:

a first region adjacent to the substrate, at least a portion of the interstitial regions of the first region including an infiltrant disposed therein; and

a second leached region adjacent to the first region and extending inwardly from the upper exterior working surface to a selected depth, the interstitial regions of the second leached region being substantially free of metal-solvent catalyst, the second region being defined by the upper exterior working surface, the at least one lateral surface, the chamfer, and a generally horizontal boundary that terminates at the at least one lateral surface at a location that is spaced from the chamfer;

wherein a cross-section of the second leached region exhibits:

a first depth measured from and substantially perpendicularly to the upper exterior working surface at an intersection of the chamfer and the upper exterior working surface; and

a second depth measured from and substantially perpendicularly to the upper exterior working surface at a generally central location on the upper exterior working surface;

wherein the first depth and the second depth are substantially equal.

9. The polycrystalline diamond compact of claim 1 wherein the boundary partially defining the second leached region is an irregular boundary.

10. A polycrystalline diamond compact, comprising:

a substrate; and

a polycrystalline diamond table bonded to the substrate and including an upper exterior working surface, at least one lateral surface, and a chamfer extending between the upper exterior working surface and the at least one lateral surface, the polycrystalline diamond table including a plurality of bonded diamond grains defining a plurality of interstitial regions, the plurality of bonded diamond grains exhibiting an average grain size of about 40 μm or less, the polycrystalline diamond table further including:

a first region adjacent to the substrate, at least a portion of the interstitial regions of the first region including cobalt disposed therein; and

a second leached region adjacent to the first region and extending inwardly from the upper exterior working surface to a selected depth of at least about 700 μm, the interstitial regions of the second leached region being substantially free of metal-solvent catalyst, the second leached region being partially defined by a boundary that terminates at the at least one lateral surface at a location that is spaced from the chamfer;

wherein a cross-section of the second leached region exhibits:

a first depth measured from and substantially perpendicularly to the upper exterior working surface at an intersection of the chamfer and the upper exterior working surface; and

a second depth measured from and substantially perpendicularly to the upper exterior working surface at a generally central location on the upper exterior working surface;

wherein the first depth and the second depth are substantially equal.

11. A polycrystalline diamond compact formed by a process comprising:

forming a polycrystalline diamond table in the presence of a metal-solvent catalyst including one of cobalt, iron, nickel, or alloys thereof in a first high-pressure/high-temperature process, the polycrystalline diamond table including a plurality of bonded diamond grains defining a plurality of interstitial regions, at least a portion of the plurality of interstitial regions including the metal-solvent catalyst disposed therein, the plurality of bonded diamond grains exhibiting an average grain size of about 40 μm or less;

at least partially leaching the polycrystalline diamond table to remove at least a portion of the metal-solvent catalyst therefrom;

subjecting the at least partially leached polycrystalline diamond table and a substrate to a second high-pressure/high-temperature process under diamond-stable temperature-pressure conditions to partially infiltrate the at least partially leached polycrystalline table with an infiltrant including one of iron, nickel, cobalt, or alloys of the foregoing metals and attach the partially infiltrated polycrystalline diamond table to the substrate;

wherein subjecting the at least partially leached polycrystalline diamond table and a substrate to a second high-pressure/high-temperature process forms a first region adjacent to the substrate including the infiltrant disposed in at least a portion of the interstitial regions thereof and a second region extending inwardly from an exterior working surface, the second region being substantially free of the infiltrant without having been leached of the infiltrant, the second leached region being partially defined by a boundary proximate to the chamfer, wherein the boundary partially defining the second leached region is generally horizontal and terminates at the at least one lateral surface;

wherein a cross-section of the second leached region exhibits:

a first depth measured from and substantially perpendicularly to the upper exterior working surface at an intersection of the chamfer and the upper exterior working surface;

and

a second depth measured from and substantially perpendicularly to the upper exterior working surface at a generally central location on the upper exterior working surface;

wherein the first depth and the second depth are substantially equal.