Polycrystalline diamond compacts including a polycrystalline diamond table having a modified region exhibiting porosity

A polycrystalline diamond compact, comprising

• a substrate;
• and
• an unleached polycrystalline diamond table attached to the substrate, the unleached polycrystalline diamond table including an upper surface, at least one lateral surface, and an interfacial surface bonded to the substrate, the unleached polycrystalline diamond table including a plurality of bonded diamond grains defining a plurality of interstitial regions and a catalyst in an unleached condition that was present during formation of diamond-to-diamond bonding between at least some of the plurality of bonded diamond grains and occupies at least some of the plurality of interstitial regions, the unleached polycrystalline diamond table further including:
• a modified first region extending from at least a portion of the upper surface, the modified first region exhibiting a porosity of at least about 2% by volume in an unleached condition, wherein the modified first region is substantially free of the catalyst;
• and
• a second region extending from the interfacial surface, the second region exhibiting a porosity that is less than the modified first region.

A rotary drill bit, comprising

• a bit body configured to engage a subterranean formation;
• and
• a plurality of polycrystalline diamond compacts mounted to the bit body, at least one of the plurality of polycrystalline diamond compacts including:
• a substrate;
• and
• an unleached polycrystalline diamond table attached to the substrate, the unleached polycrystalline diamond table including an upper surface, at least one lateral surface, and an interfacial surface bonded to the substrate, the unleached polycrystalline diamond table including a plurality of bonded diamond grains defining a plurality of interstitial regions and a catalyst in an unleached condition that was present during formation of diamond-to-diamond bonding between at least some of the plurality of bonded diamond grains and occupies at least some of the plurality of interstitial regions, the unleached polycrystalline diamond table further including:
• a modified first region extending from at least a portion of the upper surface, the modified first region exhibiting a porosity of about 1% to about 15% by volume in an unleached condition, wherein the modified first region is substantially free of the catalyst;
• and
• a second region extending from the interfacial surface, the second region exhibiting a porosity that is less than the modified first region.