Polycrystalline diamond compact including at least one mechanically-stressed polycrystalline diamond table and methods of making the same

Abstract

Embodiments disclosed herein relate to polycrystalline diamond compacts (“PDCs”) including at least one mechanically-stressed polycrystalline diamond (“PCD”) table having an upper surface that exhibits a compressive stress state. Providing a selected support structure to the mechanically-stressed PCD table and/or generating a favorable stress state in the upper surface of the mechanically-stressed PCD table may improve a toughness and/or a strength of the mechanically-stressed PCD table and the PDC. In an embodiment, a PDC includes a substrate including an interfacial surface and a preformed PCD table attached to the substrate. The preformed PCD table includes an upper surface spaced from a bottom surface that faces the interfacial surface of the substrate. In such an embodiment, the upper surface of the preformed PCD table exhibits a mechanical deflection and a concave curvature induced by deflecting the preformed PCD table toward the substrate. Methods of forming such PDCs including at least one mechanically-stressed PCD table are also disclosed.

1 . A polycrystalline diamond compact, comprising:
 a substrate including an interfacial surface; and   a mechanically-stressed polycrystalline diamond table coupled to the substrate, the mechanically-stressed polycrystalline diamond table including an upper surface spaced from a bottom surface that faces the interfacial surface of the substrate, the upper surface of the mechanically-stressed polycrystalline diamond table exhibiting a mechanical deflection and a concave curvature induced by forced contact between the bottom surface of the mechanically-stressed polycrystalline diamond table and the interfacial surface of the substrate, the forced contact comprising applying a forcing element to the upper surface under sufficient temperature and pressure to bend the polycrystalline diamond table into contact with the interfacial surface of the substrate;   wherein, prior to the forced contact, the mechanically-stressed polycrystalline diamond table is not coupled to the substrate.   
     
     
         2 . The polycrystalline diamond compact of  claim 1 , wherein, prior to the forced contact, the bottom surface of the mechanically-stressed polycrystalline diamond table and a portion of the substrate at least partially define a region into which the bottom surface of the mechanically-stressed polycrystalline diamond table is deflected. 
     
     
         3 . The polycrystalline diamond compact of  claim 1 , wherein the bottom surface of the mechanically-stressed polycrystalline diamond table contacts the interfacial surface of the substrate such that the bottom surface of the mechanically-stressed polycrystalline diamond table contacts substantially the entire interfacial surface of the substrate. 
     
     
         4 . The polycrystalline diamond compact of  claim 1 , wherein the interfacial surface of the substrate exhibits a concave curvature. 
     
     
         5 . The polycrystalline diamond compact of  claim 1 , wherein the forcing element comprises a mechanical fastener that couples the mechanically-stressed polycrystalline diamond table to the substrate. 
     
     
         6 . The polycrystalline diamond compact of  claim 5 , further comprising a washer positioned between a top portion of the mechanical fastener and the upper surface of the mechanically-stressed polycrystalline diamond table. 
     
     
         7 . The polycrystalline diamond compact of  claim 5 , wherein each of the mechanically-stressed polycrystalline diamond table and the substrate includes an aperture extending therethrough that receives the mechanical fastener. 
     
     
         8 . The polycrystalline diamond compact of  claim 1 , further comprising a washer including an upper washer surface that contacts the bottom surface of the mechanically-stressed polycrystalline diamond table and a bottom washer surface that contacts at least one of the interfacial surface of the substrate or an upper surface of a second polycrystalline diamond table. 
     
     
         9 . The polycrystalline diamond compact of  claim 1 , wherein each of the bottom surface of the mechanically-stressed polycrystalline diamond table and the interfacial surface of the substrate has a pattern thereon. 
     
     
         10 . The polycrystalline diamond compact of  claim 1 , wherein the mechanically-stressed polycrystalline diamond table includes a leached region extending inwardly from the upper surface thereof from which at least a portion of a catalyst is removed. 
     
     
         11 . The polycrystalline diamond compact of  claim 1 , wherein the substrate includes an outer region exhibiting a first modulus of elasticity and an inner region exhibiting a second modulus of elasticity less than the first modulus of elasticity. 
     
     
         12 . The polycrystalline diamond compact of  claim 1 , further comprising at least one second polycrystalline diamond table, wherein the mechanically-stressed polycrystalline diamond table and the at least one second polycrystalline diamond table form a plurality of stacked polycrystalline diamond tables that are coupled to the substrate. 
     
     
         13 . The polycrystalline diamond compact of  claim 12 , wherein the plurality of stacked polycrystalline diamond tables are bonded together. 
     
     
         14 . The polycrystalline diamond compact of  claim 1 , wherein the mechanically-stressed polycrystalline diamond table is brazed to the substrate. 
     
     
         15 . The polycrystalline diamond compact of  claim 1 , wherein the mechanically-stressed polycrystalline diamond table exhibits a thickness of from 0.120 inches to 0.400 inches. 
     
     
         16 . The polycrystalline diamond compact of  claim 1 , wherein the mechanically-stressed polycrystalline diamond table includes a first region that extends inwardly from every surface of the polycrystalline diamond table, and a second region that is remote from every surface of the polycrystalline diamond table, wherein the first region has been leached to remove at least some of a catalyst therein and the second region is substantially unleached. 
     
     
         17 . A method of forming a polycrystalline diamond compact, the method comprising:
 providing an at least partially leached polycrystalline diamond table including an upper surface and a bottom surface; and   deflecting the at least partially leached polycrystalline diamond table to form a mechanically-stressed polycrystalline diamond table, the upper surface of the mechanically-stressed polycrystalline diamond table exhibiting a mechanical deflection and a concave curvature induced by forcing contact between the bottom surface of the at least partially leached polycrystalline diamond table and an interfacial surface of a substrate, the forcing contact comprising applying a forcing element to the upper surface under sufficient temperature and pressure to bend the polycrystalline diamond table into contact with the interfacial surface fo the substrate;   wherein, prior to forcing contact, the at least partially leached polycrystalline diamond table is not coupled to the substrate.   
     
     
         18 . The method of  claim 17 , further comprising subjecting the at least partially leached polycrystalline diamond table positioned adjacent to the substrate to a high-pressure/high-temperature process effective to infiltrate the at least partially leached polycrystalline diamond table with an infiltrant from the substrate and bond the mechanically-stressed polycrystalline diamond table to the substrate. 
     
     
         19 . The method of  claim 17 , wherein deflecting the at least partially leached polycrystalline diamond table to form the mechanically-stressed polycrystalline diamond table includes deflecting the at least partially leached polycrystalline diamond table toward the substrate during a high-pressure/high-temperature process. 
     
     
         20 . The method of  claim 17 , wherein forcing element comprises a mechanical fastener. 
     
     
         21 . The method of  claim 17 , further comprising brazing the at least partially leached polycrystalline diamond table to the substrate. 
     
     
         22 . The method of  claim 17 , further comprising brazing the at least partially leached polycrystalline diamond table to a second polycrystalline diamond table. 
     
     
         23 . A rotary drill bit, comprising:
 a bit body configured to engage a subterranean formation; and   a plurality of polycrystalline diamond cutting elements attached to the bit body, at least one of the plurality of polycrystalline diamond cutting elements including:
 a substrate including an interfacial surface; and 
 a mechanically-stressed polycrystalline diamond table coupled to the substrate, the mechanically-stressed polycrystalline diamond table including an upper surface spaced from a bottom surface that faces the interfacial surface of the substrate, the upper surface of the mechanically-stressed polycrystalline diamond table exhibiting mechanical deflection induced by forced contact between the bottom surface of the mechanically-stressed polycrystalline diamond table and the interfacial surface of the substrate, the forced contact comprising applying a forcing element to the upper surface under sufficient temperature and pressure to bend the polycrystalline diamond table into contact with the interfacial surface of the substrate; 
   wherein, prior to the forced contact, the mechanically-stressed polycrystalline diamond table is not coupled to the substrate.   
     
     
         24 . The rotary drill bit of  claim 23 , further comprising at least one fastener that couples the at least one of the plurality of polycrystalline diamond cutting elements to the bit body and the mechanically-stressed polycrystalline diamond table to the substrate. 
     
     
         25 . The rotary drill bit of  claim 23 , wherein the at least one of the plurality of polycrystalline diamond cutting elements is brazed to the bit body.