A polycrystalline diamond compact includes a polycrystalline diamond material having a plurality of grains of diamond bonded to one another by inter-granular bonds and an intermetallic gamma prime () or -carbide phase disposed within interstitial spaces between the inter-bonded diamond grains. The ordered intermetallic gamma prime () or -carbide phase includes a Group VIII metal, aluminum, and a stabilizer. An earth-boring tool includes a bit body and a polycrystalline diamond compact secured to the bit body. A method of forming polycrystalline diamond includes subjecting diamond particles in the presence of a metal material comprising a Group VIII metal and aluminum to a pressure of at least 4.5 GPa and a temperature of at least 1,000 C. to form inter-granular bonds between adjacent diamond particles, cooling the diamond particles and the metal material to a temperature below 500 C., and forming an intermetallic gamma prime () or -carbide phase adjacent the diamond particles.

A polycrystalline diamond compact includes a polycrystalline diamond material having a plurality of grains of diamond bonded to one another by inter-granular bonds and an intermetallic gamma prime () or -carbide phase disposed within interstitial spaces between the inter-bonded diamond grains. The ordered intermetallic gamma prime () or -carbide phase includes a Group VIII metal, aluminum, and a stabilizer. An earth-boring tool includes a bit body and a polycrystalline diamond compact secured to the bit body. A method of forming polycrystalline diamond includes subjecting diamond particles in the presence of a metal material comprising a Group VIII metal and aluminum to a pressure of at least 4.5 GPa and a temperature of at least 1,000 C. to form inter-granular bonds between adjacent diamond particles, cooling the diamond particles and the metal material to a temperature below 500 C., and forming an intermetallic gamma prime () or -carbide phase adjacent the diamond particles.

Drill bit insert with a sintered cemented carbide body including a hard phase of tungsten carbide (WC) and a binder phase wherein the cemented carbide comprises 5.0-7.0 wt % Co, 0.10-0.35 wt % Cr, and a Cr/Co weight ratio of 0.015-0.058. The cemented carbide body has a hardness of 1520-1660 Hv30 and a toughness of K1.sub.c10.0 both measured in the bulk at the center of the longitudinal axis through the center of the insert, or 5 mm from any surface of the insert. The insert further has a surface toughness K1.sub.c12.0 measured at 0.5 mm below the surface of the body in a transverse direction to the longitudinal axis the insert. The invention also relates to a drill bit comprising the insert and the use of such a drill bit for drilling.

Drill bit insert with a sintered cemented carbide body including a hard phase of tungsten carbide (WC) and a binder phase wherein the cemented carbide comprises 5.0-7.0 wt % Co, 0.10-0.35 wt % Cr, and a Cr/Co weight ratio of 0.015-0.058. The cemented carbide body has a hardness of 1520-1660 Hv30 and a toughness of K1.sub.c10.0 both measured in the bulk at the center of the longitudinal axis through the center of the insert, or 5 mm from any surface of the insert. The insert further has a surface toughness K1.sub.c12.0 measured at 0.5 mm below the surface of the body in a transverse direction to the longitudinal axis the insert. The invention also relates to a drill bit comprising the insert and the use of such a drill bit for drilling.

A drill bit for drilling a borehole in earth formations may include a bit body having a bit axis and a bit face; a plurality of blades extending radially along the bit face; and a plurality of cutting elements disposed on the plurality of blades, the plurality of cutting elements comprising: at least one cutter comprising a substrate and a diamond table having a substantially planar cutting face; and at least two non-planar cutting elements comprising a substrate and a diamond layer having a non-planar cutting end, wherein in a rotated view of the plurality of cutting elements into a single plane, the at least one cutter is located a radial position from the bit axis that is intermediate the radial positions of the at least two non-planar cutting elements.

A drill bit for drilling a borehole in earth formations may include a bit body having a bit axis and a bit face; a plurality of blades extending radially along the bit face; and a plurality of cutting elements disposed on the plurality of blades, the plurality of cutting elements comprising: at least one cutter comprising a substrate and a diamond table having a substantially planar cutting face; and at least two non-planar cutting elements comprising a substrate and a diamond layer having a non-planar cutting end, wherein in a rotated view of the plurality of cutting elements into a single plane, the at least one cutter is located a radial position from the bit axis that is intermediate the radial positions of the at least two non-planar cutting elements.

The present disclosure relates a spark plasma sintered polycrystalline diamond and methods of spark plasma sintering leached polycrystalline diamond. Spark plasma sintering produces plasma from a reactant gas found in the pores left by catalyst removal from leached polycrystalline diamond. The plasma forms diamond bonds and/or carbide structures in the pores, which may produce polycrystalline diamond that is has a higher impact strength than the leached polycrystalline diamond or other improved properties.

The present disclosure relates a spark plasma sintered polycrystalline diamond and methods of spark plasma sintering leached polycrystalline diamond. Spark plasma sintering produces plasma from a reactant gas found in the pores left by catalyst removal from leached polycrystalline diamond. The plasma forms diamond bonds and/or carbide structures in the pores, which may produce polycrystalline diamond that is has a higher impact strength than the leached polycrystalline diamond or other improved properties.

A cutting element for a drill bit includes a PCD cutting face having a ridge that extends away from the periphery towards the center of the cutting face, terminating in a curved, central most ridge end. The cutting face further includes a surrounding surface consisting of the entire cutting face except for the ridge. The surrounding surface is free of flats and includes two side regions and a ramp region therebetween. The surrounding surface is continuously curved along a curved path that extends from the first side region to the ramp region to the other side region. In profile views, the surrounding surface may be linear moving from the top surface of the ridge to the periphery at every location along the curved path.

An earth-boring tool for removing subterranean formation material in a borehole comprises a tool body having a central axis defining an axial center thereof and a leg extending in an axial direction from the tool body. A bearing assembly is removably coupled to the leg and includes a bearing shaft and a base member. The base member encircles a portion of the bearing shaft and abuts against a surface of the leg. A roller cone is rotatably coupled to the bearing assembly and has a rotational axis about which the roller cone rotates on the bearing assembly when the roller cone removes subterranean formation material in the borehole. A method of assembling a rotatable cutting structure assembly including the bearing assembly includes coupling the bearing shaft to the leg by disposing a mechanical fastener through an aperture formed through the leg and into a cavity of the bearing shaft.