Double cemented carbide composites

A double cemented carbide composite that is prepared by combining:

• hard phase particles comprising a carbide compound and a first binder material, wherein the carbide compound is selected from the group consisting W, Ti, Mo, Nb, V, Hf, Ta, and Cr carbides, and the first binder material is selected from the group consisting of Co, Ni, Fe, alloys thereof, and alloys with materials selected from the group consisting of C, B, Cr, Si, and Mn, wherein the hard phase particles have an average particle size of less than about 500 micrometers;
• with
• a ductile second binder material separating the hard phase particles from each other, the second ductile material being selected from the group consisting of Co, Fe, Ni, W, Mo, Ti, Ta, V, Nb, alloys thereof, and alloys with materials selected from the group consisting of C, B, Cr, and Mn, and sintering the composite at a sufficient temperature for melting the second binder material;
• wherein the composite has a K.sub.Ic fracture toughness of greater than 20 ksi.in.sup.1/2, and a wear number of at least 1.5 (1,000 rev/cm.sup.3).

A roller cone drill bit comprising:

• a body having a number of legs that extend therefrom;
• cutting cones rotatably disposed on an end of each leg;
• a plurality of cutting inserts disposed in the cutting cones, wherein at least a portion of the cutting inserts are formed from a double cemented carbide composite comprising:
• a plurality of first regions, each region comprising a composite of grains and a first ductile phase bonding the grains, wherein the grains are selected from the group of carbides consisting of W, Ti, Mo, Nb, V, Hf, Ta, and Cr carbides, wherein the first ductile phase is selected from the group consisting of Co, Ni, Fe, alloys thereof, and alloys with materials selected from the group consisting of C, B, Cr, Si, and Mn;
• and
• a second ductile phase separating the first regions from each other, the second ductile phase being selected from the group consisting of Co, Ni, Fe, W, Mo, Ti, Ta, V, Nb, alloys thereof, and alloys with materials selected from the group consisting of C, B, Cr, and Mn.

A percussion drill bit comprising:

• a body having a head with a surface adapted to engage a subterranean formation during drilling;
• a plurality of inserts disposed in head surface, wherein the inserts are formed from a double cemented carbide composite comprising:
• a plurality of first regions, each region comprising a composite of grains and a first ductile phase bonding the grains, wherein the grains are selected from the group of carbides consisting of W, Ti, Mo, Nb, V, Hf, Ta, and Cr carbides, wherein the first ductile phase is selected from the group consisting of Co, Ni, Fe, alloys thereof, and alloys with materials selected from the group consisting of C, B, Cr, Si, and Mn;
• and
• a second ductile phase separating the first regions from each other, the second ductile phase being selected from the group consisting of Co, Ni, Fe, W, Mo, Ti, Ta, V, Nb, alloys thereof, and alloys with materials selected from the group consisting of C, B, Cr, and Mn.

A drag drill bit comprising:

• a body having a head and having a number of blades extending away from a head surface, the blades being adapted to engage a subterranean formation during drilling;
• a plurality of shear cutters disposed in the blades to contact the subterranean formation during drilling, each shear cutter comprising a substrate and a layer of cutting material disposed thereon, the substrate being formed from a double cemented carbide composite comprising:
• a plurality of first regions, each region comprising a composite of grains and a first ductile phase bonding the grains, wherein the grains are selected from the group of carbides consisting of W, Ti, Mo, Nb, V, Hf, Ta, and Cr carbides, wherein the first ductile phase is selected from the group consisting of Co, Ni, Fe, alloys thereof, and alloys with materials selected from the group consisting of C, B, Cr, Si, and Mn;
• and
• a second ductile phase separating the first regions from each other, the second ductile phase being selected from the group consisting of Co, Ni, Fe, W, Mo, Ti, Ta, V, Nb, alloys thereof, and alloys with materials selected from the group consisting of C, B, Cr, and Mn.