Earth-boring bits

A fixed cutter bit body comprising:

• a sintered body material made from powder, wherein the powder comprises hard particles and a
• binder, wherein:
• the binder comprises up to 35% by weight of the powder,
• the hard particles comprise at least one of a carbide, a nitride, a boride, a silicide, an
• oxide, and solid solutions thereof;
• and
• the binder comprises at least one metal selected from cobalt, nickel, iron and alloys thereof, the binder further comprising at least one of a transition metal carbide, a transition element, carbon, boron, silicon, chromium, manganese, silver, aluminum, copper, tin, rhenium, ruthenium, and zinc.

A fixed cutter bit body comprising:

• a sintered body material made from a powder, the powder comprising hard particles and a binder,
• wherein:
• the hard particles comprise at least one of a carbide, a nitride, a boride, a silicide, an
• oxide, and solid solutions thereof;
• and
• the binder comprises (i) up to 35% by weight of the powder and (ii) at least one of cobalt,
• nickel, iron, and alloys thereof;
• and
• an alloy steel shank attached to the body material.material;
• wherein the sintered body material has a transverse rupture strength greater than 280 ksi and a
• Young's modulus greater than 55 (10)6 psi.

A bit body, roller cone, insert roller cone, or cone, comprising:

• a body material, comprising:
• hard particles comprising at least one of a carbide, a nitride, a boride, a silicide, an oxide, and solid solutions thereof;
• and
• a binder, wherein the binder comprises:
• at least one metal selected from cobalt, nickel, iron and alloys thereof;
• and
• at least one melting point reducing constituent that comprises at least one of tungsten carbide, boride, or silicide in the range of 30 to 60 weight percent based on the total weight of the binder.

A bit body, roller cone, insert roller cone, or cone, comprising:

• a body material, comprising:
• hard particles comprising at least one of a carbide, a nitride, a boride, a silicide, an oxide, and solid solutions thereof;
• and
• a binder, wherein the binder comprises:
• at least one metal selected from cobalt, nickel, iron and alloys thereof;
• and
• at least one melting point reducing constituent that comprises tungsten carbide, wherein the binder comprises 40 to 50 weight percent of tungsten carbide and 40 to 60 weight percent of at least one of cobalt, nickel, or iron, all based on the total weight of the binder.

An earth-boring rotary drill bit comprising a unitary structure substantially formed of a particle-matrix composite material, the unitary structure comprising:

• a first region configured to carry a plurality of cutters for cutting an earth formation, the first region comprising a sintered powder, wherein the sintered powder comprises hard particles and a binder, wherein the binder comprises up to 35% by weight of the sintered powder;
• and
• at least one additional region configured to attach the drill bit to a shank, wherein the shank is for connection to a drill string, the at least one additional region and the shank having a threaded connection;
• wherein the first region has a first material composition, and wherein the at least one additional region has a second material composition that differs from the first material composition.

An earth-boring rotary drill bit comprising:

• a bit body substantially formed of a particle-matrix composite material comprising a plurality of hard particles randomly dispersed throughout a binder material, the plurality of hard particles selected from the group consisting of carbides, nitrides, borides, silicides, oxides, and solid solutions thereof, the binder material comprising a metal selected from the group consisting of cobalt, iron, nickel, and alloys thereof, wherein the material composition of the particle-matrix composite material varies within the bit body;
• and
• a shank attached directly to the bit body,
• wherein the bit body comprises:
• a first region configured to carry a plurality of cutters for engaging a subterranean earth formation, the first region comprising a particle-matrix composite material having a first material composition;
• and
• at least one additional region configured for attachment to a shank, wherein the shank is for attachment to a drill string, the at least one additional region comprising a particle-matrix composite material having a second material composition differing from the first material composition.