Abstract: Drill bits and associated methods of manufacture and use employ a pre-diffused mandrel bonded to a composite metal-matrix material. The pre-diffused mandrel includes a chemically altered surface composition that enhances the bond with the composite metal-matrix component formed by infiltrating a metal-matrix component with a binder. The chemically altered surface may be configured to reduce binder-rich zones adjacent the mandrel, mechanically interlock the with the composite metal-matrix component or prevent the formation of brittle intermetallic particles along the bond.

Abstract: A method for forming localized binder in a drilling tool is disclosed. A method includes placing a reinforcement material in a matrix bit body mold, placing a localized binder material within the reinforcement material at a selected location in the matrix bit body mold, wherein the localized binder material confers a selected physical property at the selected location, placing a universal binder material in the matrix bit body mold on top of the reinforcement material, heating the matrix bit body mold, the reinforcement material, the localized binder material, and the universal binder material to a temperature above the melting point of the universal binder material, infiltrating the reinforcement material and the localized binder material with the universal binder material, and cooling the matrix bit body mold, the reinforcement material, the localized binder material, and the universal binder material to form a matrix drill bit body.

Abstract: Drill bits and associated methods of manufacture and use employ a pre-diffused mandrel bonded to a composite metal-matrix material. The pre-diffused mandrel includes a chemically altered surface composition that enhances the bond with the composite metal-matrix component formed by infiltrating a metal-matrix component with a binder. The chemically altered surface may be configured to reduce binder-rich zones adjacent the mandrel, mechanically interlock the with the composite metal-matrix component or prevent the formation of brittle intermetallic particles along the bond.

Abstract: A method for forming localized binder in a drilling tool is disclosed. A method includes placing a reinforcement material in a matrix bit body mold, placing a localized binder material within the reinforcement material at a selected location in the matrix bit body mold, wherein the localized binder material confers a selected physical property at the selected location, placing a universal binder material in the matrix bit body mold on top of the reinforcement material, heating the matrix bit body mold, the reinforcement material, the localized binder material, and the universal binder material to a temperature above the melting point of the universal binder material, infiltrating the reinforcement material and the localized binder material with the universal binder material, and cooling the matrix bit body mold, the reinforcement material, the localized binder material, and the universal binder material to form a matrix drill bit body.