Alternative materials for mandrel in infiltrated metal-matrix composite drill bits

A method of fabricating an infiltrated metal-matrix composite (MMC) drill bit, comprising:

• positioning a mandrel in an interior of a mold assembly that defines an infiltration chamber, wherein the mandrel is made of a single M-based alloy selected from the group consisting of a titanium-based alloy, a nickel-based alloy, a copper-based alloy, a cobalt-based alloy, and a refractory metal-based alloy;
• depositing reinforcing materials into the infiltration chamber;
• infiltrating the reinforcing materials with a binder material and thereby generating a hard composite material;
• forming a joint between the mandrel and the hard composite material during infiltration;
• and
• attaching a shank to the mandrel.

A drilling assembly, comprising:

• a drill string extendable from a drilling platform and into a wellbore;
• a drill bit attached to an end of the drill string wherein the drill bit comprises:
• a bit body comprising a reinforced composite material made of reinforcing particles infiltrated with a binder material;
• a plurality of cutting elements coupled to an exterior of the bit body;
• a mandrel positioned within the bit body and made of a single M-based alloy selected from the group consisting of a titanium-based alloy, a nickel-based alloy, a copper-based alloy, a cobalt-based alloy, and a refractory metal-based alloy;
• and
• a shank coupled to the mandrel.