US Patent 7398840 Matrix drill bits and method of manufacture

A matrix drill bit and method of manufacturing a matrix bit body from a composite of matrix materials is disclosed. Two or more different types of matrix materials may be used to form a composite matrix bit body. A first matrix material may be selected to provide optimum fracture resistance (toughness) and optimum erosion, abrasion and wear resistance for portions of a matrix bit body such as cutter sockets, cutting structures, blades, junk slots and other portions of the bit body associated with engaging and removing formation materials. A second matrix material may be selected to provide desired infiltration of hot, liquid binder material with the first matrix material to form a solid, coherent, composite matrix bit body.