Patent ID: 7398840

Claim:
A drill bit having a matrix bit body comprising: a plurality of cutting elements disposed at selected locations on exterior portions of the matrix bit body; at least a first matrix material and a second matrix material with the first matrix material having increased resistance to impact as compared with the second matrix material; the first matrix material forming exterior portions of the matrix bit body associated with engaging and removing formation materials from a wellbore; the second matrix material forming interior portions of the matrix bit body which are generally not associated with engaging and removing formation materials from a wellbore; the second matrix material operable to improve infiltration of a hot, liquid binder material throughout the first matrix material to minimize incomplete infiltration of the first matrix material by the hot, liquid binder material; and the second matrix material having a substantially reduced amount of alloys and other potential contaminants which may be leached by hot, liquid binder material as compared with alloys and other potential contaminants which may be leached by hot, liquid binder material from the first matrix material.