Method of making composite cermet articles

Abstract

Methods for making, methods for using and articles having cermets, preferably cemented carbides and more preferably tungsten carbide, having at least two regions exhibiting at least one property that differs are discussed. Preferably, the cermets further exhibit a portion that is binder rich and which gradually or smoothly transitions to at least a second region. The multiple-region cermets are particularly useful in compressively loaded application wherein a tensile stress or fatigue limit might otherwise be excessive for monolithic articles. The cermets are manufactured by juxtaposing and densifying at least two powder blends having different properties (e.g., differential carbide grain size, differential carbide chemistry, differential binder content, differential binder chemistry, or any combination of the preceding). Preferably, a first region of the cermet has a first ceramic component and a prescribed binder content and a second region, juxtaposing or adjoining the first region, of the cermet has a second ceramic component and a second binder content less than the prescribed binder content. The multiple region cermets of the present invention may be used in materials processing technology including, for example, compression technology, extrusion, supercritical processing, chemical processing, materials processing, and ultrahigh pressure.