SBIR-STTR Award

Nanostructured WC-Co materials have the potential for revolutionizing the hard facing, cutting tool and drill bit industries. Dramatic improvements in mechanical properties and performance have already been demonstrated. Further research on decreasing WC grain size of the consolidated material is now seen to be of the highest priority, since it is known that WC-Coproperties improve systematically with decreasing nanostructural scale. State-of-the-art WC-Co nanostructures are at the 50-100nm level. We believe that the use of grain growth inhibitors will permit an order of magnitude reduction WC grain size, with corresponding improvements in mechanical properties. The cost ofnanostructured WC-Co parts manufacture can also be reduced by perfecting a net-shape forming capability, such as powder injection molding. We propose (1) to introduce VC (a known grain growth inhibitor)into nanostructured WC-Co powder by Spray Conversion Processing,(2) to demonstrate liquid phase sintering of an extruded WC,VC-Co rod, (3) to realize decreased WC grain size in the sinteredrod, and (4) to determine the degree of hardness improvement that can be attributed to the reduced WC grain size.The research will lay the groundwork for the future development of net-shape PIM processing of nanostructured WC-Co parts, which exhibit superior properties and performance.

Nanostructured WC-Co materials have the potential for revolutionizing the hard facing cutting tool and drill bit industries. Dramatic improvements in mechanical properties and performance have already been demonstrated. Further research on decreasing WC grain size of consolidated material is now seen tobe of the highest priority by the carbide industry, since experience has shown that the mechanical properties of WC-Co improve systematically with decreasing WC grain size. Development of micro grained WC powders has stalled at the 0.3 micron (300 nm)level, which has been achieved in Japan. The Phase 1 research clearly demonstrated that VC-doped WC-Co powders with 20-50 nm WC grains can be processed in a practical manner to make consolidated 'nanograined' materials, with mechanical properties that are superior to the best 'micrograined' materials. In the Phase 2 research we propose to 1) synthesize pilot-scale quantities of nanostructures WC-Co and WC-Ni alloy powders, incorporating VC or Cr3C2as grain growth inhibitors, 2) fully characterize these powders with respect to chemical composition, morphology, size distribution, and surface area, 3) consolidate these powders by powder injection molding and by cold compaction followed by sintering to form net-shape specimens, and 4)characterize consolidated specimens by measuring such materials characteristics as structure, hardness, strength, and wear resistance.This research will lay the foundation for a new PIM technology that exploits nanostructured WC-Co powders for the fabrication of net-shape parts that display superior properties and performances in a variety of end use applications.Commercial Applications:Drill Bit Inserts, cutting tools, wear parts, hard facing, punch and die sets, extrusion dies, nozzles, valve seatings, and liners.