Powdermet, Inc.

United States of America As Represented by the Secretary of the Air Force

Animesh Bose

Andrew J Sherman

Morris F Dilmore

Alan J Armstrong

A process of making useful shapes by joining of tungsten alloys. Joining of tungsten heavy alloys which are alloys typically made from W&#x2014;Ni&#x2014;Fe is used. These alloys are typically manufactured by liquid phase sintering. This leads to difficulty in producing large length to diameter ratio parts that have some significant weight (such as penetrators). A 'brick and mortar' approach is employed wherein smaller segments of this alloy (low length to diameter ratio) are joined to together to produce a larger part with higher length to diameter ratio.

Joining of tungsten alloys

Geldhart class C tungsten carbide particles are provided with a discontinuous coating of grain growth inhibitor. Further, the fine tungsten carbide coatings are preferably provided with a continuous coating of another discreet phase material, such as, for example, a continuous coating of cobalt. Compacts produced using such materials are particularly useful as WC&mdash;Co hardmetals wherein the compacts are extremely fine grained.

Method of producing fine coated tungsten carbide particles

An abrasive composite particle comprising a cubic abrasive core particle encapsulated within a deposit of hexagonal metallurgical bond forming material comprising at least about 50 volume percent rhenium, ruthenium, osmium or mixtures thereof. The metallurgical bonds serve to retain the core particle in a matrix/binder very strongly. Metallurgical bonds are formed by the encapsulating material taking into solution, at the interface with the cubic abrasive core particle, some element or compound from the abrasive particle such as, for example, carbon or cubic boron nitride, from the core particle. Chemical bonds are not formed between the abrasive particle and the deposit. Suitable abrasive core particles include diamond, cubic carbides, cubic borides, cubic nitrides, cubic oxides, and the like. Conventional fabrication procedures such as chemical vapor deposition are employed to form the metallurgical bond forming deposit on the core particle. The composite abrasive particles are useful in forming articles according to conventional powdered metal processing operations. The articles so formed are useful for their hardness as well as their abrasiveness.

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Fort Worth, TX, United States of America

Animesh Bose