Rensselaer Polytechnic Institute

E.i. Dupont De Nemours and Company

Leachgarner, Inc.

Randall M German

Animesh Bose

David M Sims

Dwarika P Agarwal

Laura L Bourguignon

Chaman Lall

Tai-Shing Wei

Shaji Faroog

Deepak S Madan

A process for making molded objects utilizes powder injection molding techniques. Powder is mixed with a binder and then cast into a compact. The compact is then subjected to a first debinding step in the presence of a wicking agent under gentle heating. In this first stage, at least 40% of the binder is removed. Additional binder is then removed in a subsequent higher temperature stage to produce a compact which is free of binder and free of cracks.

Two-stage fast debinding of injection molding powder compacts

The subject of this invention is the development of new alloys along with new processing approaches for the utilization of the alloys. A particular class of alloys comprises at least one noble metal selected from the group comprising gold, palladium, silver and copper and an amount of between about 0.20 weight percent and about 0.80 weight percent of at least one metalloid selected from the group of metalloids consisting of boron, phosphorous, silicon and lithium. Rapid solidification technology in powder fabrication and the addition of metalloids have been combined to produce a new class of palladium based alloys. The metalloid additions greatly increase the hardness, enhance the fine grain structure and aid sintering densification. Net-shape forming is a benefit derived from the characteristics of the new alloys.

Palladium based powder-metal alloys and method for making same

A tungsten heavy alloy system is modified by replacing from 2% to 10% of the tungsten by weight with tantalum to increase the strength and hardness characteristics for the alloy. This renders the alloy particularly useful for kinetic energy penetrators.

Hardness and strength of heavy alloys by addition of tantalum

A tungsten heavy alloy system is modified by partial replacement of the tungsten with substantial amounts of molybdenum ranging from 2% to 16% by weight to produce a new alloy with greater strength and hardness and moderate ductility. This new alloy is particularly useful for kinetic energy penetrators. The process involved is liquid phase sintering in an atmosphere of dry hydrogen, then wet hydrogen, then argon, followed by heat treament at 1100.degree. C. with a water quench. The resulting alloy is further hardened by swaging and strain aging which, at certain levels of molybdenum, produces a material having hardness in excess of HRC 45.

High strength, high hardness tungsten heavy alloys with molybdenum

Reactive sintering process for producing a shaped body containing the nickel aluminide compound Ni.sub.3 Al, which comprises sintering a compacted shaped mass containing an intimate mixture of substances, e.g. including elemental nickel powder and elemental aluminum powder in a stoichiometric atomic ratio generally corresponding to the compound Ni.sub.3 Al, by heating the mass, e.g. in a vacuum, to an elevated sintering temperature, e.g. 500-750.degree. C., sufficiently to initiate an exothermic reaction, and at a heating rate sufficiently for consequent progressive generation of a transient liquid below the melting point of the aluminum powder and at the corresponding eutectic temperature, and upon initiation of the exothermic reaction continuing the sintering sufficiently to form a densified shaped body containing the nickel aluminide compound Ni.sub.3 Al, and having a porosity of at most about 8%, or alternatively having an essentially fully densified structure where the heating is carried out under simultaneously applied mechanical pressure for hot isostatic compaction of the compacted shaped mass.

Production of reactive sintered nickel aluminide material

Powder metal compositions of nickel, molybdenum, boron, carbon, phosphorus and iron which exhibit low shrinkage on sintering.

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Latham, NY, United States of America

Randall M German