Abstract: A 3D Printing Rapid Prototyping process using Al/Mg particles coated with a metal (i.e. copper, nickel, zinc, or tin) that (1) prevents oxidation of the Al/Mg particles, and (2) either alone, or when alloyed with the aluminum or magnesium core metal, melts below the liquidus temperature of the core.

Abstract: A presinter treatment is provided to reduce oxygen contamination prior to sintering a predominantly iron powder compact comprising carbon powder and a liquating diffusible boron source, such as nickel boride powder optionally in combination with iron boride powder. A preferred treatment is carried out at a temperature effective to dissociate iron oxide within the compact but not to initiate a liquid phase by said boron source and further is carried out in a vacuum to evacuate oxygen released thereby from compact pores prior to sintering. The presinter treatment enhances carbon and boron diffusion into the iron during sintering. In a preferred embodiment, the fraction of borocementite particles formed by diffused carbon and boron in the sintered iron structure is increased by the presinter treatment of this invention.

Abstract: A sintering aid is disclosed for use in a powder metallurgical method for manufacturing an iron alloy article by compacting and sintering a predominantly iron powder mixture comprising carbon powder and a boron-containing additive, such as nickel boride. The sintering aid comprises an oxygen getter to inhibit boron oxidation that, if formed, is believed to retard carbon diffusion. The sintering aid also preferably includes a second constituent to produce, in combination with the getter, a melting point suitable for forming a transient liquid phase during the early stages of sintering. Preferred sintering aids include intermetallic iron titanium compounds, intermetallic ferro-vanadium compound and intermetallic nickel magnesium compound.

Abstract: A wear resistant iron alloy article is preferably formed by compacting and sintering a predominantly iron powder mixture containing additions of carbon, copper and nickel boride. The product microstructure comprises hard borocementite particles dispersed in a martensite or pearlite matrix. The particles have a cross-sectional dimension greater than 1 micron and are present in an amount preferably between 10 and 30 volume percent to improve wear resistance.

Abstract: A method for forming an iron alloy article having increased toughness comprises compacting and sintering a powder mixture composed of predominantly iron powder and carbon powder and containing a powder of a liquating nickel boride compound. Limited nickel diffusion into the iron structure during sintering produces metastable retained austenite in regions about pores in the product structure that retards crack formation and thereby improves mechanical properties.

Abstract: In the preferred embodiment, a method is presented for forming an iron-base article by powder metallurgy, which includes compacting a powder mixture comprising a major portion of iron particles and between about 2 to about 5 weight percent of a powder consisting of hypereutectic tricopper phosphide Cu.sub.3 P compound. The compact is sintered at a temperature between about 970.degree. C. to about 1100.degree. C., whereupon the copper phosphide forms a liquid that flows and wets the iron particle surfaces. During sintering, phosphorus from the copper phosphide diffuses into the iron particles and resulting copper-enriched liquid forms a film coating pore surfaces in the compact. The sintered article displays an improved combination of ductility and strength, particularly in view of the relatively low sintering temperature.

Abstract: A method is provided for forming rare earth-transition metal (RE-TM) powders directly into radially aligned, thin, curved permanent magnets supported on ferromagnetic backings. Such magnets are particularly suited for use as D.C. motor pole pieces. In the method, a powder cavity is formed between a ferromagnetic backing layer and a composite forming mandrel. The mandrel has a ferromagnetic core slidably retained in a thin magnetic sleeve. The powder in the cavity is pressed in a magnetic field to a density of about 50%. Thereafter, the core of the mandrel is first removed and then the nonmagnetic sleeve. After both mandrel sections are withdrawn, the powders are maintained in the magnet shape for further processing by mechanical interlocking of the particles, and the magnet shape itself is magnetically attracted to the backing layer by the residual magnetism of the powder. The mass may be heated to coalesce the powder and bond it to the backing.

Abstract: In a preferred embodiment thin curved rare earth-cobalt magnets supported on the interior surface of a steel casing are formed by hot isostatic compaction. Rare earth-cobalt powder is magnetically aligned and compacted to at least 65% of the theoretical density. The relatively strong, curved green compacts are positioned on a curved mandrel and placed in a closely fitting steel casing which is evacuated and sealed. The magnets are densified under isostatic gas pressure at elevated temperatures and bonded to the steel. The steel backing serves as an integral motor casing when such magnets are used in D.C. motors.

Abstract: Self-supporting magnets, suitable for use as pole pieces of D.C. motors, are made from rare earth-transition metal powders which are pressed into thin, curved shapes and radially magnetically aligned. The compacts are restrained during sintering between special dies shaped to prevent them from warping without inhibiting circumferential or radial shrinkage.

Abstract: In a preferred embodiment, thin curved rare earth-transition metal (RE-TM) compacts with good green strength are made by a stepwise process in the molding cavities of a portable compacting tooling. The powder is partially compacted and magnetically aligned in a first press equipped with magnetizing means. It is then transported in the tooling, which protects the powder from being disturbed during the transportation, to a second press where it is further compacted under much higher loads. The compacts thus formed can be further processed to form thin, curved, densified, permanent rare earth-cobalt magnets particularly suited for use as pole pieces in small, high-torque D.C. motors.

Abstract: In a preferred embodiment thin curved rare earth-cobalt magnets supported on the interior surface of a steel casing are formed by hot isostatic compaction. Rare earth-cobalt powder is magnetically aligned and compacted to at least 65% of the theoretical density. The relatively strong, curved green compacts are positioned on a curved mandrel and placed in a closely fitting steel casing which is evacuated and sealed. The magnets are densified under isostatic gas pressure at elevated temperatures and bonded to the steel. The steel backing serves as an integral motor casing when such magnets are used in D.C. motors.