Metal nanoparticles according to the present invention have at least a bimodal size distribution in which the ratio obtained by dividing the area of a first peak, which has the smallest median size on the basis of the median size of peaks in the size distribution of the metal nanoparticles, by the total area of all peaks constituting the size distribution meets 0.4-0.8, and are capped with a capping layer containing an organic acid.

Metal nanoparticles according to the present invention have at least a bimodal size distribution in which the ratio obtained by dividing the area of a first peak, which has the smallest median size on the basis of the median size of peaks in the size distribution of the metal nanoparticles, by the total area of all peaks constituting the size distribution meets 0.4-0.8, and are capped with a capping layer containing an organic acid.

A thermal mechanical treatment method includes consolidating a powder by a severe plastic deformation process and ageing the consolidated powder at low temperature. The method may include cryomilling the powder before consolidating the powder by a severe plastic deformation process; hot isostatic pressing the consolidated powder into a dense powder before aging the consolidated powder; hot extruding the dense powder into a stock shape before aging the consolidated powder; hot-working the stock shape on a gyrating forge at a predetermined temperature before aging the consolidated powder; or heating the consolidated powder to a predetermined temperature, and maintaining the consolidated powder at the predetermined temperature for a predetermined time.

A thermal mechanical treatment method includes consolidating a powder by a severe plastic deformation process and ageing the consolidated powder at low temperature. The method may include cryomilling the powder before consolidating the powder by a severe plastic deformation process; hot isostatic pressing the consolidated powder into a dense powder before aging the consolidated powder; hot extruding the dense powder into a stock shape before aging the consolidated powder; hot-working the stock shape on a gyrating forge at a predetermined temperature before aging the consolidated powder; or heating the consolidated powder to a predetermined temperature, and maintaining the consolidated powder at the predetermined temperature for a predetermined time.

A powder recycling system includes a supply tank, a continuous loss-in-weight module, a pneumatic module, a transfer channel, a recycle module, and a refilling tank. The supply tank accommodates recycling powder. The continuous loss-in-weight module includes a storage tank receiving the recycling powder from the supply tank and a rotary output pipe connected to the storage tank to output the recycling powder. The continuous loss-in-weight module controls the mass flow rate of the output of the recycling powder according to the weight change of the storage tank. The pneumatic module enables the recycling powder to float and move in the transfer channel. The recycle module is connected to the transfer channel to receive the recycling powder, sieves the recycling powder, provides virgin powder, and mixes the virgin powder with the recycling powder. The refilling tank is connected to the recycle module to receive the recycling powder and the virgin powder.

A powder recycling system includes a supply tank, a continuous loss-in-weight module, a pneumatic module, a transfer channel, a recycle module, and a refilling tank. The supply tank accommodates recycling powder. The continuous loss-in-weight module includes a storage tank receiving the recycling powder from the supply tank and a rotary output pipe connected to the storage tank to output the recycling powder. The continuous loss-in-weight module controls the mass flow rate of the output of the recycling powder according to the weight change of the storage tank. The pneumatic module enables the recycling powder to float and move in the transfer channel. The recycle module is connected to the transfer channel to receive the recycling powder, sieves the recycling powder, provides virgin powder, and mixes the virgin powder with the recycling powder. The refilling tank is connected to the recycle module to receive the recycling powder and the virgin powder.

A method for producing a metal powder includes maintaining molten reducing metal in a sealed reaction vessel that is substantially free of oxygen and water, establishing a vortex in the molten reducing metal, introducing a metal halide into the vortex so that the molten reducing metal is in a stoichiometric excess to the metal halide, thereby producing metal particles and salt, removing unreacted reducing metal, removing the salt, and recovering the metal powder. The molten reducing metal can be a Group I metal, a Group II metal, or aluminum.

A method of forming a crack-free aluminum alloy structure using additive manufacturing is presented. A powder bed of precursor aluminum alloy powder is heated. The crack-free aluminum alloy structure is formed within a laser powder bed fusion system encompassing the powder bed during heating.

Polycrystalline diamond bodies having an annular region of diamond grains and a core region of diamond grains and methods of making the same are disclosed. In one embodiment, a polycrystalline diamond body includes an annular region of inter-bonded diamond grains having a first characteristic property and a core region of inter-bonded diamond grains bonded to the annular region and having a second characteristic property that differs from the first characteristic property. The annular region decreases in thickness from a perimeter surface of the polycrystalline diamond body towards a centerline axis.

A particulate for an additive manufacturing technique includes metallic particulate bodies with exterior surfaces bearing a polymeric coating. The polymeric coating is conformally disposed over the exterior surface that prevents the underlying metallic body from oxidation upon exposure to the ambient environment by isolating the metallic particulate bodies from the ambient environment. Feedstock materials for additive manufacturing techniques, and methods of making such feedstock, are also disclosed.