Techniques for depowdering in additive fabrication are provided. According to some aspects, techniques are provided that separate powder from additively fabricated parts through liquid immersion of the parts. Motion of the liquid, such as liquid currents, may dislodge or otherwise move powder away from additively fabricated parts to which it is adhered or otherwise proximate to. The liquid may also provide a vehicle to carry away powder from the additively fabricated parts. Removed powder may be filtered or otherwise separated from the liquid to allow recirculation of the liquid to the parts and/or to enable re-use of the powder in subsequent additive fabrication processes. Techniques for depowdering through liquid immersion may be automated, thereby mitigating challenges associated with manual depowdering operations.

A powder cleaning system can include a fluidized bed reactor configured to retain powder and fluidize the powder to remove adsorbate and/or other contaminants from the powder, and one or more gas sources configured to be in selective fluid communication with the fluidized bed reactor via at least one inlet line to selectively provide an inlet flow having one or more gases to the fluidized bed reactor to fluidize the powder with the one or more gases within the fluidized bed reactor. The system can include at least one outlet line in fluid communication with the fluidized bed reactor and configured to allow removal of outlet flow which comprises the adsorbate and/or other contaminants from the fluidized bed reactor.

A powder cleaning system can include a fluidized bed reactor configured to retain powder and fluidize the powder to remove adsorbate and/or other contaminants from the powder, and one or more gas sources configured to be in selective fluid communication with the fluidized bed reactor via at least one inlet line to selectively provide an inlet flow having one or more gases to the fluidized bed reactor to fluidize the powder with the one or more gases within the fluidized bed reactor. The system can include at least one outlet line in fluid communication with the fluidized bed reactor and configured to allow removal of outlet flow which comprises the adsorbate and/or other contaminants from the fluidized bed reactor.

A method and a device are provided for removing surface oxides on nodules of a metal powder, before the nodules of the metal powder are used in an industrial process in which the nodules of the metal powder are assembled via a solid route or via a liquid route. In the method and the device, the surface oxides are stripped from the nodules of the metal powder by bringing the nodules of the metal powder into contact with vapour from at least one of: sublimation of a stripping solid material, and sublimation of the stripping solid material followed by a chemical transformation of a product of the sublimation.

A method and a device are provided for removing surface oxides on nodules of a metal powder, before the nodules of the metal powder are used in an industrial process in which the nodules of the metal powder are assembled via a solid route or via a liquid route. In the method and the device, the surface oxides are stripped from the nodules of the metal powder by bringing the nodules of the metal powder into contact with vapour from at least one of: sublimation of a stripping solid material, and sublimation of the stripping solid material followed by a chemical transformation of a product of the sublimation.

A system for treatment of atomized powder including a fluidized bed operable to treat feedstock alloy powders. A method of treating atomized powder including communicating an inert gas into a fluidized bed; communicating an atomized powder into the fluidized bed; and heating the atomized powder in the fluidized bed, eject the treated powders out of the fluidized bed to quench the powders.

A system for treatment of atomized powder including a fluidized bed operable to treat feedstock alloy powders. A method of treating atomized powder including communicating an inert gas into a fluidized bed; communicating an atomized powder into the fluidized bed; and heating the atomized powder in the fluidized bed, eject the treated powders out of the fluidized bed to quench the powders.

Some variations provide a system for producing a functionalized powder, comprising: an agitated pressure vessel; first particles and second particles contained within the agitated pressure vessel; a fluid contained within the agitated pressure vessel; an exhaust line for releasing the fluid from the agitated pressure vessel; and a means for recovering a functionalized powder containing the second particles disposed onto surfaces of the first particles. A preferred fluid is carbon dioxide in liquefied or supercritical form. The carbon dioxide may be initially loaded into the pressure vessel as solid carbon dioxide. The pressure vessel may be batch or continuous and is operated under reaction conditions to functionalize the first particles with the second particles, thereby producing a functionalized powder, such as nanofunctionalized metal particles in which nanoparticles act as grain refiners for a component ultimately produced from the nanofunctionalized metal particles. Methods for making the functionalized powder are also disclosed.

Some variations provide a system for producing a functionalized powder, comprising: an agitated pressure vessel; first particles and second particles contained within the agitated pressure vessel; a fluid contained within the agitated pressure vessel; an exhaust line for releasing the fluid from the agitated pressure vessel; and a means for recovering a functionalized powder containing the second particles disposed onto surfaces of the first particles. A preferred fluid is carbon dioxide in liquefied or supercritical form. The carbon dioxide may be initially loaded into the pressure vessel as solid carbon dioxide. The pressure vessel may be batch or continuous and is operated under reaction conditions to functionalize the first particles with the second particles, thereby producing a functionalized powder, such as nanofunctionalized metal particles in which nanoparticles act as grain refiners for a component ultimately produced from the nanofunctionalized metal particles. Methods for making the functionalized powder are also disclosed.

A system, method and apparatus for additive manufacturing is disclosed. The method includes fluidizing particles with a medium to form a fluidized bed and additively manufacturing an article formed from the particles. The article has an open porous structure defining a plurality of pores and a plurality of fluid paths through the article. The method further includes flowing the particles and the medium through the fluid paths while the fluid paths are being formed. The article may be additively manufactured by selectively sintering the particles at target areas on the article which are near the surface of the fluidized bed.