Improved gas flow systems and methods for use with powder bed-based laser additive manufacturing chambers are described. The disclosed gas flow configurations and associated build chamber designs enhance the removability of laser melting emissions. In accordance with various configurations, the clear rate of generated-spatter contamination is improved by employing system designs in which the gas flow outlet is lowered toward the substrate, the gas flow inlet channel length is increased, uniform gas flow is enabled using multi-channeled pumps, and/or one or more supplementary gas inlet flows are introduced to the chamber design.

A de-powdering basket comprises an enclosure of at least one side wall and a bottom wall. The enclosure is configured such that, when the enclosure is disposed within a build box, the outer surfaces of the at least one side wall are substantially adjacent to the interior walls of the build box. The enclosure further comprises one or more apertures disposed within the at least one side wall, each of the apertures comprising a void that extends through the at least one side wall from an interior surface of the side wall to an exterior surface of the side wall. The enclosure may be configured to accommodate a build plate situated within the enclosure. Outer edges of the build plate may cooperate with inner surfaces of the side walls of the enclosure to prevent loose powder from passing between the outer edges of the build plate and the side walls.

A de-powdering basket comprises an enclosure of at least one side wall and a bottom wall. The enclosure is configured such that, when the enclosure is disposed within a build box, the outer surfaces of the at least one side wall are substantially adjacent to the interior walls of the build box. The enclosure further comprises one or more apertures disposed within the at least one side wall, each of the apertures comprising a void that extends through the at least one side wall from an interior surface of the side wall to an exterior surface of the side wall. The enclosure may be configured to accommodate a build plate situated within the enclosure. Outer edges of the build plate may cooperate with inner surfaces of the side walls of the enclosure to prevent loose powder from passing between the outer edges of the build plate and the side walls.

An R-T-B based permanent magnet, in which R is a rare earth element, T is Fe or a combination of Fe and Co, and B is boron, includes main phase grains made of an R.sub.2T.sub.14B crystal phase and grain boundaries formed between the main phase grains. The grain boundaries include an R—O—C—N concentrated part having higher concentrations of R, O, C, and N than that of the main phase grains. The R—O—C—N concentrated part includes a heavy rare earth element. The R—O—C—N concentrated part has a core part and a shell part covering at least part of the core part. A concentration of the heavy rare earth element in the shell part is higher than a concentration of the heavy element in the core part. A covering ratio of the shell part with respect to the core part of the R—O—C—N concentrated part is 45% or more in average.

An R-T-B based permanent magnet, in which R is a rare earth element, T is Fe or a combination of Fe and Co, and B is boron, includes main phase grains made of an R.sub.2T.sub.14B crystal phase and grain boundaries formed between the main phase grains. The grain boundaries include an R—O—C—N concentrated part having higher concentrations of R, O, C, and N than that of the main phase grains. The R—O—C—N concentrated part includes a heavy rare earth element. The R—O—C—N concentrated part has a core part and a shell part covering at least part of the core part. A concentration of the heavy rare earth element in the shell part is higher than a concentration of the heavy element in the core part. A covering ratio of the shell part with respect to the core part of the R—O—C—N concentrated part is 45% or more in average.

A metal powder producing apparatus includes a molten metal supply unit, a cylinder body, and a cooling liquid introduction unit. The molten metal supply unit discharges a molten metal. The cylinder body is capable of being formed with a layer of a cooling liquid for cooling the molten metal on an inner circumference surface of the cylinder body. The cooling liquid introduction unit supplies the cooling liquid to an upper inside of the cylinder body. The inner circumference surface of the upper inside of the cylinder body has a substantially elliptical shape.

A metal powder producing apparatus includes a molten metal supply unit, a cylinder body, and a cooling liquid introduction unit. The molten metal supply unit discharges a molten metal. The cylinder body is capable of being formed with a layer of a cooling liquid for cooling the molten metal on an inner circumference surface of the cylinder body. The cooling liquid introduction unit supplies the cooling liquid to an upper inside of the cylinder body. The inner circumference surface of the upper inside of the cylinder body has a substantially elliptical shape.

A metal powder for additive manufacturing having a composition including the following elements, expressed in content by weight: 0.01%≤C≤0.2%, 2.5%≤Ti≤10%, (0.45×Ti)−1.35%≤B≤(0.45×Ti)+0.70%, S≤0.03%, P≤0.04%, N≤0.05%, O≤0.05% and optionally containing: Si≤1.5%, Mn≤3%, Al≤1.5%, Ni≤1%, Mo≤1%, Cr≤3%, Cu≤1%, Nb≤0.1%, V≤0.5% and including eutectic precipitates of TiB.sub.2 and optionally of Fe.sub.2B, the balance being Fe and unavoidable impurities resulting from the elaboration, the metal powder having a mean roundness of at least 0.70. The invention also relates to its manufacturing method by argon atomization.

A metal powder for additive manufacturing having a composition including the following elements, expressed in content by weight: 0.01%≤C≤0.2%, 2.5%≤Ti≤10%, (0.45×Ti)−1.35%≤B≤(0.45×Ti)+0.70%, S≤0.03%, P≤0.04%, N≤0.05%, O≤0.05% and optionally containing: Si≤1.5%, Mn≤3%, Al≤1.5%, Ni≤1%, Mo≤1%, Cr≤3%, Cu≤1%, Nb≤0.1%, V≤0.5% and including eutectic precipitates of TiB.sub.2 and optionally of Fe.sub.2B, the balance being Fe and unavoidable impurities resulting from the elaboration, the metal powder having a mean roundness of at least 0.70. The invention also relates to its manufacturing method by argon atomization.

An inlet manifold is for use in a laser powder bed fusion system having a build platform for carrying a powder bed and a pump or blower for supplying a gas flow in a direction relative to a surface of the build platform. The inlet manifold is made of a gas flow guide structure having a gas flow inlet to receive the gas flow and being comprised of a plurality of stacked gas flow guides, each being defined by top and bottom guide plates oriented downwards at an angle A relative to the direction of the gas flow for guiding the gas flow downwards towards a gas flow outlet. At least some of the top and the bottom guide plates have upwardly curved ends at the gas flow outlet to redirect the gas flow to be substantially parallel to the surface of the build platform.