A build unit for additively manufacturing three-dimensional objects may include an energy beam system having one or more irradiation devices respectively configured to direct one or more energy beams onto a region of a powder bed, and an inertization system including an irradiation chamber defining an irradiation plenum, one or more supply manifolds, and a return manifold. The one or more supply manifolds may include a downflow manifold configured to provide a downward flow of a process gas through at least a portion of the irradiation plenum defined by the irradiation chamber, and/or a crossflow manifold configured to provide a lateral flow of the process gas through at least a portion of the irradiation plenum defined by the irradiation chamber. The return manifold may evacuate or otherwise remove process gas from the irradiation plenum defined by the irradiation chamber. While irradiating the region of the powder bed, the process gas may flow through the one or more supply manifolds, into the irradiation plenum, and from the irradiation plenum into the return manifold.

A simple method for making low surface area alloy particles with high silicon content has been discovered. The method involves two ball milling steps in which silicon containing precursor particles undergo a first milling to render the elemental silicon present to have an average grain size less than 20 nm, followed by a second milling with incorporated binding metal particles (e.g. certain transition metals) that serve to bind the first milled particles together. Done appropriately, the two milling step method results in alloy particles with high silicon content and have relatively low surface area and large particle size. As such, the particles are desirable for use in anode electrodes in rechargeable lithium batteries.

An additively manufactured (AM) object may include a body including an opening in an exterior surface thereof, the opening having a shape and a first area at the exterior surface of the body. A mask may be positioned over the opening. The mask has the shape of the opening and a second area that is larger than the first area so as to overhang the exterior surface of the body about the opening. A plurality of support ligaments couple to the mask and the exterior surface of the body at a location adjacent to the opening to support a portion of the mask. A coating can be applied to the object, and the mask removed. The final AM object includes a plurality of ligament elements extending from the exterior surface of the body and through the coating adjacent the opening, each ligament element at least partially surrounded by the coating.

A method (100) for producing a particulate titanium alloy product can include preparing (110) a composite particulate oxide mixture with TiO.sub.2 powder and at least one alloying element powder. The composite particulate oxide mixture can be co-reduced (120) using a metallic reducing agent under a hydrogen atmosphere at a reduction temperature for a reduction time sufficient to produce a hydrogenated titanium alloy product. The hydrogenated titanium alloy product can then be heat treated (130) under a hydrogen atmosphere and a heat treating temperature to reduce pore size and specific surface area to form a heat treated hydrogenated titanium product. The heat treated hydrogenated titanium product can be deoxygenated (140) to reduce residual oxygen to less than 0.2 wt % to form a deoxygenated hydrogenated titanium product as a particulate. The deoxygenated hydrogenated titanium product can optionally be dehydrogenated (150) to form the titanium alloy product as a particulate.

A method (100) for producing a particulate titanium alloy product can include preparing (110) a composite particulate oxide mixture with TiO.sub.2 powder and at least one alloying element powder. The composite particulate oxide mixture can be co-reduced (120) using a metallic reducing agent under a hydrogen atmosphere at a reduction temperature for a reduction time sufficient to produce a hydrogenated titanium alloy product. The hydrogenated titanium alloy product can then be heat treated (130) under a hydrogen atmosphere and a heat treating temperature to reduce pore size and specific surface area to form a heat treated hydrogenated titanium product. The heat treated hydrogenated titanium product can be deoxygenated (140) to reduce residual oxygen to less than 0.2 wt % to form a deoxygenated hydrogenated titanium product as a particulate. The deoxygenated hydrogenated titanium product can optionally be dehydrogenated (150) to form the titanium alloy product as a particulate.

A process comprising providing a metallic first powder having a plurality of first particles. The process includes adding a second material to the first powder, the second material having a plurality of second particles. The process includes combining the first powder with the second material to form a modified powder including modified powder particles having an interior portion containing an interior composition, and an outer surface portion with an outer composition different from the interior composition.

A process comprising providing a metallic first powder having a plurality of first particles. The process includes adding a second material to the first powder, the second material having a plurality of second particles. The process includes combining the first powder with the second material to form a modified powder including modified powder particles having an interior portion containing an interior composition, and an outer surface portion with an outer composition different from the interior composition.

A three-dimensional (3D) printer includes a powder layer forming device (2) uniformly spreading material powder in a molding space (R) in a chamber (1) to form a powder layer (8), and a laser irradiation device (4) irradiating a laser beam (L) on a predetermined irradiation region of the powder layer to form a sintered layer (9). The powder layer forming device includes a recoater head (23) discharging the contained material powder to the molding space, a blade (31, 33) leveling the discharged material powder to a predetermined thickness, and a holding member (35, 37) holding the blade on the recoater head, wherein the blade is flexible, and the blade and the holding member are nonmagnetic and electrically conductive.

A three-dimensional (3D) printer includes a powder layer forming device (2) uniformly spreading material powder in a molding space (R) in a chamber (1) to form a powder layer (8), and a laser irradiation device (4) irradiating a laser beam (L) on a predetermined irradiation region of the powder layer to form a sintered layer (9). The powder layer forming device includes a recoater head (23) discharging the contained material powder to the molding space, a blade (31, 33) leveling the discharged material powder to a predetermined thickness, and a holding member (35, 37) holding the blade on the recoater head, wherein the blade is flexible, and the blade and the holding member are nonmagnetic and electrically conductive.

A method for obtaining a lead-free or low lead content brass billet subjects a mixture of lead-free or low lead content brass chips and graphite powder to extrusion, either direct or inverted. The method obtains lead-free or low lead content brass billets.