A process includes sintering hydrogenated titanium or titanium hydride (TiH.sub.2) and/or Ti metal in a dynamically controlled hydrogen atmosphere with hydrogen partial pressure greater than 0.01 atmosphere and at elevated temperature, to form a sintered titanium material; equilibrate the sintered material at an equilibration temperature below the sintering temperature and above the phase transformations including eutectoid decomposition temperature for an equilibration time sufficient for the hydrogen within the sample to reach equilibrium and homogenize the sintered titanium material; holding the sintered titanium material at a hold temperature below the temperature of sintering and a hold time sufficient for phase transformations including eutectoid decomposition of the sintered titanium material; and heating the sintered titanium material under vacuum, inert atmosphere, or a combination of both at a hold temperature which is less than that of the sintering temperature, to form titanium metal, or a titanium metal alloy with fine or ultrafine grain sizes; where the dynamically controlled hydrogen atmosphere varies as a function of time and temperature throughout the thermal cycle and includes hydrogen during the sintering and phase transformations including eutectoid decomposition steps.

A method of fabricating a sintered three-dimensional part, the method including: preparing an injection composition including a binder and a powder of a titanium-based alloy including aluminum and/or chromium; injecting the composition into a cavity of a mold to obtain a blank; eliminating the binder present in the blank; a first step of sintering the powder, the powder subjected to a first pressure higher than or equal to 1 mbar to obtain a preform of the part; and a second sintering step during which a second pressure, which is lower than the first pressure, is imposed, the duration for which the second pressure is applied being selected so that the content by weight of aluminum and/or chromium in a layer having a thickness of 200 μm situated at the surface of the preform does not vary by more than 5% in relative value due to the second sintering step.

A manufacturing method is performed in an additive manufacturing printing apparatus. An embodiment of the manufacturing method includes: S1—feeding inert gas into the additive manufacturing printing apparatus, and performing laser scanning on silicon steel metal particles to start to melt the silicon steel metal particles from bottom to top layer by layer into a silicon steel metal layer; S2—feeding treatment gas into the additive manufacturing printing apparatus, performing laser scanning on the silicon steel particles again to enable the treatment gas to react with the molten silicon steel metal particles to finally form an insulating nitride layer, and alternately performing S1 and S2 until the laminated iron core of a structure having a plurality of alternate silicon steel metal layers and insulating nitride layers is formed. An embodiment of the present invention may manufacture a customized laminated iron core with a complex shape and good performance.

A manufacturing method is performed in an additive manufacturing printing apparatus. An embodiment of the manufacturing method includes: S1—feeding inert gas into the additive manufacturing printing apparatus, and performing laser scanning on silicon steel metal particles to start to melt the silicon steel metal particles from bottom to top layer by layer into a silicon steel metal layer; S2—feeding treatment gas into the additive manufacturing printing apparatus, performing laser scanning on the silicon steel particles again to enable the treatment gas to react with the molten silicon steel metal particles to finally form an insulating nitride layer, and alternately performing S1 and S2 until the laminated iron core of a structure having a plurality of alternate silicon steel metal layers and insulating nitride layers is formed. An embodiment of the present invention may manufacture a customized laminated iron core with a complex shape and good performance.

A method for forming a three-dimensional article through successive fusion of parts of a metal powder bed is provided, comprising the steps of: distributing a first metal powder layer on a work table inside a build chamber, directing at least one high energy beam from at least one high energy beam source over the work table causing the first metal powder layer to fuse in selected locations, distributing a second metal powder layer on the work table, directing at least one high energy beam over the work table causing the second metal powder layer to fuse in selected locations, introducing a first supplementary gas into the build chamber, which first supplementary gas comprising hydrogen, is capable of reacting chemically with or being absorbed by a finished three-dimensional article, and releasing a predefined concentration of the gas which had reacted chemically with or being absorbed by the finished three dimensional article.

A method for forming a three-dimensional article through successive fusion of parts of a metal powder bed is provided, comprising the steps of: distributing a first metal powder layer on a work table inside a build chamber, directing at least one high energy beam from at least one high energy beam source over the work table causing the first metal powder layer to fuse in selected locations, distributing a second metal powder layer on the work table, directing at least one high energy beam over the work table causing the second metal powder layer to fuse in selected locations, introducing a first supplementary gas into the build chamber, which first supplementary gas comprising hydrogen, is capable of reacting chemically with or being absorbed by a finished three-dimensional article, and releasing a predefined concentration of the gas which had reacted chemically with or being absorbed by the finished three dimensional article.

A method for manufacturing an austenitic stainless steel workpiece including the following successive steps: 1) providing a powder and sintering the powder to form a sintered alloy with an austenitic structure; the alloy having a nitrogen content greater than or equal to 0.1% by weight, 2) treating the sintered alloy to transform the austenitic structure into a ferritic structure or ferrite+ austenite two-phase structure on a surface layer of the alloy, 3) treating the sintered alloy to transform the ferritic or ferrite+ austenite two-phase structure obtained in step 2) into an austenitic structure and, after cooling, forming the workpiece which, on the layer subjected to the transformations in steps 2) and 3), has a density higher than that of the core of the workpiece. The present description also relates to the workpiece obtained by the method which has a very dense surface layer (≥99%).

The present invention concerns a method of making sintered components made from an iron-based powder composition and the sintered component per se. The method is especially suited for producing components which will be subjected to wear at elevated temperatures, consequently the components consists of a heat resistant stainless steel with hard phases including chromium carbo-nitrides. Examples of such components are parts in turbochargers for internal combustion engines.

A method of selecting a scanning sequence of a laser beam in a selective laser solidification process, in which one or more objects are formed layer-by-layer by repeatedly depositing a layer of powder on a powder bed and scanning the laser beam over the deposited powder to selectively solidify at least part of the powder layers, includes determining an order in which areas should be scanned by: projecting a debris fallout zone that would be created when solidifying each area based on a gas flow direction of a gas flow passed over the powder bed; determining whether one or more other areas to be solidified fall within the debris fallout zone; and selecting to solidify the one or more other areas that fall within the debris fallout zone before solidifying the area from which the debris fallout zone has been projected.

A method of selecting a scanning sequence of a laser beam in a selective laser solidification process, in which one or more objects are formed layer-by-layer by repeatedly depositing a layer of powder on a powder bed and scanning the laser beam over the deposited powder to selectively solidify at least part of the powder layers, includes determining an order in which areas should be scanned by: projecting a debris fallout zone that would be created when solidifying each area based on a gas flow direction of a gas flow passed over the powder bed; determining whether one or more other areas to be solidified fall within the debris fallout zone; and selecting to solidify the one or more other areas that fall within the debris fallout zone before solidifying the area from which the debris fallout zone has been projected.