Patent Description:
Various additive manufacturing processes are known in the art for forming one or more parts. The term "additive manufacturing" may describe a process where a part or parts are formed by accumulating and/or fusing material together, typically in a layer-on-layer manner. Layers of powder material, for example, may be disposed and thereafter solidified sequentially onto one another to form the part(s). The term "solidify" may describe a process whereby material is sintered or otherwise melted thereby causing discrete particles of the sintered or melted material to fuse together.

Additive manufacturing processes may use a metal alloy powder to form metal alloy parts. Such a metal alloy powder, however, may be costly to manufacture due to limited production volumes. Many pure metal powders or some binary or simple alloy powders are commonly produced in high volumes. In addition, when melting the powders during additive manufacturing, alloying elements with lower melting or boiling points may be preferentially lost due to evaporation. It is therefore important to maintain specific alloy concentrations for specific additive processes to produce the same end component alloy. Additive manufacturing processes also require significant energy input to melt the metals and alloys used leading to more costly and higher power lasers, electron beams, so other heat source being used.

There is therefore a need in the art for improved additive manufacturing materials and processes which allow for tailored powder chemistry and lower power heat sources.

<CIT> discloses features of the preamble of claim <NUM>, and other prior art includes <CIT>, <CIT>, <CIT>, <CIT> and <CIT>, <CIT>.

According to an aspect of the invention, a process is provided for manufacturing a part as claimed in claim <NUM>. Various embodiments of the invention are set out in the dependent claims.

Systems and processes are described herein for manufacturing one or more parts using a plurality of different metal materials; e.g., metal materials with different chemical compositions. During manufacturing, these metal materials are combined together to form the part(s). Before this combination, the metal materials are distinct from one another. A first of the metal materials is not alloyed with a second of the metal materials. However, during the combination, the metal materials are alloyed with one another thereby at least partially forming the part(s) from an alloy of the metal materials.

Each of the metal materials may be or may include a substantially pure metal; e.g., a non-alloyed metal. Alternatively, one or more of the metal materials may each be or may include a metal alloy; e.g., an alloy of two or more different metals. Examples of the metal(s) that may be included in one or more of the metal materials include, but are not limited to, aluminum (Al), copper (Cu), titanium (Ti), nickel (Ni), vanadium (V), chromiun (Cr), yttrium (Y), zirconium (Zr), hafnium (Hf), and/or alloys thereof.

The metal materials are received for manufacturing as one or more powders. The term "powder" describes a quantity (e.g., an agglomeration) of discrete particles with substantially uniform or varying sizes; e.g., average diameters. The particle size of one or more of the particles may be between about five micrometers (<NUM>) and about five-hundred micrometers (<NUM>); e.g., between about twenty micrometers (<NUM>) and about ninety micrometers (<NUM>). The present invention, however, is not limited to any particular particle sizes.

The metal materials are respectively received as different powders. Each of these powders includes a plurality of discrete particles <NUM>, an exemplary one of which is illustrated in <FIG>. Each of the particles <NUM> may be configured as or include a discrete solid mass of the respective metal material. More particularly, each particle <NUM> may be configured substantially without other metal materials. Each particle <NUM> may also be configured substantially without other non-metal materials; e.g., composed solely of a respective one of the metal materials.

Some or all of the metal materials may alternatively be received together as compounded powder (or powders). This powder includes a plurality of discrete particles <NUM>, exemplary ones of which are illustrated in <FIG>. Referring to <FIG>, one or more of the particles <NUM> each includes a core <NUM> of a first of the metal materials encapsulated by a coating <NUM> of a second of the metal materials. Referring to <FIG>, and in accordance with the invention, the coating <NUM> of the second metal material is at least partially coated (e.g., encapsulated) by a coating <NUM> of another one of the metal materials; e.g., the first metal material or a third of the metal materials. Referring to <FIG>, one or more of the particles <NUM> are each configured from a spray dried blend of two or more of the metal materials. Referring to <FIG>, one or more of the particles <NUM> each includes a plurality of layers <NUM>-<NUM> that are respectively bonded (e.g., welded, adhered, etc.) to one another. One of the particles <NUM>, for example, may be produced through a mechanical milling process where the layers are bonding together through cold welding. Each of these layers <NUM>-<NUM> may be configured from or otherwise include a respective (e.g., different) one of the metal materials.

In each example of blended, agglomerated, or layered particles, the elemental combination are selected such that during the melting and alloying process the materials react exothermically.

In each example of blended, agglomerated, or layered particles, the elemental combination are selected such that during the melting and alloying process the materials react exothermically reducing the energy input required. A decision for which elements to pre-alloy and which elements to alloy during the melting process can then be based on an assessment of the thermodynamic energy balance during the deposition process.

<FIG> illustrates a system <NUM> for additive manufacturing at least one part <NUM> from metal materials <NUM> (metal powders) such as those described above. This additive manufacturing system <NUM> includes a base <NUM>, a material distribution system <NUM> and a solidification device <NUM>. The additive manufacturing system <NUM> also includes a controller <NUM> in signal communication (e.g., hardwired and/or wirelessly coupled) with one or more of the system components <NUM> and <NUM>.

The base <NUM> may be configured as or located within an enclosed housing <NUM> (e.g., a seal enclosure) in which at least a portion of one or more of the system components <NUM> and <NUM> are located. The base <NUM> includes a support surface <NUM>. This support surface <NUM> is adapted to support the metal materials <NUM> and/or at least a portion of the part(s) <NUM> during additive manufacturing. The support surface <NUM>, for example, may be substantially horizontal relative to gravity. The support surface <NUM> may also have a generally planar geometry.

The material distribution system <NUM> is adapted to deposit quantities of the metal materials <NUM> onto the support surface <NUM>. These quantities of metal materials <NUM> may be deposited as a substantially uniform layer of metal materials <NUM> over at least a portion or all of the support surface <NUM>.

The material distribution system <NUM> may include a material reservoir (e.g., a hopper), a material outlet (e.g., a conduit) and a material coater (e.g., a blade). The reservoir is adapted to contain a quantity of the metal material(s) <NUM>. The reservoir may also be adapted to mix the metal materials <NUM> together where the materials are different powders. The outlet is adapted to direct the metal materials <NUM> from the reservoir onto the support surface <NUM> into a mound (or mounds). The coater is adapted to spread the mound (or mounds) of metal materials <NUM> across at least a portion of the support surface <NUM> to provide the layer of metal materials. Of course, various other types and configurations of material distribution systems are known in the art, and the additive manufacturing system <NUM> is not limited to including any particular ones thereof.

The solidification device <NUM> is adapted to solidify at least a portion or all of the metal materials <NUM> deposited on the support surface <NUM> to form at least a portion of the part(s) <NUM>. The solidification device <NUM> melts at least some of the deposited metal materials <NUM> such that the melted metal materials fuse and alloy together to form a portion of the part(s) <NUM>.

The solidification device <NUM> includes at least one energy beam source such as, for example, a laser or an electron beam energy source. The energy beam source is adapted to generate at least one energy beam (e.g., a laser beam or electron beam) for melting or otherwise fusing and alloying a portion of the deposited metal materials together. The energy beam source is also adapted to move the energy beam over (e.g., selectively scan) at least a portion of the deposited metal materials <NUM>. Of course, various other types and configurations of solidification devices are known in the art, and the additive manufacturing system <NUM> is not limited to including any particular ones thereof.

The controller <NUM> (e.g., a processing system) is adapted to signal one or more of the system components <NUM> and <NUM> to perform at least a portion of the process described below. The controller <NUM> may be implemented with a combination of hardware and software. The hardware may include memory and one or more single-core and/or multi-core processors. The memory may be a non-transitory computer readable medium, and adapted to store the software (e.g., program instructions) for execution by the processors. The hardware may also include analog and/or digital circuitry other than that described above.

<FIG> is a flow diagram of a process for manufacturing a part <NUM> (or parts) using an additive manufacturing system such as the system <NUM>. An example of the part <NUM> is a rotor blade for a turbine engine such as, for example, a turbine blade, a compressor blade or a fan blade. Other examples of the part <NUM> include a stator blade for a turbine engine, a guide vane for a turbine engine, a gas path wall for a turbine engine as well as various other components included in a turbine engine. The process of <FIG> and the system <NUM>, however, may also or alternatively additively manufacture parts other than those described above or included in a turbine engine.

In step <NUM>, the additive manufacturing system <NUM> receives the metal materials <NUM>. The metal materials <NUM>, for example, may be deposited into the reservoir of the material distribution system <NUM>. In embodiments where the metal materials <NUM> are configured as more than one powder, these powders may be mechanically mixed (e.g., stirred) together within the reservoir by, for example, a mixing blade(s) and/or a hopper screw drive. Alternatively, the powders may be mechanically mixed on the support surface <NUM> as described below in further detail.

In step <NUM>, quantities of the metal materials <NUM> are deposited on the base <NUM>. The controller <NUM>, for example, may signal the material distribution system <NUM> to deposit a substantially uniform layer of the metal materials <NUM> (e.g., powder(s)) on the support surface <NUM>. This layer of metal materials <NUM> may be deposited directly on the support surface <NUM>. Alternatively, the layer of metal materials <NUM> may be deposited on at least one layer of metal materials that was previously deposited on the support surface <NUM>.

In step <NUM>, at least a portion of the deposited metal materials <NUM> are solidified together. The controller <NUM>, for example, may signal the solidification device <NUM> to selectively scan its energy beam over at least a portion of the deposited metal materials <NUM> to form at least a portion of the part <NUM>. The energy beam may sinter or melt the respective metal materials. The sintered or melted metal materials may fuse and alloy together and thereafter solidify providing a solid mass of metal material alloy that forms the respective portion of the part <NUM>. With certain metal materials <NUM>, and in accordance with the invention, the alloying is carried out through an exothermic reaction. Heat generated by this exothermic reaction may supplement heat generated by the energy beam, which may enable the solidification device <NUM> to reduce the energy beam power and, thus, its energy draw.

One or more of the foregoing steps of <FIG> may be repeated for one or more iterations to additively manufacture the part <NUM> (or parts) layer-by-layer.

In some embodiments, the metal material powders may be mixed together on or above the base <NUM>. The additive manufacturing system <NUM>, for example, may include at least one additional material distribution system <NUM>. Each material distribution system <NUM> may be adapted to direct its respective metal material towards a common point or points such that the metal materials <NUM> mechanically mix together as they are deposited onto the support surface <NUM>.

In some embodiments, the steps <NUM> and <NUM> may be performed substantially contemporaneously. The material distribution system <NUM> and the solidification device <NUM>, for example, may be configured together as a laser applied powder device. In some embodiments, the additive manufacturing system <NUM> may include a plurality of the laser applied powder devices. With such a configuration, the metal material powders may be mechanically mixed together on or above the base <NUM> during metal material solidification.

The process of <FIG> may include one or more additional steps other than those described above. For example, in some embodiments, the part <NUM> (or parts) may undergo additional manufacturing processes during and/or after the material buildup step <NUM>. Examples of such additional manufacturing processes may include, but are not limited to, machining, surface finishing, coating, etc..

The first and second metal materials are selected such that an exothermic reaction takes place during the alloying of these metal material. An example of this would be in creating a Nickel-Chrome-Aluminum alloy for high temperature applications. For example, a Nickel-Chrome first metal material may be combined with an aluminum second metal material. However, in other embodiments, a Nickel-Aluminum first metal material may be combined with a Chromium second metal material.

Claim 1:
A process for manufacturing a part (<NUM>), the process comprising:
receiving a plurality of metal materials (<NUM>) with different chemical compositions, wherein the metal materials (<NUM>) are received as one or more powders of discrete particles (<NUM>), wherein a first of the metal materials is not alloyed with a second of the metal materials;
subsequent to said step of receiving, solidifying the metal materials (<NUM>) together using an energy beam of an additive manufacturing system (<NUM>) to form at least a portion of the part (<NUM>) which comprises an alloy of the metal materials (<NUM>), and alloying the first of the metal materials with the second of the metal materials during the solidifying,
wherein the first of the metal materials and the second of the metal materials produce an exothermic reaction during the alloying,
wherein the plurality of discrete particles (<NUM>) includes a core (<NUM>) of the first of the metal materials at least partially coated by a coating (<NUM>) of the second of the metal materials,
wherein the coating (<NUM>) of the second of the metal materials is at least partially coated by a coating (<NUM>) of another one of the first or second metal materials, or a third of the metal materials.