WO2020014023A1

WO2020014023A1 - Methods for producing sintered articles

Info

Publication number: WO2020014023A1
Application number: PCT/US2019/040054
Authority: WO
Inventors: James C. Mcmillen; Justen R. SCHAEFER; Jen C. Lin
Original assignee: Arconic Inc.
Priority date: 2018-07-11
Filing date: 2019-07-01
Publication date: 2020-01-16

Abstract

A method of producing a sintered article comprises blending ingredients comprising a first metallic alloy powder having a first solidus temperature and a second metallic alloy powder having a second solidus temperature to provide a powder blend, wherein the second solidus temperature is lower than the first solidus temperature. An article comprising at least a portion of the powder blend is formed. The article is sintered at a temperature between the first and second solidus temperatures to form a sintered article.

Description

TITLE

METHODS FOR PRODUCING SINTERED ARTICLES CROSS-REFERENCE

[0001] This application claims priority to U.S. Provisional Patent Application No. 62/696,509, which was filed on July 11, 2018. The contents of which is incorporated by reference into this specification.

FIELD OF USE

[0002] The present disclosure is directed to methods for producing sintered articles.

BACKGROUND

[0003] Binder-jet additive manufacturing is a process in which thin layers of metal, ceramic, or other powdered materials are deposited in a powder bed and the powder particles in one or more regions of the powder layer are bonded together to form a layer of a part preform. A liquid binder is typically deposited onto one or more predetermined regions of the powder layer through a micro jet system in a computer controlled pattern. The binder is distributed through the thickness of the powder layer in a selected region, infiltrating between granules of the powder in the region via wetting or capillary action. The sequence of powder deposition and binder deposition is continued layer-by-layer until the desired geometry of the part preform is produced. In various binder-jet additive manufacturing processes, after the binder is deposited onto one or more regions of a powder layer, the binder may be cured to increase the strength of those regions. For example, in certain binder-jet additive

manufacturing processes, the binder may be a thermoset binder, and the binder may be cured after deposition by heating the powder layer. Once the part preform has been provided, excess powder that is not bound into the part preform may be removed by mechanical brushing, vacuum, flowing gas, vibration, or other means.

[0004] In conventional binder-jet additive manufacturing, fine powder material with an average particle size of up to about 100 microns is typically employed to improve packing and sintering efficiencies. However, fine powders can be flammable and/or explosive.

Therefore, to mitigate safety concerns, inert processing environments such as, for example, explosion proof machinery and appropriately classified work spaces may be used, and this can require significant capital expenditure. In addition, conventional binder-jet additive manufacturing processes have had limited applicability given of limitations in the final densification processes.

[0005] Accordingly, there is a need for improvements to conventional binder-jet additive manufacturing processes and systems.

SUMMARY

[0006] According to one aspect of the present disclosure, a non-limiting

embodiment of a method of producing a sintered article includes blending ingredients comprising a first metallic alloy powder having a first solidus temperature and a second metallic alloy powder having a second solidus temperature to provide a powder blend, wherein the second solidus temperature is lower than the first solidus temperature. An article comprising at least a portion of the powder blend is formed. In certain embodiments, the article may be a part preform. The part preform is sintered at a temperature between the first and second solidus temperatures to form a sintered article.

[0007] According to another aspect of the present disclosure, a non-limiting embodiment of a method of producing a sintered article includes blending ingredients comprising a first metallic alloy powder having a first solidus temperature and a second metallic alloy powder having a second solidus temperature to provide a powder blend, wherein the second solidus temperature is lower than the first solidus temperature. An article comprising at least a portion of the powder blend and a binder is formed by an additive manufacturing process. In certain embodiments, the article may be a part preform. The part preform is sintered at a temperature between the first and second solidus temperatures to form a sintered article.

DETAILED DESCRIPTION OF NON-LIMITING EMBODIMENTS

[0008] In the present description of non-limiting embodiments and in the claims, other than in the operating examples or where otherwise indicated, all numbers expressing quantities or characteristics of ingredients and products, processing conditions, and the like are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, any numerical parameters set forth in the following description and the attached claims are approximations that may vary depending on the desired properties one seeks to obtain in the methods and sintered articles according to the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0009] Powder metallurgy processes may produce metals and alloys having voids and relatively high levels of porosity. High levels of porosity can reduce strength and integrity of the resultant article. Accordingly, it is desirable to provide a method for producing powder metallurgy articles having low volumes of porosity. The present disclosure, in part, is directed to improved methods for producing sintered articles. As used herein, a“sintered” article is an article that has been formed by sintering. Sintering, in turn, is a process wherein a mass of powder particles, such as a powder metal part preform, is heated to cause the powder particles to fuse together and coalesce into a solid coherent mass. Sintering can remove porosity and densify green articles or bodies of crystalline material through mass transport between particles comprising the green body. The mass transport may be induced through heat and/or pressure.

[0010] As used herein,“additive manufacturing” means“a process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies”, as defined in ASTM F2792-l2a entitled “Standard Terminology for Additively Manufacturing Technologies”. Additively

manufactured metal alloy bodies may be manufactured via any appropriate additive manufacturing technique described in this ASTM standard, such as binder jetting, directed energy deposition, material extrusion, material jetting, powder bed fusion, or sheet lamination, among others. Any suitable feedstocks may be used, including one or more powders.

[0011] In some embodiments, an additively manufactured aluminum alloy product is a crack-free product. In some embodiments,“crack-free” means that the product is sufficiently free of cracks such that it can be used for its intended, end-use purpose. The determination of whether a product is“crack-free” may be made by any suitable method, such as, by visual inspection, dye penetrant inspection, and/or by non-destructive test methods. In some embodiments, the non-destructive test method is a computed topography scan (“CT scan”) inspection (e.g, by measuring density differences within the product). In one embodiment, an additively manufactured alloy product is determined to be crack-free by visual inspection. In another embodiment, an additively manufactured alloy product is determined to be crack-free by dye penetrant inspection. In yet another embodiment, an additively manufactured alloy product is determined to be crack-free by CT scan inspection, as evaluated in accordance with ASTM E1441. In another embodiment, an additively manufactured alloy product is determined to be crack-free during an additive manufacturing process, wherein in situ monitoring of the additively manufactured build is employed. The crack-free product may be a final product (e.g., a final additively manufactured alloy product, a final worked product).

[0012] According to certain non-limiting embodiments, ingredients comprising at least a first metallic alloy powder and a second metallic alloy powder are blended to provide a powder blend. The first metallic alloy powder has a first solidus temperature, and the second metallic alloy powder has a second solidus temperature. According to certain non limiting embodiments of the present disclosure, the second solidus temperature is lower than the first solidus temperature. In certain non-limiting embodiments, a green article or body comprising at least a portion of the powder blend is formed. In certain non-limiting embodiments, a green article may be comprised of individual particles of the first and second metallic alloy powders that are held together in a specific shape by binders, glues, cements, or other attractive forces without chemical bonds, material bridges, or grain boundaries.

[0013] According to certain non-limiting embodiments of the present disclosure, the green article is sintered at a temperature between the first and second solidus temperatures to form a sintered article. As used herein, the term "solidus temperature" refers to the maximum temperature of an alloy at which the alloy is in a completely solid state. In contrast, the "liquidus temperature" of an alloy is the maximum temperature at which solid crystals of the alloy coexist in thermodynamic equilibrium with a liquid phase of the alloy. At temperatures above an alloy’s liquidus temperature, the alloy is completely liquid, and at temperatures equal to or below the alloy’s solidus temperature, the alloy is completely solid. At super solidus temperatures, i.e., temperatures greater than an alloy’s solidus temperature and up to and including the alloy’s liquidus temperature, the alloy exists in a two-phase state.

Therefore, when in a sintering process an alloy is heated to a temperature between its solidus and liquidus temperatures, a volume of a liquid phase is created for the alloy being sintered.

[0014] According to certain non-limiting embodiments of the present disclosure, a combination of solid-state and liquid-phase sintering can be employed to accomplish removal of porosity present in a green article. For example, removal of porosity in a green article can be accomplished by (1) solid-state sintering wherein atoms are moved via vacancies or defects in the crystal lattice of the material and (2) liquid-phase sintering wherein liquids dissolve portions of the material being sintered and re-precipitate in pore space as the liquid solidifies. While not wishing to be bound by any particular theory, it is believed that the liquid phase produced during liquid-phase sintering can aid in the movement and re- distribution of particles within the article or part. Stated slightly differently, the liquid phase that forms may fill stable and unstable pores alike, and facilitate movement of particles to form high packing arrangements, as well as provide a medium for mass transport between particles, thereby significantly reducing the amount of porosity remaining in the final part after the sintering cycle. In certain non-limiting embodiments of the methods according to the present disclosure, the difference between the solidus temperature of the first metallic material and the solidus temperature of the second metallic material is at least 10 Celsius degrees. According to certain other non-limiting embodiments, the difference between the solidus temperatures of the first and second metallic materials is in a range of 5 to 300 Celsius degrees.

[0015] According to certain non-limiting embodiments, the first and second metallic alloy powders according to the present disclosure may be alloys within the same alloy system, but have different elemental compositions that fall within the nominal composition for that particular alloy system. The sintered article may have a composition within the compositional ranges of alloying constituents of each of the first and second metallic alloy powders. In various other embodiments, the first and second metallic alloy powders according to the present disclosure may be alloys within different alloy systems, and combine to form a sintered article having a composition outside each of the first and second metallic alloy powders.

[0016] In various non-limiting embodiments of the methods according to the present disclosure, the sintered article is formed according to or corresponding to a target alloy product. For example, the first and second metallic alloy powders having respective chemistry and average particles size are selected based on the target alloy product. A blended layer of the first and second metallic alloy powders is deposited in a powder bed. A liquid binder is deposited onto one or more predetermined regions of the blended layer through a micro jet system in a computer controlled pattern. The binder is distributed through the thickness of the blended layer in a selected region, infiltrating between granules of the first and second metallic alloy powders in the region via wetting or capillary action. The sequence of blended powder deposition and binder deposition is continued layer-by-layer until the desired geometry of the part preform is produced. The part preform is sintered to form an alloy product that corresponds to the target alloy product. In some embodiments, the sintered alloy product has the same composition as the target alloy product. In some embodiments, the sintered alloy product has a composition within a compositional range of the target alloy product. In some embodiments, the sintered alloy product has no aberrations and/or has uniform properties, characterized by an absence of cavities or pores. In some embodiments, the sintered alloy product has the targeted density. In some embodiments, the sintered alloy product has the target theoretical density. In some embodiments, the sintered alloy product has an actual density within 3%, 5%, or 10% of the target theoretical density.

[0017] According to certain non-limiting embodiments, each of the first metallic alloy powder and the second metallic alloy powder has an average particle size in the range of 5 pm to 150 pm, or in the range of 10 pm to 125 pm. According to certain non-limiting embodiments, the second metallic alloy powder may have an average particle size smaller than the first metallic alloy powder to fill the voids between the first metallic alloy powder with molten second metallic alloy powder, and to have the melt bound to the first metallic allow powder. For example, the larger sized metallic alloy powder can bond to form a backbone for the part, thereby providing structural integrity, while the smaller sized powder that creates the liquid phase can fill in gaps, at least in part, between the larger particles. The partial melting of the smaller sized metallic alloy powder can shorten the sintering time significantly.

[0018] According to certain non-limiting embodiments, the first metallic alloy powder has an average particle size in the range of 30 pm to 50 pm, and the second metallic alloy powder has an average particle size in the range of 10 pm to 30 pm. According to certain non-limiting embodiments, the first metallic alloy powder has an average particle size in the range of 100 pm to 125 pm, and the second metallic alloy powder has a larger average particle size in the range of 75 pm to 100 pm. According to various other non-limiting embodiments, the first metallic alloy powder has an average particle size in the range of 75 pm to 125 pm, and the second metallic alloy powder has an average particle size in the range of 10 pm to 50 pm. While not wishing to be bound by any particular theory, it is believed that the difference in particle size can aid in achieving the desired result of the sintering process. Additionally, if the first metallic alloy powder and the second metallic alloy powder are of the same composition but have different average particle sizes, the smaller sized powder of the two powders may have a lower melting point and/or solidus temperature, which could potentially expand the solidus temperature range ( e.g ., by a few Celsius degrees).

[0019] In certain non-limiting embodiments according to the present disclosure, at least one of the first metallic alloy powder and the second metallic alloy powder comprises a recycled material. Gas atomization is one technique conventionally used for forming a metallic powder material. In conventional gas atomization of metallic powders for use in additive manufacturing and alloy production, the recycled material, also known as the waste stream or scrap, may have an average particle size of greater than about 100 microns.

Powders having such particle size are not typically used for additive manufacturing or powder metallurgy processing methods. The recycled material may differ from typical feedstock in other ways. For example, the recycled material may have a higher oxygen or oxide content than typical feedstock used in additive manufacturing.

[0020] According to certain non-limiting embodiments of the methods disclosed herein, metallic powder having an average particle size of greater than 100 microns can be used as feedstock in additive manufacturing. The ability to use this material can significantly lower the cost of the overall powder production process. However, when such large particles are used, large volumes of pores and/or large sized pores can be present in the green part and can be difficult to remove through solid-state sintering alone or processes involving a limited volume of liquid-phase sintering. It is believed that the difficulty in removing such pores may be due to, at least in part, pore stability— pores with large dihedral angles (e.g., with a near circular cross sectional shape) are more stable and harder to remove through mass transport than pores with lower dihedral angles (e.g., with a triangular, hexagonal, rectangular, square trapezoidal, or other cross sectional shape). Pore stabilization may be enhanced when larger powder particles that create high dihedral angles in the pore space between the particles are used. Accordingly, in embodiments according to the present disclosure, the first metallic alloy powder and the second metallic alloy powder are selected to form a sufficient volume of liquid at the sintering temperature, and the liquid phase can be employed to accomplish removal of green part porosity.

[0021] Depending on the use requirements or preferences of the particular method or sintered articles, an amount of liquid phase that is more than about 50% at the sintering temperature may not provide the requisite structural integrity, rigidity, strength, or a combination thereof. Depending on the volume of pores and particle packing of the solid phase, an amount of liquid phase that is more than about 50% at the sintering temperature may cause shrinkage, distortion, cracking issues, or even cause the preformed part to collapse. According to certain non-limiting embodiments, an amount of the liquid phase at the sintering temperature can be, in volume percentages, in the range of 1% to 50%, or in the range of 1% to 30%.

[0022] According to certain non-limiting embodiments, at least a portion of the blend is sintered at a pressure in a range of lxlO ³ Pa to 101,325 Pa. According to certain non-limiting embodiments, the compact may be sintered under a pressure of less than 1 atm (i.e., less than 101,325 Pa). For example, sintering may be conducted under a pressure in a range of 0.1 Pa to less than 101,325 Pa, or according to certain non-limiting embodiments, in a range of 133 Pa to less than 101,325 Pa. According to other non-limiting embodiments, the sintering may be conducted under a pressure grater than 101,325 Pa. According to yet other non-limiting embodiments, the sintering may be accomplished through pressureless sintering.

[0023] The present method may be applied to any suitable metal alloy. According to a non-limiting embodiment, the method according to the present disclosure may be carried out to produce a metal alloy selected from an aluminum alloy, a titanium alloy, and a nickel alloy. In a non-limiting embodiment, an alloy produced by a method of the present disclosure is selected from the following alloys: Al 6061 alloy (having a nominal

composition, in weight percentages based on total alloy weight, of 0.8 to 1.2 magnesium, 0.4 to 0.8 silicon, 0.15 to 0.4 copper, 0.04 to 0.35 chromium, 0 to 0.7 iron, 0 to 0.25 zinc, 0 to 0.15 manganese, 0 to 0.15 titanium, the balance being aluminum and impurities); Al 2014 alloy (having a nominal composition, in weight percentages based on total alloy weight, 3.9 to 5 copper, 0.5 to 1.2 silicon, 0.4 to 1.2 manganese, 0.2 to 0.8 magnesium, 0 to 0.7 iron, 0 to 0.25 zinc, 0 to 0.15 titanium, 0 to 0.1 chromium, the balance being aluminum, and

impurities); Al 7050 alloy (having a nominal composition, in weight percentages based on total alloy weight, 5.7 to 6.7 zinc, 2 to 2.6 copper, 1.9 to 2.6 magnesium, 0.08 to 0.15 zirconium, 0 to 0.15 iron, 0 to 0.12 silicon, 0 to 0.1 manganese, 0 to 0.06 titanium, 0 to 0.04 chromium, the balance being aluminum, and impurities); Al 5083 alloy (having a nominal composition, in weight percentages based on total alloy weight, 4 to 4.9 magnesium, 0.4 to 1 manganese, 0 to 0.4 silicon, 0.05 to 0.25 chromium, 0 to 0.4 iron, 0 to 0.25 zinc, 0 to 0.15 titanium, 0 to 0.1 copper, the balance being aluminum, and impurities); 2xx casting alloys including 201 alloy (having a nominal composition, in weight percentages based on total alloy weight, 4.6 copper, 0.7 silver, 0.35 manganese, 0.35 magnesium, 0.25 titanium, the balance being aluminum, and impurities), 205 alloy (having a nominal composition, in weight percentages based on total alloy weight, 4.6 copper, 3.4 titanium, 1.4 boron, 0.75 silver, 0.27 magnesium, the balance being aluminum, and impurities), 224 alloy (having a nominal composition, in weight percentages based on total alloy weight, 5 copper, 0.35 titanium, 0.35 manganese, 0.20 zirconium, 0 to 0.06 silicon, the balance being aluminum, and impurities), 242 alloy (having a nominal composition, in weight percentages based on total alloy weight, 0.7 silicon, 1 iron, 3.5 to 4.5 copper, 1.7 to 2.3 nickel, 1.2 to 1.8 magnesium, 0.35 zinc, 0.25 titanium 0.35 manganese, the balance being aluminum, and impurities), and 249 alloy (having a nominal composition, in weight percentages based on total alloy weight, 4.2 copper, 0.4 magnesium, 0.4 manganese, 3.0 zirconium, the balance being aluminum, and impurities); 3xx casting alloys including 319 alloy (having a nominal composition, in weight percentages based on total alloy weight, 6 silicon, 3.5 copper, 0 to 1.0 iron, the balance being aluminum, and impurities), 356 alloy (having a nominal composition, in weight percentages based on total alloy weight, 6.5 to 7.5 silicon, 0.60 iron, 0.25 copper, 0.2 to 0.45 magnesium, 0.25 titanium, 0.35 zinc, 0.35 manganese, the balance being aluminum, and impurities), 357 alloy (having a nominal composition, in weight percentages based on total alloy weight, 6.5 to 7.5 silicon, 0.04 to 0.07 beryllium, 0.2 iron, 0.2 copper, 0.4 to 0.7 magnesium, 0.04 to 0.2 titanium, 0.1 zinc, 0.1 manganese, the balance being aluminum, and impurities), 359 alloy (having a nominal composition, in weight percentages based on total alloy weight, 8.5 to 9.5 silicon, 0.20 iron, 0.20 copper, 0.10 manganese, 0.50 to 0.7 magnesium, 0.10 zinc, 0.20 titanium, the balance being aluminum, and impurities), and 354 alloy (having a nominal composition, in weight percentages based on total alloy weight, 8.6 to 9.4 silicon, 0.20 iron, 1.6 to 2.0 copper, 0.10 manganese, 0.40 to 0.6 magnesium, 0.10 zinc, 0.20 titanium, the balance being aluminum, and impurities); 4xx casting alloys including 413 alloy (having a nominal composition, in weight percentages based on total alloy weight, 11.0 to 13.0 silicon, 2.0 iron, 1.0 copper, 0.35 manganese, 0.10 magnesium, 0.50 nickel, 0.50 zinc, 0.15 tin, the balance being aluminum, and impurities), and 443 alloy (having a nominal composition, in weight percentages based on total alloy weight, 4.5 to 6.0 silicon, 0.8 iron, 0.6 copper, 0.50 manganese, 0.05 magnesium, 0.25 chromium, 0.50 zinc, 0.25 titanium, the balance being aluminum, and impurities); 5xx casting alloys including 513 alloy (having a nominal composition, in weight percentages based on total alloy weight, 0.30 silicon, 0.40 iron, 0.10 copper, 0.30 manganese, 3.5 to 4.5 magnesium, 1.4 to 2.2 zinc, 0.20 titanium, the balance being aluminum, and impurities), 514 alloy (having a nominal composition, in weight percentages based on total alloy weight, 0.35 silicon, 0.50 iron, 0.15 copper, 0.35 manganese, 3.5 to 4.5 magnesium, 0.15 zinc, 0.25 titanium, the balance being aluminum, and impurities), 515 alloy (having a nominal composition, in weight percentages based on total alloy weight, 0.50 to 1.0 silicon, 1.3 iron, 0.20 copper, 0.40 to 0.6 manganese, 2.5 to 4.0 magnesium, 0.10 zinc, the balance being aluminum, and impurities), 518 alloy (having a nominal composition, in weight percentages based on total alloy weight, 0.35 silicon, 1.8 iron, 0.25 copper, 0.35 manganese, 7.5 to 8.5 magnesium, 0.15 nickel, 0.15 zinc, 0.15 tin, the balance being aluminum, and impurities), 520 alloy (having a nominal composition, in weight percentages based on total alloy weight, 0.25 silicon, 0.30 iron, 0.25 copper, 0.15 manganese, 9.5 to 10.6 magnesium, 0.15 zinc, 0.25 titanium, the balance being aluminum, and impurities), and 535 alloy (having a nominal composition, in weight percentages based on total alloy weight, 0.15 silicon, 0.15 iron, 0.05 copper, 0.10 to 0.25 manganese, 6.2 to 7.5 magnesium, 0.10 to 0.25 titanium, the balance being aluminum, and impurities); 7xx casting alloys including 705 alloy (having a nominal composition, in weight percentages based on total alloy weight, 0.20 silicon, 0.8 iron, 0.20 copper, 0.40 to 0.6 manganese, 1.4 to 1.8 magnesium, 0.20 to 0.40 chromium, 2.7 to 3.3 zinc, the balance being aluminum, and impurities), 712 alloy (having a nominal composition, in weight percentages based on total alloy weight, 0.30 silicon, 0.50 iron, 0.25 copper, 0.10 manganese, 0.50 to 0.65 magnesium, 0.40 to 0.6 chromium, 5.0 to 6.5 zinc, 0.15 to 0.25 titanium, the balance being aluminum, and impurities), and 713 alloy (having a nominal composition, in weight percentages based on total alloy weight, 0.25 silicon, 1.1 iron, 0.40 to 1.0 copper, 0.6 manganese, 0.20 to 0.50 magnesium, 0.35 chromium, 0.15 nickel, 7.0 to 8.0 zinc, the balance being aluminum, and impurities); Ti-6Al-4V alloy (having a nominal composition, in weight percentages based on total alloy weight, 5.50 to 6.75 aluminum, 3.50 to 4.50 vanadium, the balance being titanium, and impurities); titanium aluminide alloys including TΪ4822 alloy (having a nominal composition, in weight percentages based on total alloy weight, 48 aluminum, 2 niobium, 2 chromium, the balance being titanium, and impurities); and Inconel® 718 alloy (having a nominal composition, in weight percentages based on total alloy weight, 50.0 to 55.0 nickel, 0 to 1.0 cobalt, 17.0 to 21.0 chromium, 0 to 0.35 manganese, 2.8 to 3.3 molybdenum, 4.75 to 5.50 niobium, 0.65 to 1.15 titanium, 0.2 to 0.8 aluminum, 0 to 0.35 silicon, 0 to 0.08 carbon, 0 to 0.006 boron, the balance being iron, and impurities). Although the present description references certain specific alloys, the methods and green and sintered articles described herein are not limited in this regard, provided that they are associated with a feedstock powder or starting material that is a powder blend comprising a first metallic alloy powder having a first solidus temperature and a second metallic alloy powder having a second solidus temperature, wherein the second solidus temperature is lower than the first solidus temperature.

[0024] The examples that follow are intended to further describe non-limiting embodiments of the powder feedstock or starting materials according to the present disclosure, without restricting the scope of the present invention. It will be understood that the methods described herein are not limited to producing sintered articles from the powder feedstock or starting materials of the following examples. Instead, the powder feed materials may be selected so as to provide the desired chemical composition and a suitable or desired volume of liquid phase during the sintering process.

[0025] According to certain non-limiting embodiments, the first metallic alloy powder and the second metallic alloy powder may be aluminum alloys individually selected from lxxx series aluminum alloys, 2xxx series aluminum alloys, 3xxx series aluminum alloys, 4xxx series aluminum alloys, 5xxx series aluminum alloys, 6xxx series aluminum alloys, 7xxx series aluminum alloys, and 8xxx series aluminum alloys. Definitions of lxxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx and 8xxx series aluminum alloys are provided in International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys (2015), by the Aluminum Association. In various non limiting embodiments, the first and second metallic alloy powders may be alloys within the same aluminum alloy system, but have different elemental compositions that fall within the nominal composition for that particular alloy system. In various other embodiments, the first and second metallic alloy powders may be alloys within different aluminum alloy systems. Table 1 lists chemical compositions (in weight percentages), target levels (in volume percentages), and the solidus temperature for the first and second metallic alloy powders in various possible non-limiting embodiments of metallic powders according to the present disclosure wherein the first and second metallic alloy powders are aluminum alloy powders. The metallic powder embodiments listed in Table 1 include first and second metallic alloy powders of the same aluminum alloy system, but with different chemistries and solidus temperatures. The metallic powder embodiments listed in Table 1 also include an additional example to produce an Al 6061 alloy from first and second metallic powders that fall within different aluminum alloy systems. In certain embodiments according to the present disclosure, trace elements may be present as incidental impurities in the aluminum alloys disclosed herein. As used herein, the term“impurities” may refer to any elements of the periodic table other than the elements specifically identified, and which may be present in the aluminum alloy in minor concentrations.

Table 1

[0026] According to certain non-limiting embodiments, the first metallic alloy powder and the second metallic alloy powder may be Ti-6Al-4V alloy (having a composition as specified in UNS R56400). In various non-limiting embodiments, the first and second metallic alloy powders may be alloys within the same titanium alloy system, but have different elemental compositions that fall within the nominal composition for that particular alloy system. In various other embodiments, the first and second metallic alloy powders may be alloys within different titanium alloy systems. Generally, the methods described herein may be used in connection with any of near-a titanium alloys, a+b titanium alloys, near-b titanium alloys, and titanium aluminide alloys. Table 2 lists chemical compositions (in weight percentages), target levels (in volume percentages), and the solidus temperature for the first and second metallic alloy powders in various possible non-limiting embodiments of metallic powders according to the present disclosure wherein the first and second metallic alloy powders are titanium alloy powders. Each of the metallic powder embodiments listed in Table 2 includes first and second metallic alloy powders of the same titanium alloy system, but with different chemistries and solidus temperatures. In certain embodiments according to the present disclosure, an aluminum-rich master alloy may be used for any of the first and second metallic alloy powders. In certain embodiments according to the present disclosure, trace elements may be present as incidental impurities in the titanium alloys disclosed herein. As used herein, the term“impurities” may refer to any elements of the periodic table other than the elements specifically identified, and which may be present in the titanium alloy in minor concentrations.

Table 2

[0027] According to certain non-limiting embodiments, the first metallic alloy powder and the second metallic alloy powder may be nickel alloys individually selected from Alloy 718 (which has a composition as specified in UNS No. N07718) and Alloy 625 (which has a composition as specified in UNS No. N06625). Generally, the methods described herein may be used in connection with any nickel alloys or even cobalt alloys. In various non-limiting embodiments, the first and second metallic alloy powders may be alloys within the same nickel alloy system, but have different elemental compositions that fall within the nominal composition for that particular alloy system. In various other embodiments, the first and second metallic alloy powders may be alloys within different nickel alloy systems. Table 3 lists chemical compositions (in weight percentages), target levels (in volume percentages), and the solidus temperature for the first and second metallic alloy powders in various possible non-limiting embodiments of metallic powders according to the present disclosure wherein the first and second metallic alloy powders are nickel alloy powders. Each of the metallic powder embodiments listed in Table 3 includes first and second metallic alloy powders of the same nickel alloy system, but with different chemistries and solidus temperatures. In certain embodiments according to the present disclosure, trace elements may be present as incidental impurities in the nickel alloys disclosed herein. As used herein, the term“impurities” may refer to any elements of the periodic table other than the elements specifically identified, and which may be present in the nickel alloy in minor concentrations.

Table 3

[0028] In certain non-limiting embodiments of a method according to the present disclosure, the green article is exposed to microwave radiation to heat the article and produce a sintered article. The microwave radiation can be generated by a microwave source with power in a range of 0.1 kW to 100 kW, for example. In a non-limiting embodiment, the microwave radiation is generated by a solid-state microwave source. In certain non-limiting embodiments, the microwave radiation is generated at a frequency of 915 MHz or 2.4 GHz. In certain non-limiting embodiments, the green article is exposed to microwave radiation for a time period in the range of 1 min to 480 min.

[0029] In certain non-limiting embodiments, an electrical conductivity of the first metallic alloy powder and the second metallic alloy powder differ. While not wishing to be bound by any particular theory, it is believed that the differing electrical conductivities of the first metallic alloy powder and the second metallic power can lead to selective liquid formation within the green part and improve sintering results. For example, the second metallic alloy powder having a lower solidus temperature may be designed to possess a higher electrical conductivity, thereby promoting a microwave induced liquid phase formation from the second metallic alloy powder during sintering, and accelerating the densification rate via liquid phase sintering. According to other non-limiting embodiments, the first metallic alloy powder and the second metallic alloy powder may have the same solidus temperature, but have different elemental compositions that create a difference in electrical conductivities. The higher electrical conductivity of one powder can lead to a preferential coupling of microwave energy and thereby preferential melting of that powder if the microwave energy is controlled to increase the temperature of the powder blend above the solidus temperature of the powder having the higher electrical conductivity. The remainder of the blend will then be solid due to relatively poor coupling of microwave energy.

[0030] In certain non-limiting embodiments, the powder feed material produced according to the present disclosure is used to form a green preform or article by an additive manufacturing process. In a non-limiting embodiment, the green article is produced by binder jet additive manufacturing using at least a portion of the powder blend (comprising the first and second metallic alloy powders with differing solidus temperatures) as the powder feed material, and a binder. In certain non-limiting embodiments, the binder is at least one material selected from a heat-curable polymer, a glue, and a cement. In other non-limiting embodiments, the binder is at least one material selected from polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, and a wax. It will be understood, however, that the methods encompassed by the present disclosure are not limited in this regard. In various non-limiting embodiments of the methods according to the present disclosure, binder burn-off is part of the heating step for sintering. For example, as the temperature increases, the binder is burned off first, and as the temperature further increases, the green body is sintered. In various other embodiments, a separate heating step may be carried out for the binder burn-off.

[0031] In certain non-limiting embodiments, the sintered article can be heat treated through one or more steps of homogenizing, aging, and annealing to achieve a desired microstructure. "Homogenizing" is a term of art and will be readily understood by those having ordinary skill in the production of metallic powder materials. In general,

homogenizing may involve heat-treating a material such that the material has a more uniform composition. “Aging,” which is also referred to as precipitation aging or age hardening, is used to provide a controlled precipitation of strengthening particles in the alloy matrix.

According to further embodiments, there may be further steps such as rough and final machining and/or surface finishing, depending on the use requirements or preferences of the particular method or sintered articles. [0032] After sintering and heat-treating and/or thermal homogenization, certain non-limiting embodiments of the sintered article may comprise a density greater than 85% of theoretical full density, or in some embodiments greater than 95% of theoretical full density.

[0033] In some embodiments, the products produced by these methods have commercial end-uses in industrial applications, consumer applications ( e.g consumer electronics and/or appliances) or other areas. For example, the components or resulting products can be utilized in the aerospace field, automotive field, transportation field, building and construction field, in a variety of forms: fasteners, sheet, plate, castings, forgings, extrusions, post processed additive manufacturing forms, among others, including various applications (e.g., structural applications and components such as beams, frames, rails, brackets, bulkheads, spars, ribs, among others).

[0034] Various non-exhaustive, non-limiting aspects of novel methods and sintered articles according to the present disclosure may be useful alone or in combination with one or more other aspects described herein. Without limiting the foregoing description, in a first non-limiting aspect of the present disclosure, a method of producing a sintered article comprises blending ingredients comprising a first metallic alloy powder having a first solidus temperature and a second metallic alloy powder having a second solidus temperature to provide a powder blend, wherein the second solidus temperature is lower than the first solidus temperature; forming an article comprising at least a portion of the powder blend; and sintering the article at a temperature between the first and second solidus temperatures to form a sintered article.

[0035] In accordance with a second non-limiting aspect of the present disclosure, which may be used in combination with the first aspect, the difference between first solidus temperature and the second solidus temperature is at least 10 Celsius degrees.

[0036] In accordance with a third non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the difference between first solidus temperature and the second solidus temperature is in a range of 5 to 300 Celsius degrees.

[0037] In accordance with a fourth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder and the second metallic alloy powder are aluminum alloy powders. [0038] In accordance with a fifth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder and the second metallic alloy powder are aluminum alloys individually selected from the group consisting of lxxx series aluminum alloys, 2xxx series aluminum alloys, 3xxx series aluminum alloys, 4xxx series aluminum alloys, 5xxx series aluminum alloys, 6xxx series aluminum alloys, 7xxx series aluminum alloys, and 8xxx series aluminum alloys.

[0039] In accordance with a sixth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first and second metallic alloy powders are selected from different aluminum alloy systems.

[0040] In accordance with a seventh non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 0.4 to 0.8 silicon, 0 to 0.7 iron, 0.15 to 0.4 copper, 0 to 0.15 manganese, 0.8 to 1.2 magnesium, 0.04 to 0.35 chromium, the balance being aluminum and impurities; and the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 1.0 to 1.4 silicon, 0 to 0.7 iron, 0.15 to 0.4 copper, 0 to 0.15 manganese, 0.8 to 1.2 magnesium, 0.04 to 0.35 chromium, the balance being aluminum, and impurities.

[0041] In accordance with a eighth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 0.4 to 0.8 silicon, 0 to 0.7 iron, 0.15 to 0.4 copper, 0 to 0.15 manganese, 0.8 to 1.2 magnesium, 0.04 to 0.35 chromium, the balance being aluminum, and impurities; and the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 1.5 to 1.9 silicon, 0 to 0.7 iron, 0.15 to 0.4 copper, 0 to 0.15 manganese, 0.8 to 1.2 magnesium, 0.04 to 0.35 chromium, the balance being aluminum, and impurities.

[0042] In accordance with a ninth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 0.5 to 1.2 silicon, 0 to 0.7 iron, 3.9 to 5.0 copper, 0.4 to 1.2 manganese, 0.2 to 0.8 magnesium, 0 to 0.1 chromium, the balance being aluminum, and impurities; and the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 0.85 to 1.55 silicon, 0 to 0.7 iron, 3.9 to 5.0 copper, 0.4 to 1.2 manganese, 0.2 to 0.8 magnesium, 0 to 0.1 chromium, the balance being aluminum, and impurities.

[0043] In accordance with a tenth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 2.0 to 2.6 copper, 1.9 to 2.6 magnesium, 5.7 to 6.7 zinc, the balance being aluminum, and impurities; and the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 2.0 to 2.6 copper, 1.9 to 2.6 magnesium, 9.5 to 10.5 zinc, the balance being aluminum, and impurities.

[0044] In accordance with a eleventh non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 0.05 to 0.25 chromium, 4.0 to 4.9 magnesium, 0.4 to 1.0 manganese, the balance being aluminum, and impurities; and the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 0.05 to 0.25 chromium, 4.0 to 4.9 magnesium, 0.4 to 1.0 manganese, 0.75 to 1.25 silicon, the balance being aluminum, and impurities.

[0045] In accordance with a twelfth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder and the second metallic alloy powder are titanium alloy powders.

[0046] In accordance with a thirteenth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 5.50 to 6.75 aluminum, 3.50 to 4.50 vanadium, the balance being titanium, and impurities; and the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 5.50 to 6.75 aluminum, 3.50 to 4.50 vanadium, greater than 0 up to 3.0 silicon, the balance being titanium, and impurities.

[0047] In accordance with a fourteenth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 5.50 to 6.75 aluminum, 3.50 to 4.50 vanadium, the balance being titanium, and impurities; and the second metallic alloy powder comprises, in weight percentages based on total alloy weight, comprises, in weight percentages based on total alloy weight, 5.50 to 6.75 aluminum, 3.50 to 4.50 vanadium, 1.5 to 2.5 silicon, the balance being titanium, and impurities.

[0048] In accordance with a fifteenth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder and the second metallic alloy powder are nickel alloys powders.

[0049] In accordance with a sixteenth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder and the second metallic alloy powder are nickel alloys individually selected from the group consisting of Alloy 718 and Alloy 625.

[0050] In accordance with a seventeenth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 17.0 to 21.0 chromium, 4.75 to 5.50 niobium, 2.80 to 3.30 molybdenum, 0.65 to 1.15 titanium, 0.2 to 0.8 aluminum, 0 to 0.35 silicon, 16.5 to 20.5 iron, 0 to 0.35 manganese, the balance being nickel, and impurities; and the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 17.0 to 21.0 chromium, 4.75 to 5.50 niobium, 2.80 to 3.30 molybdenum, 0.65 to 1.15 titanium, 0.2 to 0.8 aluminum, 0.3 to 0.7 silicon, 16.5 to 20.5 iron, 0 to 0.35 manganese, the balance being nickel, and impurities.

[0051] In accordance with a eighteenth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 17.0 to 21.0 chromium, 4.75 to 5.50 niobium, 2.80 to 3.30 molybdenum, 0.65 to 1.15 titanium, 0.2 to 0.8 aluminum, 0 to 0.35 silicon, 16.5 to 20.5 iron, 0 to 0.35 manganese, the balance being nickel, and impurities; and the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 17.0 to 21.0 chromium, 4.75 to 5.50 niobium, 2.80 to 3.30 molybdenum, 0.65 to 1.15 titanium, 0.2 to 0.8 aluminum, 0.75 to 1.25 silicon, 16.5 to 20.5 iron, 0 to 0.35 manganese, the balance being nickel, and impurities.

[0052] In accordance with a nineteenth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, sintering the article comprises exposing the article to microwave radiation.

[0053] In accordance with a twentieth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, each of the first metallic alloy powder and the second metallic alloy powder has an average particle size in the range of 5 pm to 150 pm.

[0054] In accordance with a twenty -first non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the second metallic alloy powder has an average particle size smaller than the first metallic alloy powder.

[0055] In accordance with a twenty-second non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, at least one of the first metallic alloy powder and the second metallic alloy powder comprises a recycled material.

[0056] In accordance with a twenty -third non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, forming the article comprises forming the article by an additive manufacturing process.

[0057] In accordance with a twenty-fourth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, forming the article comprises forming the article by a binder jet additive

manufacturing process, wherein the article comprises the at least a portion of the powder blend and a binder.

[0058] In accordance with a twenty-fifth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the article further comprises at least one binder selected from the group consisting of a heat-curable polymer, a glue, and a cement.

[0059] In accordance with a twenty-sixth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the article further comprises at least one binder selected from the group consisting of polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, and a wax.

[0060] In accordance with a twenty-seventh non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the sintered article comprises a density greater than 85% of theoretical full density. [0061] In accordance with a twenty-eighth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the sintered article comprises, in weight percentages based on total alloy weight: 0.8 to 1.2 magnesium; 0.4 to 0.8 silicon; 0.15 to 0.4 copper; 0.04 to 0.35 chromium; 0 to 0.7 iron; 0 to 0.25 zinc; 0 to 0.15 manganese; 0 to 0.15 titanium; the balance being aluminum; and impurities.

[0062] In accordance with a twenty-ninth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the sintered article comprises, in weight percentages based on total alloy weight: 3.9 to 5 copper; 0.5 to 1.2 silicon; 0.4 to 1.2 manganese; 0.2 to 0.8 magnesium; 0 to 0.7 iron; 0 to 0.25 zinc; 0 to 0.15 titanium; 0 to 0.1 chromium; the balance being aluminum; and impurities.

[0063] In accordance with a thirtieth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the sintered article comprises, in weight percentages based on total alloy weight: 5.7 to 6.7 zinc; 2 to 2.6 copper; 1.9 to 2.6 magnesium; 0.08 to 0.15 zirconium; 0 to 0.15 iron; 0 to 0.12 silicon; 0 to 0.1 manganese; 0 to 0.06 titanium; 0 to 0.04 chromium; the balance being aluminum; and impurities.

[0064] In accordance with a thirty-first non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the sintered article comprises, in weight percentages based on total alloy weight: 4 to 4.9 magnesium; 0.4 to 1 manganese; 0 to 0.4 silicon; 0.05 to 0.25 chromium; 0 to 0.4 iron; 0 to 0.25 zinc; 0 to 0.15 titanium; 0 to 0.1 copper; the balance being aluminum; and impurities.

[0065] In accordance with a thirty-second non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the sintered article comprises, in weight percentages based on total alloy weight:

5.50 to 6.75 aluminum; 3.50 to 4.50 vanadium; the balance being titanium; and impurities.

[0066] In accordance with a thirty -third non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the sintered article comprises, in weight percentages based on total alloy weight:

50.0 to 55.0 nickel; 0 to 1.0 cobalt; 17.0 to 21.0 chromium; 0 to 0.35 manganese; 2.8 to 3.3 molybdenum; 4.75 to 5.50 niobium; 0.65 to 1.15 titanium; 0.2 to 0.8 aluminum; 0 to 0.35 silicon; 0 to 0.08 carbon; 0 to 0.006 boron; the balance being iron; and impurities. [0067] In accordance with a thirty-fourth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the sintered article is an automotive component.

[0068] In accordance with a thirty-fifth non-limiting aspect of the present disclosure, which may be used in combination with each or any of the above-mentioned aspects, the sintered article is an aerospace component.

[0069] In accordance with a thirty-sixth non-limiting aspect of the present disclosure, a method of producing a sintered article comprises blending ingredients comprising a first metallic alloy powder having a first solidus temperature and a second metallic alloy powder having a second solidus temperature to provide a powder blend, wherein the second solidus temperature is lower than the first solidus temperature; forming an article comprising at least a portion of the powder blend and a binder by an additive manufacturing process; and sintering the article at a temperature between the first and second solidus temperatures to form a sintered article.

[0070] Although the foregoing description has necessarily presented only a limited number of embodiments, those of ordinary skill in the relevant art will appreciate that various changes in the methods and other details of the examples that have been described and illustrated herein may be made by those skilled in the art, and all such modifications will remain within the principle and scope of the present disclosure as expressed herein and in the appended claims. It is understood, therefore, that the present invention is not limited to the particular embodiments disclosed or incorporated herein, but is intended to cover

modifications that are within the principle and scope of the invention, as defined by the claims. It will also be appreciated by those skilled in the art that changes could be made to the embodiments above without departing from the broad inventive concept thereof.

[0071] The methods described in this specification can comprise, consist of, or consist essentially of the various features and characteristics described in this specification. The grammatical articles“one”,“a”,“an”, and“the”, as used in this specification, are intended to include“at least one” or“one or more”, unless otherwise indicated. Thus, the articles are used in this specification to refer to one or more than one (i.e., to“at least one”) of the grammatical objects of the article. By way of example,“at least a first metallic alloy powder and a second metallic alloy powder” means two or more metallic alloy powders, and thus, possibly, more than two metallic alloy powders are contemplated and can be employed or used in an implementation of the described methods. Further, the use of a singular noun includes the plural, and the use of a plural noun includes the singular, unless the context of the usage requires otherwise.

Claims

What is claimed is:

1. A method of producing a sintered article, the method comprising:

blending ingredients comprising a first metallic alloy powder having a first solidus temperature and a second metallic alloy powder having a second solidus temperature to provide a powder blend, wherein the second solidus temperature is lower than the first solidus temperature;

forming an article comprising at least a portion of the powder blend; and sintering the article at a temperature between the first and second solidus temperatures to form a sintered article.

2. The method of claim 1, wherein the difference between first solidus temperature and the second solidus temperature is at least 10 Celsius degrees.

3. The method of claim 1, wherein the difference between first solidus temperature and the second solidus temperature is in a range of 5 to 300 Celsius degrees.

4. The method of claim 1, wherein the first metallic alloy powder and the second metallic alloy powder are aluminum alloy powders.

5. The method of claim 4, wherein the first metallic alloy powder and the second metallic alloy powder are aluminum alloys individually selected from the group consisting of lxxx series aluminum alloys, 2xxx series aluminum alloys, 3xxx series aluminum alloys, 4xxx series aluminum alloys, 5xxx series aluminum alloys, 6xxx series aluminum alloys, 7xxx series aluminum alloys, and 8xxx series aluminum alloys.

6. The method of claim 5, wherein the first and second metallic alloy powders are selected from different aluminum alloy systems.

7. The method of claim 1, wherein:

the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 0.4 to 0.8 silicon, 0 to 0.7 iron, 0.15 to 0.4 copper, 0 to 0.15 manganese, 0.8 to 1.2 magnesium, 0.04 to 0.35 chromium, the balance being aluminum and impurities; and

the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 1.0 to 1.4 silicon, 0 to 0.7 iron, 0.15 to 0.4 copper, 0 to 0.15 manganese, 0.8 to 1.2 magnesium, 0.04 to 0.35 chromium, the balance being aluminum, and impurities.

8. The method of claim 1, wherein:

the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 0.4 to 0.8 silicon, 0 to 0.7 iron, 0.15 to 0.4 copper, 0 to 0.15 manganese, 0.8 to 1.2 magnesium, 0.04 to 0.35 chromium, the balance being aluminum, and impurities; and the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 1.5 to 1.9 silicon, 0 to 0.7 iron, 0.15 to 0.4 copper, 0 to 0.15 manganese, 0.8 to 1.2 magnesium, 0.04 to 0.35 chromium, the balance being aluminum, and impurities.

9. The method of claim 1, wherein:

the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 0.5 to 1.2 silicon, 0 to 0.7 iron, 3.9 to 5.0 copper, 0.4 to 1.2 manganese, 0.2 to 0.8 magnesium, 0 to 0.1 chromium, the balance being aluminum, and impurities; and the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 0.85 to 1.55 silicon, 0 to 0.7 iron, 3.9 to 5.0 copper, 0.4 to 1.2 manganese, 0.2 to 0.8 magnesium, 0 to 0.1 chromium, the balance being aluminum, and impurities.

10. The method of claim 1, wherein:

the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 2.0 to 2.6 copper, 1.9 to 2.6 magnesium, 5.7 to 6.7 zinc, the balance being aluminum, and impurities; and

the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 2.0 to 2.6 copper, 1.9 to 2.6 magnesium, 9.5 to 10.5 zinc, the balance being aluminum, and impurities.

11. The method of claim 1, wherein:

the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 0.05 to 0.25 chromium, 4.0 to 4.9 magnesium, 0.4 to 1.0 manganese, the balance being aluminum, and impurities; and

the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 0.05 to 0.25 chromium, 4.0 to 4.9 magnesium, 0.4 to 1.0 manganese, 0.75 to 1.25 silicon, the balance being aluminum, and impurities.

12. The method of claim 1, wherein the first metallic alloy powder and the second metallic alloy powder are titanium alloy powders.

13. The method of claim 1, wherein:

the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 5.50 to 6.75 aluminum, 3.50 to 4.50 vanadium, the balance being titanium, and impurities; and

the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 5.50 to 6.75 aluminum, 3.50 to 4.50 vanadium, greater than 0 up to 3.0 silicon, the balance being titanium, and impurities.

14. The method of claim 1, wherein:

the second metallic alloy powder comprises, in weight percentages based on total alloy weight, comprises, in weight percentages based on total alloy weight, 5.50 to 6.75 aluminum, 3.50 to 4.50 vanadium, 1.5 to 2.5 silicon, the balance being titanium, and impurities.

15. The method of claim 1, wherein the first metallic alloy powder and the second metallic alloy powder are nickel alloy powders.

16. The method of claim 15, wherein the first metallic alloy powder and the second metallic alloy powder are nickel alloys individually selected from the group consisting of Alloy 718 and Alloy 625.

17. The method of claim 1, wherein:

the first metallic alloy powder comprises, in weight percentages based on total alloy weight, 17.0 to 21.0 chromium, 4.75 to 5.50 niobium, 2.80 to 3.30 molybdenum, 0.65 to 1.15 titanium, 0.2 to 0.8 aluminum, 0 to 0.35 silicon, 16.5 to 20.5 iron, 0 to 0.35 manganese, the balance being nickel, and impurities; and

the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 17.0 to 21.0 chromium, 4.75 to 5.50 niobium, 2.80 to 3.30 molybdenum, 0.65 to 1.15 titanium, 0.2 to 0.8 aluminum, 0.3 to 0.7 silicon, 16.5 to 20.5 iron, 0 to 0.35 manganese, the balance being nickel, and impurities.

18. The method of claim 1, wherein:

the second metallic alloy powder comprises, in weight percentages based on total alloy weight, 17.0 to 21.0 chromium, 4.75 to 5.50 niobium, 2.80 to 3.30 molybdenum, 0.65 to 1.15 titanium, 0.2 to 0.8 aluminum, 0.75 to 1.25 silicon, 16.5 to 20.5 iron, 0 to 0.35 manganese, the balance being nickel, and impurities.

19. The method of any one of claims 1-18, wherein sintering the article comprises exposing the article to microwave radiation.

20. The method of any one of claims 1-19, wherein each of the first metallic alloy powder and the second metallic alloy powder has an average particle size in the range of 5 pm to

150 pm.

21. The method of any one of claims 1-20, wherein the second metallic alloy powder has an average particle size smaller than the first metallic alloy powder.

22. The method of any one of claims 1-21, wherein at least one of the first metallic alloy powder and the second metallic alloy powder comprises a recycled material.

23. The method of any one of claims 1-22, wherein forming the article comprises forming the article by an additive manufacturing process.

24. The method of claim 23, wherein forming the article comprises forming the article by a binder jet additive manufacturing process, wherein the article comprises the at least a portion of the powder blend and a binder.

25. The method of any one of claims 1-24, wherein the article further comprises at least one binder selected from the group consisting of a heat-curable polymer, a glue, and a cement.

26. The method of any one of claims 1-25, wherein the article further comprises at least one binder selected from the group consisting of polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, and a wax.

27. The method of any one of claims 1-26, wherein the sintered article comprises a density greater than 85% of theoretical full density.

28. The method of claim 1, wherein the sintered article comprises, in weight percentages based on total alloy weight:

0.8 to 1.2 magnesium;

0.4 to 0.8 silicon;

0.15 to 0.4 copper;

0.04 to 0.35 chromium;

0 to 0.7 iron;

0 to 0.25 zinc;

0 to 0.15 manganese; 0 to 0.15 titanium;

the balance being aluminum; and

impurities.

29. The method of claim 1, wherein the sintered article comprises, in weight percentages based on total alloy weight:

3.9 to 5 copper;

0.5 to 1.2 silicon;

0.4 to 1.2 manganese;

0.2 to 0.8 magnesium;

0 to 0.7 iron;

0 to 0.25 zinc;

0 to 0.15 titanium;

0 to 0.1 chromium;

the balance being aluminum; and

impurities.

30. The method of claim 1, wherein the sintered article comprises, in weight percentages based on total alloy weight:

5.7 to 6.7 zinc;

2 to 2.6 copper;

1.9 to 2.6 magnesium;

0.08 to 0.15 zirconium;

0 to 0.15 iron;

0 to 0.12 silicon;

0 to 0.1 manganese;

0 to 0.06 titanium;

0 to 0.04 chromium;

the balance being aluminum; and

impurities.

31. The method of claim 1, wherein the sintered article comprises, in weight percentages based on total alloy weight: 4 to 4.9 magnesium;

0.4 to 1 manganese;

0 to 0.4 silicon;

0.05 to 0.25 chromium;

0 to 0.4 iron;

0 to 0.25 zinc;

0 to 0.15 titanium;

0 to 0.1 copper;

the balance being aluminum; and

impurities.

32. The method of claim 1, wherein the sintered article comprises, in weight percentages based on total alloy weight:

5.50 to 6.75 aluminum;

3.50 to 4.50 vanadium;

the balance being titanium; and

impurities.

33. The method of claim 1, wherein the sintered article comprises, in weight percentages based on total alloy weight:

50.0 to 55.0 nickel;

0 to 1.0 cobalt;

17.0 to 21.0 chromium;

0 to 0.35 manganese;

2.8 to 3.3 molybdenum;

4.75 to 5.50 niobium;

0.65 to 1.15 titanium;

0.2 to 0.8 aluminum;

0 to 0.35 silicon;

0 to 0.08 carbon;

0 to 0.006 boron;

the balance being iron; and

impurities.

34. The method of any one of claims 1-33, wherein the sintered article is an automotive component.

35. The method of any one of claims 1-33, wherein the sintered article is an aerospace component.

36. A method of producing a sintered article, the method comprising:

forming an article comprising at least a portion of the powder blend and a binder by an additive manufacturing process; and

sintering the article at a temperature between the first and second solidus temperatures to form a sintered article.