WO2019161137A1

WO2019161137A1 - Aluminum alloy products and methods for producing the same

Info

Publication number: WO2019161137A1
Application number: PCT/US2019/018116
Authority: WO
Inventors: Jen C. Lin
Original assignee: Arconic Inc.
Priority date: 2018-02-14
Filing date: 2019-02-14
Publication date: 2019-08-22

Abstract

The present disclosure relates to new aluminum alloy products. In one embodiment, an aluminum alloy product comprises at least one of (i) equiaxed grains, (ii) an average grain size of not greater than 50 micrometers, (iii) at least 10 vol. % of a eutectic-type structure, and (iv) a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 micrometers. In one embodiment, the aluminum alloy products may realize a non- equilibrium freezing range of not greater than 200°C. In one embodiment, the aluminum alloy products may be one of an Al-Li-Si or Al-Mg-Si aluminum alloy product.

Description

ALUMINUM ALLOY PRODUCTS AND METHODS FOR PRODUCING THE SAME

FIELD OF THE INVENTION

[001] The present patent application relates to aluminum alloy products and methods for producing the same.

BACKGROUND

[002] The Aluminum Association Global Advisory Group defines“aluminum alloys” as “aluminum which contains alloying elements, where aluminum predominates by mass over each of the other elements and where the aluminum content is not greater than 99.00%.” (Global Advisory Group GAG - Guidance, GAG Guidance Document 001, Terms and Definitions, Edition 2009-01, March 2009, § 2.2.2.) An“alloying element” is a“metallic or non-metallic element which is controlled within specific upper and lower limits for the purpose of giving the aluminum alloy certain special properties” (§ 2.2.3). A casting alloy is defined as“alloy primarily intended for the production of castings,” (§ 2.2.5) and a“wrought alloy” is “alloy primarily intended for the production of wrought products by hot and/or cold working” (§ 2.2.5).

SUMMARY OF THE DISCLOSURE

[003] Broadly, the present patent application relates to new aluminum alloy products, and methods for making the same. Due to the unique compositions and/or methods of production described herein, the new aluminum alloy products may realize a combination of unique microstructural features. The microstructural features may include at least one of (i) equiaxed grains, (ii) an average grain size of not greater than 50 pm (micrometers), (iii) at least 10 vol. % of a eutectic-type structure, and (iv) a eutectic-type structure having an average eutectic- type structure spacing of not greater than 5.0 pm, among others. Furthermore, in some embodiments, the aluminum alloy products may realize a non-equilibrium freezing range of not greater than 200°C. The new aluminum alloy products may realize improved properties, such as a unique combination of, for instance, two or more of strength, ductility, thermal stability, fracture toughness, fatigue resistance, creep resistance, and corrosion resistance, among others. In one embodiment, the alloys may be thermally stable, facilitating use of the new aluminum alloy products in elevated temperature conditions (e.g., > 200°C). In one embodiment, a new aluminum alloy product may be used in structural applications (e.g., aerospace and/or automotive applications). These and other aspects of the new aluminum alloys, including compositions, methods of production, microstructural features, and product applications, are described in further detail below. i. Microstructural Features

[004] As noted above, due to at least the unique compositions and/or manufacturing processes described herein, the new aluminum alloy products may realize one or more unique microstructural features. The unique microstructural features may include one or more of (i) equiaxed grains, (ii) an average grain size of not greater than 50 pm, (iii) at least 10 vol. % of a eutectic-type structure, and (iv) a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm, among others. Furthermore, in some embodiments, the new aluminum alloy products may realize a non-equilibrium freezing range of not greater than 200°C.

[005] In some embodiments, the new aluminum alloy products realize equiaxed grains (defined below). Equiaxed grains may facilitate production of crack-free aluminum alloy products. For instance, aluminum alloy products having equiaxed grains may have improved ductility, which may minimize and/or eliminate cracking during production. As defined below, equiaxed grains are grains that realize an average aspect ratio of not greater than 4 to 1 (4: 1). However, finer equiaxed grains (e.g., having an aspect ratio closer to 1 : 1) may be realized. For instance, in one embodiment, an aluminum alloy product realizes equiaxed grains having an average aspect ratio of not greater than 3 to 1 (3 : 1). In another embodiment, an aluminum alloy product realizes equiaxed grains having an average aspect ratio of not greater than 2 to 1 (2: 1). In yet another embodiment, an aluminum alloy product realizes equiaxed grains having an average aspect ratio of not greater than 1.5 to 1 (1.5: 1). In another embodiment, an aluminum alloy product realizes equiaxed grains having an average aspect ratio of not greater than 1.2 to 1 (1.2: 1). In yet another embodiment, an aluminum alloy product realizes equiaxed grains having an average aspect ratio of not greater than 1.1 to 1 (1.1 : 1).

[006] In some embodiments, the word“grain” takes on the meaning defined in ASTM El 12 §3.2.2, i.e.,“the area within the confines of the original (primary) boundary observed on the two-dimensional plane of-polish or that volume enclosed by the original (primary) boundary in the three-dimensional object.” As noted above,“equiaxed grains” are grains having an average aspect ratio of not greater than 4 to 1 (4: 1) as measured in the XY, YZ, and XZ planes. “Aspect ratio” is the inverse of the length of the minor axis of the ellipse divided by the length of the major axis of the ellipse. In one embodiment, an aspect ratio or an average aspect ratio is determined using commercial software Edax OIM version 8.0 or equivalent (see below). The commercial software fits an ellipse to the perimeter points of the grain. The amount (volume percent) of equiaxed grains in an aluminum alloy product may be determined by EBSD (electron backscatter diffraction) analysis of a suitable number of SEM micrographs of the aluminum alloy product. Generally, at least 5 micrographs should be analyzed.

[007] In one embodiment, grain dimensions and/or grain size are determined in two- dimensional space in accordance with the“Heyn Lineal Intercept Procedure” method described in ASTM standard El 12-13, entitled,“Standard Test Methods for Determining Average Grain Size.” In another embodiment, grain dimensions and/or grain size are calculated using the following equation:

. AAL

v/ = square root (— )

• wherein A i is the area of the individual grain as measured using commercial software Edax OIM version 8.0 or equivalent; and

• wherein vi is the calculated individual grain size assuming the grain is a circle.

[008] In one embodiment, grain size is determined based on a two-dimensional plane that includes the build direction of an additively manufactured product.

[009] In one embodiment, the“average grain size” is calculated using the following equation

v-bar

• wherein A i is the area of each individual grain as measured using commercial software Edax OIM version 8.0 or equivalent;

• wherein vi is the calculated individual grain size assuming the grain is a circle; and

• wherein v-bar is the average grain size.

[0010] In some embodiments, the aluminum alloy products described herein may realize an average grain size of not greater than 50 pm. Realization of grains having an average grain size of not greater than 50 pm may facilitate the production of crack-free aluminum alloy products. For instance, aluminum alloy products having an average grain size of not greater than 50 pm may realize improved ductility that may restrict, minimize and/or eliminate cracking during their production. Improved ductility may restrict, minimize and/or eliminate the cracking that may occur after the material has reached a temperature that is below its solidus, i.e.,“cold cracking”, as well cracking that may occur as the material cools from a temperature above its liquidus to below its solidus, i.e., "hot cracking”. In one embodiment, an aluminum alloy product realizes an average grain size of not greater than 40 pm. In another embodiment, an aluminum alloy product realizes an average grain size of not greater than 30 mih. In yet another embodiment, an aluminum alloy product realizes an average grain size of not greater than 20 pm. In another embodiment, an aluminum alloy product realizes an average grain size of not greater than 15 pm. In yet another embodiment, an aluminum alloy product realizes an average grain size of not greater than 10 pm. In one embodiment, an aluminum alloy product realizes an average grain size of at least 1 pm. In another embodiment, an aluminum alloy product realizes an average grain size of at least 2 pm. In one embodiment, an aluminum alloy product realizes an average grain size of from 1 to 20 pm. In another embodiment, an aluminum alloy product realizes an average grain size of from 2 to 10 pm.

[0011] In some embodiments, the aluminum alloy products described herein are produced via additive manufacturing. In this regard, one or more of the microstructural features of the aluminum alloy products described herein may prevent, reduce, and/or eliminate defects that may occur during additive manufacturing (e.g., hot and/or cold cracking). For instance, fine equiaxed grains (e.g., average grain size < 50 pm) may facilitate reduced cracking of additively manufactured products. In one embodiment, a new aluminum alloy is in the form of a crack- free product. In one embodiment, the crack-free product is an additively manufactured crack- free product.

[0012] As used herein,“crack-free product” means a product that 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 an ultrasonic inspection. 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 aluminum alloy product is determined to be crack-free by visual inspection. In another embodiment, an aluminum alloy product is determined to be crack-free by dye penetrant inspection. In yet another embodiment, an aluminum alloy product is determined to be crack-free by CT scan inspection. In another embodiment, an aluminum alloy product is determined to be crack-free during an additive manufacturing process, wherein in situ monitoring of the additively manufactured build is employed.

[0013] In some embodiments, the aluminum alloy products described herein may realize at least 10 vol. % of a eutectic-type structure (defined below). The production of aluminum alloy products having at least 10 vol. % of a eutectic-type structure may facilitate the production of crack-free aluminum alloy products. For instance, greater than 10% of a eutectic-type structure may reduce, limit or minimize the temperature range of the semi-solid state, thereby reducing, limiting or minimizing temperature gradients and/or thermal stresses that may cause an aluminum alloy product to crack during production. In one embodiment, an aluminum alloy product realizes at least 15 vol. % of a eutectic-type structure. In another embodiment, an aluminum alloy product realizes at least 20 vol. % of a eutectic-type structure. In general, the eutectic-type structure is realized in at least the as-solidified condition. However, the eutectic- type structure may also be realized in one or more thermally treated conditions (e.g., after exposure to one or more elevated temperatures).

[0014] In some embodiments, a eutectic-type structure is an alloy microstructure comprising microcellular, lamellar, and/or wavy structures. In one embodiment, an alloy microstructure comprises the matrix phase (e.g., fee aluminum) and at least one intermetallic phase, such as one or more of a microcellular, lamellar, and/or wavy structure. As one example, and referring now to FIG. la, a micrograph of an aluminum alloy product having a eutectic- type structure is shown. The additively manufactured alloy includes a matrix and various eutectic-type structures, including microcellular (20), lamellar (22) and wavy (24) structures. Other eutectic structures may be realized. Further, any combination of microcellular (20), lamellar (22), and wavy (24) structures may be realized.

[0015] In one embodiment, the“vol. % of a eutectic-type structure” is the volumetric percentage (vol. %) of a eutectic-type structure of an alloy product, which may be determined as follows:

1. Determine the alloy composition of the product using any suitable method (e.g., ICP analysis);

2. Calculate a Scheil solidification curve (temperature versus the volume percent of solids) for the alloy composition determined in Step 1 using the computation of phase diagram (“CALPHAD”) method;

3. From the Scheil diagram produced in Step 2, determine the interval of the Scheil solidification curve that realizes a slope of close to 0 (e.g., not greater than a 5° angle from horizontal), wherein the interval is defined by an upper bound volume percentage of solids and a lower bound volume percentage of solids; and

4. Calculate the size of the interval by subtracting the lower bound volume percentage of solids from the higher bound volume percentage of solids to arrive at the volume percentage (vol. %) of the eutectic-type structure. [0016] The aluminum alloy products described herein may realize a eutectic-type structure. The eutectic-type structure may comprise one or more of microcellular structures, lamellar structures, and wavy structures. In one embodiment, the eutectic-type structures are selected from the group consisting of microcellular structures, lamellar structures, wavy structures, and combinations thereof. These one or more eutectic-type structures may facilitate, for instance, production of aluminum alloy products having improved properties, such as improved strength, ductility, fracture toughness, fatigue resistance, creep resistance, corrosion resistance, and combinations thereof, among others. In one embodiment, one or more eutectic-type structures facilitate thermal stability, which may allow for use of the new aluminum alloy products in elevated temperature conditions (e.g., > 200°C). Thermal stability may be facilitated, for instance, by eutectic-type structure spacing (e.g., spacing between microcellular structures, lamellar structures, wavy structures), the characteristics of any discrete particles (e.g., intermetallic particles, silicon particles) within the eutectic-type structure (described below), and/or the amount of eutectic-type structure (e.g., the area or volume fraction of eutectic-type structure of an aluminum alloy product). In one embodiment, a finer spacing between eutectic- type structures (e.g., < 5.0 pm) may facilitate thermal stability, potentially in combination with increased strength. In one embodiment, the spacing between microcellular structures, lamellar structures, and wavy structures is generally not greater than 5.0 pm. Thus, in one embodiment, the average eutectic-type structure spacing is not greater than 5.0 pm. In another embodiment, the average eutectic-type structure spacing is not greater than 4.0 pm. In yet another embodiment, the average eutectic-type structure spacing is not greater than 3.0 pm. In another embodiment, the average eutectic-type structure spacing is not greater than 2.5 pm. In yet another embodiment, the average eutectic-type structure spacing is not greater than 2.0 pm. In another embodiment, the average eutectic-type structure spacing is not greater than 1.5 pm. In one embodiment, the average eutectic-type structure spacing is at least 0.05 pm. In another embodiment, the average eutectic-type structure spacing is at least 0.1 pm.

[0017] As used herein, “average eutectic-type structure spacing” means the average spacing between eutectic-type structures (e.g., microcellular structures, lamellar structures, and/or wavy structures). In one embodiment, the average eutectic-type structure spacing is determined by the“Heyn Lineal Intercept Procedure” method described in ASTM standard El 12-13, entitled,“Standard Test Methods for Determining Average Grain Size”, wherein the size between eutectic-type structures are measured as opposed to the grains. In another embodiment, computerized methods may be used to determine the average eutectic-type structure spacing.

[0018] In some embodiments, an aluminum alloy product comprises a eutectic-type structure, wherein the predominant structures of the eutectic-type structure are microcellular structures. One illustrative, non-limiting example is provided in FIG. lb, which shows an Al- Mg-Si alloy predominately comprised of microcellular structures. As depicted, the microcellular structures are comprised of dendritic structures having sub-micrometer (i.e., smaller than 1 micrometer) intermetallic particles at the cell walls (40). FIG. lb illustrates alternating structures of matrix phase (face-centered cubic (“fee”) aluminum) (42) and intermetallic particles (40). Further, illustrative examples of the eutectic-type structure spacing are shown (44). In this regard, the spacing between the illustrated eutectic-type structures is measured from the end of one cell to another (e.g., the cell size). Similar measurements can be made for lamellar and wavy structures. The eutectic-type structures may be alternating phases of matrix phase and one or more intermetallic phases. Thus, the eutectic-type structure spacing is generally measured as the distance between alternating phases (e.g., one intermetallic structure to another intermetallic structure). In this regard, FIG. lc illustrates the lamellar structures (22) portion of FIG. la. Further, FIG. lc illustrates the intermetallic particles (50), matrix phase (52), and the eutectic-type structure spacing (54) (e.g., lamella spacing).

[0019] In some embodiments, a eutectic-type structure comprises discrete particles (e.g., intermetallic particles and/or silicon particles that may form during solidification and/or thermal treatment). The discrete particles may be non-spheroidal or spheroidal. In some embodiments, discrete particles of a eutectic-type structure may be located at, for instance, the cell walls and/or lamella of the aluminum alloy product. In some embodiments, non-spheroidal discrete particles may be spheroidized (e.g., via a thermal treatment). Spheroidizing the discrete particles may lead to improved properties (e.g., ductility and/or fracture toughness). In one embodiment, the discrete particles are (or comprise) intermetallic particles. Intermetallic particles suitable for spheroidization in an aluminum alloy product may include, for instance, AlLi, AlLiSi, and Mg₂Si, particles, among others. Another type of discrete particle suitable for spheroidization may be silicon particles (e.g., diamond phase silicon particles). For instance, in one embodiment, an aluminum alloy product (e.g., an Al-Mg-Si or Al-Li-Si aluminum alloy product) comprises silicon particles, and such silicon particles may be spheroidized / subject to spheroidization. In some embodiments, the discrete particles are Mg₂Si particles (e.g., Mg₂Si particles located at cell walls and/or lamella of a eutectic-type structure). In one embodiment, an aluminum alloy product (e.g., an Al-Mg-Si or an Al-Li-Si alloy product) comprises a eutectic-type structure, wherein the cell walls comprise Mg₂Si particles. The cell wall Mg₂Si particles may facilitate improved properties, such as enhanced ductility and/or fracture toughness, among others. As noted above, the Mg₂Si particles may be spheroidized (e.g., via thermal treatment).

[0020] In one embodiment, an aluminum alloy product comprises at least 1.0 vol. % of Mg₂Si particles. In another embodiment, an aluminum alloy product comprises at least 1.5 vol. % of Mg₂Si particles. In yet another embodiment, an aluminum alloy product comprises at least 2.0 vol. % of Mg₂Si particles. In another embodiment, an aluminum alloy product comprises at least 2.5 vol. % of Mg₂Si particles. In yet another embodiment, an aluminum alloy product comprises at least 3.0 vol. % of Mg₂Si particles. In another embodiment, an aluminum alloy product comprises at least 3.5 vol. % of Mg₂Si particles. In one embodiment, an aluminum alloy product comprises not greater than 5.0 vol. % of Mg₂Si particles. The volume amounts of Mg₂Si particles of this paragraph apply to both the Al-Mg-Si and the Al-Li-Si alloys described herein.

[0021] The aluminum alloy products described herein may realize a narrow freezing range (e.g., a non-equilibrium freezing range of not greater than 200°C). A narrow freezing range may restrict, reduce and/or limit the temperature range of the semi-solid state, thereby restricting, reducing, and/or limiting temperature gradients and/or thermal stresses that may tend to cause an aluminum alloy product to crack during production. In one embodiment, an aluminum alloy product realizes a non-equilibrium freezing range of not greater than l00°C. In another embodiment, an aluminum alloy product realizes a non-equilibrium freezing range of not greater than 50°C.

[0022] As used herein,“Non-equilibrium freezing range” means the solidification range calculated using the Scheil solidification model implemented in commercial software PANDAT®. The Scheil solidification range is the non-equilibrium freezing range (complete diffusion in the liquid; no diffusion in the solid).

[0023] Generally, one or more of the microstructural features described herein are realized in at least the as-solidified condition (defined below). However, one or more of the microstructural features may be realized in several states of the aluminum alloy products during their production. In other embodiments, one or more of the microstructural features described herein may be realized following thermal treatment and/or working operations. Suitable thermal treatments may include solution heat treatment, aging (e.g., artificial and/or natural), and/or annealing. In one embodiment, an aluminum alloy product is solution heat treated. Solution heat treatment is typically followed by a rapid quench, such as an air or liquid quench. Artificial aging may be conducted after the quench. In another embodiment, the aluminum alloy product is annealed. In one embodiment, an anneal may, inter alia , stress relieve an aluminum alloy product. In one embodiment, one or more of the microstructural features may be retained from the as-solidified condition after one or more thermal treatment and/or working operations. For instance, at least 10 vol. % of a eutectic-type structure may be retained from the as-solidified condition following (a) a thermal treatment, (b) a mechanical treatment (hot and/or cold working), or (c) both thermal and mechanical treatment operations (i.e., TMT).

[0024] As used herein,“as-solidified condition” means the condition of a product that is realized by heating a material to a temperature above its liquidus followed by cooling to a temperature below its solidus, absent of any thermal treatments. Post-solidification thermal treatments may include, for instance, solution heat treating, aging (e.g., artificial and/or natural), and annealing, among others. The as-solidified condition may be referred to as, for instance, the as-built condition for additively manufactured products. ii. Al-Li-Si Alloys

[0025] In one approach, the aluminum alloy is an Al-Li-Si alloy. In one embodiment, an Al-Li-Si aluminum alloy comprises 0.1 - 5 wt. % Li and 2 - 18 wt. % Si. In one embodiment, an Al-Li-Si alloy comprises (and in some instances consists essentially of, or consists of) 0.1 - 5 wt. % Li, 2 - 18 wt. % Si, and up to 7 wt. % Mg, the balance being aluminum, optional incidental elements and impurities. As described in further detail below, the optional incidental elements may include, for instance, eutectic structure modifiers (e.g., cell wall modifiers), and/or grain refiners (defined below), among other things.

[0026] An Al-Li-Si alloy product may realize unique microstructural features. For instance, an Al-Li-Si aluminum alloy product may realize at least one of (i) equiaxed grains, (ii) an average grain size of not greater than 50 pm, (iii) at least 10 vol. % of a eutectic-type structure, and (iv) a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm, among others. In one embodiment, an Al-Li-Si aluminum alloy product may realize a non-equilibrium freezing range of not greater than 200°C. In one embodiment, an Al-Li-Si alloy may be any one of a hypo-, near-, or hyper-eutectic composition. In this regard, the at least 10 vol. % of eutectic-type structure may form via the following eutectic reaction: liquid ^face-centered cubic Al + AlLi +AlLiSi

The above eutectic reaction may occur at approximately 11 l3°F (600°C), and at approximately a composition of 7.8 wt. % Li, 0.6 wt. % Si, and 91.6 wt. % Al.

[0027] As noted above, when the aluminum alloy is an Al-Li-Si alloy, the alloy generally includes 0.1 - 5.0 wt. % Li. Lithium may facilitate, for instance, production of aluminum alloy products having high strength, high modulus, and/or low density. In one embodiment, an Al- Li-Si alloy includes at least 0.1 wt. % Li. In another embodiment, an Al-Li-Si alloy includes at least 0.2 wt. % Li. In yet another embodiment, an Al-Li-Si alloy includes at least 0.3 wt. % Li. In another embodiment, an Al-Li-Si alloy includes or at least 0.4 wt. % Li. In yet another embodiment, an Al-Li-Si alloy includes at least 0.5 wt. % Li. In another embodiment, an Al- Li-Si alloy includes at least 0.75 wt. % Li. In yet another embodiment, an Al-Li-Si alloy includes at least 1.0 wt. % Li. In one embodiment, an Al-Li-Si alloy includes not greater than 4.5 wt. % Li. In yet another embodiment, an Al-Li-Si alloy includes not greater than 4.0 wt. % Li. In another embodiment, an Al-Li-Si alloy includes not greater than 3.5 wt. % Li. In yet another embodiment, an Al-Li-Si alloy includes not greater than 3.0 wt. % Li. In one embodiment, an Al-Li-Si alloy includes 0.5 - 4.0 wt. % Li. In another embodiment, an Al-Li- Si includes 1.0 - 3.0 wt. % Li.

[0028] As noted above, when the aluminum alloy is an Al-Li-Si alloy, the alloy generally includes 2.0 - 18.0 wt. % Si. Silicon may facilitate, for instance, reduced solidification shrinkage and/or thermal shrinkage of the alloy during manufacturing, which may facilitate the production of crack-free aluminum alloy products. In one embodiment, an Al-Li-Si alloy includes at least 2.0 wt. % Si. In another embodiment, an Al-Li-Si alloy includes at least 2.5 wt. % Si. In yet another embodiment, an Al-Li-Si alloy includes at least 3.0 wt. % Si. In another embodiment, an Al-Li-Si alloy includes at least 3.5 wt. % Si. In yet another embodiment, an Al-Li-Si alloy includes at least 4.0 wt. % Si. In one embodiment, an Al-Li-Si alloy includes not greater than 18.0 wt. % Si. In another embodiment, an Al-Li-Si alloy includes not greater than 15 wt. % Si. In yet another embodiment, an Al-Li-Si alloy includes not greater than 13 wt. % Si. In another embodiment, an Al-Li-Si alloy includes not greater than 10 wt. % Si. In yet another embodiment, an Al-Li-Si alloy includes not greater than 8.0 wt. % Si. In another embodiment, an Al-Li-Si alloy includes not greater than 7.0 wt. % Si. In yet another embodiment, an Al-Li-Si alloy includes not greater than 6.0 wt. % Si. In one embodiment, an Al-Li-Si alloy includes 3.0 - 13.0 wt. % Si. In another embodiment, an Al-Li- Si alloy includes 4.0 - 6.0 wt. % Si. [0029] As noted above, when the aluminum alloy is an Al-Li-Si alloy, the alloy may include up to 7 wt. % Mg. Magnesium may facilitate, for instance, production of aluminum alloy products having high strength, ductility and/or fracture toughness. When included, an Al-Li-Si generally includes at least 0.1 wt. % Mg. Thus, in one embodiment, an Al-Li-Si alloy includes at least 0.1 wt. % Mg. In another embodiment, an Al-Li-Si alloy includes at least 0.3 wt. % Mg. In yet another embodiment, an Al-Li-Si alloy includes at least 0.4 wt. % Mg. In another embodiment, an Al-Li-Si alloy includes at least 0.5 wt. % Mg. In yet another embodiment, an Al-Li-Si alloy includes at least 0.6 wt. % Mg. In another embodiment, an Al- Li-Si alloy includes at least 0.7 wt. % Mg. In yet another embodiment, an Al-Li-Si alloy includes at least 0.8 wt. % Mg. In one embodiment, an Al-Li-Si alloy includes not greater than 6.0 wt. % Mg. In another embodiment, an Al-Li-Si alloy includes not greater than 5.0 wt. % Mg. In yet another embodiment, an Al-Li-Si alloy includes not greater than 4.0 wt. % Mg. In another embodiment, an Al-Li-Si alloy includes not greater than 3.0 wt. % Mg. In yet another embodiment, an Al-Li-Si alloy includes not greater than 2.5 wt. % Mg. In another embodiment, an Al-Li-Si alloy includes not greater than 2.0 wt. % Mg. In yet another embodiment, an Al- Li-Si alloy includes not greater than 1.75 wt. % Mg. In another embodiment, an Al-Li-Si alloy includes not greater than 1.5 wt. % Mg. In yet another embodiment, an Al-Li-Si alloy includes not greater than 1.2 wt. % Mg. In one embodiment, an Al-Li-Si alloy includes 0.5 - 3 wt. % Mg. In another embodiment, an Al-Li-Si alloy includes 0.8 - 1.2 wt. % Mg.

[0030] As noted above, a new Al-Li-Si alloy may include optional incidental elements. As used herein,“incidental elements” means elements or materials, that may optionally be added to the alloy for one or more specific purposes. For purposes of this patent application, non limiting examples of incidental elements include eutectic structure modifiers, casting aids and/or grain structure control materials (e.g., grain refiners). Eutectic structure modifiers and grain refiners are described in further detail below. Additionally, some incidental elements may be added to the alloy to reduce or restrict (and is some instances eliminate) cracking in the additively manufactured part due to, for example, folds (e.g., oxide folds), pits and patches (e.g., oxide patches). These types of incidental elements are generally referred to herein as deoxidizers. Examples of some deoxidizers include Ca, Sr, P and Be. When calcium (Ca) is included in the alloy, it is generally present in an amount of up to 0.3 wt. %, or up to 0.2 wt. %, or up to 0.1 wt. %. In some embodiments, Ca is included in the alloy in an amount of 0.001- 0.1 wt. % or 0.001- 0.2 wt. % or 0.001-0.3 wt. %, such as 0.001-0.25 wt. % (or 10 to 2500 ppm). Strontium (Sr) may be included in the alloy as a substitute for Ca (in whole or in part), and thus may be included in the alloy in the same or similar amounts as Ca. Phosphorus (P) may be included in the alloy as a substitute for Ca or Sr (in whole or in part), and thus may be included in the alloy in the same or similar amounts as Ca or Sr. Traditionally, beryllium (Be) additions have helped to reduce the tendency of cracking in aluminum alloys, though for environmental, health and safety reasons, some embodiments of the alloy are substantially Be- free. When Be is included in the alloy, it is generally present in an amount of up to 0.05 wt. % (e.g., from 10 ppm to 500 ppm of Be). Incidental elements may be present in minor amounts, or may be present in significant amounts, and may add desirable or other characteristics on their own without departing from the alloy described herein, so long as the alloy retains the desirable characteristics described herein. It is to be understood, however, that the scope of this disclosure should not/cannot be avoided through the mere addition of an element or elements in quantities that would not otherwise impact on the combinations of properties desired and attained herein.

[0031] In one embodiment, the incidental elements comprise at least one eutectic structure modifier. In one embodiment, an Al-Li-Si alloy includes not greater than 9 wt. % of eutectic structure modifiers. Eutectic structure modifiers may facilitate, for instance increased thermal stability of eutectic-type structures. Increased thermal stability may be realized, for instance, via particles located at cell walls and/or lamella, among others. Increased thermal stability may facilitate retention of one or more of the microstructural features during and/or after thermal treatment (e.g., anneal and/or solution heat treatment and aging). In one embodiment, an Al- Li-Si alloy includes not greater than 7.0 wt. % of eutectic structure modifiers. In another embodiment, an Al-Li-Si alloy includes not greater than 5.0 wt. % of eutectic structure modifiers. In one embodiment, an Al-Li-Si alloy includes at least 0.1 wt. % of eutectic structure modifiers. In another embodiment, an Al-Li-Si alloy includes at least 0.5 wt. % of eutectic structure modifiers. In yet another embodiment, an Al-Li-Si alloy includes at least 0.8 wt. % of eutectic structure modifiers. In one embodiment, an Al-Li-Si alloy includes not greater than 3.0 wt. % of eutectic structure modifiers. In another embodiment, an Al-Li-Si alloy includes not greater than 2.0 wt. % of the eutectic structure modifiers. In yet another embodiment, an Al-Li-Si alloy includes not greater than 1.2 wt. % of the eutectic structure modifiers.

[0032] Suitable eutectic structure modifiers for an Al-Li-Si alloy include, for instance, elements such as Ti, Hf, Ni, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, rare earth elements, and combinations thereof, and compounds based thereon. Such elements may facilitate increased thermal stability of eutectic-type structures. In one embodiment, the eutectic structure modifiers for an Al-Li-Si alloy are elements selected from the group consisting of Ti, Hf, Ni, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, rare earth elements and combinations thereof. In another embodiment, the eutectic modifiers for an Al-Li-Si alloy are selected from the group consisting of Mn, Ni, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, and combinations thereof. In one embodiment, an Al-Li-Si aluminum alloy product comprises not greater than 3 wt. % of any one element of the eutectic structure modifiers, e.g., not greater than 3 wt. % of any of Ti, Hf, Ni, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, and any one rare earth element. In another embodiment, an Al-Li-Si aluminum alloy product comprises not greater than 2 wt. % of any one element of the eutectic structure modifiers, e.g., not greater than 2 wt. % of any of Ti, Hf, Ni, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, and any one rare earth element. In yet another embodiment, an Al-Li-Si aluminum alloy product comprises not greater than 1.2 wt. % of any one element of the eutectic structure modifiers, e.g., not greater than 1.2 wt. % of any of Ti, Hf, Ni, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, and any one rare earth element.

[0033] As used herein,“rare earth elements” includes one or more of, for instance, yttrium and any of the fifteen lanthanides elements.

iii. Al-Mg-Si Alloys

[0034] In another approach, the aluminum alloy is an Al-Mg-Si alloy. In one embodiment, an Al-Mg-Si aluminum alloy comprises 0.5 - 7 wt. % Mg, 3 - 18 wt. % Si, up to 5 wt. % Li, and up to 13 wt. % Ni. In one embodiment, an Al-Mg-Si alloy comprises (and in some instances consists essentially of, or consists of) 0.5 - 7 wt. % Mg, 3 - 18 wt. % Si, up to 5 wt. % Li, and up to 13 wt. % Ni, the balance being aluminum, optional incidental elements and impurities. As described in further detail below, the optional incidental elements may include, for instance, eutectic structure modifiers (e.g., cell wall modifiers), and/or grain refiners (defined below), among other things.

[0035] An Al-Mg-Si alloy product may realize unique microstructural features. For instance, an Al-Mg-Si alloy product may realize at least one of (i) equiaxed grains, (ii) an average grain size of not greater than 50 pm, (iii) at least 10 vol. % of a eutectic-type structure, and (iv) a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm, among others. In one embodiment, an Al-Mg-Si aluminum alloy product may realize a non-equilibrium freezing range of not greater than 200°C. In one embodiment, an Al-Mg-Si alloy may be any one of a hypo-, near-, or hyper-eutectic composition. For instance, the at least 10 vol. % of eutectic-type structure may form via the following eutectic reaction:

liquid -> face-centered cubic Al + Si (diamond) + Mg₂Si

The above eutectic reaction may occur at approximately l035°F (557°C), and at approximately a composition of 5.5 wt. % Mg, 14.6 wt. % Si, and 79.9 wt. % Al.

[0036] As noted above, when the aluminum alloy is an Al-Mg-Si alloy, the alloy generally includes 0.5 - 7 wt. % Mg. Magnesium may, for instance, facilitate production of aluminum alloy products having high ductility and/or fracture toughness (e.g., via production of Mg₂Si particles). In one embodiment, an Al-Mg-Si alloy includes at least 1.0 vol. % of Mg₂Si particles. However, an excess amount of Mg₂Si particles (e.g., greater than 5.0 vol. %) may degrade properties. Thus, in one embodiment, an Al-Mg-Si alloy includes not greater than 5.0 vol. % of Mg₂Si particles. In one embodiment, an Al-Mg-Si alloy includes at least 0.75 wt. % Mg. In another embodiment, an Al-Mg-Si alloy includes at least 1.0 wt. % Mg. In yet another embodiment, an Al-Mg-Si alloy includes at least 1.5 wt. % Mg. In another embodiment, an Al-Mg-Si alloy includes at least 2.0 wt. % Mg. In yet another embodiment, an Al-Mg-Si alloy includes at least 2.5 wt. % Mg. In another embodiment, an Al-Mg-Si alloy includes at least 3.0 wt. % Mg. In one embodiment, an Al-Mg-Si alloy includes not greater than 6.5 wt. % Mg. In another embodiment, an Al-Mg-Si alloy includes 6.0 wt. % Mg. In yet another embodiment, an Al-Mg-Si alloy includes not greater than 5.5 wt. % Mg. In another embodiment, an Al-Mg- Si alloy includes not greater than 5.0 wt. % Mg. In one embodiment, an Al-Mg-Si alloy includes 2.0 - 6.0 wt. % Mg. In another embodiment, an Al-Mg-Si alloy includes 3.0 - 5.0 wt. % Mg.

[0037] As noted above, when the aluminum alloy is an Al-Mg-Si alloy, the alloy generally includes 3.0 - 18.0 wt. % Si. Silicon may, for instance, facilitate reduced solidification and/or thermal shrinkage of the alloy during manufacturing which may facilitate the production of crack-free aluminum alloy products. In one embodiment, an Al-Mg-Si alloy includes at least 3.0 wt. % Si. In another embodiment, an Al-Mg-Si alloy includes at least 4.25 wt. % Si. In yet another embodiment, an Al-Mg-Si alloy includes at least 5.5 wt. % Si. In another embodiment, an Al-Mg-Si alloy includes at least 6.75 wt. % Si. In yet another embodiment, an Al-Mg-Si alloy includes at least Si 8.0 wt. % Si. In another embodiment, an Al-Mg-Si alloy includes at least 10 wt. % Si. In yet another embodiment, an Al-Mg-Si alloy includes at least 12.0 wt. % Si. In one embodiment, an Al-Mg-Si alloy includes not greater than 17.0 wt. % Si. In another embodiment, an Al-Mg-Si alloy includes not greater than 16.0 wt. % Si. In yet another embodiment, an Al-Mg-Si alloy includes not greater than 15.0 wt. % Si. In one embodiment, an Al-Mg-Si alloy includes 8.0 - 16.0 wt. % Si. In another embodiment, an Al- Mg-Si alloy includes 12.0 - 15.0 wt. % Si.

[0038] As noted above, when the aluminum alloy is an Al-Mg-Si alloy, the alloy may include up to 5 wt. % Li. Lithium may, for instance, facilitate production of aluminum alloy products having higher strength, higher modulus, and/or lower density. When included, an Al- Mg-Si alloy generally includes at least 0.1 wt. % Li. Thus, in one embodiment, an Al-Mg-Si alloy includes at least 0.1 wt. % Li. In another embodiment, an Al-Mg-Si alloy includes at least 0.2 wt. % Li. In yet another embodiment, an Al-Mg-Si alloy includes at least 0.3 wt. % Li. In another embodiment, an Al-Mg-Si alloy includes at least 0.4 wt. % Li. In yet another embodiment, an Al-Mg-Si alloy includes at least 0.5 wt. % Li. In another embodiment, an Al- Mg-Si alloy includes at least 0.75 wt. % Li. In yet another embodiment, an Al-Mg-Si alloy includes at least 1.0 wt. % Li. In one embodiment, an Al-Mg-Si alloy includes not greater than 4.5 wt. % Li. In another embodiment, an Al-Mg-Si alloy includes not greater than 4.0 wt. % Li. In yet another embodiment, an Al-Mg-Si alloy includes not greater than 3.5 wt. % Li. In another embodiment, an Al-Mg-Si alloy includes not greater than 3.0 wt. % Li. In one embodiment, an Al-Mg-Si alloy includes 0.5 - 4.0 wt. % Li. In another embodiment, an Al- Mg-Si alloy includes 1.0 - 3.0 wt. % Li.

[0039] As noted above, when the aluminum alloy is an Al-Mg-Si alloy, the alloy may include up to 13 wt. % Ni. In the case of Al-Mg-Si alloys, nickel may, for instance, facilitate increased thermal stability of eutectic-type structures. Increased thermal stability may be realized, for instance, via particles (e.g., intermetallic particles; silicon particles) located at cell walls and/or lamella, among others. Increased thermal stability may facilitate retention of one or more of the microstructural features during and/or after thermal treatment (e.g., anneal and/or solution heat treatment and aging). When included, an Al-Mg-Si alloy generally includes at least 0.1 wt. % Ni. Thus, in one embodiment, an Al-Mg-Si alloy includes at least 0.1 wt. % Ni. In another embodiment, an Al-Mg-Si alloy includes at least 0.5 wt. % Ni. In yet another embodiment, an Al-Mg-Si alloy includes at least 4.0 wt. % Ni. In another embodiment, an Al-Mg-Si alloy includes at least 7.0 wt. % Ni. In yet another embodiment, an Al-Mg-Si alloy includes at least 9.0 wt. % Ni. In one embodiment, an Al-Mg-Si alloy includes not greater than 12.0 wt. % Ni. In another embodiment, an Al-Mg-Si alloy includes not greater than 11.0 wt. % Ni. In one embodiment, an Al-Mg-Si alloy includes 7.0 - 12.0 wt. % Ni. In another embodiment, an Al-Mg-Si alloy includes 9.0 - 11.0 wt. % Ni. [0040] As noted above, a new Al-Mg-Si alloy may include optional incidental elements (defined above). In one embodiment, an Al-Mg-Si alloy comprises incidental elements. In one embodiment, the incidental element comprise eutectic structure modifiers. In one embodiment, an Al-Mg-Si alloy includes up to 9 wt. % of eutectic structure modifiers. As described above, eutectic structure modifiers may, for instance, facilitate thermal stability of eutectic-type structures. Increased thermal stability may be realized, for instance, for particles (e.g., intermetallic particles; silicon particles) located at cell walls and/or lamella, among others. Increased thermal stability may facilitate retention of the microstructural features during and/or after thermal treatment (e.g., anneal and/or solution heat treatment and aging). In one embodiment, an Al-Mg-Si alloy includes not greater than 7.0 wt. % of eutectic structure modifiers. In another embodiment, an Al-Mg-Si alloy includes not greater than 5.0 wt. % of eutectic structure modifiers. In one embodiment, an Al-Mg-Si alloy includes at least 0.1 wt. % of eutectic structure modifiers. In another embodiment, an Al-Mg-Si alloy includes at least 0.5 wt. % of eutectic structure modifiers. In yet another embodiment, an Al-Mg-Si alloy includes at least 0.8 wt. % of eutectic structure modifiers. In one embodiment, an Al-Mg-Si alloy includes not greater than 3.0 wt. % of the eutectic structure modifiers. In another embodiment, an Al-Mg-Si alloy includes not greater than 2.0 wt. % of eutectic structure modifiers. In yet another embodiment, an Al-Mg-Si alloy includes not greater than 1.2 wt. % of eutectic structure modifiers.

[0041] Suitable eutectic structure modifiers for an Al-Mg-Si alloy include, for instance, elements such as Ti, Hf, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, rare earth elements, and combinations thereof, and compounds based thereon. Such elements may facilitate increased thermal stability of eutectic-type structures. In one embodiment, the eutectic structure modifiers for an Al-Mg-Si alloy are elements selected from the group consisting of Ti, Hf, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, rare earth elements and combinations thereof. In another embodiment, the eutectic modifiers for an Al-Mg-Si alloy are selected from the group consisting of Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, and combinations thereof. In one embodiment, an Al-Mg-Si aluminum alloy product comprises not greater than 3 wt. % of any one element of the eutectic structure modifiers, e.g., not greater than 3 wt. % of any of Ti, Hf, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, and any one rare earth element. In another embodiment, an Al-Mg-Si aluminum alloy product comprises not greater than 2 wt. % of any one element of the eutectic structure modifiers, e.g., not greater than 2 wt. % of any of Ti, Hf, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, and any one rare earth element. In yet another embodiment, an Al-Mg-Si aluminum alloy product comprises not greater than 1.2 wt. % of any one element of the eutectic structure modifiers, e.g., not greater than 1.2 wt. % of any of Ti, Hf, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, and only one rare earth element.

iv. Grain Refiner Materials

[0042] As noted above, an aluminum alloy may optionally contain incidental elements. In one embodiment, an aluminum alloy (e.g., an Al-Mg-Si or Al-Li-Si alloy) comprises at least one grain refiner as an incidental element. In one embodiment, an aluminum alloy product may include up to 5 wt. % of one or more grain refiners (defined below). In this regard, the inclusion of grain refmer(s) within the alloy may have several benefits, including facilitating the production of equiaxed grains and/or improved mechanical properties. For instance, the grain refmer(s) may facilitate the production of equiaxed grains that may increase the ductility of the aluminum alloy products. Increased ductility may facilitate the production of crack-free aluminum alloy products. Furthermore, the inclusion of an appropriate amount of grain refmer(s) (e.g., not greater than 5 wt. %) may improve mechanical properties (e.g., strength, ductility, among others). However, too much grain refiner (e.g., greater than 5 wt. %) may impair properties (e.g., decrease the strength, fatigue resistance, and/or fracture toughness of the aluminum alloy product). Thus, in one embodiment, the aluminum alloy product comprises a sufficient amount of the grain refiner to facilitate production of a crack-free aluminum alloy product (e.g., via equiaxed grains and/or via fine grains (average grain size < 50 pm)), but the amount of grain refiner in the aluminum alloy product is limited so that the aluminum alloy product retains its strength (e.g., tensile yield strength (TYS) and/or ultimate tensile strength (UTS)), fatigue resistance, and/or fracture toughness. In some embodiments, the amount of grain refmer(s) may be limited such that the strength of the aluminum alloy product substantially corresponds to its strength without the grain refmer(s) (e.g., within 5 ksi; within 1-4 ksi). In some embodiments, the amount of grain refmer(s) may be limited such that the strength of the aluminum alloy product substantially corresponds to its strength without the grain refmer(s) (e.g., within 5%).

[0043] As used herein, “grain refiner” means a nucleant or nucleants that facilitates aluminum crystal formation. Suitable grain refiners include ceramic materials, intermetallic materials, and combinations thereof, among others.

[0044] In one approach, a ceramic material is used to facilitate grain refinement. Examples of ceramics include oxide materials, boride materials, carbide materials, nitride materials, silicon materials, carbon materials, and/or combinations thereof. Some additional examples of ceramics include metal oxides, metal borides, metal carbides, metal nitrides and/or combinations thereof. Additionally, some non-limiting examples of ceramics include: TiB, TiB₂, TiC, SiC, AI2O3, BC, BN, S13N4, AI4C3, A1N, their suitable equivalents, and/or combinations thereof. In another approach, intermetallic particles are used to facilitate grain refinement. For instance, the aluminum alloy compositions described herein may include materials that may facilitate the formation of intermetallic particles (e.g., during solidification). In this regard, non-limiting examples of such materials that may be used include titanium (Ti), zirconium (Zr), scandium (Sc), hafnium (Hf), vanadium (V), molybdenum (Mo), niobium (Nb), tantalum (Ta) and tungsten (W), optionally in elemental form, among others. As noted above, ceramic materials may be used in combination with intermetallic materials, or grain refinement may be achieved solely with ceramic materials or solely with intermetallic materials. Further, elements such as Ti, Zr, Sc, Hf, V, Mo, Nb, Ta, and W, among others, may serve multiple functions (e.g., both grain refinement and eutectic structure modification). Such elements may be cumulatively included in the aluminum alloy products described herein in any suitable amounts, as described above, e.g., up to 3 wt. % for eutectic structure purposes and up to 5 wt. % for grain refinement purposes, for a potential total content of up to 8 wt. %. However, the amounts of these elements should generally be low enough that primary particles are not formed in the aluminum alloy product.

[0045] As described above, the inclusion of up to 5 wt. % of one or more grain refiners in the aluminum alloy may facilitate the production of aluminum alloy products having equiaxed grains (defined above) and/or fine grains (average grain size < 50 pm). Equiaxed grains and/or fine grains may offer several benefits, including facilitating production of crack-free aluminum alloy products, increased ductility, and/or increased strength, among others. In one embodiment, an aluminum alloy product (e.g., an Al-Mg-Si or Al-Li-Si aluminum alloy product) includes at least 0.005 wt. % of at least one grain refiner. In one embodiment, an aluminum alloy product includes at least 0.05 wt. % of at least one grain refiner. In another embodiment, an aluminum alloy product includes at least 0.5 wt. % of at least one grain refiner. In yet another embodiment, an aluminum alloy product includes at least 0.8 wt. % of at least one grain refiner. In one embodiment, an aluminum alloy product includes not greater than 3.0 wt. % of at least one grain refiner. In another embodiment, an aluminum alloy product includes not greater than 1.6 wt. % of at least one grain refiner. In one embodiment, an aluminum alloy product includes 0.5 - 3.0 wt. % of at least one grain refiner. In another embodiment, an aluminum alloy product includes 0.8 - 1.6 wt. % of at least one grain refiner. In one embodiment, an aluminum alloy product comprises at least one grain refiner comprising TiB₂ and AhTi.

v. Methods of Manufacture

[0046] In one approach, and referring now to FIG. 2, the new aluminum alloy products may be produced via additive manufacturing. 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”. In one embodiment, a method of making an additively manufactured body includes the steps of: (a) selectively heating (200) at least a portion of an additive manufacturing feedstock (e.g., via a laser and/or electron beam) to a temperature above the liquidus temperature of the particular body to be formed, thereby forming a molten pool, and (b) cooling (300) the molten pool thereby forming a solidified mass, the solidified mass having at least one of (i) equiaxed grains, (ii) an average grain size of not greater than 50 pm, (iii) at least 10 vol. % of a eutectic-type structure, and (iv) a eutectic-type structure having an average a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm. In another embodiment, a method of making an additively manufactured product includes the steps of: (a) dispersing an additive manufacturing feedstock (e.g., a metal powder) in a bed (or other suitable container), (b) selectively heating (200) at least a portion of the additive manufacturing feedstock (e.g., via an energy source or laser) to a temperature above the liquidus temperature of the particular body to be formed, thereby forming a molten pool, and (c) cooling (300) the molten pool thereby forming a solidified mass, the solidified mass having at least one of (i) equiaxed grains, (ii) an average grain size of not greater than 50 pm, (iii) at least 10 vol. % of a eutectic-type structure, and (iv) a eutectic-type structure having an average a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm. In one embodiment, the cooling comprises cooling at a rate of at least l000°C per second. In another embodiment, the cooling rate is at least l0,000°C per second. In yet another embodiment, the cooling rate is at least l00,000°C per second. In another embodiment, the cooling rate is at least l,000,000°C per second. Steps (a)-(c) may be repeated as necessary until the product is completed, i.e., until the final additively manufactured product is formed / completed.

[0047] Any suitable additive manufacturing feedstocks may be used, including one or more powders, one or more wires, one or more sheets, and combinations thereof. In some embodiments, an additive manufacturing feedstock is comprised of one or more wires. In some embodiments, an additive manufacturing feedstock is comprised of one or more sheets. Foil is a type of sheet.

[0048] In some embodiments, the additive manufacturing feedstock is comprised of one or more powders. In this regard, the powder(s) used to create the final additively manufactured product may be of any suitable composition, including any combination of metallic, alloy, and non-metallic (e.g., ceramic material) powders. For instance, any combination of metallic powders, alloy powders, and/or non-metallic powders may be used to realize an aluminum alloy composition described above.

[0049] After its production, the final additively manufactured product may be thermally treated (400) at one or more temperatures and for a time sufficient to stress relieve and/or create a thermally processed aluminum alloy product. In the case of stress relief operations, the elevated temperature may be sufficiently low such that stress relief is imparted to the product, and one or more of the microstructural features is/are maintained. The aluminum alloy product may optionally be worked (500) into a final worked product. This working (500) may occur before, after or during (e.g., concomitant to) the thermally treating step (400). The working may include hot working and/or cold working. The working (500) may include working all of the product, or a portion of the product. The working (500) may include, for instance, rolling, extruding, forging, and other known methods of working aluminum alloy products. In one embodiment, the working (500) comprises die forging the final additively manufactured product into the final worked product, wherein the final worked product is a complex shape (e.g., having a plurality of non-planar surfaces). In another embodiment, the working (500) comprises hot isostatic pressing (HIP) of the final additively manufactured product into a final HIP product. As noted above, one or more of the microstructural features may be retained after one or more of the thermally treating (400) and/or working (500) steps.

[0050] As noted above, the new aluminum alloy products may be produced via additive manufacturing, and all additive manufacturing processes and apparatuses defined in ASTM F2792-l2a may be used to produce the new aluminum alloy products having at least one of (i) equiaxed grains, (ii) an average grain size of not greater than 50 pm, (iii) at least 10 vol. % of a eutectic-type structure, and (iv) a eutectic-type structure having an average a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm. As one example, selective laser sintering and/or binder j etting may be used, where the metal powder itself realizes the microstructural features. This metal powder may be dispersed in a bed, and selective laser sintering may be employed and/or a binder may be selectively jetted onto the powder. This process may be repeated, as appropriate, until a green additively manufactured part is completed, after which the green additively manufactured part may be further processed, such as by sintering and/or HIP’ing (hot isostatic pressing), thereby producing a final additively manufactured product. After this final additively manufactured product is completed, it may be subjected to the thermal treatment (400) and/or working (500) steps, described above.

[0051] As another example, the new aluminum alloys described herein may be in the form of sheets (e.g., foils) for use in additive manufacturing processes such as sheet lamination, per ASTM F2792-l2a.

[0052] As another specific example, directed energy deposition may be used, where one or more metal powders are sprayed in a controlled environment, and concomitant to the spraying, a laser is used to melt and/or solidify the sprayed metal powder(s). This spraying and concomitant energy deposition may be repeated, as necessary to facilitate production of a final additively manufactured product having at least one of (i) equiaxed grains, (ii) an average grain size of not greater than 50 pm, (iii) at least 10 vol. % of a eutectic-type structure, and (iv) a eutectic-type structure having an average a eutectic-type structure having an average eutectic- type structure spacing of not greater than 5.0 pm. After this final additively manufactured product is completed, it may be subjected to the thermal treatment (400) and/or working (500) steps, described above.

[0053] While the disclosure generally relates to aluminum alloy products produced via additive manufacturing, in some embodiments, one or more of the aluminum alloy compositions described herein may also find utility as ingot, casting alloys and/or wrought alloys. Thus, the present patent application also relates to ingot, casting alloys and wrought alloys made from the above-described aluminum alloy compositions. In one embodiment, the new aluminum alloy products described herein may be produced by processes capable of generating solidification rates sufficient to impart one or more of the microstructural features described herein. For instance, some continuous casting processes, such as those described in U.S. Patent No. 7,182,825, may be capable of sufficiently high solidification rates.

[0054] Further, the thermally treating step (400) may be useful in producing discrete particles (e.g., intermetallic particles and/or silicon particles). In this regard, the thermally treating step is optional, and the products described herein may be sold or utilized without employing the thermally treating step.

[0055] In another approach, one or more of the above aluminum alloy compositions may also find utility in powder metallurgy methods. For instance, an aluminum alloy powder comprising a fine eutectic-type structure may be used to produce a powder metallurgy product. In this regard, the powder may be produced by suitable methods, such as by plasma atomization, gas atomization, or impingement of molten metal (e.g., solidification of an impinging molten metal droplet on a cold substrate).

[0056] Aluminum alloy powders having one or more of (i) equiaxed grains, (ii) an average grain size of not greater than 50 pm, (iii) at least 10 vol. % of a eutectic-type structure, and (iv) a eutectic-type structure having an average a eutectic-type structure having an average eutectic- type structure spacing of not greater than 5.0 pm, may be compacted into final or near-final product form. For instance, the powder may be compacted via low pressure methods and/or via pressurized methods. In this regard, low pressure methods such as, loose powder sintering, slip casting, slurry casting, tape casting, or vibratory compaction may be used. In another aspect, pressurized methods may be used to realize the compaction such as, for instance, die compaction, cold/hot isostatic pressing, and/or sintering. In some embodiments, one or more of the above aluminum alloy compositions may also find utility in powder metallurgy methods, where powders are cold isostatically pressed to a green compact (e.g. sufficiently densified to enable further hot pressing, such as greater than 70% theoretical density), then vacuum hot pressed or hot isostatically pressed to form a substantially dense billet substantially corresponding to near theoretical density (e.g. above 99% theoretical density). Such powder metallurgy methods may facilitate production of crack-free final or near-final products. In any event, the crack-free product may be further processed to obtain a wrought final product. This further processing may include any combination of thermal treating and/or working steps. In this regard, the crack-free product may be further processed via hot or cold rolling, extruding, forging, and/or combinations thereof.

iv. Additive Manufacturing Feedstocks

[0057] As noted above, various methods of producing the new aluminum alloy products may be employed. For instance, the new aluminum alloy products may be produced via additive manufacturing methods. In this regard, the new aluminum alloy products may be produced via additive manufacturing using a variety of additive manufacturing feedstocks. In one embodiment, an additive manufacturing feedstock may be capable of realizing one or more of (i) equiaxed grains, (ii) an average grain size of not greater than 50 pm, (iii) a eutectic-type structure having a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm, and (iv) at least 10 vol. % of a eutectic-type structure, among others. In some embodiments, the additive manufacturing feedstock is a powder. In one embodiment, an additive manufacturing powder feedstock may be comprised of any combination of metallic powders, alloy powders, and non-metallic powders (e.g., ceramic powders). For instance, any combination of metallic powders, alloy powders, and/or non-metallic powders may be used to realize an aluminum alloy composition described above. Furthermore, an additive manufacturing feedstock powder may comprise metallic powders and/or alloy powders, where the particles comprise the metallic powders and/or alloy particles having grain refining material therein (e.g., ceramic materials). By way of non-limiting example, an additive manufacturing feedstock powder may be comprised of alloy particles, and the alloy particles may include a plurality of non-metallic particles therein, wherein the non-metallic particles have a smaller size than the alloy particles.

[0058] For powder additive manufacturing feedstocks, the powder itself may comprise one or more of (i) equiaxed grains, (ii) an average grain size of not greater than 50 pm, (iii) a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm, and (iv) at least 10 vol. % of a eutectic-type structure, among others. The additive manufacturing feedstock powders may be produced via any suitable method. In one embodiment, the powder is produced via a process employing rapid solidification (e.g., at least l000°C per second). In some embodiments, the aluminum alloy powder is produced via a method having a sufficient solidification rate to facilitate production of a powder having at least one of (i) equiaxed grains, (ii) an average grain size of not greater than 50 pm, (iii) a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm, and (iv) at least 10 vol. % of a eutectic-type structure. For instance, the aluminum alloy powder may be produced via any one of plasma atomization, gas atomization, or impingement of a molten aluminum alloy (e.g., solidification of an impinging molten metal droplet on a cold substrate).

[0059] In some embodiments, one or more of the above aluminum alloy compositions may also find utility in wire-based additive manufacturing methods. For instance, in one approach, electron beam (EB) or plasma arc techniques are utilized to produce at least a portion of the additively manufactured aluminum alloy body. Electron beam techniques may facilitate production of larger parts than readily produced via laser additive manufacturing techniques. In one embodiment, a method comprises feeding a wire (e.g., < 5 mm in diameter) of the new aluminum alloys described herein to the wire feeder portion of an electron beam gun. The wire may be of the compositions, described above. The electron beam (EB) heats the wire above the liquidus point of the body to be formed, followed by rapid solidification (e.g., at least l00°C per second) of the molten pool to form the deposited material. The wire may be fabricated by a conventional ingot process or by a powder consolidation process. These heating and cooling steps may be repeated as necessary until the final aluminum alloy body is produced. Plasma arc wire feed may similarly be used with the aluminum alloys disclosed herein. In one embodiment, not illustrated, an electron beam (EB) or plasma arc additive manufacturing apparatus may employ multiple different wires with corresponding multiple different radiation sources, each of the wires and sources being fed and activated, as appropriate to provide the aluminum alloy product.

vii. Product Applications

[0060] The aluminum alloy products described herein may be used in a variety of product applications. In one embodiment, the aluminum alloy products are utilized in an elevated temperature application, such as in an aerospace (e.g. engines or structures), automotive vehicle (e.g. piston, valve, among others), defense, electronics (e.g. consumer electronics) or space applications. In one embodiment, an aluminum alloy product is used in a ground transportation application. In one embodiment, an aluminum alloy product is utilized as an engine component in an aerospace vehicle (e.g., in the form of a blade, such as a compressor blade incorporated into the engine). In another embodiment, the aluminum alloy product is used as a heat exchanger for the engine of the aerospace vehicle. The aerospace vehicle including the engine component / heat exchanger may subsequently be operated. In one embodiment, an aluminum alloy product is an automotive engine component. The automotive vehicle including the engine component may subsequently be operated. For instance, an aluminum alloy product may be used as a turbocharger component (e.g., a compressor wheel of a turbocharger, where elevated temperatures may be realized due to recycling engine exhaust back through the turbocharger), and the automotive vehicle including the turbocharger component may be operated. In another embodiment, an aluminum product may be used as a blade in a land based (stationary) turbine for electrical power generation, and the land based turbine included the aluminum product may be operated to facilitate electrical power generation.

[0061] In another aspect, the new aluminum alloy products are utilized in a structural application. In one embodiment, the new aluminum alloy products are utilized in an aerospace structural application. For instance, the new aluminum alloy products may be formed into various aerospace structural components, including floor beams, seat rails, fuselage framing, bulkheads, spars, ribs, longerons, and brackets, among others. In another embodiment, the new aluminum alloy products are utilized in an automotive structural application. For instance, the new aluminum alloy products may be formed into various automotive structural components including nodes of space frames, shock towers, and subframes, among others.

[0062] Aside from the applications described above, the new aluminum alloy products of the present disclosure may also be utilized in a variety of consumer products, such as any consumer electronic products, including laptops, cell phones, cameras, mobile music players, handheld devices, computers, televisions, microwave, cookware, washer/dryer, refrigerator, sporting goods, or any other consumer electronic product requiring durability and selective visual appearance. In one embodiment, the visual appearance of the consumer electronic product meets consumer acceptance standards.

[0063] In some embodiments, the new aluminum alloy products of the present disclosure may be utilized in a variety of products including non-consumer products including the likes of medical devices, transportation systems and security systems, to name a few. In other embodiments, the new aluminum alloy bodies may be incorporated in goods including the likes of car panels, media players, bottles and cans, office supplies, packages and containers, among others.

[0064] As noted above, the new aluminum alloys may be used in a variety of product applications. In this regard, at least a portion of a product (e.g., an additively manufactured product) may comprise any of the new aluminum alloy compositions described above. For instance, at least a portion of an aluminum alloy product may comprise one of the new aluminum alloy compositions, and at least one other portion may be comprised of a different material (e.g., a different aluminum alloy). Furthermore, the new aluminum alloy compositions may be present in a product comprising a compositional gradient (i.e., a graded product). At least a portion of a graded product may comprise any of the new aluminum alloy compositions described above.

[0065] The figures constitute a part of this specification and include illustrative embodiments of the present disclosure and illustrate various objects and features thereof. In addition, any measurements, specifications and the like shown in the figures are intended to be illustrative, and not restrictive. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0066] Among those benefits and improvements that have been disclosed, other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying figures. Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative of the invention that may be embodied in various forms. In addition, each of the examples given in connection with the various embodiments of the invention is intended to be illustrative, and not restrictive.

[0067] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases“in one embodiment” and“in some embodiments” as used herein do not necessarily refer to the same embodiment(s), though it may. Furthermore, the phrases“in another embodiment” and“in some other embodiments” as used herein do not necessarily refer to a different embodiment, although it may. Thus, as described below, various embodiments of the invention may be readily combined, without departing from the scope or spirit of the invention.

[0068] In addition, as used herein, the term "or" is an inclusive "or" operator, and is equivalent to the term "and/or," unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of "a," "an," and "the" include plural references, unless the context clearly dictates otherwise. The meaning of "in" includes "in" and "on", unless the context clearly dictates otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

[0069] FIG. la shows an SEM micrograph of an alloy having a eutectic-type structure showing microcellular, lamellar, and wavy eutectic-type structures. Note·. FIG. la is provided for illustrative purposes only; the alloy of FIG. la is not an Al-Li-Si alloy or an Al-Mg-Si alloy. However, it is expected that the new aluminum alloys described herein are capable of achieving results consistent with those illustrated in FIG. la.

[0070] FIG. lb shows an SEM micrograph of Alloy 1 from the Examples at 20,000x magnification illustrating a eutectic-type structure having a predominately microcellular structure.

[0071] FIG. lc shows a portion of the micrograph of FIG. la illustrating the lamellar structures.

[0072] FIG. 2 shows a method for producing a new aluminum alloy product.

[0073] FIG. 3a shows an SEM micrograph of Alloy 2 from the Examples at lOOx magnification. [0074] FIG. 3b shows an SEM micrograph of Alloy 2 from the Examples at lOOOx magnification.

[0075] FIG. 4a shows an SEM micrograph of Alloy 3 from the Examples at lOOx magnification.

[0076] FIG. 4b shows an SEM micrograph of Alloy 3 from the Examples at lOOOx magnification.

[0077] FIG. 5a shows an SEM micrograph of Alloy 4 from the Examples at lOOx magnification.

[0078] FIG. 5b shows an SEM micrograph of Alloy 4 from the Examples at lOOOx magnification.

[0079] FIG. 6a shows an SEM micrograph of Alloy 5 from the Examples at lOOx magnification.

[0080] FIG. 6b shows an SEM micrograph of Alloy 5 from the Examples at lOOOx magnification.

[0081] FIG. 7a shows an SEM micrograph of Alloy 6 from the Examples at lOOx magnification.

[0082] FIG. 7b shows an SEM micrograph of Alloy 6 from the Examples at lOOOx magnification.

[0083] FIG. 8a shows an SEM micrograph of Alloy 7 from the Examples at lOOx magnification.

[0084] FIG. 8b shows an SEM micrograph of Alloy 7 from the Examples at lOOOx magnification.

DETAILED DESCRIPTION

Examples

[0085] Seven experimental alloys were heated above their solidus temperature and then solidified at various solidification rates, as described in further detail below. Target compositions of the experimental alloys are given in Table 1, below.

Table 1: Target Compositions (in wt. %)

[0086] The experimental alloys were evaluated for hardness using the Vickers hardness test, and in accordance with ASTM standard E92-17. The experimental alloy samples were evaluated at two different solidification rates: about l0-l00°C/s and about 10,000 - l,000,000°C/s. Results from the hardness evaluation are given in Table 2, below. As demonstrated in Table 2, all of the alloys realized higher hardness values at the higher solidification rate.

Table 2: Hardness Values (in HV) at Various Solidification Rates

[0087] The tendency for the seven experimental alloy materials to crack was evaluated using micrograph inspection. The samples used to produce the micrographs were solidified at a solidification rate of 10,000 - l,000,000°C/s. The micrographs are shown in FIGS. 3a-8b. As illustrated, all of the experimental alloys demonstrated a low tendency to crack. Furthermore, all of the as-solidified samples realized one or more of equiaxed grains, an average grain size of not greater than 50 pm, at least 10 vol. % of a eutectic-type structure, and a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm. Additionally, the alloys are expected to have solidified with a non-equilibrium freezing range of not greater than 200°C.

[0088] Aspects of the invention will now be described with reference to the following numbered clauses:

Clause 1. An aluminum alloy, comprising:

(a) 0.1 to 5 wt. % Li; (b) 2 - 18 wt. % Si; and

(c) up to 7 wt. % Mg.

Clause 2. The aluminum alloy of clause 1, wherein the balance of the aluminum alloy is aluminum, optional incidental elements and impurities.

Clause 3. The aluminum alloy of clause 2, wherein the optional incidental elements comprise up to 9 wt. % of eutectic structure modifiers and up to 5 wt. % of one or more grain refiners, wherein:

(a) the eutectic structure modifiers are selected from the group consisting of Ti, Hf,

Ni, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, rare earth elements, and combinations thereof;

(b) the one or more grain refiners comprise at least one of ceramic materials and intermetallic particles;

(i) wherein, when present, the ceramic materials are selected from the group consisting of TiB, TiB₂, TiC, SiC, Al₂0₃, BC, BN, Si₃N₄, Al₄C₃, A1N and

combinations thereof; and

(ii) wherein, when present, the intermetallic particles include elements selected from the group consisting of Ti, Zr, Sc, Hf, V, Mo, Nb, Ta, W, and combinations thereof.

Clause 4. The aluminum alloy of any of the preceding clauses, wherein the aluminum alloy comprises at least 0.2 wt. % Li, or at least 0.3 wt. % Li, or at least 0.4 wt. % Li, or at least 0.5 wt. % Li, or at least 0.75 wt. % Li, or at least 1.0 wt. % Li.

Clause 5. The aluminum alloy of any of the preceding clauses, wherein the aluminum alloy comprises not greater than 4.5 wt. % Li, or not greater than 4.0 wt. % Li, or not greater than 3.5 wt. % Li, or not greater than 3.0 wt. % Li.

Clause 6. The aluminum alloy of any of the preceding clauses, wherein the aluminum alloy comprises at least 2.5 wt. % Si, or at least 3.0 wt. % Si, or at least 3.5 wt. % Si, or at least 4.0 wt. % Si.

Clause 7. The aluminum alloy of any of the preceding clauses, wherein the aluminum alloy comprises not greater than 15 wt. % Si, or not greater than 13 wt. % Si, or not greater than 10 wt. % Si, or not greater than 8.0 wt. % Si, or not greater than 7.0 wt. % Si, or not greater than 6.0 wt. % Si. Clause 8. The aluminum alloy of any of the preceding clauses, wherein the aluminum alloy comprises at least 0.1 wt. % Mg, or at least 0.3 wt. % Mg, or at least 0.4 wt. % Mg, or at least 0.5 wt. % Mg, or at least 0.6 wt. % Mg, or at least 0.7 wt. % Mg, or at least 0.8 wt. % Mg. Clause 9. The aluminum alloy of any of the preceding clauses, wherein the aluminum alloy comprises not greater than 6.0 wt. % Mg, or not greater than 5.0 wt. % Mg, or not greater than 4.0 wt. % Mg, or not greater than 3.0 wt. % Mg, or not greater than 2.5 wt. % Mg, or not greater than 2.0 wt. % Mg, or not greater than 1.75 wt. % Mg, or not greater than 1.5 wt. % Mg, or not greater than 1.2 wt. % Mg.

Clause 10. The aluminum alloy of any of clauses 3-9, wherein the optional incidental elements comprise at least 0.1 wt. % of the eutectic structure modifiers, or at least 0.5 wt. % of the eutectic structure modifiers, or at least 0.8 wt. % of the eutectic structure modifiers. Clause 11. The aluminum alloy of any of clauses 3-10, wherein the optional incidental elements comprise not greater than 7 wt. % of the eutectic structure modifiers, or not greater than 5 wt. % of the eutectic structure modifiers, or not greater than 3 wt. % of the eutectic structure modifiers, or not greater than 1.2 wt. % of the eutectic structure modifiers.

Clause 12. The aluminum alloy of any of clauses 3-11, wherein the optional incidental elements comprise at least 0.005 wt. % of the one or more grain refiners, or at least 0.05 wt.

% of the one or more grain refiners, or at least 0.5 wt. % of the one or more grain refiners, or at least 0.8 wt. % of the one or more grain refiners.

Clause 3. The aluminum alloy of any of clauses 3-12, wherein the optional incidental elements comprise not greater than 3.0 wt. % of the one or more grain refiners, or not greater than 1.6 wt. % of the one or more grain refiners.

Clause 14. The aluminum alloy of any of the preceding clauses, wherein the aluminum alloy realizes a non-equilibrium freezing range of not greater than 200°C, or not greater than l00°C, or not greater than 50°C.

Clause 15. An additively manufactured aluminum alloy product made from the aluminum alloy of any of the preceding clauses, wherein the additively manufactured alloy product comprises at least one of:

(i) a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm, or not greater than 4.0 pm, or not greater than 3.0 pm, or not greater than 2.5 pm, or not greater than 2.0 pm, or not greater than 1.5 pm;

(ii) equiaxed grains, wherein the equiaxed grains have an average aspect ratio of not greater than 1.5: 1, or not greater than 1.2: 1, or not greater than 1.1 : 1; (iii) an average grain size of not greater than 50 pm, or not greater than 40 pm, or not greater than 30 pm, or not greater than 20 pm, or not greater than 15 pm, or not greater than 10 mih; and

(iv) at least 10 vol. % of a eutectic-type structure, or at least 15 vol. % of a eutectic-type structure, or at least 20 vol. % of a eutectic-type structure.

Clause 16. The additively manufactured aluminum alloy product of clause 15, wherein the additively manufactured alloy product comprises a eutectic-type structure having an average eutectic-type structure spacing of at least 0.05 pm, or at least 0.1 pm.

Clause 17. The additively manufactured aluminum alloy product of clause 15 or 16, wherein

(i)-(iv) are realized in an as-solidified condition.

Clause 18. An additive manufacturing feedstock made from the aluminum alloy of any of clauses 1-17.

Clause 9. The additive manufacturing feedstock of clause 18, wherein the additive manufacturing feedstock is capable of realizing at least one of:

(i) equiaxed grains, wherein the equiaxed grains realize an average aspect ratio of not greater than 1.5 : 1 , or not greater than 1.2 : 1 , or not greater than 1.1 : 1;

(ii) an average grain size of not greater than 50 pm, or not greater than 40 pm, or not greater than 30 pm, or not greater than 20 pm, or not greater than 15 pm, or not greater than 10 pm;

(iii) a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm, or not greater than 4.0 pm, or not greater than 3.0 pm, or not greater than 2.5 pm, or not greater than 2.0 pm, or not greater than 1.5 pm;

(iv) at least 10 vol. % of a eutectic-type structure, or at least 15 vol. % of a eutectic- type structure, or at least 20 vol. % of a eutectic-type structure; and

wherein the additive manufacturing feedstock is capable of realizing at least one of (i)- (iv) in the as-solidified condition of an additively manufactured product.

Clause 20. The additive manufacturing feedstock of clause 19, wherein the additive manufacturing feedstock is capable of realizing a eutectic-type structure having an average eutectic-type structure spacing of at least 0.05 pm, or at least 0.1 pm in the as-solidified condition of an additively manufactured product.

Clause 21. The additive manufacturing feedstock of clause 18 or 19, wherein the additive manufacturing feedstock is capable of realizing an average grain size of at least 1 pm, or at least 2 pm in the as-solidified condition of an additively manufactured product. Clause 22. An additively manufactured aluminum alloy product, comprising:

(a) 0.5 - 7 wt. % Mg;

(b) 3 - 18 wt. % Si;

(c) up to 5 wt. % Li;

(d) up to 13 wt. % Ni; and

the balance being aluminum, optional incidental elements and impurities; and wherein the additively manufactured aluminum alloy product comprises at least 1.0 vol. % of Mg₂Si particles.

Clause 23. The additively manufactured aluminum alloy product of clause 22, wherein the optional incidental elements comprise up to 9 wt. % of eutectic structure modifiers and up to 5 wt. % of one or more grain refiners, wherein:

(a) the eutectic structure modifiers are selected from the group consisting of Ti, Hf, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, rare earth elements, and combinations thereof;

combinations thereof; and

Clause 24. The additively manufactured aluminum alloy product of clause 22 or 23, wherein the additively manufactured aluminum alloy product comprises at least 0.75 wt. % Mg, or at least 1.0 wt. % Mg, or at least 1.5 wt. % Mg, or at least 2.0 wt. % Mg, or at least 2.5 wt. % Mg, or at least 3.0 wt. % Mg.

Clause 25. The additively manufactured aluminum alloy product of any of clauses 22-24, wherein the additively manufactured aluminum alloy product comprises not greater than 6.5 wt. % Mg, or not greater than 6.0 wt. % Mg, or not greater than 5.5 wt. % Mg, or not greater than 5.0 wt. % Mg.

Clause 26. The additively manufactured aluminum alloy product of any of clauses 22-25, wherein the additively manufactured aluminum alloy product comprises at least 4.25 wt. %

Si, or at least 5.5 wt. % Si, or at least 6.75 wt. % Si, or at least Si 8.0 wt. % Si, or at least 10 wt. % Si, or at least 12.0 wt. % Si. Clause 27. The additively manufactured aluminum alloy product of any of clauses 22-26, wherein the additively manufactured aluminum alloy product comprises not greater than 17.0 wt. % Si, or not greater than 16.0 wt. % Si, or not greater than 15.0 wt. % Si.

Clause 28. The additively manufactured aluminum alloy product of any of clauses 22-27, wherein the additively manufactured aluminum alloy product comprises at least 0.1 wt. % Li, or at least 0.2 wt. % Li, or at least 0.3 wt. % Li, or at least 0.4 wt. % Li, or at least 0.5 wt. % Li, or at least 0.75 wt. % Li, or at least 1.0 wt. % Li.

Clause 29. The additively manufactured aluminum alloy product of any of clauses 22-28, wherein the additively manufactured aluminum alloy product comprises not greater than 4.5 wt. % Li, or not greater than 4.0 wt. % Li, or not greater than 3.5 wt. % Li, or not greater than 3.0 wt. % Li.

Clause 30. The additively manufactured aluminum alloy product of any of clauses 22-29, wherein the additively manufactured aluminum alloy product comprises at least 0.1 wt. % Ni or at least 0.5 wt. % Ni, or at least 4.0 wt. % Ni, or at least 7.0 wt. % Ni, or at least 9.0 wt. % Ni.

Clause 31. The additively manufactured aluminum alloy product of any of clauses 22-30, wherein the additively manufactured aluminum alloy product comprises not greater than 12.0 wt. % Ni, or not greater than 11.0 wt. % Ni.

Clause 32. The additively manufactured aluminum alloy product of any of clauses 23-31, wherein the optional incidental elements comprise at least 0.1 wt. % of the eutectic structure modifiers, or at least 0.5 wt. % of the eutectic structure modifiers, or at least 0.8 wt. % of the eutectic structure modifiers.

Clause 33. The additively manufactured aluminum alloy product of any of clauses 23-32, wherein the optional incidental elements comprise not greater 9.0 wt. % of the eutectic structure modifiers, or not greater than 7.0 wt. % of the eutectic structure modifiers, or not greater than 5.0 wt. % of the eutectic structure modifiers, or not greater than 3.0 wt. % of the eutectic structure modifiers, or not greater than 2.0 wt. % of the eutectic structure modifiers, or not greater than 1.2 wt. % of the eutectic structure modifiers.

Clause 34. The additively manufactured aluminum alloy product of any of clauses 23-33, wherein the optional incidental elements comprise at least 0.005 wt. % of the one or more grain refiners, or at least 0.05 wt. % of the one or more grain refiners, or at least 0.5 wt. % of the one or more grain refiners, or at least 0.8 wt. % of the one or more grain refiners. Clause 35. The additively manufactured aluminum alloy product of any of clauses 23-34, wherein the optional incidental elements comprise not greater than 3.0 wt. % of the one or more grain refiners, or not greater than 1.6 wt. % of the one or more grain refiners.

Clause 36. The additively manufactured aluminum alloy product of any of clauses 22-35, wherein the additively manufactured aluminum alloy product comprises not greater than 5.0 vol. % Mg₂Si particles.

Clause 37. The additively manufactured aluminum alloy product of any of clauses 22-36, wherein the additively manufactured aluminum alloy product realizes a non-equilibrium freezing range of not greater than 200°C, or not greater than l00°C, or not greater than 50°C. Clause 38. The additively manufactured aluminum alloy of any of clauses 22-37, wherein the additively manufactured aluminum alloy product comprises one or more of:

(i) equiaxed grains having an average aspect ratio of not greater than 1.5: 1, or not greater than 1.2: 1, or not greater than 1.1 : 1

Clause 39. The additively manufactured aluminum alloy product of clause 38, wherein the additively manufactured aluminum alloy product comprises a eutectic-type structure having an average eutectic-type structure spacing of at least 0.05 pm, or at least 0.1 pm.

Clause 40. The additively manufactured aluminum alloy product of clause 38 or 39, wherein the additively manufactured aluminum alloy product comprises an average grain size of at least 1 pm, or at least 2 pm.

Clause 41. The additively manufactured aluminum alloy product of any of clauses 38-40, wherein (i)-(iv) are realized in an as-solidified condition.

Clause 42. The additively manufactured aluminum alloy product of any of clauses 22-41, wherein the additively manufactured aluminum alloy product comprises a eutectic-type structure, and wherein the eutectic-type structure comprises cell walls comprising Mg₂Si particles. [0089] Other clauses based on any of the above paragraphs of the specification and the attached drawings are contemplated and apply to the present patent application.

[0090] While a number of embodiments of the present invention have been described, it is understood that these embodiments are illustrative only, and not restrictive, and that many modifications may become apparent to those of ordinary skill in the art. Further still, the various steps may be carried out in any desired order (and any desired steps may be added and/or any desired steps may be eliminated).

Claims

CLAIMS What is claimed is:

1. An aluminum alloy, comprising:

(a) 0.1 to 5 wt. % Li;

(b) 2 - 18 wt. % Si; and

(c) up to 7 wt. % Mg.

2. The aluminum alloy of claim 1, wherein the aluminum alloy comprises at least 0.2 wt. % Li, or at least 0.3 wt. % Li, or at least 0.4 wt. % Li, or at least 0.5 wt. % Li, or at least 0.75 wt. % Li, or at least 1.0 wt. % Li.

3. The aluminum alloy of claim 2, wherein the aluminum alloy comprises not greater than 4.5 wt. % Li, or not greater than 4.0 wt. % Li, or not greater than 3.5 wt. % Li, or not greater than 3.0 wt. % Li.

4. The aluminum alloy of claim 1, wherein the aluminum alloy comprises at least 2.5 wt. %

Si, or at least 3.0 wt. % Si, or at least 3.5 wt. % Si, or at least 4.0 wt. % Si.

5. The aluminum alloy of claim 4, wherein the aluminum alloy comprises not greater than 15 wt. % Si, or not greater than 13 wt. % Si, or not greater than 10 wt. % Si, or not greater than 8.0 wt. % Si, or not greater than 7.0 wt. % Si, or not greater than 6.0 wt. % Si.

6. The aluminum alloy of claim 1, wherein the aluminum alloy comprises at least 0.1 wt. % Mg, or at least 0.3 wt. % Mg, or at least 0.4 wt. % Mg, or at least 0.5 wt. % Mg, or at least 0.6 wt. % Mg, or at least 0.7 wt. % Mg, or at least 0.8 wt. % Mg.

7. The aluminum alloy of claim 6, wherein the aluminum alloy comprises not greater than 6.0 wt. % Mg, or not greater than 5.0 wt. % Mg, or not greater than 4.0 wt. % Mg, or not greater than 3.0 wt. % Mg, or not greater than 2.5 wt. % Mg, or not greater than 2.0 wt. % Mg, or not greater than 1.75 wt. % Mg, or not greater than 1.5 wt. % Mg, or not greater than 1.2 wt. % Mg.

8. The aluminum alloy of claim 1, wherein the balance of the aluminum alloy is aluminum, optional incidental elements and impurities.

9. The aluminum alloy of claim 8, wherein the optional incidental elements comprise up to 9 wt. % of eutectic structure modifiers and up to 5 wt. % of one or more grain refiners, wherein:

Ni, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, rare earth elements, and combinations thereof; (b) the one or more grain refiners comprise at least one of ceramic materials and intermetallic particles;

(i) wherein, when present, the ceramic materials are selected from the group consisting of TiB, TiB₂, TiC, SiC, AI2O3, BC, BN, Si₃N₄, AI4C3, A1N and

combinations thereof; and

10. The aluminum alloy of claim 8, wherein optional incidental elements comprise greater 9.0 wt. % of the eutectic structure modifiers, or not greater than 7.0 wt. % of the eutectic structure modifiers, or not greater than 5 wt. % of the eutectic structure modifiers, or not greater than 3.0 wt. % of the eutectic structure modifiers, or not greater than 2.0 wt. % of the eutectic structure modifiers, or not greater than 1.2 wt. % of the eutectic structure modifiers.

11. The aluminum alloy of claim 8, wherein optional incidental elements comprise at least 0.005 wt. % of the one or more grain refiners, or at least 0.05 wt. % of the one or more grain refiners, or at least 0.5 wt. % of the one or more grain refiners, or at least 0.8 wt. % of the one or more grain refiners.

12. An additive manufacturing feedstock made from the aluminum alloy of any of claims 1- 11

13. An additively manufactured aluminum alloy product made from the additive manufacturing feedstock of claim 12, wherein the additively manufactured alloy product comprises at least one of:

(ii) equiaxed grains, wherein the equiaxed grains have an average aspect ratio of not greater than 1.5: 1, or not greater than 1.2: 1, or not greater than 1.1 : 1;

(iii) an average grain size of not greater than 50 pm, or not greater than 40 pm, or not greater than 30 pm, or not greater than 20 pm, or not greater than 15 pm, or not greater than 10 pm; and

14. An additively manufactured aluminum alloy product, comprising:

(a) 0.5 - 7 wt. % Mg;

(b) 3 - 18 wt. % Si;

(c) up to 5 wt. % Li;

(d) up to 13 wt. % Ni; and

15. The additively manufactured aluminum alloy product of claim 14, wherein the additively manufactured aluminum alloy product comprises at least 0.75 wt. % Mg, or at least 1.0 wt. % Mg, or at least 1.5 wt. % Mg, or at least 2.0 wt. % Mg, or at least 2.5 wt. % Mg, or at least 3.0 wt. % Mg.

16. The additively manufactured aluminum alloy product of claim 15, wherein the additively manufactured aluminum alloy product comprises not greater than 6.5 wt. % Mg, or not greater than 6.0 wt. % Mg, or not greater than 5.5 wt. % Mg, or not greater than 5.0 wt. %

Mg.

17. The additively manufactured aluminum alloy product of claim 14, wherein additively manufactured aluminum alloy product comprises at least 4.25 wt. % Si, or at least 5.5 wt. % Si, or at least 6.75 wt. % Si, or at least Si 8.0 wt. % Si, or at least 10 wt. % Si, or at least 12.0 wt. % Si.

18. The additively manufactured aluminum alloy product of claim 17, wherein the additively manufactured aluminum alloy product comprises not greater than 16.0 wt. % Si, or not greater than 15.0 wt. % Si.

19. The additively manufactured aluminum alloy product of claim 14, wherein the additively manufactured aluminum alloy product comprises at least 0.1 wt. % Li, or at least 0.2 wt. %

Li, or at least 0.3 wt. % Li, or at least 0.4 wt. % Li, or at least 0.5 wt. % Li, or at least 0.75 wt. % Li, or at least 1.0 wt. % Li.

20. The additively manufactured aluminum alloy product of claim 19, wherein the additively manufactured aluminum alloy product comprises not greater than 4.5 wt. % Li, or not greater than 4.0 wt. % Li, or not greater than 3.5 wt. % Li, or not greater than 3.0 wt. % Li.

21. The additively manufactured aluminum alloy product of claim 14, wherein the additively manufactured aluminum alloy product comprises at least 0.1 wt. % Ni or at least 0.5 wt. % Ni, or at least 4.0 wt. % Ni, or at least 7.0 wt. % Ni, or at least 9.0 wt. % Ni.

22. The additively manufactured aluminum alloy product of claim 21, wherein the additively manufactured aluminum alloy product comprises not greater than 12.0 wt. % Ni, or not greater than 11.0 wt. % Ni.

23. The additively manufactured product of claim 15, wherein the optional incidental elements comprise up to 9 wt. % of eutectic structure modifiers and up to 5 wt. % of one or more grain refiners, wherein:

combinations thereof; and

24. The additively manufactured aluminum alloy product of claim 23, wherein the optional incidental elements comprise at least 0.1 wt. % of the eutectic structure modifiers, or at least 0.5 wt. % of the eutectic structure modifiers, or at least 0.8 wt. % of the eutectic structure modifiers.

25. The additively manufactured aluminum alloy product of claim 24, wherein the optional incidental elements comprise not greater 9.0 wt. % of the eutectic structure modifiers, or not greater than 7.0 wt. % of the eutectic structure modifiers, or not greater than 5.0 wt. % of the eutectic structure modifiers, or not greater than 3.0 wt. % of the eutectic structure modifiers, or not greater than 2.0 wt. % of the eutectic structure modifiers, or not greater than 1.2 wt. % of the eutectic structure modifiers.

26. The additively manufactured aluminum alloy product of claim 23, wherein the optional incidental elements comprise at least 0.005 wt. %, or at least 0.05 wt. %, or at least 0.5 wt. %, or at least 0.8 wt. % of one or more grain refiners.

27. The additively manufactured aluminum alloy product of any of claims 15-26, wherein the additively manufactured aluminum alloy product comprises one or more of:

(i) equiaxed grains, wherein the equiaxed grains realize an average aspect ratio of not greater than 1.5 : 1 , or not greater than 1.2 : 1 , or not greater than 1.1 : 1; (ii) an average grain size of not greater than 50 pm, or not greater than 40 pm, or not greater than 30 pm, or not greater than 20 pm, or not greater than 15 pm, or not greater than 10 pm;

(iii) a eutectic-type structure having an average eutectic-type structure spacing of not greater than 5.0 pm, or not greater than 4.0 pm, or not greater than 3.0 pm, or not greater than 2.5 pm, or not greater than 2.0 pm, or not greater than 1.5 pm; and

(iv) at least 10 vol. % of a eutectic-type structure, or at least 15 vol. % of a eutectic- type structure, or at least 20 vol. % of a eutectic-type structure.

28. An aluminum alloy consisting of:

(a) 0.1 to 5 wt. % Li;

(b) 2 - 18 wt. % Si; and

(c) up to 7 wt. % Mg;

the balance being aluminum, optional incidental elements and impurities;

wherein the optional incidental elements include up to 9 wt. % of eutectic structure modifiers and up to 5 wt. % of grain refiners;

wherein the eutectic structure modifiers are selected from the group consisting of Ni, Ti, Hf, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, rare earth elements, and combinations thereof;

wherein, the grain refiners are selected from the group consisting of ceramic materials, intermetallic particles, and combinations thereof;

wherein, when present, the ceramic materials are selected from the group consisting of TiB, TiB₂, TiC, SiC, Al₂0₃, BC, BN, Si₃N₄, Al₄C₃, A1N, and

combinations thereof; and

wherein, when present, the intermetallic particles include elements selected from the group consisting of Ti, Zr, Sc, Hf, V, Mo, Nb, Ta, W, and combinations thereof.

29. An aluminum alloy consisting of:

(a) 0.5 - 7 wt. % Mg;

(b) 3 - 18 wt. % Si;

(c) up to 5 wt. % Li; and

(d) up to 13 wt. % Ni;

the balance being aluminum, optional incidental elements, and impurities;

wherein the aluminum alloy comprises at least 1.0 vol. % of Mg₂Si particles; wherein the optional incidental elements include up to 9 wt. % of eutectic structure modifiers and up to 5 wt. % of grain refiners;

wherein the eutectic structure modifiers are selected from the group consisting of Ti, Hf, Mn, Fe, Co, Cr, V, Zr, Mo, Sc, Cu, Nb, Ta, W, rare earth elements, and combinations thereof;

wherein, when present, the ceramic materials are selected from the group consisting of TiB, TiB₂, TiC, SiC, Al₂0₃, BC, BN, Si₃N₄, Al₄C₃, A1N, and combinations thereof; and