CN115380127A

CN115380127A - Aluminium-chromium-zirconium alloy

Info

Publication number: CN115380127A
Application number: CN202080099012.8A
Authority: CN
Inventors: 约翰·马丁; 达尔比·拉普兰特; 朱莉·米勒
Original assignee: HRL Laboratories LLC
Current assignee: HRL Laboratories LLC
Priority date: 2020-01-31
Filing date: 2020-12-15
Publication date: 2022-11-22
Also published as: EP4097266A1; WO2021154409A1; EP4097266A4

Abstract

Some variations provide an aluminum (Al) alloy containing at least 0.1at% zirconium (Zr) and/or at least 0.1at% chromium (Cr), wherein the aluminum alloy is in the form of an additively manufactured object. Other variations provide an aluminum-containing powder comprising Al particles, cr particles, and Zr particles, wherein at least some of the Cr particles and at least some of the Zr particles are physically and/or chemically assembled on a surface of the Al particles, and wherein the aluminum-containing powder contains at least 0.1at% Zr and at least 0.1at% Cr. In the present invention, the combination of surface functionalization and additive manufacturing fundamentally creates a new compositional space for valuable aluminum alloys. The disclosed Al alloys are strong, thermally stable, and corrosion resistant.

Description

Aluminium-chromium-zirconium alloy

Priority data

This international patent application claims priority from U.S. provisional patent application No. 62/968,238, filed on 31/2020, and U.S. patent application No. 17/121,601, filed on 14/12/2020, each of which is hereby incorporated by reference.

Technical Field

The present invention generally relates to aluminum-chromium-zirconium alloys, raw materials for aluminum-chromium-zirconium alloys, and methods of making and using aluminum-chromium-zirconium alloys.

Background

Aluminum and its alloys are characterized by relatively low density, high electrical and thermal conductivity, and corrosion resistance in some common environments, including ambient atmosphere. Recently, aluminum alloys have been noted as engineering materials for transportation to reduce fuel consumption due to high specific strength. The low density of aluminum (and thus part weight) is advantageous for parts that are heavy weight demanding.

There is a commercial need for structures formed from aluminum alloys that exhibit high strength at high temperatures, such as 300 c. Such structures include, for example, aluminum alloy structures in propulsion and exhaust systems of commercial and military aircraft exposed to high temperatures; aluminum alloy structures of high speed vehicles exposed to high temperatures due to pneumatic thermal heating; and motor vehicle powertrain aluminum alloy parts exposed to high temperatures, such as pistons, connecting rods, cylinder heads, and brake calipers.

The mechanical strength of aluminum can be enhanced by cold working and alloying. Common alloying elements include copper, magnesium, silicon, zinc, and manganese. Generally, aluminum alloys are classified as cast or forged. Some common cast, heat treatable aluminum alloys include Al 295.0 and Al 356.0 (decimal points indicate cast alloys). Wrought alloys include heat treatable alloys (e.g., al 2104, al 6061, and Al 7075) and non-heat treatable alloys (e.g., al 1100, al 3003, and Al 5052). Heat treatable aluminum alloys generally have superior mechanical strength compared to other types of Al alloys.

Metal-based additive manufacturing or three-dimensional (3D) printing has applications in many industries, including the aerospace industry and the automotive industry. Building metal parts layer by layer increases design freedom and manufacturing flexibility, thereby enabling complex geometries while eliminating traditional economies of scale constraints. However, limitations of printable alloys, particularly with respect to specific strength, fatigue life, and fracture toughness, have hindered metal-based additive manufacturing. See Martin et al, "3D printing of high-strength aluminum alloys [ 3D printing of high-strength aluminum alloys ]," Nature [ Nature ] Vol.549, p.365 i 369.

In relation to aluminium alloys in particular printable aluminium alloys based on binary Al-Si systems tend to concentrate around a yield strength of about 200MPa with a low ductility of 4%. Most aluminum alloys for automotive, aerospace, and consumer applications are 2000, 5000, 6000, or 7000 series wrought alloys that can exhibit strengths in excess of 400MPa and ductility in excess of 10%, but have not been commercially additive manufactured. These systems have low cost alloying elements (Cu, mg, zn, and Si) to produce a composite strengthening phase during subsequent aging. These same elements promote a large solidification range, leading to hot tearing (cracking) during solidification.

There is a need for an additive manufactured aluminum alloy that has good mechanical properties at high temperatures for the aforementioned commercial and other applications. Previous attempts at high temperature aluminum alloys have relied on the introduction of high cost elements (e.g., sc) or the use of rapid solidification (e.g., generation of Al-Si-Fe-V) to form metastable high temperature strengthening phases.

In particular, aluminum-chromium-zirconium (Al-Cr-Zr) alloys are predicted to have good mechanical strength. However, attempts to produce Al-Cr-Zr alloys have heretofore been limited in composition due to the high melting points of Cr (1907 ℃ C.) and Zr (1855 ℃ C.) relative to aluminum (660 ℃ C.). This limitation is emphasized in Yan, "Strenggthening Aluminum By Zirconium and Chromium enhanced Aluminum" (2013), master thesis, worcester Polytechnical Institute, which is incorporated By reference. Yan notes the high thermal stability of Al-Cr-Zr alloys, but the hardness is low due to the inability to introduce high Cr and Zr contents.

Other techniques such as melt spinning and gas atomization have been used to process Al-Cr-Zr alloys, but these known techniques are limited by the high casting temperatures required at elevated Cr and Zr concentrations. In particular, temperatures of several hundred degrees celsius above typical casting temperatures are necessary due to the high liquidus temperatures associated with elevated Cr and Zr concentrations.

In view of the commercial drive for high strength, temperature stable aluminum alloys and the theoretical (but heretofore unrealized) prospects embodied by Al-Cr-Zr alloys having relatively high concentrations of Cr and/or Zr, there is a need for Al-Cr-Zr alloy compositions that have not been produced industrially or enabled in the prior art. In addition, raw materials such as powders are required for manufacturing such Al — Cr — Zr alloys. Finally, there is a need for a method of making an Al-Cr-Zr alloy having a relatively high concentration of Cr and/or Zr.

SUMMARY

The present invention addresses the foregoing needs in the art as will now be summarized and then further described in detail below.

Some variations provide an aluminum (Al) alloy containing at least 0.1at% zirconium (Zr) and/or at least 0.1at% chromium (Cr), wherein the aluminum alloy is in the form of an additively manufactured object.

In some embodiments, the aluminum alloy contains at least 0.1at% zr.

In some embodiments, the aluminum alloy contains at least 0.1at% cr.

In some embodiments, the aluminum alloy contains at least 0.3at% Cr and/or at least 0.3at% Zr.

In some embodiments, the aluminum alloy contains at least 0.5at%Cr and/or at least 0.5at%.

In some embodiments, the aluminum alloy contains at least 1.0at% Cr and/or at least 1.0at% Zr.

In some embodiments, the aluminum alloy contains at least 2.0at% Cr and/or at least 2.0at% Zr.

The Zr/Cr ratio may be selected from 0.1 to 10, such as, for example, from 0.2 to 2.

In some embodiments, the aluminum alloy contains precipitated intermetallic Al-Cr particles and/or precipitated intermetallic Al-Zr particles.

In some embodiments, the aluminum alloy contains equiaxed grains nucleated by Cr and/or Zr.

The aluminum alloy may further contain one or more elements selected from the group consisting of Cu, mg, zn, li, mn, fe, si, ag, V, nb, ta, ti, hf, mo, W, sc, Y, ca, be, sr, la, ce, re, ru, os, co, ni, pd, pt, ir, rh, au, cd, sn, bi, pb, B, C, N, O, H, S, er, pr, nd, sm, gd, tb, dy, ho, tm, yb, and Lu.

In some embodiments, the aluminum alloy is characterized by a Vickers Pyramid Number (HV) of at least 50, such as at least 75.

In some embodiments, the aluminum alloy is characterized by a tensile strength of at least 250MPa, 300MPa, 350MPa, 400MPa, 450MPa, 500MPa, 550MPa, 600MPa, 650MPa, or 700 MPa.

In some embodiments, the aluminum alloy is thermally stable at 300 ℃, 350 ℃, 400 ℃, 450 ℃, or 500 ℃.

In some embodiments, the aluminum alloy is corrosion resistant.

In some embodiments, the aluminum alloy has a crack-free microstructure.

The additive manufactured object may be selected from the group consisting of, for example, a structural part, a coating, an ingot, a sheet, a plate, a bar, a wire, and combinations thereof. Various structures may contain an additive manufactured object (aluminum alloy).

Some variations of the invention provide an aluminum (Al) alloy containing at least 0.1at% zirconium (Zr) and at least 0.1at% chromium (Cr), where the aluminum alloy is in the form of an article of manufacture. The manufactured object need not be an additive manufactured object.

In some embodiments, the aluminum alloy contains at least 0.25at% cr and/or at least 0.25at% zr.

The Zr/Cr ratio in the aluminum alloy may be selected from 0.1 to 10, such as, for example, from 0.2 to 2.

The aluminum alloy may contain precipitated intermetallic Al-Cr particles, precipitated intermetallic Al-Zr particles, and/or precipitated intermetallic Zr-Cr particles.

In some embodiments, the aluminum alloy may contain equiaxed grains nucleated by Cr and/or Zr.

The object of manufacture may be selected from the group consisting of structural parts, coatings, ingots, sheets, plates, rods, wires, and combinations thereof.

Other variations of the invention provide an aluminum-containing powder comprising:

(a) First particles comprising aluminum (Al), wherein the first particles have an average first particle size;

(b) Second particles containing zirconium (Zr), wherein the second particles have an average second particle diameter smaller than the average first particle diameter; and

(c) Third particles comprising chromium (Cr), wherein the third particles have an average third particle size that is less than the average first particle size, and wherein the third particles are compositionally different from the second particles,

wherein at least some of the second particles and at least some of the third particles are physically and/or chemically assembled on the surface of the first particles,

and wherein the aluminum-containing powder contains at least 0.1at% Zr and at least 0.1at% Cr.

In some embodiments, the aluminiferous powder contains at least 0.3at%Cr and/or at least 0.3at%.

In some embodiments, the aluminum-containing powder contains at least 0.5at% cr and/or at least 0.5at% zr.

In some embodiments, the aluminum-containing powder contains at least 1.0at% Cr and/or at least 1.0at% Zr.

In some embodiments, the aluminum-containing powder contains at least 2.0at% Cr and/or at least 2.0at% Zr.

In the aluminum containing powder, the Zr/Cr ratio may be selected from 0.1 to 10, such as from 0.2 to 2.

The first particles optionally further contain one or more elements selected from the group consisting of Cu, mg, zn, li, mn, fe, si, ag, V, nb, ta, ti, hf, mo, W, sc, Y, ca, be, sr, la, ce, re, ru, os, co, ni, pd, pt, ir, rh, au, cd, sn, bi, pb, B, C, N, O, H, S, er, pr, nd, sm, gd, tb, dy, ho, tm, yb, and Lu.

The aluminum-containing powder may further contain one or more elements selected from the group consisting of Cu, mg, zn, li, mn, fe, si, ag, V, nb, ta, ti, hf, mo, W, sc, Y, ca, be, sr, la, ce, re, ru, os, co, ni, pd, pt, ir, rh, au, cd, sn, bi, pb, B, C, N, O, H, S, er, pr, nd, sm, gd, tb, dy, ho, tm, yb, and Lu. The one or more additional elements may be contained within the first particle, the second particle, the third particle, or as additional particles, or a combination of the foregoing.

In some embodiments, the average second particle size is at least one order of magnitude smaller than the average first particle size.

In some embodiments, the average third particle size is at least one order of magnitude smaller than the average first particle size.

In some embodiments, the ratio of the average second particle size to the average third particle size is selected from 0.1 to 10.

In some aluminum-containing powders, at least 50 volume percent of the second particles are physically and/or chemically assembled on the surface of the first particles. In certain embodiments, at least 90% by volume or at least 99% by volume of the second particles are physically and/or chemically assembled on the surface of the first particles.

In some aluminum-containing powders, at least 50 volume percent of the third particles are physically and/or chemically assembled on the surface of the first particles. In certain embodiments, at least 90% by volume or at least 99% by volume of the third particles are physically and/or chemically assembled on the surface of the first particles.

In some embodiments, the aluminum-containing powder contains one or more intermetallic compounds of Zr and Cr.

In some embodiments, the second particles further comprise Cr and/or the third particles further comprise Zr. In these embodiments, cr and Zr may be present as a physical mixture, as an alloy, or as an intermetallic compound (e.g., zrCr ₂ ) Are present.

Drawings

FIG. 1 shows the Al-rich side of the Al-Zr equilibrium phase diagram.

FIG. 2 shows the Al-rich side of the Al-Cr equilibrium phase diagram.

Fig. 3 is a photomicrograph (scale bar =1000 micrometers) of the surface of the additive manufactured aluminum alloy in example 2.

Fig. 4 is a photomicrograph (scale =1000 micrometers) of the surface of the additive manufactured aluminum alloy in example 3.

Fig. 5 is a photomicrograph (scale =1000 micrometers) of the surface of the additive manufactured aluminum alloy in example 4.

Fig. 6 is a photomicrograph (scale =1000 micrometers) of the surface of the additive manufactured aluminum alloy in example 5.

Fig. 7 is a photomicrograph of the surface of an additively manufactured aluminum alloy made in the form of dog bone (dogbone) in example 6.

FIG. 8 is a plot of as-built hardness (as-built hardness) for the aluminum alloys of examples 1, 2, 3, 4, 5, and 6.

FIG. 9 is a plot of hardness versus aging time at a fixed aging temperature of 350 ℃ for the aluminum alloys of examples 1, 2, 3, 4, 5, and 6.

FIG. 10 is a plot of hardness versus aging time at a fixed aging temperature of 200 ℃ for the aluminum alloys of examples 1, 2, 3, 4, 5, and 6.

Fig. 11 shows tensile stress versus elongation for the aluminum alloys of examples 5 and 6 with various heat treatments.

Fig. 12 shows X-ray diffraction patterns of the aluminum alloys of examples 1, 2, 3, 4, and 5.

Detailed Description

The compositions, structures, systems and methods of this invention are described in detail by reference to various non-limiting examples.

This description will enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention. These and other embodiments, features and advantages of the present invention will become more apparent to those skilled in the art when the following detailed description of the invention is taken in conjunction with the accompanying drawings.

As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Unless otherwise indicated, all numbers expressing conditions, concentrations, dimensions, and so forth, used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon, at least, the particular analytical technique.

The term "comprising" synonymous with "including", "containing", or "characterized by" is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. "comprising" is a term of art used in claim language that means that the specified claim element is essential, but that other claim elements can be added and still constitute a concept within the scope of the claims.

As used herein, the phrase "consisting of" does not include any elements, steps, or ingredients not specified in the claims. The phrase "consisting of" (or variants thereof) when it appears in the clause of the subject matter of the claims, rather than immediately following the preamble, is intended to limit only the elements set forth in the clause; other elements are not excluded from the claims as a whole. As used herein, the phrase "consisting essentially of" limits the scope of the claims to the specified elements or method steps, plus those that do not materially affect the basic and one or more novel features of the claimed subject matter.

Where one of these three terms is used herein with respect to the terms "comprising," "consisting of," and "consisting essentially of," the presently disclosed and claimed subject matter may include the use of either of the other two terms, except for the markush group. Thus, in some embodiments that are not explicitly enumerated otherwise, any instance of "comprising" may be replaced with "consisting of," or alternatively "consisting essentially of.

Some variations of the invention provide a new aluminum alloy composition containing chromium (Cr) and zirconium (Zr) at a concentration of at least 0.1at% for each of Cr and Zr, such as at least 0.2at%, at least 0.3at%, at least 0.4at%, or at least 0.5at% for each of Cr and/or Zr. In this specification, at% is the atomic percentage in the alloy. The base material of the aluminum alloy is aluminum (Al).

The peritectic properties of Cr and Zr make the Al-Cr-Zr alloy extremely high in melting point. As detailed in this specification, surface functionalization and additive manufacturing with fast solidification provide a convenient processing route to produce Al-Cr-Zr alloys with high strength and good thermal stability. A new composition space for Al-Cr-Zr alloys has been discovered.

FIG. 1 shows the Al-rich side of the Al-Zr equilibrium phase diagram. FIG. 2 shows the Al-rich side of the Al-Cr equilibrium phase diagram. As shown in fig. 1 and 2, the peritectic nature of both Al-Zr and Al-Cr systems indicates a significant increase in melting point with increasing concentration. This fact limits the processing of Al-Cr, al-Zr, and Al-Cr-Zr alloys due to the reactive nature of the composition and the subsequent difficulty of processing the reactive material at high temperatures, particularly given the significant vapor pressure of Al at temperatures above about 800 ℃. Completely melting these alloys while avoiding significant coarsening of the intermetallic compounds requires maintaining the Al melt above 1000 ℃ for long periods of time, making processing both expensive and difficult.

In some variants, the present invention solves the technical problem by exploiting the functionalization of Al surfaces with Cr and/Zr in conjunction with additive manufacturing or similar processing techniques. Short-life (preferably less than 1 second), high temperature (> 1000 ℃) melt pools with small Cr and Zr particles (preferably less than 100 microns) enable rapid dissolution or suspension of the Cr and Zr elements into the melt. Subsequent rapid solidification may provide solute trapping and precipitation of intermetallic Al-Cr and/or Al-Zr phases to provide additional strength. Notably, the disclosed method is capable of producing aluminum alloys having Zr and/or Cr at concentrations greater than the respective equilibrium solubilities.

Solute trapping provides solid solution strengthening by adding atoms of Cr and/or Zr into the lattice of Al. Nucleation of dispersed intermetallic compounds (e.g., al-Cr and/or Al-Zr) provides dispersion strengthening (also referred to as dispersion hardening) that limits dislocation motion. In addition, the use of Cr and Zr provides thermal stability due to the very low diffusivity of these materials. The low diffusivity retards or inhibits significant coarsening of the intermetallic compound at moderate temperatures, such as about 450 ℃ or less. In some embodiments, the additive manufactured aluminum alloy has sufficient strength and/or other mechanical properties. Optionally, a subsequent heat treatment may be applied to precipitate at least some of the trapped solute to provide additional strengthening.

In addition to the base Al-Cr-Zr alloy, additional alloying elements may be added to provide additional strengthening or for other reasons. Optional additional alloying elements may include, but are not limited to, cu, mg, zn, li, mn, fe, si, ag, V, nb, ta, ti, hf, nb, mo, and W. For some elements, such as Ti, cr, V, zr, nb, mo, hf, ta, or W, the concentration may be relatively high compared to Cr and Zr, i.e. at least higher than those elements, where aluminum remains the predominant element in the alloy. For example, the optional alloying elements may be in the form of pure metals or may be in the form of hydrides, oxides, nitrides, carbides, sulfides, or borides.

Other elements on the periodic table may be used to improve the strength or other properties of the alloy. For example, the aluminum alloy can contain Sc, Y, ca, be, sr, la, ce, re, ru, os, co, ni, pd, pt, ir, rh, au, cd, sn, bi, pb, B, C, N, O, H, S, er, pr, nd, sm, gd, tb, dy, ho, tm, yb, lu, or hydrides, oxides, nitrides, carbides, sulfides, or borides thereof, or combinations of any of the foregoing. Typically, aluminum alloys contain and tolerate trace contaminants from typical aluminum processing; that is, the starting aluminum may be, but need not be, ultra-high purity. Typical trace elements in aluminum processing include Si and Fe. Preferably, the total impurities in the final aluminum alloy are no greater than 1 wt.%.

Some variations of the invention provide an aluminum (Al) alloy containing at least 0.1at% zirconium (Zr) and/or at least 0.1at% chromium (Cr), where the aluminum alloy is in the form of an additively manufactured object.

In some embodiments, the aluminum alloy contains at least 0.1at% zr. In some embodiments, the aluminum alloy contains at least 0.1at% cr. In some embodiments, the aluminum alloy contains at least 0.2at% cr and/or at least 0.2at% zr. In some embodiments, the aluminum alloy contains at least 0.3at%Cr and/or at least 0.3at%. In some embodiments, the aluminum alloy contains at least 0.4at% cr and/or at least 0.4at% zr. In some embodiments, the aluminum alloy contains at least 0.5at%Cr and/or at least 0.5at%. In some embodiments, the aluminum alloy contains at least 1.0at% Cr and/or at least 1.0at% Zr. In some embodiments, the aluminum alloy contains at least 2.0at% Cr and/or at least 2.0at% Zr.

In some embodiments, the aluminum alloy contains at least 0.9at% Cr and/or at least 0.5at% Zr. In certain embodiments, the aluminum alloy contains at least 0.85at% Cr and/or at least 0.45at% Zr. In certain embodiments, the aluminum alloy contains greater than 0.80at% Cr and/or greater than 0.40at% Zr.

<xnotran> , , , 0.05at%, 0.1at%, 0.15at%, 0.2at%, 0.25at%, 0.3at%, 0.35at%, 0.4at%, 0.45at%, 0.5at%, 0.55at%, 0.6at%, 0.65at%, 0.7at%, 0.75at%, 0.8at%, 0.85at%, 0.9at%, 0.95at%, 1.0at%, 1.1at%, 1.2at%, 1.3at%, 1.4at%, 1.5at%, 1.6at%, 1.7at%, 1.8at%, 1.9at%, 2.0at%, 2.1at%, 2.2at%, 2.3at%, 2.4at%, 2.5at%, 2.6at%, 2.7at%, 2.8at%, 2.9at%, 3.0at%, 3.1at%, 3.2at%, 3.3at%, 3.4at%, 3.5at%, 3.6at%, 3.7at%, 3.8at%, 3.9at%, 4.0at%, 4.1at%, 4.2at%, 4.3at%, 4.4at%, 4.5at%, 4.6at%, 4.7at%, 4.8at%, 4.9at%, 5.0at%Cr, . </xnotran> In some embodiments, the aluminum alloys disclosed herein contain greater than 5at% cr, such as about 6at%, 7at%, 8at%, 9at%, 10at%, 15at%, 20at%, or 25at% cr.

<xnotran> , , , 0.05at%, 0.1at%, 0.15at%, 0.2at%, 0.25at%, 0.3at%, 0.35at%, 0.4at%, 0.45at%, 0.5at%, 0.55at%, 0.6at%, 0.65at%, 0.7at%, 0.75at%, 0.8at%, 0.85at%, 0.9at%, 0.95at%, 1.0at%, 1.1at%, 1.2at%, 1.3at%, 1.4at%, 1.5at%, 1.6at%, 1.7at%, 1.8at%, 1.9at%, 2.0at%, 2.1at%, 2.2at%, 2.3at%, 2.4at%, 2.5at%, 2.6at%, 2.7at%, 2.8at%, 2.9at%, 3.0at%, 3.1at%, 3.2at%, 3.3at%, 3.4at%, 3.5at%, 3.6at%, 3.7at%, 3.8at%, 3.9at%, 4.0at%, 4.1at%, 4.2at%, 4.3at%, 4.4at%, 4.5at%, 4.6at%, 4.7at%, 4.8at%, 4.9at%, 5.0at%Zr, . </xnotran> In some embodiments, the aluminum alloys disclosed herein contain greater than 5at% zr, such as about 6at%, 7at%, 8at%, 9at%, 10at%, 15at%, 20at%, or 25at% zr.

<xnotran> , , , 0.1at%, 0.15at%, 0.2at%, 0.25at%, 0.3at%, 0.35at%, 0.4at%, 0.45at%, 0.5at%, 0.55at%, 0.6at%, 0.65at%, 0.7at%, 0.75at%, 0.8at%, 0.85at%, 0.9at%, 0.95at%, 1.0at%, 1.1at%, 1.2at%, 1.3at%, 1.4at%, 1.5at%, 1.6at%, 1.7at%, 1.8at%, 1.9at%, 2.0at%, 2.1at%, 2.2at%, 2.3at%, 2.4at%, 2.5at%, 2.6at%, 2.7at%, 2.8at%, 2.9at%, 3.0at%, 3.1at%, 3.2at%, 3.3at%, 3.4at%, 3.5at%, 3.6at%, 3.7at%, 3.8at%, 3.9at%, 4.0at%, 4.1at%, 4.2at%, 4.3at%, 4.4at%, 4.5at%, 4.6at%, 4.7at%, 4.8at%, 4.9at%, 5.0at%, 5.1at%, 5.2at%, 5.3at%, 5.4at%, 5.5at%, 5.6at%, 5.7at%, 5.8at%, 5.9at%, 6.0at%, 6.1at%, 6.2at%, 6.3at%, 6.4at%, 6.5at%, 6.6at%, 6.7at%, 6.8at%, 6.9at%, 7.0at%, 7.1at%, 7.2at%, 7.3at%, 7.4at%, 7.5at%, 7.6at%, 7.7at%, 7.8at%, 7.9at%, 8.0at%, 8.1at%, 8.2at%, 8.3at%, 8.4at%, 8.5at%, 8.6at%, 8.7at%, 8.8at%, 8.9at%, 9.0at%, 9.1at%, 9.2at%, 9.3at%, 9.4at%, 9.5at%, 9.6at%, 9.7at%, 9.8at%, 9.9at%, 10.0at% (Cr + Zr), . </xnotran> In some embodiments, an aluminum alloy disclosed herein contains greater than 10at% (Cr + Zr), such as about 11at%, 12at%, 13at%, 14at%, 15at%, 16at%, 17at%, 18at%, 19at%, 20at%, 25at%, 30at%, 35at%, 40at%, 45at%, or 50at% (Cr + Zr).

When both Cr and Zr are present, the Zr/Cr ratio may be selected from 0.1 to 10, such as, for example, from 0.2 to 2. In various embodiments, the Zr/Cr ratio is about 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, or 100, including all intermediate ranges (e.g., 0.1-10 or 0.5-5).

In some embodiments, the aluminum alloy contains precipitated intermetallic Al-Cr particles and/or precipitated intermetallic Al-Zr particles. Exemplary intermetallic Al-Cr particles include, but are not limited to, al ₁₁ Cr ₂ 、Al ₇ Cr、Al ₄ Cr、Al ₉ Cr ₄ And Al ₈ Cr ₅ . Exemplary intermetallic Al-Zr particles include, but are not limited to, al ₃ Zr、Al ₂ Zr、Al ₃ Zr ₂ And AlZr.

In some embodiments, the aluminum alloy contains equiaxed grains nucleated directly or indirectly by Cr and/or Zr. Direct nucleation herein refers to Cr and/or Zr nucleating grain growth, while indirect nucleation refers to intermetallic Al-Cr particles and/or intermetallic Al-Zr particles nucleating grain growth (which may be continuous or simultaneous with the reaction forming the intermetallic species).

The aluminum alloy may further contain one or more elements selected from the group consisting of Cu, mg, zn, li, mn, fe, si, ag, V, nb, ta, ti, hf, mo, W, sc, Y, ca, be, sr, la, ce, re, ru, os, co, ni, pd, pt, ir, rh, au, cd, sn, bi, pb, B, C, N, O, H, S, er, pr, nd, sm, gd, tb, dy, ho, tm, yb, and Lu. When such additional alloying element is denoted as X, the aluminum alloy can contain about, at least about, or at most about 0.05at%, 0.1at%, 0.15at%, 0.2at%, 0.25at%, 0.3at%, 0.35at%, 0.4at%, 0.45at%, 0.5at%, 0.55at%, 0.6at%, 0.65at%, 0.7at%, 0.75at%, 0.8at%, 0.85at%, 0.9at%, 0.95at%, 1.0at%, 1.1at%, 1.2at%, 1.3at%, 1.4at%, 1.5at%, 1.6at%, 1.7at%, 1.8at%, 1.9at%, 2.0at%, 2.1at%, 2.2at%, 2.3at%, 2.4at%, 2.5at%, 2.6at%, 2.7at%, 2.8at%, 2.9at%, 3.0at%, 2.3at%, 2.4at%, 2.5at%, 2.6at%, 2.7at%, 2.8at%, 2.9at%, 3at%, 4.4at%, 4at%, 3at%, 4.5at%, 4at%, 3at%, 4.7at%, 4at%, 3at%, 4.4at%, 3at%, 4.7at%, 4at%, 3at%, 4.4at%, 4.7at%, 3at%, 4.4at%, 3at%, or any of the stated ranges including X. When a plurality of elements X are present, each of the elements X may have a concentration as described above, and the total concentration of all elements X may be as described above or higher, such as about, or at least about 5at%, 6at%, 7at%, 8at%, 9at%, 10at%, 15at%, or 20at% X.

The vickers pyramid number, also known as "HV", is a well-known measure of the mechanical hardness of aluminum alloys. See Smith et al, "An Accurate Method of Determining the Hardness of the Metals, with partial Reference to the same of a High Degree of Hardness of Hardness [ methods for Determining the Hardness of Metals, particularly methods relating to High Hardness ]," Proceedings of the institute of Mechanical Engineers [ Proceedings of the institute of Mechanical Engineers ], vol.I, 1922, pp.623-641, which are incorporated herein by Reference. The standard unit for HV is kilogram-force per square millimeter, which can be converted to other units of force per area.

In some embodiments, the aluminum alloy is characterized by a vickers pyramid number of at least 50, such as at least 75. For example, the aluminum alloy can be characterized by a vickers pyramid number of about, or at least about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, or 150, including all intermediate ranges (e.g., 80-130). These hardness values may be characteristic of as-built aluminum alloys, such as an additive manufactured aluminum alloy prior to aging.

The aluminum alloy may be aged. "aged", "heat aged", and the like, which means that the alloy is intentionally held at an elevated temperature (above 25 ℃) for a period of time. During aging, the aluminum alloy may undergo precipitation hardening (also referred to as age hardening). In some embodiments, the purpose of aging is to cause an amount of precipitation hardening for enhancing mechanical properties, such as ultimate tensile strength, yield strength, or hardness. The heat treatment may cause stress relief while avoiding quench sensitivity effects caused by subsequent deformation or thickness. Preferably, the heat aging results in a uniform dispersion of intermetallic precipitates. Without being limited by theory, it is believed that strengthening is achieved by dispersing intermetallic precipitates containing Al and Cr, and/or intermetallic precipitates containing Al and Zr, as well as other strengthening mechanisms that may occur. Al-Cr and Al-Zr precipitates are stable at temperatures above the melting point of aluminum, and are therefore capable of providing strength at high temperatures-with other precipitates such as MgZn dissolved in the aluminum alloy at high temperatures ₂ Or a Guinier-Preston zone (Guinier-Preston zone).

In some embodiments, the heat aging treatment is similar to the T5 treatment of aluminum alloys. See Kaufman, introduction to Aluminum Alloys and Tempers, ASM International [ American society for materials and information ] (2000), the teachings of which in Chapter 4 of Al alloy temperament designation system [ Al alloy temper designation system ], is hereby incorporated by reference. T5 refers to an aluminum alloy strengthened by heat treatment, with or without subsequent strain hardening, wherein the alloy is cooled from a high temperature forming process and then artificially aged. In this context, a "forming process" may be additive manufacturing, and an "artificial aging" process is intentional thermal aging of an alloy at a selected temperature and time. Solution processing is preferably avoided, noting that solution processing is substantially impossible with super-periodic systems.

In some embodiments, the aluminum alloy is aged at 200 ℃ for a period of time, such as from 1 hour to 80 hours, for example, 2 hours, 4 hours, 6 hours, 10 hours, 20 hours, 24 hours, 30 hours, 32 hours, 40 hours, 48 hours, 50 hours, 55 hours, 60 hours, 70 hours, or 72 hours. After aging at 200 ℃ for at least 24 hours, the vickers pyramid number can be, for example, about, or at least about 100, 110, 120, 130, or 140, including all intermediate ranges.

In some embodiments, the aluminum alloy is aged at 350 ℃ for a period of time, such as from 1 hour to 100 hours, for example, 2 hours, 4 hours, 6 hours, 10 hours, 20 hours, 24 hours, 30 hours, 32 hours, 40 hours, 48 hours, 50 hours, 60 hours, 70 hours, 72 hours, 80 hours, or 90 hours. After aging at 350 ℃ for at least 24 hours, the vickers pyramid number can be, for example, about, or at least about 100, 110, 120, 130, 140, or 150, including all intermediate ranges.

In some embodiments, the aluminum alloy is aged at 400 ℃ for a period of time, such as from 1 hour to 100 hours, for example, 2 hours, 4 hours, 6 hours, 10 hours, 20 hours, 24 hours, 30 hours, 32 hours, 40 hours, 48 hours, 50 hours, 60 hours, 70 hours, 72 hours, 80 hours, or 90 hours. After aging at 400 ℃ for at least 24 hours, the vickers pyramid number can be, for example, about, or at least about 110, 120, 130, 140, or 150, including all intermediate ranges.

In some embodiments, the aluminum alloy is aged at 500 ℃ for a period of time, such as from 1 hour to 50 hours, e.g., 2 hours, 4 hours, 6 hours, 10 hours, 20 hours, 24 hours, 30 hours, 32 hours, 40 hours, or 48 hours. After aging at 500 ℃ for at least 24 hours, the vickers pyramid number can be, for example, about, or at least about 110, 120, 130, 140, or 150, including all intermediate ranges.

In some embodiments, the aluminum alloy is characterized by a tensile strength of at least 200MPa, preferably at least 250 MPa. Unless otherwise indicated, "tensile strength" herein refers to Ultimate Tensile Strength (UTS). For example, the aluminum alloy can be characterized by a tensile strength of about, or at least about 200MPa, 225MPa, 250MPa, 275MPa, 300MPa, 310MPa, 320MPa, 325MPa, 330MPa, 335MPa, 340MPa, 350MPa, 375MPa, 400MPa, 425MPa, 450MPa, 475MPa, 500MPa, 525MPa, 550MPa, 575MPa, 600MPa, 625MPa, 650MPa, 675MPa, or 700MPa, including all intermediate ranges.

In some embodiments, the aluminum alloy is characterized by a yield strength of at least 150MPa, preferably at least 200 MPa. For example, the aluminum alloy can be characterized by a yield strength of about, or at least about 175MPa, 200MPa, 225MPa, 250MPa, 275MPa, 300MPa, 325MPa, 350MPa, 375MPa, 400MPa, 425MPa, 450MPa, 475MPa, 500MPa, 525MPa, 550MPa, 575MPa, or 600MPa, including all intermediate ranges.

The aluminum alloy may be characterized by a tensile strength of at least 300MPa, such as at least 310MPa or at least 320MPa, when aged at a temperature of 350 ℃ for at least 4 hours. The aluminum alloy may be characterized by a tensile strength of at least 310MPa, such as at least 320MPa or at least 330MPa, when aged at a temperature of 350 ℃ for at least 32 hours. The aluminum alloy may be characterized by a tensile strength of at least 300MPa, such as at least 310MPa or at least 320MPa, when aged at a temperature of 400 ℃ for at least 2 hours.

The aluminum alloy may be characterized by a tensile strength at least 10%, 15%, 20%, or 25% greater than an unaged as-built aluminum alloy after aging for at least 4 hours at 350 ℃. The aluminum alloy may be characterized by a tensile strength at least 10%, 15%, 20%, 25%, or 30% greater than an unaged as-built aluminum alloy after aging for at least 32 hours at 350 ℃. The aluminum alloy may be characterized by a tensile strength at least 10%, 15%, 20%, or 25% greater than an unaged as-built aluminum alloy after aging for at least 2 hours at 400 ℃.

As discussed above, aging conditions may vary, and the resulting mechanical properties may vary. Those skilled in the art, given the benefit of this disclosure, will be able to carry out experiments to determine the best conditions for a given mechanical property.

In some embodiments, the heat aged aluminum alloy is thermally stable at the use temperature, such as a temperature selected from 100 ℃ -500 ℃ (e.g., 300 ℃) that causes thermal exposure. Thermal stability in the present disclosure refers to the resistance of an aluminum alloy to degradation of strength and hardness when subjected to long-term thermal exposure during long-term use. Note that the heat exposure is different from the initial heat aging utilized during production of the aluminum alloy. That is, optional heat aging may be performed to enhance the mechanical properties of the aluminum alloy. Then, during use, the aluminum alloy is exposed to high temperatures in many cases.

One measure of thermal stability is the room temperature tensile strength measured at 25 ℃ after thermal exposure. In preferred embodiments, the aluminum alloy retains a room temperature tensile strength of at least 50%, preferably at least 75%, more preferably at least 90%, and most preferably at least 95% (possibly 100% or even greater than 100%) after exposure to a use temperature of about, or at least about 200 ℃, 250 ℃,300 ℃, 350 ℃, 400 ℃, 450 ℃, or 500 ℃.

Another measure of thermal stability is the room temperature yield strength measured at 25 ℃ after thermal exposure. In preferred embodiments, the aluminum alloy retains a room temperature yield strength of at least 50%, preferably at least 75%, more preferably at least 90%, and most preferably at least 95% (possibly 100% or even greater than 100%) after exposure to a use temperature of about, or at least about 200 ℃, 250 ℃,300 ℃, 350 ℃, 400 ℃, 450 ℃, or 500 ℃.

Yet another measure of thermal stability is room temperature hardness measured at 25 ℃ after thermal exposure. In preferred embodiments, the aluminum alloy retains a room temperature hardness of at least 50%, preferably at least 75%, more preferably at least 90%, and most preferably at least 95% (possibly 100% or even greater than 100%) after exposure to a use temperature of about, or at least about 200 ℃, 250 ℃,300 ℃, 350 ℃, 400 ℃, 450 ℃, or 500 ℃.

Aluminum alloys may also be characterized by the property of maintaining at high temperatures (e.g., 300 ℃ to 1000 ℃) after thermal exposure. Some applications require the use of materials at high temperatures, and may be used at transient peak to even higher temperatures.

One measure of high temperature thermal stability is the high temperature tensile strength measured at 300 ℃, 400 ℃, or 500 ℃ after thermal exposure. In preferred embodiments, the aluminum alloy retains at least 50%, preferably at least 75%, more preferably at least 90%, and most preferably at least 95% of the high temperature tensile strength after exposure to a use temperature of about, or at least about 200 ℃, 250 ℃,300 ℃, 350 ℃, 400 ℃, 450 ℃, or 500 ℃. In related embodiments, the high temperature tensile strength may be measured at different related temperatures (other than 300 ℃), such as 200 ℃, 400 ℃, 500 ℃, 600 ℃, or 650 ℃.

Another measure of high temperature thermal stability is the high temperature yield strength measured at 300 ℃, 400 ℃, or 500 ℃ after thermal exposure. In preferred embodiments, the aluminum alloy retains at least 50%, preferably at least 75%, more preferably at least 90%, and most preferably at least 95% of the high temperature yield strength after exposure to a use temperature of about, or at least about 200 ℃, 250 ℃,300 ℃, 350 ℃, 400 ℃, 450 ℃, or 500 ℃. In related embodiments, the high temperature yield strength may be measured at different related temperatures (other than 300 ℃), such as 200 ℃, 400 ℃, 500 ℃, 600 ℃, or 650 ℃.

Yet another measure of high temperature thermal stability is the high temperature hardness measured at 300 ℃, 400 ℃, or 500 ℃ after thermal exposure. In preferred embodiments, the aluminum alloy retains at least 50%, preferably at least 75%, more preferably at least 90%, and most preferably at least 95% of the high temperature hardness after exposure to a use temperature of about, or at least about 200 ℃, 250 ℃,300 ℃, 350 ℃, 400 ℃, 450 ℃, or 500 ℃. In related embodiments, the high temperature hardness may be measured at different related temperatures (other than 300 ℃), such as 200 ℃, 400 ℃, 500 ℃, 600 ℃, or 650 ℃.

In some embodiments, the aluminum alloy is corrosion resistant. When exposed to air, al, cr and Zr all form highly stable oxides, which are expected to limit the reactivity of the alloy with common environmental salts and/or with corrosive environments. In addition, the added Cr and Zr solutes can increase the precious nature of the aluminum, thereby providing a lower risk of galvanic corrosion (a benefit of making Al-Cr-Zr alloys more suitable for use in carbonaceous structures). In addition, cr and Zr are not expected to be electrochemically active at grain boundaries. The lower electrochemical activity reduces the tendency for intergranular corrosion and stress corrosion cracking.

In some embodiments, the aluminum alloy has a substantially crack-free microstructure. "substantially crack-free" means at least 999 volume% aluminum alloy does not contain linear or bending cracks having a width greater than 0.1 micrometers and a length greater than 10 micrometers. In other words, to be considered a crack, a defect must be a void space having a width of at least 0.1 microns and a length of at least 10 microns. Regardless of the width, void spaces less than 10 microns but greater than 1 micron in length may be considered porous voids (see below). Void spaces at least 10 microns in length but less than 0.1 microns in width are molecular scale gaps that are not considered defects. Typically, cracks contain open spaces, which may be vacuum or may contain gases, such as air, CO ₂ 、N ₂ And/or Ar. The cracks may also contain solid material other than the primary material phase of the aluminum alloy.

The aluminum alloy microstructure may be substantially free of porous defects in addition to being substantially free of cracks. By "substantially free of porous defects" is meant that at least 99 volume percent of the aluminum alloy does not contain porous voids having an effective diameter of at least 1 micron. Preferably, at least 80 volume percent, more preferably at least 90 volume percent, even more preferably at least 95 volume percent, and most preferably at least 99 volume percent of the aluminum alloy does not contain porous voids having an effective diameter of at least 1 micron. Porous voids having an effective diameter of less than 1 micron are typically not considered defects because they are generally difficult to detect by routine non-destructive evaluation. Also preferably, at least 90 volume percent, more preferably at least 95 volume percent, even more preferably at least 99 volume percent, and most preferably at least 99.9 volume percent of the aluminum alloy does not contain larger pore voids having an effective diameter of at least 5 microns.

Typically, the porous voids contain open spaces, which may be vacuum or may contain a gas, such as air, CO ₂ 、N ₂ And/or Ar. In some embodiments, porous voids may be reduced or eliminated. For example, the additively manufactured metallic part may be hot isostatically pressed to reduce residual porosity, optionally resulting in a final additively manufactured metallic part that is substantially free of porous defects in addition to being substantially free of cracks. In various embodiments, the aluminum alloy or parts containing the alloy can have from 0% to about 50%, for exampleSuch as about 5%, 10%, 20%, 30%, 40%, or 50% porosity. Porosity can result from both the space within the particles (e.g., hollow shapes) as well as the space outside and between the particles. The total porosity is the source of both porosities.

In some embodiments, the aluminum alloy microstructure has "equiaxed grains," which means that at least 90 volume percent, preferably at least 95 volume percent, and more preferably at least 99 volume percent of the aluminum alloy contains grains that are approximately equal in length, width, and height. In a preferred embodiment, at least 99 volume percent of the aluminum alloy contains grains characterized by: there is a standard deviation of less than 50%, preferably less than 25%, more preferably less than 10%, and most preferably less than 5% in each of the average grain length, average grain width, and average grain height. In aluminum alloys, the crystals of the metal alloy form grains in a solid. Each grain is a different crystal with its own orientation. The regions between the grains are called grain boundaries. Within each grain, the individual atoms form a crystal lattice. Equiaxed grains are produced when there are many nucleation sites resulting from intermetallic precipitates (Al — Cr and/or Al — Zr) contained in the microstructure of the aluminum alloy.

Other variations of the invention provide an aluminum (Al) alloy containing at least 0.1at% zirconium (Zr) and at least 0.1at% chromium (Cr), wherein the aluminum alloy is in the form of a manufactured object that is not an additively manufactured object. The object of manufacture may be selected from the group consisting of structural parts, coatings, ingots, sheets, plates, rods, wires, and combinations thereof.

In some embodiments, the aluminum alloy contains at least 0.25at% cr and/or at least 0.25at% zr. In some embodiments, the aluminum alloy contains at least 0.3at% Cr and/or at least 0.3at% Zr. In some embodiments, the aluminum alloy contains at least 0.5at%Cr and/or at least 0.5at%. In some embodiments, the aluminum alloy contains at least 1.0at% Cr and/or at least 1.0at% Zr. In some embodiments, the aluminum alloy contains at least 2.0at% Cr and/or at least 2.0at% Zr.

When both Cr and Zr are present in the manufactured object, the Zr/Cr ratio may be selected from 0.1 to 10, such as, for example, from 0.2 to 2. In various embodiments, the Zr/Cr ratio is about 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, or 100, including all intermediate ranges (e.g., 0.1-10 or 0.5-5).

In some embodiments, the aluminum alloy contains equiaxed grains nucleated directly or indirectly by Cr and/or Zr. Direct nucleation refers herein to Cr and/or Zr nucleating grain growth, while indirect nucleation refers to intermetallic Al-Cr particles and/or intermetallic Al-Zr particles nucleating grain growth (which may be continuous or simultaneous with the reaction to form the intermetallic species).

The aluminum alloy of the fabricated object may further contain one or more elements selected from the group consisting of Cu, mg, zn, li, mn, fe, si, ag, V, nb, ta, ti, hf, mo, W, sc, Y, ca, be, sr, la, ce, re, ru, os, co, ni, pd, pt, ir, rh, au, cd, sn, bi, pb, B, C, N, O, H, S, er, pr, nd, sm, gd, tb, dy, ho, tm, yb, and Lu.

In some powders, the aluminum-containing powder contains at least 0.2at% cr and/or at least 0.2at% zr. In some powders, the aluminum-containing powder contains at least 0.3at% Cr and/or at least 0.3at% Zr. In some powders, the aluminum-containing powder contains at least 0.5at% cr and/or at least 0.5at% zr. In some powders, the aluminum-containing powder contains at least 1.0at% Cr and/or at least 1.0at% Zr. In some powders, the aluminum-containing powder contains at least 2.0at% Cr and/or at least 2.0at% Zr.

In some powders, the aluminum alloy contains at least 0.9at% Cr and/or at least 0.5at% Zr. In certain powder embodiments, the aluminum alloy contains at least 0.85at% Cr and/or at least 0.45at% Zr. In certain powder embodiments, the aluminum alloy contains greater than 0.80at% cr and/or greater than 0.40at% zr.

When both Cr and Zr are present in the starting powder, the Zr/Cr ratio may be selected from 0.1 to 10, such as, for example, from 0.2 to 2. In various embodiments, the Zr/Cr ratio is about 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, or 100, including all intermediate ranges (e.g., 0.1-10 or 0.5-5).

In some embodiments, the average second particle size is at least one order of magnitude smaller than the average first particle size. In various embodiments, the average second particle size is at least 2 x, 3 x, 4 x, 5 x, 10 x, 20 x, 30 x, 40 x, 50 x, or 100 x smaller than the average first particle size, including all intermediate ranges.

In some embodiments, the average third particle size is at least one order of magnitude smaller than the average first particle size. In various embodiments, the average third particle size is at least 2 x, 3 x, 4 x, 5 x, 10 x, 20 x, 30 x, 40 x, 50 x, or 100 x smaller than the average first particle size, including all intermediate ranges.

In some embodiments, the ratio of the average second particle size to the average third particle size is selected from 0.1 to 10. In various embodiments, the ratio of the average second particle size to the average third particle size is about 0.15, 0.2, 0.5, 0.8, 0.9, 1.0, 1.1, 1.2, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, or 9, including all intermediate ranges.

When the aluminum-containing powder further contains an additional alloying element X optionally selected from the group consisting of Cu, mg, zn, li, mn, fe, si, ag, V, nb, ta, ti, hf, mo, W, sc, Y, ca, be, sr, la, ce, re, ru, os, co, ni, pd, pt, ir, rh, au, cd, sn, bi, pb, B, C, N, O, H, S, er, pr, nd, sm, gd, tb, dy, ho, tm, yb, and Lu, the average X particle size may Be at least one order of magnitude smaller than the average first particle size. In various embodiments, the average X particle size is at least 2X, 3X, 4X, 5X, 10X, 20X, 30X, 40X, 50X, or 100X smaller than the average first particle size, including all intermediate ranges.

In some aluminum-containing powders, at least 50 volume percent of the second particles are physically and/or chemically assembled on the surface of the first particles. In certain embodiments, at least 90% by volume or at least 99% by volume of the second particles are physically and/or chemically assembled on the surface of the first particles. In various embodiments, at least 5 vol%, 10 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol%, 40 vol%, 50 vol%, 60 vol%, 70 vol%, 80 vol%, 85 vol%, 90 vol%, 95 vol%, 98 vol%, 99 vol%, 99.5 vol%, 99.9 vol%, or 100 vol% (including all intermediate ranges) of the second particles are physically and/or chemically assembled on the surface of the first particles.

In some aluminum-containing powders, at least 50% by volume of the third particles are physically and/or chemically assembled on the surface of the first particles. In certain embodiments, at least 90% by volume or at least 99% by volume of the third particles are physically and/or chemically assembled on the surface of the first particles. In various embodiments, at least 5 vol%, 10 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol%, 40 vol%, 50 vol%, 60 vol%, 70 vol%, 80 vol%, 85 vol%, 90 vol%, 95 vol%, 98 vol%, 99 vol%, 99.5 vol%, 99.9 vol%, or 100 vol% (including all intermediate ranges) of the third particles are physically and/or chemically assembled on the surface of the first particles.

In some aluminum-containing powders, less than 5 vol% of the second particles physically and/or chemically assemble on the surface of the first particles. In these or other embodiments, less than 5% by volume of the third particles are physically and/or chemically assembled on the surface of the first particles. In certain embodiments, no second particles, no third particles, or no second or third particles are physically and/or chemically assembled on the surface of the first particles. In such embodiments, the surface functionalization may be created during powder processing (such as additive manufacturing).

In some embodiments, the aluminum-containing powder contains one or more intermetallic compounds of Zr and Cr. Exemplary intermetallic compounds include, but are not limited to, al ₁₁ Cr ₂ 、Al ₇ Cr、Al ₄ Cr、Al ₉ Cr ₄ 、Al ₈ Cr ₅ 、AlCr ₂ 、Al ₃ Zr、Al ₂ Zr、Al ₃ Zr ₂ 、AlZr、AlZr ₂ 、AlZr ₃ . These intermetallic compounds may be present, for example, when the powder is made from recycled parts containing Al-Cr and/or Al-Zr intermetallic precipitates, or when the starting powder is allowed to react in other ways.

In some embodiments, the second particles further comprise Cr and/or the third particles further comprise Zr. In these embodiments, cr and Zr may be present as a physical mixture, as an alloy, or as an intermetallic compound (e.g., zrCr ₂ ) Are present. In certain embodiments, when there are individual particles containing both Cr and Zr, those particles may be Cr surface functionalized with Zr, or Zr surface functionalized with Cr.

Various additional embodiments will now be described without limiting the invention. Although much of the remainder of this specification will describe variations of the invention with respect to additive manufacturing, it should be understood that the principles disclosed herein may be applied to joining techniques such as welding, or other metal working that melts and solidifies at least a portion of the starting powder or other raw material.

Some variants utilize a high volume fraction of Al _n X _m Precipitates, wherein X is selected from Zr, cr, or a combination thereof, and wherein n =1 to 15 and m =1 to 15. In various embodiments, al is present _n X _m Precipitates wherein X is not Zr or Cr but is selected from the group consisting of Cu, mg, zn, li, mn, fe, si, ag, V, nb, ta, ti, hf, mo, W, sc, Y, ca, be, sr, la, ce, re, ru, os, co, ni, pd, pt, ir, rh, au, cd, sn, biPb, er, pr, nd, sm, gd, tb, dy, ho, tm, yb, or Lu, or a hydride, oxide, nitride, carbide, sulfide, or boride thereof. In principle, the alloying element X may be selected from IUPAC (international Union of Pure and Applied Chemistry) group 3, 4, 5, 6, and/or lanthanide elements.

When the aluminum alloy contains precipitated intermetallic Al-Cr particles and/or precipitated intermetallic Al-Zr particles, and when other elements (other than Al, cr, and Zr) are present, for some or all of the other elements X, intermetallic Al-X particles may additionally be precipitated.

When the aluminum alloy does not contain precipitated intermetallic Al-Cr particles or precipitated intermetallic Al-Zr particles, and when other elements (other than Al, cr, and Zr) are present, other element X may be present in the precipitated intermetallic Al-X particles.

In some embodiments of the aluminum alloy, the one or more X elements are present at a concentration above their solubility limit in aluminum. Without limitation, the variations of the present invention enable aluminum alloys to have X element fractions above the equilibrium solubility limit by adding small particles containing the X element to the powders of the remaining components of the target alloy, and then additively manufacturing the part.

In some embodiments, the X element is initially provided in the form of a 0.01-20 micron powder and mixed with a 10-500 micron powder of the other desired components of the aluminum alloy feedstock. The aluminum alloy feedstock may then be processed by additive manufacturing to produce the desired part, or potentially to produce an aluminum alloy object that may itself be a feedstock for future processes.

The additively manufactured aluminium alloy preferably contains intermetallic precipitates of Al-Cr and/or Al-Zr, preferably homogeneously dispersed throughout the additively manufactured aluminium alloy. At high volume fractions, it is not possible to achieve a uniform distribution of these precipitates using conventional processing. The reason for this is that since the solubilities of Cr and Zr in Al are each in the order of 0.1wt%, al-Cr and Al-Zr precipitates are not generated in a large weight fraction. This limitation can be overcome by adding small particles containing Cr and/or Zr to the surface of the remaining components of the target alloy, and then additively manufacturing the part.

Some variations of the invention provide an aluminum alloy comprising aluminum and from about 0.1wt% to about 60wt% of one or more alloying elements X selected from the group consisting of Cr, zr, ti, hf, V, ta, nb, mo, W, sc, Y, la, ce, pr, nd, sm, eu, gd, tb, dy, ho, er, tm, yb, lu, and combinations or alloys of any of the foregoing, wherein at least one X element is Cr or Zr. The aluminum alloy may include at least two, at least three, at least four, at least five, or more alloying elements X. Preferably, at least one of these alloying elements X is present in the aluminum alloy as intermetallic precipitates containing Al and X. The wt% is based on the total weight concentration of alloying element X, on an elemental basis (i.e., in a compound containing X, the weight of element X is calculated only).

The intermetallic precipitates may be Al _n X _m (n =1 to 15,m =1 to 15) precipitates. The value of n may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and/or 15. Independently, the value of m can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and/or 15. For example, in some embodiments, the intermetallic precipitates are Al ₃ X precipitates (e.g., al) ₃ Zr)。

The melting points of Zr, ti, hf, V, ta, nb, cr, mo, W, sc, Y, la, ce, pr, nd, sm, eu, gd, tb, dy, ho, er, tm, yb, and Lu all exceed the melting point of Al at about 660 ℃. For example, the melting point of Zr is 1855 ℃. It is preferred that the alloying elements, and the intermetallic precipitates formed from them, have a higher melting point than aluminium, because the intention is generally that during additive manufacturing, the X element does not melt but forms intermetallic inclusions (which themselves have a higher melting point than aluminium and therefore also do not melt).

In some embodiments, the one or more alloying elements X are present at a total weight concentration in excess of their equilibrium solubility in aluminum calculated at 750 ℃ and 1 bar. When more than one alloying element X is present, some or all of the X elements may exceed their equilibrium solubility in aluminum (calculated at 750 ℃ and 1 bar). When more than one alloying element X is present, at least one element X is preferably present as intermetallic precipitates comprising Al and X, while the other elements X may or may not be in the form of intermetallic precipitates.

The equilibrium solubility of the element X in aluminum is known. See, for example, smithlls Metals Reference Book [ smith metal Reference manual ], gale and Totemeier, eds, eighth edition, 2004 (hereinafter, "smithlls"), which is incorporated herein by Reference (along with all internal citations) for all purposes. In particular, chapter 11 of smithlls includes a number of binary equilibrium phase diagrams suitable for use in the present disclosure.

For example, the equilibrium phase diagram of the Al — Zr system at pages 11-58 of smithlls indicates the following intermetallic precipitates in order of increasing zirconium content: al (aluminum) ₃ Zr、Al ₂ Zr、Al ₃ Zr ₂ 、AlZr、Al ₃ Zr ₅ 、Al ₂ Zr ₃ 、Al ₃ Zr ₄ 、Al ₄ Zr ₅ 、AlZr ₂ And AlZr ₃ . Thus, in embodiments where X = Zr, any of these intermetallic precipitates may form or be present in the aluminum alloy as inclusions, even if not expected to be present at thermodynamic equilibrium (e.g., for kinetic reasons). The equilibrium phase diagram for the Al-Cr system is on pages 11-35 of Smithlls.

At typical casting temperatures (e.g., 670 ℃ to 800 ℃), liquid aluminum has very limited solubility for X. For example, according to Smithlls, the solubility of the elements Zr, ta, V, nb, hf, and Ti in liquid Al is only about 0.1wt% at about 670 ℃.

At X concentrations greater than about 0.1wt%, but less than about 60wt%, and at temperatures at which aluminum melts, there is typically no single liquid phase at equilibrium, but a liquid phase and an Al-X phase. That is, when more of the X element is present than its solubility limit, at equilibrium, al — X will form in the liquid. Unless the temperature is so high that Al-X melts on its own, al-X will be in the form of a solid precipitate. For example, al ₃ The melting point of Zr is 1580 deg.C, the ratio of which is less than 1000 deg.C (e.g. 670 deg.C-800 deg.C) typical processing temperatureMuch higher. Unless the concentration of Al — X becomes too high such that precipitates aggregate in the liquid aluminum, solid precipitates are desirable. The aggregation of the Al — X precipitates produces large chunks having diameters greater than 100 microns, which is referred to herein as coarsening of the precipitates.

Generally, for increased strength, only small Al — X precipitates (100 microns or less) are desired in the aluminum alloy. Large precipitates (greater than 100 microns) are generally detrimental, at least for strength purposes, because such large precipitates are generally brittle. In certain instances, such as when strength is not a critical factor, the intermetallic precipitates (or a portion thereof) may be greater than 100 microns, such as about 150 microns, 200 microns, 250 microns, 300 microns, 400 microns, or 500 microns.

In order to strengthen the aluminum alloy while maintaining ductility, substantially uniformly distributed small Al — X precipitates are desirable. Preferably, the Al-X precipitates are less than 100 μm in average size, and more preferably less than 10 μm in average size. By uniform distribution of intermetallic precipitates is meant that they are randomly dispersed throughout the aluminum alloy and that the local concentration of intermetallic precipitates in any selected region of the aluminum alloy is statistically the same as any other arbitrary region of the aluminum alloy.

Generally, more Al-X precipitates (i.e., al) _n X _m Precipitates) will result in higher strength until the threshold at which coarsening occurs is reached, rather than stabilization of individual precipitates. The threshold concentration will depend on the identity of the alloying elements (i.e., cr, zr, and optionally other elements), the diffusivity of the precipitate species within the aluminum-rich matrix, and the temperature and temperature history of the process.

It is noted that at very high X concentrations (typically greater than 60 wt%), a stable X solid phase can be formed. For example, in the case of zirconium in aluminum, a stable β -Zr phase is formed about 90wt% Zr (10 wt% Al). Because the present invention utilizes aluminum alloys preferably having 0.1wt% -60wt% x element, the alloy will not be expected to contain thermodynamically stable B-Zr phases at equilibrium. However, in embodiments including Zr, even if not expected to be present at thermodynamic equilibrium (e.g., for kinetic reasons), zirconium (without aluminum) metallic inclusions may form.

In some embodiments, the one or more X elements are present at a concentration above their equilibrium solubility limit in aluminum, such as, for example, 2 ×,3 ×, 5 ×,10 ×, 25 ×, 50 ×, or 100 ×, of the equilibrium solubility calculated at a temperature of 750 ℃ and a pressure of 1 bar. By way of illustration, if the equilibrium solubility limit of X in aluminum at 750 ℃ and 1 bar is about 0.2 wt.%, the aluminum alloy can comprise about 0.4 wt.%, about 0.6 wt.%, about 1 wt.%, about 2 wt.%, about 5 wt.%, about 10 wt.%, or about 20 wt.%, respectively, of alloying element X on an elemental weight basis.

When more than one X element is present, the equilibrium phase diagram becomes more complex due to thermodynamic interactions between each X element and Al, as well as between all X elements. On pages 11-533, smithlls notes "a large number of documents" and provides a list of references. Those skilled in the art of material science will appreciate that aluminum alloy multi-component phase diagrams can be found in the literature or, if not readily available, can be generated via experimentation.

As set forth above, non-equilibrium phases may be present due to kinetic limitations (e.g., reaction kinetics and/or mass transfer rates) that prevent equilibrium among all materials present. The present invention is not limited to any system in thermodynamic equilibrium and does not exclude non-equilibrium phases present in any aluminum alloy or precursor thereof. In some cases, an unbalanced composition is desirable. As is known, whether a metal alloy system will reach true thermodynamic equilibrium is determined by kinetic constraints including temperature, time, and the presence of a catalyst or nucleation site. Even when a new phase is expected in the phase diagram, atomic rearrangement via diffusion is necessary, and there is an increase in energy associated with the phase boundary generated between the parent phase and the child phase. This energy must be overcome, such as via heat transfer. In some embodiments, additive manufacturing is performed using an effective temperature profile and time such that the manufactured aluminum alloy has a composition predicted by equilibrium.

In some embodiments, the intermetallic precipitates are characterized by an average effective diameter of less than 100 microns. In various embodiments, the intermetallic precipitates are characterized by an average effective diameter of about 10 microns or less, about 1 micron or less, or about 100 nanometers or less. In some embodiments, the intermetallic precipitates are characterized by an average effective diameter of about, or at least about 0.01 microns, 0.1 microns, 0.5 microns, 1 micron, 5 microns, 10 microns, 20 microns, 50 microns, or 75 microns. In various embodiments, the intermetallic precipitates are characterized by an average effective diameter of from about 0.1 micron to about 100 microns, or about 0.1 micron to about 50 microns, or about 0.1 micron to about 20 microns, or about 0.1 micron to about 10 microns, or about 1 micron to about 100 microns, or about 1 micron to about 50 microns, or about 1 micron to about 20 microns, or about 1 micron to about 10 microns. Intermetallic precipitates can also be very small, such as from about 0.001 microns (1 nanometer) to about 0.1 microns (100 nanometers).

The aluminum alloy further may comprise from about 0.1wt% to about 15wt% of one or more additional alloying elements selected from the group consisting of: zn, si, mg, cu, li, ag, mn, fe, co, ni, sn, sb, bi, pb, B, C, ir, os, re, ca, sr, be, and combinations or alloys of any of the foregoing, wherein the wt% is based on the total weight concentration of the additional alloying element on an elemental basis. In various embodiments, the aluminum alloy comprises about, or at least about 0.2 wt.%, 0.5 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%, or 14 wt.% of such one or more additional alloying elements.

When present, the one or more additional alloying elements may be added for a variety of reasons. For example, elements such as Mn may provide solid solution strengthening, mg and Zn may form MgZn ₂ Precipitates, cu may form θ -phase precipitates, and Si may form an immiscible Si structure. Typical precipitation additives (e.g., mg, zn, and/or Cu) and other less common precipitation systems and alloying additives (e.g., fe, co, ni, ag, li, sn, sb, bi, pb, B, C, ir, os, re, ca, sr, and/or Be) may Be added to the alloy to not only form strengthening precipitates, but also to operate as desiredDissolves at temperature to provide solid solution strengthening. In addition, these elements may segregate to precipitate boundaries, thereby reducing the activity of these boundaries and providing an energy barrier that inhibits coarsening, giving improved characteristics at high temperatures over longer durations without microstructural degradation.

In addition to intermetallic precipitates containing Al-Cr and/or Al-Zr, the other precipitates may contain inclusions of the metal X with another element other than Al. For example, the X-containing precipitates may be ceramics formed from metal X, and/or X hydrides, X carbides, X oxides, X nitrides, X borides, X sulfides, or combinations thereof. Exemplary ceramics are zirconium dioxide, zrO ₂ 。

In addition to intermetallic precipitates and any other metallic alloying elements, non-metallic inclusions may also be present in the aluminum alloy. Such non-metallic inclusions can include ceramics, hydrides, carbides, oxides, nitrides, borides, sulfides, or combinations thereof (e.g., silicon carbide, silicon nitride, boron oxide, etc.).

The aluminum alloy may be an additive manufactured aluminum alloy. In other embodiments, the aluminum alloy may be a welded aluminum alloy. In some embodiments, the aluminum alloy forms a feedstock alloy (e.g., a feedstock ingot) intended for future processes, such as additive manufacturing.

The aluminum alloy may be present in an aluminum alloy-based part, sheet, or structural object. The aluminium alloy based part or structural object is preferably an additive manufactured part or structural object. The aluminum alloy may be selected from the group consisting of: sintered structures, coatings, geometric objects, blanks, ingots, net-shape parts, near-net-shape parts, and combinations thereof.

Some variations of the invention provide a feedstock powder for an aluminum alloy, the feedstock powder comprising:

(a) From about 80wt% to about 99.9wt% of an aluminum-containing base powder, wherein the aluminum-containing base powder has an average base particle size of from about 10 microns to about 500 microns, and wherein the aluminum-containing base powder contains at least 75wt% (e.g., at least 80wt% or at least 85 wt%) aluminum; and

(b) From about 0.1wt% to about 20wt% of an alloy powder, wherein the alloy powder has an average alloy particle size of from about 0.01 microns to about 90 microns, wherein the alloy powder contains at least 50wt% (based on total weight concentration on an elemental basis) of one or more alloying elements X selected from the group consisting of: cr, zr, ti, hf, V, ta, nb, mo, W, sc, Y, la, ce, pr, nd, sm, eu, gd, tb, dy, ho, er, tm, yb, lu; hydrides, carbides, oxides, nitrides, borides, or sulfides thereof; and combinations or alloys of any of the foregoing, wherein at least one X element is Cr or Zr,

wherein if the average alloy particle size is greater than 20 microns, the average alloy particle size is preferably less than the average base particle size,

and wherein the aluminum-containing base powder and the alloy powder are in intimate physical contact within the feedstock powder.

The "base powder" contains at least the aluminum present in the powder particles. The base powder has a composition calculated to contain components that, when combined with the intended portion of the alloy powder, will form the target alloy composition. The "alloy powder" is rich in Cr and/or Zr and typically has a smaller particle size than the base powder.

The feedstock powder may be in any form in which the discrete particles are suitably distinguished from the cake. For example, the powder may be present as a loose powder, a paste, a suspension, or a green body. A green body is an object whose main component prior to melting and solidification is a weakly bonded powder material. The particles may be solid, hollow, or a combination thereof. The particles may be prepared by any means including, for example, gas atomization, milling, cryogenic milling, wire explosion (wire explosion), laser ablation, electrical discharge machining, or other techniques known in the art.

By "intimate physical contact" between the base powder and the alloy powder is meant that the two powders are physically blended (mixed) together to form the raw powder. In some embodiments, there is a chemical bond between the alloy particles and the base powder particles. The chemical bonding results in intimate physical contact between the alloy powder and the aluminum-containing base powder.

Some embodiments of the invention utilize the materials, methods, and principles described in commonly-owned U.S. patent application No. 15/209,903, 2016, 14, and/or commonly-owned U.S. patent application No. 15/808,877, 2017, 11, 9, each of which is hereby incorporated by reference. For example, certain embodiments utilize functionalized powder feedstock as described in U.S. patent application Ser. No. 15/209,903. The present disclosure is not limited to these functionalized powders. This specification also incorporates Martin et al, "3D printing of high-strength aluminum alloys," Nature [ Nature ] Vol.549, pp.365-369 and supplementary on-line contents (extended data), 2017, 9, 21, which are hereby incorporated by reference in their entirety.

In some embodiments, the alloy powder particles coat the base powder in the form of a continuous coating or an intermittent coating, any of which may be referred to as a surface-functionalized base powder. The continuous coating covers at least 90% of the surface, such as about 95%, 99%, or 100% of the surface (recognizing that defects, voids, or impurities may be present on the surface). The intermittent coating is discontinuous and covers less than 90%, such as about 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, 5%, 2%, 1%, or less of the surface. The intermittent coating may be uniform (e.g., having some repeating pattern on the surface) or non-uniform (e.g., random). Generally, the coating may be continuous or discontinuous.

Methods of producing surface functionalized powder materials are generally not limited and may include immersion deposition, electroless deposition, vapor phase coating, solution/suspension coating of particles with or without organic ligands, attachment of particles by electrostatic and/or van der waals forces through mixing, and the like. U.S. patent application No. 14/720,757 (filed on 23/5/2015), U.S. patent application No. 14/720,756 (filed on 23/5/2015), and U.S. patent application No. 14/860,332 (filed on 21/2015), each of which is commonly owned by the assignee of the present patent application, are hereby incorporated by reference.

In some embodiments, the feedstock powder is provided such that the aluminum-containing base powder and the alloy powder are initially physically separated, such as in different containers, for storage or transport. At the time and place of use as a raw material for manufacturing an aluminum alloy (e.g., at the site of additive manufacturing), the respective powders may then be blended together such that the aluminum-containing base powder and the alloy powder are in intimate physical contact with each other. The alloy powder and base powder are mixed or blended in respective amounts to produce the target aluminum alloy composition. This is a typical, preferred embodiment, which is capable of producing intermetallic precipitates that are uniformly dispersed throughout the additively manufactured aluminium alloy. However, in certain situations where non-uniform dispersion is desired, regions of the feedstock powder containing lower or higher concentrations of the alloy powder may be beneficial, such as to create a gradient in alloy composition in the final part.

In some embodiments, the average base particle size is from about 10 microns to about 100 microns. In various embodiments, the average base particle size is from about 10 microns to about 200 microns, from about 5 microns to about 100 microns, or from about 5 microns to about 50 microns. In various embodiments, the average base particle size is about, or at least about 1 micron, 5 microns, 10 microns, 20 microns, 50 microns, 100 microns, 200 microns, 300 microns, or 400 microns.

The base powder (base particles) may have a narrow or broad particle size distribution, although a narrow particle size distribution is generally preferred. The particle size distribution can be characterized by a particle size dispersion index, which is the ratio of the standard deviation of the particle size to the average particle size (also known as the coefficient of variation). In various embodiments, the base powder particle size dispersion index is about 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0.

The particle size distribution of the base powder can also be characterized by reference to, for example, D10, D50, and D90. D10 is the diameter where ten percent of the distribution has a smaller particle size and ninety percent has a larger particle size. D50 is the diameter where fifty percent of the distribution has a smaller particle size and fifty percent has a larger particle size. D90 is the diameter where ninety percent of the distribution has a smaller particle size and ten percent has a larger particle size. Exemplary base powders for additive manufacturing via selective laser melting have D10=20 microns and D90=60 microns. In various embodiments, D10 is about 1 micron, 5 microns, 10 microns, 20 microns, 30 microns, 40 microns, or 50 microns, and D90 is about 5 microns, 10 microns, 20 microns, 30 microns, 40 microns, 50 microns, 60 microns, 70 microns, 80 microns, 90 microns, or 100 microns.

The aluminium-containing base powder preferably contains base particles (base particles) which are nominally spherical. By "nominally spherical" is meant that the base particles have a sphericity of at least 0.9, preferably at least 0.95, and more preferably at least 0.99 on average. Sphericity is a measure of how close the shape of an object is to the shape of a perfect sphere. The sphericity of a particle is the ratio of the surface area of a reference sphere to the surface area of the particle having the same volume as a given particle. The sphericity of an ideal sphere is exactly 1. As a negative example, the sphericity of a perfect cube is about 0.8, which means that the cube particles are not nominally spherical as defined herein.

In some embodiments, the average alloy particle size is from about 0.01 microns to about 50 microns. In various embodiments, the average alloy particle size is from about 0.01 microns to about 20 microns, from about 0.01 microns to about 10 microns, or from about 0.01 microns to about 1 micron. In various embodiments, the average alloy particle size is about 10 microns or less, about 1 micron or less, about 100 nanometers or less, about 50 nanometers or less, or about 25 nanometers or less. In some embodiments, the average alloy particle size is about, or at least about 0.01, 0.1, 0.5, 1, 5, 10, or 20 microns. In various embodiments, the average alloy particle size is from about 0.01 microns to about 50 microns, or about 0.01 microns to about 20 microns, or about 0.01 microns to about 10 microns, or about 0.1 microns to about 50 microns, or about 0.1 microns to about 20 microns, or about 0.1 microns to about 10 microns, or about 0.1 microns to about 1 micron.

Preferably, the average alloy particle size is less than the average base particle size, noting that there may be overlap depending on the particle size distributions of the base and alloy particles. In some embodiments, the average base grain size is at least 2 times, at least 3 times, at least 4 times, at least 5 times, at least 6 times, at least 7 times, at least 8 times, at least 9 times, or at least 10 times greater than the average alloy grain size.

The alloy powder may have a narrow or broad particle size distribution, although a narrow particle size distribution is preferred. In various embodiments, the alloy powder particle size dispersion index is about 0.01, 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, or 0.5.

The particle size distribution of the alloy powder can also be characterized by reference to, for example, D10, D50, and D90. In various embodiments, the D10 of the alloy powder is about 0.01, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 10, 15, or 20 microns, and the D90 of the alloy powder is about 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, 70, or 80 microns.

Particle size can be measured by a variety of techniques including, for example, dynamic light scattering, laser diffraction, image analysis, or sieve separation. Dynamic light scattering is a non-invasive established technique for measuring the size and size distribution of particles, typically in the sub-micron region (and even the latest technology to 1 nanometer). Laser diffraction is a widely used particle measurement technique for materials ranging in size from hundreds of nanometers to several millimeters. Exemplary dynamic light scattering Instruments and laser diffraction Instruments for measuring particle size are available from malvern Instruments ltd, worcestershire, UK. Image analysis can be performed directly on the photomicrograph, scanning electron micrograph, or other image to estimate particle size and distribution.

The alloy powder preferably contains alloying particles that are nominally spherical. The same definition applies for the particles of the base powder, i.e. the "nominally spherical" alloy particles have an average sphericity of at least 0.9, preferably at least 0.95, and more preferably at least 0.99, where sphericity is the ratio of the surface area of a reference sphere having the same volume as a given alloy particle to the surface area of the alloy particle.

In some embodiments, the alloy powder is a mixture of particles having at least two different compositions. In these or other embodiments, the alloying powder comprises at least two, at least three, at least four, at least five, or more of the alloying elements disclosed herein. The alloy powder itself may be an alloy of Cr and/or Zr.

Hydrides, carbides, oxides, nitrides, borides, or sulfides of alloying elements (Cr, zr, or other elements) may be desirable as compared to pure forms for various reasons, including stability, cost, or other factors. For example, in certain embodiments, due to ZrH ₂ Stability in air and ability to decompose at melting temperature, hydrogen-stabilized zirconium particles (ZrH) ₂ ) Preferred over pure Zr particles, resulting in advantageous Al formation ₃ Zr nucleation phase (intermetallic precipitates). Hydrogen is evolved from the system and does not interfere with the alloying chemistry. In certain embodiments, hydrogen, carbon, oxygen, nitrogen, boron, or sulfur is incorporated into the final aluminum alloy. In particular, carbon and boron may be additional alloying elements.

The feedstock powder further may comprise from about 0.1wt% to about 15wt% of one or more additional alloying elements selected from the group consisting of: zn, si, mg, cu, li, ag, mn, fe, co, ni, sn, sb, bi, pb, B, C, ir, os, re, ca, sr and Be; hydrides, carbides, oxides, nitrides, borides, or sulfides thereof; and combinations or alloys of any of the preceding, wherein wt% is based on the total weight concentration of the additional alloying element on an elemental basis. These additional alloying elements may be present in the aluminum-containing base powder or may be provided as separate components within the total raw powder.

It is known that some high vapour pressure elements, such as Zn and Mg, evaporate faster during additive manufacturing and therefore the raw powder composition can be adjusted to contain an excess of these one or more light elements so that the correct final composition for the intended aluminium alloy is obtained after additive manufacturing. The present specification is hereby incorporated by reference into the commonly owned U.S. patent application No. 15/996, 438 filed on 2.6.2018, which teaches how to enrich a feedstock powder for additive manufacturing with certain light elements in order to achieve a desired final concentration of an additively manufactured part.

In certain embodiments, the aluminum-containing base powder is a 2000 series aluminum alloy. In certain embodiments, the aluminum-containing base powder contains from about 2wt% to about 6wt% Cu, from 0 to about 0.6wt% Mn, and from 0 to about 0.8wt% Si. The final aluminum alloy (after additive manufacturing) may be considered a modified 2000-series aluminum alloy, such as a modified 2219 aluminum alloy.

The aluminum-containing base powder may be selected from 1000 series, 2000 series, 3000 series, 4000 series, 5000 series, 6000 series, 7000 series, 8000 series, or combinations thereof.

The aluminium-containing base powder may be selected from 2000 series aluminium alloys. The 2000 series aluminum alloys include aluminum alloys 2011, 2014, 2024, 2036, 2048, 2055, 2090, 2091, 2099, 2124, 2195, 2218, 2219, 2319, and 2618. In certain embodiments, the aluminum alloy is selected from aluminum alloy 2024, aluminum alloy 2219, or combinations thereof.

The aluminum-containing base powder may be selected from 6000 series of aluminum alloys. 6000 series aluminum alloys include aluminum alloys 6005, 6009, 6010, 6060, 6061, 6063A, 6065, 6066, 6070, 6081, 6082, 6101, 6105, 6151, 6162, 6201, 6205, 6262, 6351, 6463, and 6951. In certain embodiments, the aluminum alloy is selected from aluminum alloy 6061, aluminum alloy 6063, or a combination thereof.

The aluminium-containing base powder may be selected from the 7000 series of aluminium alloys. 7000 series aluminum alloys include aluminum alloys 7005, 7034, 7039, 7049, 7050, 7068, 7072, 7075, 7175, 7079, 7116, 7129, 7178, and 7475. In certain embodiments, the aluminum alloy is selected from aluminum alloy 7050, aluminum alloy 7075, or combinations thereof.

In other embodiments, the aluminum-containing base powder is substantially pure aluminum (e.g., at least 99 wt.%, 99.5 wt.%, or 99.9 wt.% al).

In certain embodiments, the powder feedstock consists essentially of Al and Cr, or Al and Zr, or Al and Cr and Zr.

The feedstock powder may be used in any powder-based additive manufacturing process, including but not limited to Selective Laser Melting (SLM), electron Beam Melting (EBM), or Laser Engineered Net Shaping (LENS). In certain embodiments, the feedstock powder is first converted into another form of feedstock, such as a wire, which may be shaped itself via additive manufacturing, extrusion, wire drawing, or other metal working techniques. The raw object (e.g., wire) may then be subjected to additive manufacturing.

"bath temperature" refers to a temperature characteristic of the bath, which may be the bath volume average temperature, the bath time average temperature, the bath surface temperature, or the bath peak temperature (the highest temperature reached by any surface or region within the bath). For the weld puddle time average temperature, the time is the time span of formation and solidification of the weld puddle in the additive manufacturing or welding process. The bath temperature may also be an overall average temperature, which is averaged over both space and time.

The bath temperature will vary depending at least on the particular metal to be melted, the intensity of the power applied to the bath, and the geometry of the bath. For example, the bath temperature may vary from about 800 ℃ to about 2000 ℃, such as about or at least about 900 ℃, 1000 ℃, 1100 ℃, 1200 ℃, 1300 ℃, 1400 ℃, 1500 ℃, 1600 ℃, 1700 ℃, 1800 ℃, or 1900 ℃, noting that these temperatures may be the volume average temperature, time average temperature, surface temperature, and/or peak temperature of the bath. In various embodiments, the high vapor pressure metal is selected to have a vapor pressure of 1kPa or higher at 1000 ℃, 1100 ℃, 1200 ℃, 1300 ℃, 1400 ℃, 1500 ℃, 1600 ℃, 1700 ℃, or 1800 ℃.

Additive manufacturing via selective laser melting, electron beam melting, or laser engineered net shape can process raw material powders into alloy parts with a uniform distribution (good dispersion) of Al-Cr and/or Al-Zr precipitates to provide strength and ductility. During local heating to an elevated temperature, but below the melting point of Cr or Zr, one or more alloying elements are dissolved and/or suspended in the melt pool. The high energy input results in a preferably turbulent mixing of the molten bath, ensuring a uniform composition within the molten bath. The rapid cooling of the bath results in uniform precipitates and mitigates agglomeration and coarsening of the precipitates. Then, if desired, an additional heat treatment (such as an aging heat treatment) can be used to optimize the precipitate size and overall microstructure.

In some embodiments, the alloy powder itself contains the intermetallic inclusion Al _n X _m I.e. inclusions are made before the additive manufacturing process and added to the raw material powder itself. Intermetallic impurity Al _n X _m May be in addition to or instead of the alloying element X or its hydrides, carbides, oxides, nitrides or sulfides. In other words, an aluminide of alloying element X may be included in the alloy powder.

The disclosed feedstock powder, and/or the disclosed aluminum alloy, may be made of, or used in: additive manufacturing, welding, pressing, sintering, mixing, dispersing, friction stir welding, extrusion, bonding (such as with a polymeric binder), melting, semi-solid melting, casting, or combinations thereof. Melting may include induction melting, resistance melting, skull melting, arc melting, laser melting, electron beam melting, semi-solid melting, or other types of melting (including conventional and unconventional melt processing techniques). Casting may include, for example, centrifugal, casting, or gravity casting. Sintering may include, for example, spark discharge, capacitive discharge, resistive, or furnace sintering. Mixing may include, for example, convection, diffusion, shear mixing, or ultrasonic mixing.

The additive manufacturing method may be selected from the group consisting of, for example, selective laser melting, energy beam melting, laser engineered net shaping, and combinations thereof. For example, in additive manufacturing, the solidification rate may vary from about 0.01m/s to about 10m/s, such as, for example, from about 0.1m/s to about 5m/s.

The additive manufacturing feedstock may be any size compatible with common or custom additive manufacturing equipment. When the feedstock is in the form of a powder, the powder particles may have an average diameter of, for example, from about 1 micron to about 500 microns, such as from about 10 microns to about 100 microns. When the feedstock is in the form of a wire, the wire may have an average diameter of, for example, from about 10 microns to about 1000 microns, such as from about 50 microns to about 500 microns.

The powdered raw material may be in any form in which the discrete particles can be suitably distinguished from one another. For example, the powder may be present as a loose powder, a paste, a suspension, or a green body. A green body is an object whose main component prior to melting and solidification is a weakly bonded powder material.

In some embodiments, the metalliferous feed material may be in the form of a powder having an average particle size of, for example, from about 5 microns to about 150 microns. In some embodiments, the average particle size is about 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 microns.

By "component" it is meant any object of additive manufacturing having any geometry and size. During additive manufacturing, materials are deposited layer by layer to build up parts of arbitrary geometry. Conventional machining, such as casting or machining, is limited by specific process design criteria or line-of-sight (line-of-sight) manufacturing, which limits the potential geometries. Additive manufacturing overcomes these limitations by starting with powders or wires at finer scales than the target geometry being built, and locally melting or sintering these materials together to build the part from scratch. In principle, any geometric shape can be created.

The energy source is preferably a laser-diode energy source, such as configured with from 10J/mm ³ To 2000J/mm ³ The energy source of laser energy density of (1). In various embodiments, the laser-diode energy source is configured with about 10J/mm ³ 、50J/mm ³ 、100J/mm ³ 、200J/mm ³ 、300J/mm ³ 、400J/mm ³ 、500J/mm ³ 、600J/mm ³ 、700J/mm ³ 、800J/mm ³ 、900J/mm ³ 、1000J/mm ³ 、1100J/mm ³ 、1200J/mm ³ 、1300J/mm ³ 、1400J/mm ³ 、1500J/mm ³ 、1600J/mm ³ 、1700J/mm ³ 、1800J/mm ³ 、1900J/mm ³ Or 2000J/mm ³ Laser energy density of (1). In some embodiments, the laser diode operates at a shorter laser wavelength (e.g., 808 nm) than conventional fiber lasers (e.g., 1064 nm), and is able to absorb energy more efficiently.

Conventional additive manufacturing utilizes a grating laser to build up a part layer by layer. A process utilizing a gradient energy mode (e.g., from a laser-diode system) allows a 2D exposure to be projected onto the powder bed to produce a large area melt pool in the shape of the layer to be built. Using a gradient energy mode has the advantage of speeding up the additive manufacturing process.

For example, additive manufacturing may utilize exposure times (to the energy source) from 1 microsecond to 1 minute. In various embodiments, the exposure time is about 10 microseconds, 100 microseconds, 1 millisecond, 10 milliseconds, 100 milliseconds, 1 second, or 10 seconds. For example, the exposure time can be easily varied by turning the energy source on and off, or by spatially controlling the energy source.

Additive manufacturing may be controlled to maintain from 10K/m to 10K/m within the first melt layer and/or additional melt layers ⁶ An average thermal gradient of K/m, such as about, or less than about 10K/m, 10 ² K/m、10 ³ K/m、10 ⁴ K/m, or 10 ⁵ K/m. In some embodiments, the average thermal gradient in the first melt layer and/or the additional melt layer is less than 10 ⁵ K/m or less than 10 ³ K/m. In various embodiments, the average thermal gradient in step (c) is, for example, from 10K/m to 100K/m, or from 10K/m to 10 ³ K/m, or from 10K/m to 10 ⁴ K/m, or from 10K/m to 10 ⁵ K/m。

In some embodiments, the powder bed temperature is a temperature within about 50 ℃ from about room temperature (e.g., about 25 ℃) to about the solidus temperature (the highest temperature at which the metal alloy is a solid).

Additive manufacturing may be controlled to maintain less than 10 in the first solid layer and/or in the additional solid layer ⁶ K/m (order of magnitude) average thermal gradient. Additive manufacturing may be controlled to maintain from 10K/m to 10K/m within the first solid layer and/or within the additional solid layer ⁶ An average thermal gradient of K/m, such as about, or less than about 10K/m, 10 ² K/m、10 ³ K/m、10 ⁴ K/m, or 10 ⁵ K/m. In some embodiments, the average thermal gradient in the first solid layer and/or in the additional solid layer is less than 10 ⁵ K/m or less than 10 ³ K/m. In various embodiments, the average thermal gradient is, for example, from 10K/m to 100K/m, or from10K/m to 10 ³ K/m, or from 10K/m to 10 ⁴ K/m, or from 10K/m to 10 ⁵ K/m。

Additive manufacturing may be controlled to maintain an average solidification speed from 0.01m/s to 10m/s within the first solid layer and/or the additional solid layer. In various embodiments, the average solidification speed is about, less than about, or greater than about 0.01m/s, 0.1m/s, 0.5m/s, 1m/s, 1.5m/s, 2m/s, 3m/s, 4m/s, or 5m/s within the first solid layer and/or the additional solid layer.

The first solid layer may have a thickness of, for example, from 10 to 500 micrometers. The additional solid layer may have an average thickness of, for example, from 10 to 500 microns. In various embodiments, the first layer and/or the additional layer may have a thickness of about 10, 20, 30, 40, 50, 75, 100, 150, 200, 250, 300, 350, 400, 450, or 500 microns. The layer thickness may vary along the additive manufacturing build direction, or the layer thickness may be constant.

The method may further comprise repeating the melting and solidifying steps a plurality of times to produce a plurality of solid layers by sequentially solidifying a plurality of melt layers in the additive manufacturing build direction. The method is in principle not limited to the number of solid layers that can be produced. By "plurality of solid layers" is meant at least 2 layers in the additively manufactured component, such as at least 10 individual solid layers. The number of solid layers may be much greater than 10, such as about 100, 1000, 10000 or more. The plurality of solid layers may be characterized by an average layer thickness of at least 10 microns, such as about, or at least about 10, 20, 30, 40, 50, 75, 100, 150, 200, 250, 300, 350, 400, 450, or 500 microns.

In some embodiments, the additive-fabricated aluminum alloy microstructure has a crystallographic texture that is not solely oriented in the direction of the additive-fabrication build. For example, the additively-manufactured aluminum alloy microstructure can contain a plurality of dendritic layers having different primary growth orientation angles relative to one another.

Selective laser melting is an additive manufacturing technique designed to melt metal powders and fuse them together using a high power density laser. Selective laser melting can completely melt metallic materials into solid 3D parts.

Electron beam melting is a type of additive manufacturing for metal parts. The metal powders are welded together layer by layer under vacuum using an electron beam as a heat source.

Laser engineered net shaping is an additive manufacturing technique developed to fabricate metal parts directly from a computer aided designed solid model by using metal powder injected into a melt pool created by a focused high power laser beam. Laser engineered net shape is similar to selective laser sintering, but the metal powder is only applied where material is being added to the part at that time. Note that "net shape" is meant to also encompass "near net" manufacturing.

In any of these additive manufacturing techniques, post-production processes may be applied, such as heat treatment, light machining, surface finishing, painting, stamping, or other finishing operations. Additionally, several additively manufactured parts may be chemically or physically joined together (e.g., sintered) to produce a final object.

Examples of the invention

Materials and methods.

The starting aluminum (Al) powder was treated in example 1 with zirconium particles (as ZrH) at the concentrations described below ₂ ) Surface functionalization, or use of zirconium particles (as ZrH) in examples 2 to 6 ₂ ) And surface functionalization of both chromium (as Cr) particles. The average particle size of the zirconium particles is at least one order of magnitude smaller than the average particle size of the Al powder, and the average particle size of the chromium particles is at least one order of magnitude smaller than the average particle size of the Al powder. The trace elements include Fe and Si in the surface functionalized Al powder.

The resulting surface functionalized feedstock powder was processed into parts and test samples by selective Laser melting using a Concept Laser M2D printer (Concept Laser GmbH, grace, texas, USA) to build parts layer by layer. The treatment was carried out under a flowing inert argon atmosphere with oxygen monitoring. The samples were removed from the machine and dried with clean, dry air.

Tensile testing was performed on a servo-powered INSTRON 5960 frame equipped with a 50-kN load cell. The sample was clamped through the ends of the dog bone sample. The stretching rate was 0.2mm/min and the sample was loaded to rupture. Testing was performed according to ASTM E8. Hardness testing was performed to measure vickers pyramid number, denoted "HV". X-ray diffraction measurements were performed using a standard XRD diffractometer.

Example 1: production of an aluminum alloy with 4at Zr.

Processing of the aluminum alloy having the composition Al-4 wt.% Zr (Cr-free) via additive manufacturing.

As shown in fig. 8, the as-built hardness of the aluminum alloy was HV =86.2. FIG. 9 shows the beneficial effect of aging time on aluminum alloy hardness at a fixed aging temperature of 350 ℃.

FIG. 10 shows the moderate effect of additional aging on the hardness of the aluminum alloy at a fixed aging temperature of 200 ℃. The samples shown in fig. 10 have previously been aged at 350 ℃ for about 70 hours, indicating that a temperature of 200 ℃ has little effect on HV over an extended period of time.

The X-ray diffraction pattern of the aluminum alloy aged at 350 ℃ for 32 hours is shown in fig. 12.

Example 2: production of aluminum alloys having 0.5at% Cr and 0.5at% Zr.

Processing an aluminum alloy having a composition Al-0.5wt% Cr-0.5wt% Zr via additive manufacturing.

Fig. 3 shows a micrograph of the surface of an additive manufactured aluminum alloy (scale bar =1000 microns).

As shown in fig. 8, the as-built hardness of the aluminum alloy was HV =57.9. FIG. 9 shows the beneficial effect of aging time on aluminum alloy hardness at a fixed aging temperature of 350 ℃.

Example 3: production of aluminum alloys having 1.0at% Cr and 1.0at% Zr.

Processing an aluminum alloy having a composition Al-1.0wt% Cr-1.0wt% Zr via additive manufacturing.

Fig. 4 shows a micrograph of the surface of an additive manufactured aluminum alloy (scale bar =1000 microns).

As shown in fig. 8, the as-built hardness of the aluminum alloy was HV =85.2. FIG. 9 shows the beneficial effect of aging time on aluminum alloy hardness at a fixed aging temperature of 350 ℃.

Example 4: production of aluminum alloys having 1.0at% Cr and 2.0at% Zr.

Processing an aluminum alloy having a composition Al-1.0wt% Cr-2.0wt% Zr via additive manufacturing.

Fig. 5 shows a micrograph of the surface of an additive manufactured aluminum alloy (scale bar =1000 microns). A small amount of porosity is present in the material.

As shown in fig. 8, the as-built hardness of the aluminum alloy was HV =90.5. FIG. 9 shows the beneficial effect of aging time on aluminum alloy hardness at a fixed aging temperature of 350 ℃.

FIG. 10 shows the moderate effect of additional aging on the hardness of the aluminum alloy at a fixed aging temperature of 200 ℃. The sample shown in fig. 10 has previously been aged at 350 ℃ for about 70 hours, indicating that a temperature of 200 ℃ has little effect on HV over an extended period of time.

Example 5: production of aluminum alloys having 2.0at% Cr and 1.0at% Zr.

Processing the aluminum alloy having the composition Al-2.0wt% Cr-1.0wt% Zr via additive manufacturing.

Fig. 6 shows a micrograph of the surface of an additive manufactured aluminum alloy (scale bar =1000 microns).

As shown in fig. 8, the as-built hardness of the aluminum alloy was HV =97.9. FIG. 9 shows the beneficial effect of aging time on the hardness of an aluminum alloy at a fixed aging temperature of 350 ℃.

Fig. 11 shows tensile stress versus elongation for aluminum alloys. The ultimate tensile strength is about 263MPa. FIG. 11 also shows that when the aluminum alloy is aged at 350 ℃ for 32 hours, the ultimate tensile strength increases to about 337MPa. Fig. 11 also shows that when the aluminum alloy was aged at 350 ℃ for 4 hours and at 400 ℃ for 2 hours, the ultimate tensile strength increased to about 333MPa.

Example 6: production of aluminum alloys having 2.0at% Cr and 2.0at% Zr.

Processing an aluminum alloy having a composition Al-2.0wt% Cr-2.0wt% Zr via additive manufacturing.

Fig. 7 shows a micrograph of a surface of an additively manufactured aluminum alloy manufactured in the form of a dog bone.

As shown in fig. 8, the as-built hardness of the aluminum alloy was HV =96.1. FIG. 9 shows the moderate effect of aging time on the hardness of an aluminum alloy at a fixed aging temperature of 350 ℃.

FIG. 11 shows tensile stress versus elongation for aluminum alloys aged under different conditions. FIG. 11 shows that the ultimate tensile strength is about 325MPa when the aluminum alloy is aged at 350 ℃ for 32 hours. FIG. 11 also shows that when the aluminum alloy is aged at 350 ℃ for 4 hours and at 400 ℃ for 2 hours, the ultimate tensile strength is about 313MPa.

The present invention can be widely applied to a structure containing an aluminum alloy exhibiting high strength at temperatures up to 300 ℃ or higher. Such structures include, for example, aluminum alloy structures in the propulsion and exhaust systems of commercial and military aircraft that are exposed to high temperatures; aluminum alloy structures of high speed vehicles exposed to high temperatures due to pneumatic thermal heating; and motor vehicle powertrain aluminum alloy parts exposed to high temperatures, such as pistons, connecting rods, cylinder heads, and brake calipers. Other potential applications include improved tooling, replacement of steel or titanium components at low weight, complete topology optimization of aluminum components, low cost replacement of production down components, and replacement of existing additive manufactured aluminum systems.

In this detailed description, reference has been made to various embodiments and to the accompanying drawings, in which specific exemplary embodiments of the invention are shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that modifications may be made to the various embodiments disclosed by those skilled in the art.

Where methods and steps described above indicate certain events occurring in a certain order, those of ordinary skill in the art will recognize that the order of certain steps may be modified and that such modifications are in accordance with the variations of the present invention. In addition, certain steps may be performed concurrently in a parallel process, or may be performed sequentially where possible.

All publications, patents, and patent applications cited in this specification are herein incorporated by reference in their entirety as if each individual publication, patent, or patent application were specifically and individually indicated to be incorporated herein by reference.

The above-described embodiments, variations and drawings are intended to provide an indication of the utility and versatility of the present invention. Other embodiments that do not provide all of the features and advantages set forth herein may also be utilized without departing from the spirit and scope of the present invention. Such modifications and variations are considered to be within the scope of the invention as defined by the appended claims.

Claims

1. An aluminum (Al) alloy containing at least 0.1at% zirconium (Zr) and/or at least 0.1at% chromium (Cr), wherein the aluminum alloy is in the form of an additively manufactured object.

2. The aluminum alloy of claim 1, wherein the aluminum alloy contains at least 0.3at%Cr, and/or wherein the alloy contains at least 0.3at%Zr.

3. The aluminum alloy of claim 1, wherein the aluminum alloy contains at least 0.5at%Cr, and/or wherein the alloy contains at least 0.5at%.

4. The aluminum alloy of claim 1, wherein the aluminum alloy contains at least 1.0at% cr, and/or wherein the alloy contains at least 1.0at% zr.

5. The aluminum alloy of claim 1, wherein the aluminum alloy contains at least 2.0at% cr, and/or wherein the alloy contains at least 2.0at% zr.

6. The aluminum alloy of claim 1, wherein the Zr/Cr ratio is selected from 0.1 to 10.

7. The aluminum alloy of claim 6, wherein the Zr/Cr ratio is selected from 0.2 to 2.

8. The aluminum alloy according to claim 1, wherein the aluminum alloy contains precipitated intermetallic Al-Cr particles and/or precipitated intermetallic Al-Zr particles.

9. The aluminum alloy of claim 1, wherein the aluminum alloy contains equiaxed grains nucleated by Cr and/or Zr.

10. The aluminum alloy of claim 1, wherein the aluminum alloy further contains one or more elements selected from the group consisting of Cu, mg, zn, li, mn, fe, si, ag, V, nb, ta, ti, hf, mo, W, sc, Y, ca, be, sr, la, ce, re, ru, os, co, ni, pd, pt, ir, rh, au, cd, sn, bi, pb, B, C, N, O, H, S, er, pr, nd, sm, gd, tb, dy, ho, tm, yb, and Lu.

11. The aluminum alloy of claim 1, wherein the aluminum alloy is characterized by a vickers pyramid number of at least 50.

12. The aluminum alloy of claim 1, wherein the aluminum alloy is characterized by a vickers pyramid number of at least 75.

13. The aluminum alloy of claim 1, wherein the aluminum alloy is characterized by a tensile strength of at least 300 MPa.

14. The aluminum alloy of claim 1, wherein the aluminum alloy is thermally stable at 300 ℃.

15. The aluminum alloy of claim 1, wherein the additively manufactured object is selected from the group consisting of a structural part, a coating, an ingot, a sheet, a plate, a rod, a wire, and combinations thereof.

16. A structure comprising the aluminum alloy of claim 15.

17. An aluminum (Al) alloy containing at least 0.1at% zirconium (Zr) and at least 0.1at% chromium (Cr), wherein the aluminum alloy is in the form of an article of manufacture.

18. The aluminum alloy of claim 17, wherein the aluminum alloy contains at least 0.3at%Cr, and/or wherein the aluminum alloy contains at least 0.3at%Zr.

19. The aluminum alloy of claim 17, wherein the aluminum alloy contains at least 0.5at% cr, and/or wherein the aluminum alloy contains at least 0.5at% zr.

20. The aluminum alloy of claim 17, wherein the aluminum alloy contains at least 1.0at% cr, and/or wherein the aluminum alloy contains at least 1.0at% zr.

21. The aluminum alloy of claim 17, wherein the aluminum alloy contains at least 2.0at% cr, and/or wherein the aluminum alloy contains at least 2.0at% zr.

22. The aluminum alloy of claim 17, wherein the Zr/Cr ratio is selected from 0.1 to 10, and optionally wherein the Zr/Cr ratio is selected from 0.2 to 2.

23. The aluminum alloy of claim 17, wherein the aluminum alloy contains precipitated intermetallic Al-Cr particles, precipitated intermetallic Al-Zr particles, and/or precipitated intermetallic Zr-Cr particles.

24. The aluminum alloy of claim 17, wherein the aluminum alloy contains equiaxed grains nucleated with Cr and/or Zr.

25. The aluminum alloy of claim 17, wherein the aluminum alloy further contains one or more elements selected from the group consisting of Cu, mg, zn, li, mn, fe, si, ag, V, nb, ta, ti, hf, mo, W, sc, Y, ca, be, sr, la, ce, re, ru, os, co, ni, pd, pt, ir, rh, au, cd, sn, bi, pb, B, C, N, O, H, S, er, pr, nd, sm, gd, tb, dy, ho, tm, yb, and Lu.

26. The aluminum alloy of claim 17, wherein the manufactured object is selected from the group consisting of structural parts, coatings, ingots, sheets, plates, rods, wires, and combinations thereof.

27. An aluminum-containing powder comprising:

28. The aluminiferous powder of claim 27, wherein said aluminiferous powder comprises at least 0.3at% cr, and/or wherein said aluminiferous powder comprises at least 0.3at% zr.

29. The aluminum-containing powder of claim 27, wherein said aluminum-containing powder comprises at least 0.5at%Cr, and/or wherein said aluminum-containing powder comprises at least 0.5at%Zr.

30. The aluminum-containing powder of claim 27, wherein the aluminum-containing powder contains at least 1.0at% cr, and/or wherein the aluminum-containing powder contains at least 1.0at% zr.

31. The aluminum-containing powder of claim 27, wherein the aluminum-containing powder contains at least 2.0at%Cr, and/or wherein the aluminum-containing powder contains at least 2.0at%Zr.

32. The aluminum-containing powder of claim 27, wherein the Zr/Cr ratio is selected from 0.1 to 10.

33. The aluminum-containing powder of claim 32, wherein the Zr/Cr ratio is selected from 0.2 to 2.

34. The aluminum-containing powder of claim 27, wherein the first particles further comprise one or more elements selected from the group consisting of Cu, mg, zn, li, mn, fe, si, ag, V, nb, ta, ti, hf, mo, W, sc, Y, ca, be, sr, la, ce, re, ru, os, co, ni, pd, pt, ir, rh, au, cd, sn, bi, pb, B, C, N, O, H, S, er, pr, nd, sm, gd, tb, dy, ho, tm, yb, and Lu.

35. The aluminum-containing powder of claim 27 further comprising one or more elements selected from the group consisting of Cu, mg, zn, li, mn, fe, si, ag, V, nb, ta, ti, hf, mo, W, sc, Y, ca, be, sr, la, ce, re, ru, os, co, ni, pd, pt, ir, rh, au, cd, sn, bi, pb, B, C, N, O, H, S, er, pr, nd, sm, gd, tb, dy, ho, tm, yb, and Lu.

36. The aluminum-containing powder of claim 27, wherein the average second particle size is at least one order of magnitude smaller than the average first particle size.

37. The aluminum-containing powder of claim 27, wherein the average third particle size is at least one order of magnitude smaller than the average first particle size.

38. The aluminum-containing powder of claim 27, wherein the ratio of the average second particle size to the average third particle size is selected from 0.1 to 10.

39. The aluminum-containing powder of claim 27, wherein at least 50 vol.% of the second particles are physically and/or chemically assembled on the surface of the first particles.

40. The aluminum-containing powder of claim 39, wherein at least 90% by volume of the second particles are physically and/or chemically assembled on the surface of the first particles.

41. The aluminum-containing powder of claim 40, wherein at least 99 vol.% of the second particles are physically and/or chemically assembled on the surface of the first particles.

42. The aluminum-containing powder of claim 27, wherein at least 50 vol.% of the third particles are physically and/or chemically assembled on the surface of the first particles.

43. The aluminum-containing powder of claim 42, wherein at least 90 vol.% of the third particles are physically and/or chemically assembled on the surface of the first particles.

44. The aluminum-containing powder of claim 43, wherein at least 99 vol.% of the third particles are physically and/or chemically assembled on the surface of the first particles.

45. The aluminum-containing powder of claim 27, wherein the aluminum-containing powder comprises one or more intermetallic compounds of Zr and Cr.

46. The aluminum-containing powder of claim 27, wherein the second particles further comprise Cr, and/or wherein the third particles further comprise Zr.