Aluminum alloys with improved intergranular corrosion resistance properties and methods of making and using the same
Disclosed herein are embodiments of aluminum-based alloys having improved intergranular corrosion resistance. Methods of making and using the disclosed alloy embodiments also are disclosed herein.
1. An aluminum alloy, comprising copper, magnesium in an amount ranging from 0.27 wt % to 8 wt %, a rare earth element (REE) component selected from cerium, lanthanum, or a combination thereof, wherein the total amount of the rare earth element (REE) component ranges from greater than 1 wt % to 4 wt %; iron, and balance of aluminum and trace impurities, wherein the aluminum alloy has an Al 11 REE 3 intermetallic phase, wherein Al is aluminum and the REE is cerium, lanthanum, or a combination thereof, and wherein at least 40% of all copper and at least 60% of all iron present in the aluminum alloy is contained in the Al 11 REE 3 intermetallic phase.
2. The aluminum alloy of claim 1 , wherein the aluminum alloy comprises copper in grain boundaries of the aluminum alloy and wherein 80% of any such copper present is contained in the Al 11 REE 3 intermetallic phase.
3. The aluminum alloy of claim 1 , wherein the REE is cerium.
4. The aluminum alloy of claim 1 , wherein the Al 11 REE 3 intermetallic phase comprises an atomic % of copper and an atomic % of the REE that provides a ratio ranging from 2.1:1 to higher than 2.1:1 (copper:REE).
5. The aluminum alloy of claim 4 , wherein the ratio ranges from 2.1:1 to 3:1.
6. The aluminum alloy of claim 4 , wherein the ratio ranges from 2.1:1 to 2.6:1.
7. The aluminum alloy of claim 1 , wherein the alloy comprises one or more intermetallics having a formula selected from Cu(REE)Al 3 , Cu 4 (REE)Al 8 , or Cu 7 (REE) 2 Al 10 .
8. The aluminum alloy of claim 1 , wherein the copper is present in an amount ranging from 0.1 wt % to 7 wt %.
9. The aluminum alloy of claim 1 , further comprising titanium in an amount ranging from greater than 0 wt % to 0.3 wt %; and wherein the magnesium is present in an amount ranging from greater than 0.27 wt % to 3 wt % and the iron is present in an amount ranging from greater than 0 wt % to 2 wt %.
10. The aluminum alloy of claim 9 , wherein the aluminum alloy further comprises an Al-REE-Ti ternary intermetallic phase and wherein the Al-REE-Ti ternary phase comprises an atomic % of titanium and an atomic % of the REE that provides a ratio of REE to titanium ranging from 0.3:1 to higher than 0.3:1.
11. The aluminum alloy of claim 1 , further comprising silicon, manganese, zinc, chromium, or zirconium.
12. A method for making the alloy of claim 1 , comprising:
melting a solid aluminum-based alloy comprising aluminum, copper, iron, magnesium, and titanium and that is free of a rare earth element to provide a molten aluminum-based alloy;
adding to the molten aluminum-based alloy a rare earth element (REE) component selected from cerium, lanthanum, or a combination thereof, to form a molten REE-modified aluminum-based alloy, wherein the REE component is added in an amount sufficient to form the Al 11 REE 3 intermetallic capable of isolating an amount of the copper or the titanium present in the molten REE-modified aluminum-based alloy from an aluminum matrix; and
allowing the molten REE-modified aluminum-based alloy to solidify, thereby providing a solidified molten REE-modified aluminum-based alloy having increased intergranular corrosion resistance as compared to a solidified aluminum-based alloy that is not modified with an REE.
13. The method of claim 12 , wherein adding the REE changes the chemical composition of grain boundary precipitates within the molten aluminum-based alloy such that the grain boundary precipitates become more anodic than grain boundary precipitates present in a solidified aluminum-based alloy that is not modified with an REE.
14. The method of claim 12 , wherein adding the REE changes the chemical composition of grain boundary precipitates within the molten aluminum-based alloy such that the galvanic potential difference between the grain boundary precipitates and precipitate free zones and the galvanic potential difference between the grain boundary precipitates and a grain matrix are both less than 0.020V.
15. The method of claim 12 , wherein the presence of the Al 11 REE 3 intermetallic capable of isolating an amount of the copper or the titanium present in the molten REE-modified aluminum-based alloy from an aluminum matrix is determined using scanning electron microscopy and/or energy dispersive spectroscopy.
16. The method of claim 12 , wherein the amount of the REE added to the molten aluminum-based alloy ranges from greater than 0 wt % to 4 wt %.
17. The method of claim 12 , wherein the amount of the REE added to the molten aluminum-based alloy ranges from 0.1 wt % to 1 wt %.
18. A method, comprising forming a coating on a base alloy by depositing the aluminum alloy of claim 1 on a surface of the base alloy, wherein the base alloy is more susceptible to corrosion than the aluminum alloy of claim 1 .
19. The method of claim 18 , wherein depositing comprises cold spray deposition, twin-wire arc deposition, thermal spray deposition, roll bonding deposition, electrodeposition, physical vapor deposition, or additive manufacturing deposition.