High-performance 5000-series aluminum alloys and methods for making and using them
5000 series aluminum wrought alloys with high strength, high formability, excellent corrosion resistance, and friction-stir weldability, and methods of making those alloys.
1. An aluminum alloy comprising:
about 3% to about 5% by weight magnesium;
about 0.1% to about 4% by weight zinc;
about 0.6% to about 1% by weight manganese;
about 0.1% to about 0.3% by weight chromium;
about 0.4% to about 0.8% by weight zirconium;
aluminum as the remainder; and
a dispersion of coherent Al 3 Zr nanoscale precipitates with an L1 2 crystal structure in an aluminum matrix, the Al 3 Zr nanoscale precipitates having an average radius of no more than about 20 nm and having an average number density of no less than about 5×10 20 per m 3 .
2. The aluminum alloy of claim 1 , further comprising scandium at a concentration of no more than about 0.15% by weight.
3. The aluminum alloy of claim 1 , further comprising copper at a concentration of no more than about 1% by weight.
4. The aluminum alloy of claim 1 , further comprising a dispersion of the incoherent Al 6 Mn dispersoids having an average radius in the range of about 50 nm to about 200 nm.
5. The aluminum alloy of claim 1 , further comprising a dispersion of Al 12 Mn, Al 7 Cr or Al 45 Cr 7 intermetallic phases in the range of about 50 nm to about 800 nm in size.
6. The aluminum alloy of claim 5 , further comprising a dispersion of the incoherent Al 6 Mn dispersoids having an average radius in the range of about 50 nm to about 200 nm.
7. The aluminum alloy of claim 1 , wherein the alloy has mechanical strength comparable to commercial high-strength AA7039-T6 and AA7075-T6 alloys.
8. The aluminum alloy of claim 1 , wherein the alloy has the same or better corrosion resistance compared to commercial AA5083 alloy.
9. The aluminum alloy of claim 1 , wherein the alloy has better creep resistance compared to commercial AA5083 alloy at a temperature range from about 25° C. to about 450° C.
10. The aluminum alloy of claim 1 , wherein the alloy is weldable by a gas welding method.
11. The aluminum alloy of claim 10 , wherein the gas welding method is selected from a group consisting of Metal Inert Gas (MIG) welding, Tungsten Inert Gas (TIG) welding, and friction-stir welding.
12. The aluminum alloy of claim 1 , wherein the alloy maintains high room temperature strength after exposure at about 375° C. for at least about two weeks.
13. The aluminum alloy of claim 1 , wherein the alloy comprises about 3.5% to 4% by weight magnesium and about 0.85% to 1.2% by weight zinc.
14. The aluminum alloy of claim 13 , wherein the alloy further comprises about 0.5% to about 0.7% by weight zirconium.
15. The aluminum alloy of claim 14 , further comprising about 0.1% to about 1% by weight copper.
16. The aluminum alloy of claim 14 , further comprising about 0.08% to about 0.12% by weight scandium.
17. The aluminum alloy of claim 16 , further comprising about 0.1% to about 1% by weight copper.
18. The aluminum alloy of claim 1 , wherein the alloy further comprises about 3.3% to about 4% by weight magnesium and about 3.5% to about 4.2% by weight zinc.
19. The aluminum alloy of claim 18 , wherein the alloy further comprises about 0.5% to about 0.7% by weight zirconium.
20. The aluminum alloy of claim 19 , further comprising about 0.1% to about 1% by weight copper.
21. The aluminum alloy of claim 19 , further comprising about 0.08% to about 0.12% by weight scandium.
22. The aluminum alloy of claim 21 , further comprising about 0.1% to about 1% by weight copper.
23. A method of making the aluminum alloy of claim 1 , the method comprising:
melting an alloy mixture in a temperature range of about 750° C. to about 950° C.;
casting the melted alloy mixture with a high solidification cooling rate that is above about 50° C./s; and
after the casting step, aging the cast alloy at a temperature in a range of about 275° C. to about 475° C. for about 2 hours to about 72 hours.
24. The method of claim 23 , wherein the aging step comprises aging the cast alloy at a temperature in a range of about 350° C. to about 475° C. for about 2 hours to about 72 hours.
25. The method of claim 23 , wherein the aging step comprises:
aging the cast alloy at a temperature in a range of about 275° C. to about 375° C. for about 2 hours to about 24 hours; and
then aging the cast alloy at a temperature in a range of about 375° C. to about 475° C. for about 1 hour to about 24 hours.
26. The method of claim 23 , wherein the aging step comprises aging the cast alloy at a temperature in a range of about 350° C. to about 475° C. for about 24 hours to about 72 hours.
27. The method of claim 23 , wherein the casting step is performed using a casting method selected from a group consisting of squeeze casting, twin-belt casting, twin-roll casting, strip casting, and bar casting.
28. The method of claim 23 , further comprising hot rolling the cast alloy after the casting step and before aging step.
29. The method of claim 23 , further comprising cold rolling the cast alloy either before or after the aging step to fabricate cast articles into shape.
30. The method of claim 23 , further comprising: after the aging step, additionally aging the cast alloy at a temperature in a range of about 120° C. to about 200° C. for about 8 hours to about 72 hours.
31. A cast aluminum component comprising the alloy of claim 1 .
32. The aluminum component of claim 31 , the component being selected from a group consisting of automotive body panels, boat or ship body structures, storage tanks, pressure vessels, and vessels for land or marine structures.