Al-Mg alloy product suitable for armour plate applications
View Patent ↗Aluminum alloy plate having improved resistance against incoming kinetic energy projectiles, the plate having a gauge of 10 mm or more and the aluminum alloy having a chemical composition including, in weight percent: Mg 4.0 to 6.0, Mn 0.2 to 1.4, Zn 0.9 max., Zr<0.3, Cr<0.3, Sc≦0.5, Ti≦0.3, Fe<0.5, Si<0.45, Ag<0.4, Cu<0.25, other elements and unavoidable impurities each <0.05, total <0.20, balance aluminum, and wherein the alloy plate is obtained by a manufacturing process including casting, preheating and/or homogenization, hot rolling, a first cold working operation, an annealing treatment at a temperature of less than 350° C., followed by a second cold working operation.
1. A method of manufacturing an aluminium alloy plate having improved resistance against incoming kinetic energy projectiles, the plate having a final gauge of 10 mm or more, the method comprising the following steps:
(a) casting an aluminum alloy having a chemical composition comprising, in weight percent:
Mg 4.0 to 6.0
Mn 0.2 to 1.4
Zn 0.9 max.
Zr<0.3
Cr<0.3
Sc≦0.5
Ti≦0.3
Fe<0.5
Si<0.45
Ag<0.4
Cu<0.25,
other elements and unavoidable impurities each <0.05, total <0.20, balance aluminum,
(b) preheating and/or homogenisation,
(c) hot rolling,
(d) a first cold working operation selected from the group consisting of stretching in the range of 2 to 15% and cold rolling with a cold rolling reduction of 4 to 12%,
(e) an annealing treatment at a temperature of less than 350° C., followed by
(f) a second cold working operation consisting of stretching in a range of 2 to 15%, and
wherein the manufacturing process of the alloy plate at final gauge after the cold working operation is devoid of a further heat treatment, such that no substantial recovery occurs in the alloy plate.
2. The method according to claim 1 , wherein the aluminum alloy plate has an at least 4 improvement in the V50 limit compared to an AA5083-H131 counterpart, as measured by the 30 AMP2 test according to MIL-DTL-46027J of September 1998.
3. The method according to claim 1 , wherein the aluminum alloy plate has a proof strength of at least 255 MPa.
4. The method according to claim 1 , wherein the aluminum alloy plate has an ultimate tensile strength of at least 330 MPa.
5. The method according to claim 1 , wherein the aluminum alloy plate has an elongation in the L-direction of more than 10%.
6. The method according to claim 1 , wherein the aluminum alloy plate has an elongation in the LT-direction of more than 13%.
7. The method according to claim 1 , wherein the Mg content in the aluminum alloy plate is 4.9% or more.
8. The method according to claim 1 , wherein the Mg content in the aluminum alloy plate is in a range of 5.0 to 5.6%.
9. The method according to claim 1 , wherein the Mn content in the aluminum alloy plate is in a range of 0.4 to 1.2%.
10. The method according to claim 1 , wherein the Mn content in the aluminum alloy plate is in a range of 0.65 to 1.2%.
11. The method according to claim 1 , wherein in the aluminum alloy plate the Mg+Mn>6.8% or Mg+Mn<5.9%.
12. The method according to claim 1 , wherein the Zn content in the aluminum alloy plate is in a range of 0.20 to 0.90%.
13. The method according to claim 1 , wherein the Zn content in the aluminum alloy plate is in a range of 0.35 to 0.70%.
14. The method according to claim 1 , wherein the Zr content in the aluminum alloy plate is in a range of 0.05 to 0.25.
15. The method according to claim 1 , wherein the Cr content in the aluminum alloy plate is in a range of 0.08 to 0.25% and the Ti content is in a range of 0.1 to 0.2%.
16. The method according to claim 1 , wherein the chemical composition of the aluminum alloy plate is within the range of AA5059.
17. The method according to claim 1 , wherein the aluminum alloy plate has a gauge of less than 100 mm.
18. The method according to claim 1 , wherein the aluminum alloy plate has a gauge in the range of 15 to 75 mm.
19. The method according to claim 1 , wherein the aluminum alloy plate has a gauge in the range of 25 to 75 mm.
20. The method according to claim 1 , wherein the first cold working operation consists of stretching in a range of 4 to 10%.
21. The method according to claim 1 , wherein the second cold working operation consists of stretching in a range of 4 to 10%.
22. The method according to claim 1 , wherein the first cold working operation consists of stretching in a range of 4 to 10% and the second cold working operation consists of stretching in a range of 4 to 10%; wherein the Zn content in the aluminium alloy plate is in a range of 0.35 to 0.70%.
23. The method according to claim 1 , wherein the annealing treatment is carried out at a temperature in a range of less than 300° C.
24. The method according to claim 1 , wherein the annealing treatment is carried out at a temperature in a range of 220° C. to 300° C.