Method of making a structural element for aeronautical construction comprising differential work-hardening
A process for fabricating a worked product or a monolithic multi-functional structural element comprising aluminium alloy includes a hot working step and at least one transformation step by cold plastic deformation after the hot transformation step. At least two zones of the structural element have imposed generalized average plastic deformations and the imposed deformations are different by at least 2%. Structural elements can be fabricated, particularly for aeronautical construction, with properties that are variable while their geometric characteristics are identical to those of existing components. The process is economic and controllable, and properties can be varied for parts not requiring any artificial ageing.
1. Worked product consisting of a 2XXX alloy in the T3X temper prepared by a hot working step, and at least one working step by cold plastic deformation after the hot working step, wherein at least two zones of said worked product have imposed generalized average plastic deformations, wherein the imposed deformations are different by at least 2%; wherein said at least two zones Z 1 and Z 2 have mechanical properties selected from the group consisting of
(i) Z 1 : R m (L)>500 MPa and Z 2 : A(L)(%)>16%
(ii) Z 1 : R m (L)>450 MPa and Z 2 : A(L)(%)>18%
(iii) Z 1 : R m (L)>550 MPa and Z 2 : A(L)(%)>10%
(iv) Z 1 : R m (L)>550 MPa and Z 2 : K 1c (L-T)>45 MPa√m; and
wherein the worked product consisting of a 2XXX alloy in the T3X temper is naturally aged.
2. Worked product consisting of a 2XXX alloy in the T3X temper prepared by a hot working step, and at least one working step by cold plastic deformation after the hot working step, wherein at least two zones of said worked product have imposed generalized average plastic deformations, wherein the imposed deformations are different by at least 2%; wherein at least two zones Z 1 and Z 2 have mechanical properties wherein at least one of the following is satisfied
(i) the difference in the Rp 0.2 values measured in the L direction or in the LT direction R p 0.2(Z 1 )−R p 0.2(Z 2 ) is equal to at least 50 MPa
(ii) the difference in the Rm values measured in the L direction or in the LT direction R m (Z 1 )−R m (Z 2 ) is equal to at least 20 MPa
(iii) the difference K 1c measured in the L-T direction, K 1c (Z 1 )−K 1c (Z 2 ), is equal to at least 5 MPa√m; and
wherein the worked product consisting of a 2XXX alloy in the T3X temper is naturally aged.
3. Worked product consisting of a 2XXX alloy containing lithium in the T8X temper prepared by a hot working step, and at least one working step by cold plastic deformation after the hot working step, wherein at least two zones of said worked product have imposed generalized average plastic deformations, wherein the imposed deformations are different by at least 2%; wherein at least two zones Z 1 and Z 2 have mechanical properties selected from the group consisting of
(i) Z 1 : R m (L)>630 MPa and Z 2 : A(L)(%)>8%
(ii) Z 1 : R m (L)>640 MPa and Z 2 : A(L)(%)>7%
(iii) Z 1 : R m (L)>630 MPa and Z 2 K 1c (L-T)>25 MPa√m.
4. Structural elements made of a 2XXX alloy in the T3X temper comprising the worked product of claim 1 .
5. Structural element made of a 2XXX alloy in the T3X temper comprising the worked product of claim 2 .
6. Structural element made of a 2XXX alloy containing lithium in the T8X temper comprising the worked product of claim 3 .
7. Worked product according to claim 1 wherein
(i) Z 1 : R m (L)>520 MPa and Z 2 : A(L)(%)>18%
(ii) Z 1 : R m (L)>470 MPa and Z 2 : A(L)(%)>20%
(iii) Z 1 : R m (L)>590 MPa and Z 2 : A(L)(%)>14%
(iv) Z 1 : R m (L)>590 MPa and Z 2 : K 1c (L-T)>55 MPa√m.
8. Worked product according to claim 2
(i) the difference in the Rp 0.2 values measured in the L direction or in the LT direction R p 0.2(Z 1 )−R p 0.2(Z 2 ) is equal to at least 70 MPa
(ii) the difference in the Rm values measured in the L direction or in the LT direction R m (Z 1 )−R m (Z 2 ) is equal to at least 30 MPa
(iii) the difference K 1c measured in the L-T direction, K 1c (Z 1 )−K 1c (Z 2 ), is equal to at least 15 MPa√m.
9. Worked product according to claim 2 wherein
(i) Z 1 : R m (L)>630 MPa and Z 2 : A(L)(%)>8%
(ii) Z 1 : R m (L)>640 MPa and Z 2 : A(L)(%)>7%
(iii) Z 1 : R m (L)>630 MPa and Z 2 K 1c (L-T)>25 MPa√m.
10. Structural elements according to claim 4 wherein
(i) Z 1 : R m (L)>520 MPa and Z 2 : A(L)(%)>18%
(ii) Z 1 : R m (L)>470 MPa and Z 2 : A(L)(%)>20%
(iii) Z 1 : R m (L)>590 MPa and Z 2 : A(L)(%)>14%
(iv) Z 1 : R m (L)>590 MPa and Z 2 : K 1c (L-T)>55 MPa√m.
11. Structural element according to claim 5 wherein
(i) the difference in the Rp 0.2 values measured in the L direction or in the LT direction R p 0.2(Z 1 )−R p 0.2(Z 2 ) is equal to at least 70 MPa
(ii) the difference in the Rm values measured in the L direction or in the LT direction R m (Z 1 )−R m (Z 2 ) is equal to at least 30 MPa
(iii) the difference K 1c measured in the L-T direction, K 1c (Z 1 )−K 1c (Z 2 ), is equal to at least 15 MPa√m.
12. Structural element according to claim 6 wherein
(i) Z 1 : R m (L)>640 MPa and Z 2 : A(L)(%)>9%
(ii) Z 1 : R m (L)>650 MPa and Z 2 : A(L)(%)>8%
(iii) Z 1 : R m (L)>640 MPa and Z 2 : K 1c (L-T)>30 MPa√m.
13. Worked product according to claim 1 , wherein the imposed deformations are different by at least 3%.
14. Worked product according to claim 2 , wherein the imposed deformations are different by at least 3%.
15. Worked product according to claim 3 , wherein the imposed deformations are different by at least 3%.
16. Worked product according to claim 1 , wherein the 2XXX alloy comprises from about 3.81 to about 4.3 weight percent copper and from about 0.39 to about 1.36 weight percent magnesium.
17. Worked product according to claim 2 , wherein the 2XXX alloy comprises from about 3.81 to about 4.3 weight percent copper and from about 0.39 to about 1.36 weight percent magnesium.
18. Worked product according to claim 3 , wherein the 2XXX alloy comprises from about 3.81 to about 4.3 weight percent copper and from about 0.39 to about 1.36 weight percent magnesium.
19. Worked product according to claim 1 , wherein the 2XXX alloy comprises AA2195.