Thin sheets made of an aluminium-magnesium-scandium alloy for aerospace applications
Abstract
The invention relates to a method for producing a wrought product made of an aluminum alloy composed, in wt %, of Mg: 3.8-4.2; Mn: 0.3-0.8 and preferably 0.5-0.7; Sc: 0.1-0.3; Zn: 0.1-0.4; Ti: 0.01-0.05; Zr: 0.07-0.15; Cr: <0.01; Fe: <0.15; Si<0.1; wherein the homogenization is carried out at a temperature of between 370° C. and 450° C., for between 2 and 50 hours, such that the equivalent time at 400° C. is between 5 and 100 hours, and the hot deformation is carried out at an initial temperature of between 350° C. and 450° C. The invention also relates to hot-worked products obtained by the method according to the invention, in particular sheets with a thickness of less than 12 mm. The products according to the invention are advantageous as they offer a better compromise in terms of mechanical strength, toughness and hot-formability.
Claims
exact text as granted — not AI-modified1 . A method for producing a wrought product made of an aluminum alloy comprising:
a) producing a molten metal bath having an aluminum base, comprising, in wt %,
Mg: 3.8-4.2;
Mn: 0.3-0.8;
Sc: 0.1-0.3;
Zn: 0.1-0.4;
Ti: 0.01-0.05;
Zr: 0.07-0.15;
Cr: <0.01;
Fe: <0.15;
Si<0.1;
other elements ≤0.03 each and ≤0.10 combined, the remainder being aluminum;
b) casting an unwrought product from said metal bath; c) homogenizing said unwrought product at a temperature that lies in a range of from 370° C. to 450° C., for a duration that lies in a range of from 2 to 50 hours such that the equivalent time at 400° C. lies in a range of from 5 to 100 hours,
the equivalent time t(eq) at 400° C. being defined by formula:
t
(
eq
)
=
∫
exp
(
-
2
9
1
2
2
/
T
)
d
t
exp
(
-
2
9
1
2
2
/
T
ref
)
where T is the current temperature expressed in Kelvin, which changes over time t (in hours) and T ref is a reference temperature of 400° C. (673 K), t(eq) being expressed in hours, the constant Q/R=29122 K being derived from the activation energy for the diffusion of Zr, Q=242000 J/mol,
d) hot-working the unwrought product thus homogenized with an initial temperature in a range of from 350° C. to 450° C. and is optionally cold-worked;
e) a flattening and/or straightening process is optionally carried out;
f) an annealing process is carried out at a temperature that lies in a range of from 300° C. to 350° C.
2 . The method according to claim 1 , wherein the homogenization duration lies in a range of from 5 to 30 hours.
3 . The method according to claim 1 , wherein working is carried out by rolling in order to obtain a sheet and wherein a final thickness of the sheet obtained is less than 12 mm.
4 . The method according to claim 1 , wherein working is carried out by extrusion in order to obtain a profile.
5 . The method according to claim 1 , wherein at the end of f), forming is carried out at a temperature that lies in a range of from 300° C. to 350° C.
6 . The method of claim 1 , wherein in a), the aluminum base comprises, in wt %,
Mg: 3.8-4.2; Mn: 0.5-0.7; Sc: 0.1-0.3; Zn: 0.1-0.4; Ti: 0.015-0.030; Zr: 0.08-0.12; Cr: <0.01; Fe: <0.15; Si<0.1; other elements ≤0.03 and ≤0.10 combined, the remainder being aluminum.
7 . The method of claim 1 , wherein in c), the equivalent time at 400° C. is in a range of from 6 to 30 hours.Join the waitlist — get patent alerts
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