7XX aluminum casting alloys, and methods for making the same

Patent metadata

Field	Value
Publication number	US-11697151-B2
Application number	US-202017000779-A
Country	US
Kind code	B2
Filing date	Aug 24, 2020
Priority date	Apr 30, 2014
Publication date	Jul 11, 2023
Grant date	Jul 11, 2023

Abstract

New shape-cast 7xx aluminum alloys products are disclosed. The new shape-cast products may include from 3.0 to 8.0 wt. % Zn, from 1.0 to 3.0 wt. % Mg, where the wt. % Zn exceeds the wt. % Mg, from 0.35 to 1.0 wt. % Cu, where the wt. % Mg exceeds the wt. % Cu, from 0.05 to 0.30 wt. % V, from 0.01 to 1.0 wt. % of at least one secondary element (Mn, Cr, Zr, Ti, B, and combinations thereof), up to 0.50 wt. % Fe, and up to 0.25 wt. % Si, the balance being aluminum and other elements, wherein the aluminum casting alloy include not greater than 0.05 wt. % each of the other elements, and wherein the aluminum casting alloy includes not greater than 0.15 wt. % in total of the other elements.

First claim

What is claimed is:

1. A method comprising:
(a) shape casting a 7xx aluminum casting alloy into a shape-cast part, wherein the 7xx casting alloy consists of:
(i) from 3.0 to 8.0 wt. % Zn;
(ii) from 1.0 to 3.0 wt. % Mg;
wherein the wt. % Zn exceeds the wt. % Mg;

(iii) from 0.35 to 1.0 wt. % Cu;
wherein the wt. % Mg exceeds the wt. % Cu;

(iv) from 0.05 to 0.30 wt. % V;
(v) from 0.01 to 1.0 wt. % of at least one secondary element, wherein the at least one secondary element is selected from the group consisting of Mn, Cr, Zr, Ti, B, and combinations thereof;
wherein, when present, the aluminum casting alloy includes not greater than 0.50 wt. % Mn as a secondary element;
wherein, when present, the aluminum casting alloy includes not greater than 0.40 wt. % Cr as a secondary element;
wherein, when present, the aluminum casting alloy includes not greater than 0.25 wt. % Zr as a secondary element;
wherein, when present, the aluminum casting alloy includes not greater than 0.25 wt. % Ti as a secondary element;
wherein, when present, the aluminum casting alloy includes not greater than 0.05 wt. % B as a secondary element;

(vi) up to 0.50 wt. % Fe
(vii) up to 0.25 wt. % Si; and
(viii) the balance being aluminum and other elements, wherein the aluminum casting alloy includes not greater than 0.05 wt. % each of the other elements, and wherein the aluminum casting alloy includes not greater than 0.15 wt. % in total of the other elements;

wherein the shape casting process is selected from the group consisting of low pressure die casting, gravity permanent mold casting, semi-permanent mold casting, sand mold casting and centrifugal casting;
(b) solution heat treating and then quenching the shape-cast part; and
(c) artificially aging the shape-cast part to a T6 or T7 temper:

wherein the shape-cast part is stress corrosion cracking (SCC) resistant being capable of passing SCC testing in accordance with ASTM G109-97(2011), wherein the SCC testing is conducted at a net stress of 240 MPa for 14 days, wherein 5 specimens are tested, and wherein all 5 specimens do not fail during the 14 days of testing.

2. The method of claim 1 , wherein the shape casting process is low pressure die casting.

3. The method of claim 1 , wherein the 7xx casting alloy includes not greater than 0.20 wt. % V.

4. The method of claim 1 , wherein the 7xx casting alloy includes not greater than 0.18 wt. % V.

5. The method of claim 1 , wherein the 7xx casting alloy includes not greater than 0.16 wt. % V.

6. The method of claim 1 , wherein the 7xx casting alloy includes not greater than 0.14 wt. % V.

7. The method of claim 1 , wherein the 7xx casting alloy includes at least 0.07 wt. % V.

8. The method of claim 1 , wherein the 7xx casting alloy includes at least 0.09 wt. % V.

9. The method of claim 1 , wherein the shape-cast part is an automobile part.

10. The method of claim 9 , wherein the automotive part is a body-in-white (BIW) part or a suspension part.

Assignees

• Alcoa Usa Corp

Inventors

• Yan Xinyan
• Simielli Eider
• Lin Jen C
• Zhang Wenping
• Bryant James Daniel

Classifications

• B22D21/04 Primary

  Casting aluminium or magnesium {(no material; see B22D21/007)} · CPC title

• C22F1/053

  of alloys with zinc as the next major constituent · CPC title

• C22C21/10 Primary

  with zinc as the next major constituent · CPC title