	US 11,697,151 B2
	7XX aluminum casting alloys, and methods for making the same
Xinyan Yan, Murrysville, PA (US); Eider Simielli, Monroeville, PA (US); Jen C. Lin, Export, PA (US); Wenping Zhang, Murrysville, PA (US); and James Daniel Bryant, Murrysville, PA (US)
Assigned to ALCOA USA CORP., Pittsburgh, PA (US)
Filed by ALCOA USA CORP., Pittsburgh, PA (US)
Filed on Aug. 24, 2020, as Appl. No. 17/779.
Application 17/000,779 is a continuation of application No. 14/694,109, filed on Apr. 23, 2015.
Claims priority of provisional application 61/986,249, filed on Apr. 30, 2014.
Prior Publication US 2020/0384529 A1, Dec. 10, 2020
Int. Cl. B22D 21/04 (2006.01); C22C 21/10 (2006.01); C22F 1/053 (2006.01)

CPC B22D 21/04 (2013.01) [C22C 21/10 (2013.01); C22F 1/053 (2013.01)]

10 Claims

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

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.