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

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.