High performance AlSiMgCu casting alloy

1. A cast aluminum part made from an aluminum casting alloy consisting of:

8. 5-9.5 wt. % silicon;

1. 35-2.0 wt. % copper (Cu);

0. 27-0.445 wt. % magnesium (Mg);

wherein the aluminum casting alloy includes copper and magnesium such that 4.7≤(Cu+10Mg) ≤5.8;

0 wt. % zinc;

up to 0.01 wt. % silver;

up to 1.0 wt. % nickel;

up to 1.0 wt. % hafnium;

0. 14-0.3 wt. % manganese

0.08-0.33 wt. % iron

0.05-0.12 wt. % titanium;

0. 08-0.19 wt. % zirconium;

0. 1-0.14 wt. % vanadium;

up to 0.10 wt. % of one or more of strontium, sodium and antimony;

other elements being ≤0.04 wt. % each and ≤0.12 wt. % in total; and the balance being aluminum;

wherein the cast aluminum part contains spherodized silicon particles;

wherein the cast aluminum part contains a sufficient amount of the Cu and the Mg to form Q phase precipitates;

wherein the cast aluminum part contains a sufficient amount of the Cu and the Mg such that the cast aluminum part is free of undissolved Q phase constituent particles;

wherein the amount of undissolved Q phase constituent particles is determined by using the following test method:

(a) heating the cast aluminum part to 10° C. below the solidus temperature of the cast aluminum part for at least 2 hours; and

(b) using SEM to view the microstructure of the cast aluminum part;

wherein, when cast in the form of an ASTM B108 tensile-bar casting, the aluminum casting alloy realizes:

(i) an ultimate tensile strength of from 450 to 480 MPa;

(ii) a first tensile yield strength of from 360 to 390 MPa;

(iii) an elongation of from 5 to 9%;

(iv) a quality index of from 560 to 610 MPa; and

(v) a second tensile yield strength of from 50.8 to 56.7 MPa;

wherein properties (i)-(iv) are tested at room temperature and after the ASTM B108 tensile-bar casting has been artificially aged at 155° C. for 15 to 60 hours; and

wherein property (v) is tested at 300° C. after the ASTM B108 tensile-bar casting has been exposed to a temperature of 300° C. for 500 hours.

2. The cast aluminum part of claim 1 , wherein the aluminum casting alloy includes copper and magnesium such that 5.0≤(Cu+10Mg)≤5.5.

3. The cast aluminum part of claim 1 , wherein the aluminum casting alloy includes copper and magnesium such that 5.1≤(Cu+10Mg)≤5.4.

4. The cast aluminum part of claim 1 , wherein the aluminum casting alloy includes 0.1-0.12 wt. % titanium.

5. The cast aluminum part of claim 4 , wherein the aluminum casting alloy includes 0.1-0.12 wt. % vanadium.

6. The cast aluminum part of claim 4 , wherein the aluminum casting alloy includes 0.11-0.13 wt. % zirconium.

7. The cast aluminum part of claim 1 , wherein the aluminum casting alloy includes 0 wt. % nickel.

8. The cast aluminum part of claim 7 , wherein the cast aluminum part is one of an engine block, a cylinder head, and a piston.

9. The cast aluminum part of claim 1 , wherein the cast aluminum part contains undissolved iron-containing particles.

10. The cast aluminum part of claim 1 , wherein the aluminum casting alloy includes at least 1.72 wt. % Cu.