High crashworthiness Al-Si-Mg alloy and methods for producing automotive casting
View Patent ↗The present invention provides a casting having increased crashworthiness including an aluminum alloy of about 6.0 wt % to about 8.0 wt % Si; about 0.12 wt % to about 0.25 wt % Mg; less than or equal to about 0.35 wt % Cu; less than or equal to about 4.0 wt % Zn; less than or equal to about 0.6 wt % Mn; and less than or equal to about 0.15 wt % Fe, wherein the cast body is treated to a T5 or T6 temper and has a tensile strength ranging from 100 MPa to 180 MPa and has a critical fracture strain greater than 10%. The present invention further provides a method of forming a casting having increased crashworthiness.
1. An Al—Si—Mg alloy composition used to produce a cast product having a critical fracture strain of at least about 10%, the alloy comprising:
about 6.0 wt % to about 7.8 wt % Si;
about 0.10 wt % to about 0.18 wt % Mg;
less than or equal to about 0.35 wt % Cu;
less than or equal to about 0.6 wt % Mn;
less than or equal to about 0.15 wt % Fe;
and a balance of aluminum and impurities; wherein, the composition is capable of producing a cast product having a critical fracture strain of at least about 10% and a tensile yield strength of at least 100 MPa when
the composition undergoes a heat treating process that includes solution heating, quenching, and aging at aging times of less than about 10 hours.
2. The alloy of claim 1 , further comprising at least one silicon modifier in an amount less than or equal to 0.02 wt %, wherein the modifier comprises Ca, Na, Sr, Sb or a combination thereof.
3. The alloy of claim 1 , further comprising a grain refiner in an amount less than or equal to 0.1 wt %, wherein said at least one grain refiner comprises TiB 2 or TiC.
4. The alloy of claim 1 , wherein the Mn content is less than about 0.05 wt % Mn.
5. The alloy of claim 1 , wherein the critical fracture strain of the heat treated alloy composition exceeds 10%, the yield tensile strength exceeds 100 MPa, and the heat treatment process comprises T6 or T7 to further provide an elongation that exceeds 14%.
6. The alloy of claim 1 having about 7.0 wt % Si and from about 0.10 wt % to about 0.18 wt % Mg.
7. The alloy of claim 1 having about 0.12 wt % Mg and from about 6.0 wt % to about 7.8 wt % Si.
8. An Al—Si—Mg casting having a critical fracture strain and tensile yield strength, the casting comprising:
a cast body of an alloy composition comprising:
about 6.0 wt % to about 7.8 wt % Si;
about 0.10 wt % to about 0.18 wt % Mg;
less than or equal to about 0.35 wt % Cu;
less than or equal to about 0.6 wt % Mn;
less than or equal to about 0.15 wt % Fe;
and a balance of aluminum and impurities; wherein, the casting has a critical fracture strain of at least about 10% and a tensile yield strength of at least 100 MPa when
the composition has undergone a heat treating process that includes solution heating, quenching, and aging.
9. The casting of claim 8 , wherein the cast body is in a T6 temper and has a tensile yield strength ranging from 100 MPa to 180 MPa.
10. The casting of claim 8 , wherein the cast body has an elongation of 14% or greater.
11. The casting of claim 8 wherein the alloy composition further comprises at least one Si modifier present in an amount less than or equal to 0.02 wt %, wherein the at least one Si modifier comprises Ca, Na, Sr, Sb or a combination thereof.
12. The casting of claim 8 wherein the alloy composition further comprises at least one grain refiner present in an amount less than or equal to 0.1 wt %, wherein the at least one grain refiner is selected from the group consisting of Ti, B and C.
13. The casting of claim 8 wherein the heat treating includes aging times of less than about 10 hours.
14. The casting of claim 8 having about 7.0 wt % Si and from about 0.10 wt % to about 0.18 wt % Mg.
15. The casting of claim 8 having about 0.12 wt % Mg and from about 6.0 wt % to about 7.8 wt % Si.
16. The casting of claim 8 , wherein the critical fracture strain of the heat treated alloy composition is greater than 10%, the yield tensile strength exceeds 100 MPa, and the heat treatment process comprises T6 or T7 to further provide an elongation that exceeds 14%.