Impact toughness and heat treatment for cast aluminum
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorJonathan A Lee
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Abstract
A method for transforming a cast component made of modified aluminum alloy by increasing the impact toughness coefficient using minimal heat and energy. The aluminum alloy is modified to contain 0.55%-0.60% magnesium, 0.10%-0.15% titanium or zirconium, less than 0.07% iron, a silicon-to-magnesium product ratio of 4.0, and less than 0.15% total impurities. The shortened heat treatment requires an initial heating at 1,000° F. for up to 1 hour followed by a water quench and a second heating at 350° F. to 390° F. for up to 1 hour. An optional short bake paint cycle or powder coating process further increases the impact toughness coefficient of the cast component.
Claims11
A method for transforming the impact toughness coefficient of an aluminum component consisting essentially of the steps of:
- casting a cast component from a modified aluminum alloy using a low pressure permanent mold (LPPM) casting process,
- wherein said modified aluminum alloy consists essentially of up to 0.20% copper, up to 0.10% manganese, less than 0.12% iron, up to 0.10% zinc, up to 0.90% magnesium by weight, up to 0.20% titanium by weight, silicon and a balance of aluminum,
- wherein said modified aluminum alloy contains a silicon-to-magnesium product ratio R of 4.0, wherein R is determined using the formula R=M×S, wherein M is a percentage of Magnesium in said modified aluminum alloy and S is a percentage of Silicon in said modified aluminum alloy;
- heating said cast component at a solution treatment temperature for up to one hour;
- cooling said cast component by quenching;
- heating said cast component at a second temperature for up to one hour;
- and
- cooling said cast component.
Dependencies are inferred from the claim text.