What does T6 in the designation 6061-T6 stand for?

In the designation 6061-T6, the "T6" refers to a specific heat treatment process that the aluminum alloy has undergone. The "T" indicates that the alloy has been thermally treated, while "6" specifies the particular treatment method, which involves solution heat treatment followed by aging. This process enhances the strength and hardness of the aluminum, making it suitable for various applications.