The heat treatments applied to aluminum alloys can be carried out in various ways, and the applied process is indicated by the TX symbols next to the alloy number. These processes are expressed as follows:

• O: Annealed
• F: As fabricated
• H: Hardened
• T: Thermally treated

Here are the specific treatments under the T category:

• T1: After hot working, cooled and left to naturally age.
• T2: After hot working, cooled, cold worked, and left to naturally age.
• T3: Solution heat-treated, cold worked, and left to naturally age.
• T4: Solution heat-treated and left to naturally age.
• T5: After hot working, cooled, and artificially aged.
• T6: Solution heat-treated and artificially aged.
• T7: Solution heat-treated and over-aged.
• T8: Solution heat-treated, cold worked, and artificially aged.
• T9: Solution heat-treated, artificially aged, and cold worked.
• T10: After hot working, cooled, cold worked, and artificially aged.