FAA Aviation Mechanic Airframe (AMA)Airframe StructuresMedium
A technician reviews a maintenance manual specifying replacement of a skin panel with 2024-T3 aluminum alloy. What does the 'T3' temper designation indicate about this material?
- AAs fabricated with no thermal treatment applied
- BAnnealed and fully softened for maximum formability
- CSolution heat treated and then cold worked
- DSolution heat treated and artificially aged
Show answer & explanationAnswer & explanation
Correct answer: C. Solution heat treated and then cold worked
The T3 temper means the aluminum alloy was solution heat treated and then strain-hardened (cold worked), such as by stretching, which increases strength. T4 would indicate solution heat treatment followed only by natural aging without cold work, and T6 indicates artificial aging after solution heat treatment.
Why the other options are wrong
- A. 'As fabricated' with no treatment is the F temper designation.
- B. Annealed material is designated 'O', not T3.
- D. Artificial aging after solution treatment is the T6 temper, not T3.
Aluminum Temper Designations
A letter-number code following the alloy number that describes the heat treatment and/or mechanical working applied to aluminum sheet.
- O = annealed (softest)
- T3 = solution heat treated + cold worked
- T4 = solution heat treated + naturally aged
- T6 = solution heat treated + artificially aged
Memory trick: 'T3, Three steps: Treat, then Twist (cold work).'