Sheet and clad sheet
Skins and formed parts. Alclad sheet carries a thin pure-aluminium layer on each face for corrosion protection; specify bare or clad explicitly.
Guide
Aerospace Aluminium: Material Requirements Guide
For aircraft parts the alloy number is only the starting point. What makes material acceptable is the controlling drawing, the material specification (usually SAE AMS), the exact temper and product form, and documented traceability from the mill to the part. This guide explains how aerospace aluminium is specified, which alloys are used where, and what evidence a buyer should expect with every delivery.
Four rules of aerospace material buying
- The drawing governsThe approved engineering drawing names the material specification, temper, any cladding and special processes. A "equivalent" grade is not acceptable without engineering approval, however close its properties look.
- Design to allowables, not typical valuesStructural design uses statistically based allowables (for example from MMPDS or company data). Typical values in catalogues are not design values.
- Traceability is part of the productEach piece must be traceable to its heat or lot and the certificate that reports its chemistry and properties. Lose the trace and the material becomes scrap for flight use.
- Temper and form are specific7075-T6 sheet, 7075-T651 plate and 7075-T7351 plate are different products under different specifications, with different strength and stress-corrosion behaviour.
Common aerospace aluminium alloys and where they are used
| Alloy and temper | Typical tensile / yield (MPa) | Key property | Typical parts |
|---|---|---|---|
| 2024-T3 / T351 | 483 / 345 (sheet, typical) | Damage tolerance and fatigue resistance | Fuselage skins, lower wing skins, tension-dominated structure |
| 7075-T6 / T651 | 572 / 503 (typical) | Very high static strength | Highly loaded fittings, upper wing structure, machined parts |
| 7075-T73 / T7351 | 505 / 435 (typical) | Strength with much better stress-corrosion resistance | Forgings and thick-plate parts exposed to sustained stress |
| 7050-T7451 | about 524 / 469 (thick plate, typical) | Strength and toughness in thick sections, good SCC resistance | Bulkheads, wing spars, frames machined from plate |
| 6061-T6 / T651 | 310 / 276 (typical) | Weldable, corrosion resistant, economical | Secondary structure, ducting, ground equipment |
| 2219-T87 / T851 | about 476 / 393 (typical) | Weldable, good at cryogenic and elevated temperature | Launch-vehicle tanks, high-temperature parts |
| Al-Li (2050, 2195, 2099, 2196) | Varies by product | Lower density, higher stiffness | Modern fuselage, wing and tank structures |
Typical values from ASM and Aluminum Association data, for orientation only. Use the minimums in the governing AMS specification or the approved allowables for design.
AMS and related specifications you will meet
| Specification | Covers |
|---|---|
| AMS 4037 | 2024 sheet and plate, T3 / T351 |
| AMS 4041 | Alclad 2024 sheet and plate, T3 / T351 |
| AMS 4045 | 7075 sheet and plate, T6 / T651 |
| AMS 4078 | 7075 plate, T7351 |
| AMS 4050 | 7050 plate, T7451 |
| AMS 4027 | 6061 sheet and plate, T6 / T651 |
| AMS-QQ-A-250 series | Aluminium alloy plate and sheet (successor to the old federal QQ-A-250 specifications) |
| AMS 2772 / AMS 2770 | Heat treatment of aluminium alloy raw materials and of parts |
| AMS-STD-2154 | Ultrasonic inspection of wrought metals |
| AMS 2658 | Hardness and conductivity verification of heat-treated aluminium |
European programmes may call up EN 4000-series aerospace standards or prime-contractor specifications instead. In every case the purchase order should quote the specification and its revision exactly as the drawing does.
Choosing the product form
Plate
Machined structure. Stress-relieved tempers (T351, T651, T7351, T7451) keep plate stable during heavy machining; thick plate requires ultrasonic inspection.
Extrusions
Stringers, floor beams and seat tracks. Tempers such as T3511 and T6511 are stretched and straightened.
Forgings
Highly loaded fittings, landing-gear and engine-mount parts where grain flow matters. Usually 7075-T73, 7050-T74 or 2014-T6.
Bar, rod and wire
Machined fittings, fasteners and rivets; rivet wire is a specialised product with its own specifications.
Honeycomb core
Lightweight sandwich panels for floors, control surfaces and interiors.
What should arrive with aerospace material
- Mill certificate (EN 10204 3.1 or equivalent) stating specification and revision, alloy, temper, dimensions, heat or lot number, chemistry and tensile results
- Heat-treatment and inspection records where the specification requires them, such as ultrasonic class for plate
- Unbroken traceability: each cut piece marked so it can be linked back to the certificate
- Certificate of conformity from the distributor if material was cut or processed after the mill
- Any customer-specific flow-down requirements, for example approved-source lists, export-control notes or first-article documents
Buyers working under AS9100 quality systems normally require suppliers to flow down these requirements and to preserve original mill documents. Ask for them at quotation stage, not after delivery.
Common mistakes when buying aerospace aluminium
- Ordering by alloy alone ("7075") without temper, form and specification
- Substituting T6 for T73 or T7351 to save cost, which removes the stress-corrosion margin the designer relied on
- Treating commercial plate certified to ASTM B209 as equivalent to AMS-certified plate
- Cutting plate without transferring the heat number to each piece
- Ignoring grain direction: plate and extrusion properties differ in the longitudinal, long-transverse and short-transverse directions
- Assuming any joining method works: 2024 and 7075 are not fusion-welded in structure, and friction stir welding needs qualified procedures and tooling
References and standards
- SAE AMS 4045 – Aluminum Alloy Sheet and Plate 7075-T6 / T651
- SAE AMS 4027 – Aluminum Alloy Sheet and Plate 6061-T6 / T651
- MMPDS – Metallic Materials Properties Development and Standardization
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
- ASM Handbook, Vol. 2 – Properties and Selection: Nonferrous Alloys
Aerospace aluminium (aluminum) requirements: FAQs
Is 6061 an aerospace alloy?
Yes, for secondary structure, ducting, fittings and ground equipment, usually to AMS 4027 or AMS-QQ-A-250/11. Primary structure normally uses 2xxx and 7xxx alloys for their higher strength and fatigue performance.
What is the difference between 7075-T6 and 7075-T73?
T73 is over-aged. It gives up roughly 10 – 15 % of strength in exchange for far better resistance to stress-corrosion cracking and exfoliation, which is why it is specified for forgings and parts under sustained stress.
Can commercial-grade plate be used for aircraft parts?
Only if the drawing permits it. Flight hardware almost always requires material certified to the specified AMS or prime specification with full traceability.
Why does thick plate need ultrasonic inspection?
Internal discontinuities in thick plate can become fatigue initiation sites in machined parts. AMS-STD-2154 defines the inspection classes that the material specification calls up.
What does "Alclad" mean?
A high-strength core alloy such as 2024 or 7075 roll-bonded with thin layers of pure or low-alloy aluminium that protect the core sacrificially against corrosion.
Sourcing aerospace aluminium?
Send the drawing callout, specification, temper, sizes and quantity. We will confirm certification and traceability before quoting.
