7050-T7451 (AMS 4050)
Solution treated, stretched and over-aged. The default for thick machined airframe parts: high strength with very good resistance to stress corrosion cracking in the short-transverse direction.
Thick-section aerospace plate
7050 Aluminium Plate
7050 is a high-strength Al-Zn-Mg-Cu alloy developed for thick aerospace plate. Its zirconium-based grain control makes it far less quench-sensitive than 7075, so thick plate keeps high strength through the section, while the over-aged T7451 and T7651 tempers give good resistance to stress corrosion and exfoliation. Metline supplies 7050 plate to AMS and ASTM specifications, with full certification, worldwide.
- Alloy
- 7050 (Al-Zn-Mg-Cu-Zr)
- Tempers
- T7451, T7651
- Specs
- AMS 4050 · AMS 4201 · ASTM B209
- Thickness
- 6 – 200 mm
What is 7050 aluminium plate?
7050 was developed to overcome the main weakness of 7075 in thick sections. 7075 uses chromium for grain control, which makes it quench-sensitive: the centre of a thick plate cools too slowly and loses strength. 7050 replaces chromium with zirconium and raises copper and zinc, so it keeps strength, toughness and stress-corrosion resistance through plates more than 150 mm thick.
This makes 7050-T7451 the standard plate for large machined airframe parts: wing spars and ribs, bulkheads, fuselage frames and landing-gear support structure, where a part is hogged out of a thick plate and most of the metal ends up as chips. It is also used in high-end tooling and moulds where 7075 thick plate would be soft in the middle.
7050 chemical composition (wt %)
| Element | Minimum | Maximum |
|---|---|---|
| Zinc (Zn) | 5.7 | 6.7 |
| Magnesium (Mg) | 1.9 | 2.6 |
| Copper (Cu) | 2.0 | 2.6 |
| Zirconium (Zr) | 0.08 | 0.15 |
| Silicon (Si) | — | 0.12 |
| Iron (Fe) | — | 0.15 |
| Manganese (Mn) | — | 0.10 |
| Chromium (Cr) | — | 0.04 |
| Titanium (Ti) | — | 0.06 |
| Others, each / total | — | 0.05 / 0.15 |
| Aluminium (Al) | Remainder |
Low iron and silicon limits improve fracture toughness and fatigue performance.
7050 mechanical and physical properties
Typical longitudinal values for comparison. Specified minimums in AMS 4050 and AMS 4201 depend on thickness and test direction, and short-transverse values are lower; design to the specification or MMPDS allowables.
| Temper | Tensile strength | Yield strength (0.2 %) | Elongation | Character |
|---|---|---|---|---|
| T7451 | about 524 MPa | about 469 MPa | about 11 % | Best stress-corrosion and toughness balance |
| T7651 | about 552 MPa | about 490 MPa | about 10 % | Higher strength, good exfoliation resistance |
Physical properties
- Density
- 2.83 g/cm³
- Modulus of elasticity
- about 71.7 GPa
- Thermal conductivity
- about 155 W/m·K (T74 tempers)
- Coefficient of thermal expansion
- about 23.5 µm/m·°C
- Melting range
- about 490 – 630 °C
7050 tempers and specifications
7050-T7651 (AMS 4201)
Stretched and aged to a higher-strength over-aged condition with good exfoliation resistance. Often used for thinner plate and wing skins.
ASTM B209 / EN
Commercial 7050 plate to ASTM B209 or EN 485 (EN AW-7050) for tooling and industrial use where AMS certification is not needed.
| System | Designation |
|---|---|
| UNS | A97050 |
| EN | EN AW-7050 (AlZn6CuMgZr) |
| Werkstoff | 3.4144 |
| Aerospace plate | AMS 4050 (T7451), AMS 4201 (T7651) |
7050 plate sizes and weights
Supply range
- Thickness
- 6 – 200 mm (0.25 – 8 in)
- Width × length
- Up to about 1500 – 2500 mm wide; full plates or cut blocks
- Processing
- Saw-cut blocks and blanks to drawing
- Inspection
- Ultrasonic testing to AMS-STD-2154 class as specified
| Thickness (mm) | kg per m² | 1250 × 2500 mm (kg) | 1500 × 3000 mm (kg) |
|---|---|---|---|
| 6 | 16.98 | 53.1 | 76.4 |
| 10 | 28.30 | 88.4 | 127.4 |
| 12 | 33.96 | 106.1 | 152.8 |
| 16 | 45.28 | 141.5 | 203.8 |
| 20 | 56.60 | 176.9 | 254.7 |
| 25 | 70.75 | 221.1 | 318.4 |
| 30 | 84.90 | 265.3 | 382.1 |
| 40 | 113.20 | 353.8 | 509.4 |
| 50 | 141.50 | 442.2 | 636.8 |
| 60 | 169.80 | 530.6 | 764.1 |
| 80 | 226.40 | 707.5 | 1018.8 |
| 100 | 283.00 | 884.4 | 1273.5 |
| 125 | 353.75 | 1105.5 | 1591.9 |
| 150 | 424.50 | 1326.6 | 1910.2 |
Machining and processing
Machining
Excellent. Stretched tempers keep distortion low even when 90 % of the plate is removed. Use high-speed machining with sharp carbide and balanced roughing on both faces.
Welding
Not fusion-weldable for structural use; join by fastening. Friction-stir welding is used in some aerospace applications.
Corrosion
T74 tempers resist stress corrosion and exfoliation far better than 7075-T6. Protect with anodising, conversion coating and primer as for other aerospace alloys.
Temperature
Avoid service above about 120 °C, which over-ages the alloy further and lowers strength.
Where 7050 plate is used
- Airframes: wing spars, ribs, bulkheads, fuselage frames and stringers machined from thick plate
- Landing gear and support structure: fittings and supports
- Defence: high-strength machined structural parts
- Tooling: large moulds and fixtures that need uniform hardness through thickness
7050 vs 7075 and 7150
| Property | 7075-T7351 | 7050-T7451 | 7150-T7751 |
|---|---|---|---|
| Typical tensile strength | 505 MPa | 524 MPa | about 600 MPa |
| Thick-section strength | Falls off | Retained | Retained |
| Stress-corrosion resistance | Very good | Very good | Good |
| Typical use | Fittings, thinner plate | Thick machined parts | Compression-loaded wing structure |
Read more in 7075 vs 7050.
How to order 7050 plate
- SpecifyAlloy and temper (for example 7050-T7451 to AMS 4050), thickness, width and length or a drawing, quantity, and the governing standard (AMS 4050, AMS 4201 or ASTM B209).
- QuoteWe confirm availability, tolerances, certification and delivery terms (EXW, FOB, CIF or DAP) for your destination.
- ProcessPlate is saw-cut or waterjet-cut to size where required, film-protected on request and inspected for dimensions and surface.
- DocumentEach shipment carries a mill test certificate to EN 10204 3.1 with chemistry and mechanical results, plus the packing list; third-party inspection can be arranged.
- ShipSeaworthy wooden cases or fumigated pallets, dispatched by sea or air to your port or door.
References and standards
- SAE AMS 4050 – Aluminum Alloy Plate, 7050-T7451
- SAE AMS 4201 – Aluminum Alloy Plate, 7050-T7651
- ASTM B209 – Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
- MMPDS – Metallic Materials Properties Development and Standardization
7050 aluminium (aluminum) plate: FAQ
What is the difference between 7050-T7451 and T7651?
Both are stretched and over-aged. T7451 is aged further for maximum stress-corrosion resistance and toughness; T7651 has higher strength with good exfoliation resistance.
Why use 7050 instead of 7075 for thick plate?
7050 is much less quench-sensitive, so thick plate keeps its strength and toughness through the section. 7075 loses strength in the centre of thick plate.
Can 7050 be welded?
Not by conventional fusion welding for structural parts. It is joined mechanically; friction-stir welding is used in some specialised applications.
What does 7050 plate weigh?
2.83 kg per m² per millimetre. A 50 mm plate weighs about 141.5 kg per m².
Do you supply 7050 to AMS specifications?
Yes. We supply 7050 to AMS 4050, AMS 4201 or ASTM B209 with EN 10204 3.1 certificates, and ultrasonic testing on request.
Need 7050 plate?
Send the temper, thickness, size, quantity and specification. We will confirm availability, certification and a delivered price.
