7050-T7451 Aerospace Aluminum: High-Strength with SCC Resistance
ASTM B209 / AMS 4050 · Published: 2026-06-01 · Updated: 2026-06-02
7050-T7451 is an advanced Al-Zn-Mg-Cu-Zr alloy developed as a higher-toughness, stress-corrosion-cracking (SCC)-resistant alternative to 7075 for thick aerospace plate (75-150 mm). The T7451 temper (solution-treated, stress-relieved by...
7050-T7451 is an advanced Al-Zn-Mg-Cu-Zr alloy developed as a higher-toughness, stress-corrosion-cracking (SCC)-resistant alternative to 7075 for thick aerospace plate (75-150 mm). The T7451 temper (solution-treated, stress-relieved by stretching, and over-aged) provides approximately 10% lower strength than 7075-T651 but with dramatically improved SCC resistance in the short-transverse (through-thickness) direction—critical for thick-section structural parts. The zirconium addition (replacing chromium in 7075) reduces quench sensitivity, enabling uniform properties in sections up to 150 mm vs 7075's practical limit of approximately 80 mm. Standard material for Airbus A380 wing spars and Boeing 777 fuselage frames in thick sections. Not weldable; joined by fasteners or friction stir welding.
Quick Facts
| Category | Aluminum Alloy |
| Standard | ASTM B209 / AMS 4050 |
| Density | 2.83 g/cm³ |
| Yield Strength | 470 MPa (68 ksi) |
| Tensile Strength | 524 MPa (76 ksi) |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| EN AW-7050 | Compare |
| AlZn6CuMgZr | Compare |
| A7050 | Compare |
| AA7050-T7451 | Compare |
| 3.4344 | Compare |
Related Materials
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Frequently Asked Questions
7050 vs 7075: which to choose for aerospace?
For sections thinner than 50mm where SCC is not the primary concern: 7075-T6/T651 (higher strength, lower cost). For thick sections (50-150mm) requiring through-thickness SCC resistance: 7050-T7451 (mandatory above 80mm for most OEM specs). For maximum damage tolerance (fatigue crack growth): 2024-T351. For maximum strength with moderate SCC resistance: 7050-T7651 (peak-aged, higher strength than T7451).
References & International Standards
- ASTM International. Standard Specifications for Steel & Metal Alloys. astm.org
- International Organization for Standardization (ISO). Metallic Materials — Cross-Reference Database. iso.org
- American Iron and Steel Institute (AISI). Steel Grade Designations & Equivalents. steel.org
- European Committee for Standardization (CEN). EN Steel Standards & Numbering System. cencenelec.eu