The 7040 T7651 aluminum alloy is an Al-Zn-Mg-Cu alloy specifically developed for applications requiring high strength and good corrosion resistance. Its chemical composition consists of approximately 5.7–6.7% zinc, 1.7–2.4% magnesium, 1.5–2.3% copper, with the remainder being aluminum. Additionally, very small amounts of silicon, chromium, manganese, and titanium or zirconium are added to the alloy. These additions stabilize the material's grain structure during heat treatment, preventing recrystallization and helping to preserve mechanical properties. Thanks to these characteristics, 7040 T7651 stands out as an alloy that provides high strength, especially in thick plates and structural components.

In terms of mechanical properties, 7040 T7651 typically offers a yield strength of 400 MPa and a tensile strength of 450 MPa. With an elongation of around 7%, it balances high hardness and toughness. The T7651 heat treatment condition optimizes the alloy's mechanical properties and ensures stable performance for thick plates. Because of these properties, it is particularly suitable for the aerospace sector, including aircraft wing spars, fuselage frames, and other large structural components.

Regarding machinability, 7040 T7651 performs well and can be processed using milling, turning, and other mechanical operations. However, its weldability is limited, as the high zinc and copper content increases the risk of cracking and microstructure degradation during welding. Formability is moderate; it is more suitable for thick and flat plate components rather than complex geometries. Therefore, the alloy is better suited for precision machined parts and large structural elements.

In terms of corrosion resistance, 7040 T7651 exhibits relatively high resistance among 7000 series alloys. Especially in thick plates and structural components, it provides stable performance against corrosion after heat treatment. However, in humid environments, stress-corrosion cracking and hydrogen embrittlement risks exist, so surface treatments or protective coatings are important. Considering all these properties, 7040 T7651 is a preferred alloy for aerospace, space, and defense industry applications that require high strength, good hardness, and reasonable corrosion resistance.
 

MATERIAL COMPOSITION STANDARDS

7040 T7651 is available in the following standards:
• 7040 T7651 Plate/Sheet; ISO AlZn6Mg2Cu2, UNS A97040, AIMS 03-02-023, ASTM B209
 

Characteristic Properties of 7040 T7651: 

• Strength: Excellent
• Machinability: Good
• Weldability: Poor
• Formability: Moderate
• Corrosion Resistance: High
• Heat Treatable: Yes
   

Some Well-Known Applications of 7040 T7651: 
In the aerospace industry,
In wing spars and connecting components,
Used in integrated main frames.
 

STOCK
7040 T7651 is available in sheet form.

• Sheet/Plate