7055 T7751

"7055-T7751" refers to a specific high-strength aluminum alloy and its tempering process, primarily used in aerospace applications and often employed in high-performance scenarios.

7055-T7751 belongs to the 7xxx series (aluminum-zinc-magnesium-copper system) of wrought aluminum alloys, specially designed for aerospace structural components.

7055 aluminum alloy is a heat-treatable wrought alloy with zinc as the primary alloying element, offering high strength. The T7751 temper indicates a specific sequence of heat treatment and mechanical processing:

T7: Indicates that the alloy has undergone solution heat treatment and over-aging/stabilization. This process enhances stress corrosion resistance and dimensional stability but sacrifices peak strength.
75: Indicates stress relief through stretching.
751/7751: Additional digits represent further processing techniques:
Stress relief: May involve post-heat-treatment stretching or compressing to reduce residual stress (common in thick plates or forgings).

7055 T7751 Properties

Corrosion resistance: Due to the T7 temper, this alloy shows improved performance over earlier 7xxx series alloys, reducing susceptibility to stress corrosion cracking.
Fatigue resistance: Well-suited for cyclic loading environments (e.g., aircraft wings).
High strength: 7055 is one of the strongest aluminum alloys, with tensile strength exceeding that of 7075-T6 (a widely used aerospace alloy).
Zinc content: Compared to 7075, 7055 has a higher zinc content (around 8%), which contributes to its superior strength.
Applications: Mainly used in aerospace (e.g., aircraft fuselage, wing components), military equipment, and high-stress structural parts.

7055 T7751 Composition and Heat Treatment

‌Alloy composition‌: 7055 is one of the most highly alloyed members of the 7xxx series, with zinc, magnesium, and copper as its main alloying elements. Its zinc content exceeds 8%, and precise aging treatments are employed to achieve high strength.
‌Heat treatment state‌: T7751 indicates that the material has undergone solution heat treatment, followed by pre-stretching (approximately 1–3% elongation), and then dual-stage artificial aging (T77 condition). This process significantly reduces residual stress and enhances overall performance.

7055 T7751 Key Performance

Ultimate tensile strength: approximately 593 MPa.
Yield strength: between 480–510 MPa.
Density: 2.86 g/cm³.
Elongation at break: 9–12%.
Fracture toughness: 24.2 MPa·√m.

Compared to other alloys such as 7075-T651, 7055-T7751 offers around 5% higher strength, making it more suitable for high-load applications.

7055 T7751 Aerospace Applications

7055-T7751 is widely used in aerospace structures where a high strength-to-weight ratio is critical:

Wing structures: upper wing skins and spars.
Fuselage components: frames and bulkheads.
Landing gear: struts and support structures.
Engine housings: covers and brackets.

Aerospace: Key structural components in commercial and military aircraft (such as Boeing 777 and Airbus A380).

Other Applications of 7055 T7751

Defense: missile components, armored vehicles.
Automotive: high-performance racing components.
‌Precision manufacturing‌: formed thin sheets via age-relaxation forming processes to reduce springback, suitable for complex curved parts.

Its high strength and corrosion resistance make it an ideal choice for load-bearing structures.

Advantages of 7055 T7751

High strength: Higher tensile and yield strength compared to many other aluminum alloys.
Corrosion resistance: Improved resistance to stress corrosion cracking.
Lightweight: Lower density helps reduce overall aircraft weight.
Good machinability: Suitable for various manufacturing processes.

Comparison of 7055 T7751 with Other Tempers

T6 vs. T7: T6 offers higher peak strength, while T7 sacrifices some strength for better corrosion resistance and stability.
T7751 vs. T73: Both offer similar stress corrosion resistance, but T7751 may feature tailored performance for specific manufacturing needs.

7055-T7751 is a premium aluminum alloy optimized for environments requiring extremely high strength, durability, and corrosion resistance. Its unique toughness makes it a top choice for advanced aerospace and defense applications.

7055-T7751 aluminum alloy is specifically engineered to meet the rigorous demands of the aerospace industry, achieving a balance between strength, durability, and weight efficiency.