7055 T74511

7055-T74511 is a high-strength wrought aluminum alloy known for its exceptional strength, commonly used in aerospace applications such as aircraft fuselage and wings.

Compared with older alloys such as 7075, 7055 T74511 offers excellent stress corrosion resistance. Typical applications include critical structural components requiring lightweight and durability.

The 7055-T74511 alloy features outstanding mechanical properties and corrosion resistance, making it a preferred material for aircraft structural components.

‌7055‌: Represents an aluminum-zinc-magnesium-copper alloy, belonging to the 7xxx series of wrought aluminum alloys. The numbering system follows international standards (the first digit 7 indicates Zn as the main alloying element, and the last three digits denote the sequence number).

‌T74511‌: Indicates the heat treatment temper, where:

• T7 indicates solution heat-treated then artificially overaged
• "45" may refer to specific cold working or aging parameters
• The final "1" may be a subclass code (such as surface treatment or special processing requirements)

7055 T74511 Specifications

The 7055 alloy is available in extruded forms such as rods, tubes, and profiles, with a maximum cross-sectional area of 24 square inches and a maximum diameter of 10.5 inches.

7055 T74511 Alloy Composition and Processing

7055-T74511 is an aluminum-zinc alloy with the following nominal chemical composition:

• Zinc (Zn): 8.0%
• Copper (Cu): 2.3%
• Magnesium (Mg): 2.0%
• Zirconium (Zr): 0.16%
• Aluminum (Al): Balance

The 74511 temper indicates that the alloy undergoes solution heat treatment, stress relief by stretching, followed by artificial overaging. This specialized tempering process enhances both the strength and corrosion resistance of the material.

7055 T74511 Mechanical Properties and Performance

7055-T74511 combines high tensile and compressive strength, excellent fracture toughness, and outstanding resistance to stress corrosion cracking (SCC) and exfoliation corrosion. These characteristics make it suitable for manufacturing critical aerospace components such as upper wing structures and fuselage frames.

Compared with older alloys such as 7075-T6511 and 7178-T6511, 7055-T74511 offers the following advantages:

• Higher strength
• Better corrosion resistance
• Greater damage tolerance
• Easier to form and heat treat

These improvements help extend the service life of aircraft structures and reduce maintenance costs.

7055 T74511 Key Characteristics

• ‌Ultra-high strength‌: Achieved through solution strengthening and precipitation hardening, the strength exceeds that of ordinary steels, making it suitable for primary load-bearing aerospace structures.
• ‌Machinability‌: Good plasticity after solution treatment; secondary aging is required after cold working to stabilize performance.
• ‌Corrosion resistance‌: Overaging treatment reduces stress corrosion sensitivity, though the welding performance is relatively poor.

7055 T74511 Applications

7055 T74511 is primarily used in aerospace industries where high strength and corrosion resistance are critical. Typical applications include:

• Aerospace: Aircraft wing spars, fuselage frames, landing gear components, and other primary load-bearing structures
• Precision Molds: Tooling fixtures requiring high wear resistance and dimensional stability
• Marine Equipment: Hull structures resistant to seawater corrosion
• Other critical structural components in military and commercial aircraft

7055 T74511 vs. 7075-T7451 Comparison

7075-T7451: A lower-cost alternative to 7055, with slightly lower strength but excellent machinability. Commonly used for aerospace fittings and gears.