Aluminium ENAW-7075 Plates & Sheets (7075-O, 7075-T6, T651)

Product Description

EN AW-7075 (AlZn5.5MgCu) is the "super-strength" grade of the aluminum world. Primarily used in aerospace and high-end engineering, it provides a strength profile comparable to many steels while remaining lightweight.

The mechanical performance of 7075 is entirely dependent on its temper (heat treatment).

1. Comparing Tempers: O, T6, and T651

Choosing the right temper is critical for the success of your fabrication process.

2. Mechanical Properties (Typical for T6/T651)

7075 is specifically engineered for high-stress environments where weight must be minimized.

• Tensile Strength ($R_m$): 540 “ 600 MPa

• Yield Strength ($R_{p0.2}$): 480 “ 540 MPa

• Hardness (Brinell): 150 HBW

• Modulus of Elasticity: 71 GPa

• Fatigue Strength: Excellent, though sensitive to surface notches.

3. Plate vs. Sheet Applications

7075 Sheets (0.5mm “ 6mm)

• Fuselage & Wing Skins: High tensile loads require the extreme strength of 7075.

• Alclad Versions: Since 7075 has poor corrosion resistance (due to Zinc and Copper), sheets are often "Clad" with a thin layer of pure aluminum to provide a sacrificial barrier against oxidation.

7075 Plates & Blocks (> 6mm)

• Tooling & Mold Making: Used for high-pressure injection molds and vacuum forming tools due to its high thermal conductivity and ability to hold a mirror finish.

• Structural Bulkheads: Heavy-duty load-bearing parts in aircraft and high-performance automotive chassis.

• Gears and Shafts: Often used for high-speed rotating parts where low inertia is required.

4. Engineering Trade-offs

While 7075 is exceptionally strong, it comes with specific limitations:

• 🚫 Welding: 7075 is generally not weldable. Fusion welding creates severe brittle zones and micro-cracking. Mechanical fastening (rivets/bolts) is the industry standard for this alloy.

• šï Corrosion: It is highly susceptible to Stress Corrosion Cracking (SCC) and exfoliation. If the part will be exposed to marine or industrial environments, it must be anodized or primed/painted.

• ðŸ—ï Formability: In the T6/T651 state, 7075 is very brittle. If you try to bend it at a tight radius, it will likely crack. If heavy forming is required, use 7075-O and then heat-treat to T6 afterward.

5. Technical Designations Table