MATERIALS · ALUMINIUM
AA 7075-T6 / T651. 7075 is a heat-treatable aluminium–zinc–magnesium–copper alloy and one of the strongest aluminium alloys in common use. In T6/T651 its tensile strength is nearly double that of 6061-T6, so it is used for highly stressed aircraft, defence, tooling and sports parts. It is not normally fusion welded.
DENSITY
2.81 g/cm³HARDNESS
~150 HBTENSILE STRENGTH
510–572 MPaMACHINABILITY
FairTURNING, CARBIDE
300–600 m/minCALCULATOR
Enter your part size and your own rates. Density and a starting cutting speed are filled in for this material.
EQUIVALENT GRADES
Nearest equivalents across standards. Check the exact standard on critical parts.
| Standard | Grade |
|---|---|
| UNS | A97075 |
| EN / ISO | EN AW-7075 / AlZn5.5MgCu |
| DIN | 3.4365 (AlZnMgCu1.5) |
| IS | 76528 (IS 733; close, not identical) |
| Old BS | 2L95 |
Also known as: 7075-T6, 7075-T651, AlZn5.5MgCu, A97075, Zicral, Ergal, 76528
CHEMICAL COMPOSITION
| Element | Weight % |
|---|---|
| Zn | 5.10–6.10 |
| Mg | 2.10–2.90 |
| Cu | 1.20–2.00 |
| Cr | 0.18–0.28 |
| Fe | 0–0.50 |
| Si | 0–0.40 |
| Mn | 0–0.30 |
| Ti | 0–0.20 |
| Al | Balance |
MECHANICAL PROPERTIES
| Condition | T6 / T651 (ranges run from lower published values to typical value; thick plate is at the low end) |
| Tensile strength (MPa) | 510–572 |
| Yield strength (MPa) | 430–503 |
| Elongation (%) | 3–11 |
| Hardness | ~150 HB |
| Density (g/cm³) | 2.81 |
MACHINING
| Turning, carbide (m/min) | 300–600 |
| Turning, HSS (m/min) | 100–150 |
| Machinability | Fair |
7075-T6/T651 is much harder than the 6000 series (about 150 HB), so it breaks chips more readily and takes a good finish, but it wears cutting edges faster. Use sharp, polished uncoated or DLC-coated carbide with a positive rake, run slightly lower surface speeds than for 6061, and keep a steady feed. Use flood emulsion or mist to clear chips and hold size. T651 plate is stretched to reduce residual stress, yet deep pockets and thin webs can still move, so rough first, let the part relax, then finish. Deburr carefully; hard burrs can cut hands.
APPLICATIONS
INDUSTRIES THAT USE IT
PROCESSING
| Heat treatment | Heat-treatable: T6 is solution treated, quenched and artificially aged to peak strength (typical ageing about 120 °C for 24 h), and T651 is also stretched to relieve stress. Over-aged T73/T7351 tempers give up some strength for much better resistance to stress-corrosion cracking. |
| Welding | Poor: 7075 is prone to cracking in fusion welding and is not normally welded, so parts are usually bolted, riveted or bonded. |
| Supplied as | Round bar, Flat bar, Plate, Sheet |
QUESTIONS
7075-T6 is much stronger, with typical values of about 500 MPa yield and 570 MPa tensile against about 276 MPa and 310 MPa for 6061-T6. 6061 is easier to weld and form, so 7075 is chosen only where the extra strength is needed.
Not by normal fusion welding, because it is prone to cracking and the weld zone loses much of its T6 strength. 7075 parts are usually bolted, riveted or bonded; where a welded structure is needed, a weldable alloy such as 6082 is used instead.
Both are solution treated and artificially aged to peak strength. T651 is also stretched by a controlled amount after quenching to relieve residual stress, so plate and bar distort less when machined. Their strength values are similar.
RELATED MATERIALS
ALUMINIUM
AA 6061-T6 · 2.7 g/cm³
ALUMINIUM
AA 6082-T6 / T651 (HE30) · 2.7 g/cm³
ALUMINIUM
AA 5052-H32 · 2.68 g/cm³
Data reviewed 2026-10-02 against:
Typical values for reference. Always check the mill certificate and the standard your customer specifies.
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