Forming
In O temper, thin 6061 bends flat on itself and draws well. Heat-treat after forming to reach T4 or T6.
Heat-treatable thin-gauge strip
6061 Aerospace Aluminium Foil & Thin Strip
6061 foil is thin cold-rolled 6061 strip, usually 0.1 – 0.2 mm thick and supplied soft in O temper. Unlike the 1xxx and 8xxx alloys used for packaging foil, 6061 can be heat-treated after forming, so thin parts such as shims, laminated shim packs, etched components and formed covers can reach far higher strength. Metline supplies 6061 thin strip slit to width and cut to length, to customers worldwide.
- Alloy
- 6061 (Al-Mg-Si-Cu)
- Temper
- O (T4 / T6 on request)
- Thickness
- About 0.1 – 0.2 mm
- Width
- 100 – 1700 mm
What is 6061 aluminium foil used for?
Most aluminium foil is made from 1xxx and 8xxx alloys, which are soft, cheap and cannot be strengthened by heat treatment. 6061 is a different proposition: it is a structural alloy rolled very thin. In the annealed O temper it bends, draws and etches easily; after solution treatment and ageing the same part can reach T6 strength.
That makes thin 6061 useful for engineered parts rather than wrapping. Typical aerospace and high-technology uses are shims and laminated (peelable) shim packs for fitting assemblies, chemically milled or photo-etched parts, thin formed covers and clips, layers in bonded laminates, gasket and EMI shield inserts, and test coupons where the part must match the chemistry of a 6061 structure.
It is not the right material for galley foil containers, meal trays or insulation blankets. Those use 3003, 8011 or 1xxx foil, which are cheaper and form more easily. Choose 6061 foil when you need either its chemistry or the option to heat-treat after forming.
6061 chemical composition (wt %)
Thin strip uses the same registered composition as 6061 sheet and plate (EN 573-3, Aluminum Association).
| Element | Minimum | Maximum | Role in the alloy |
|---|---|---|---|
| Silicon (Si) | 0.40 | 0.80 | Forms the strengthening Mg2Si phase with magnesium |
| Iron (Fe) | — | 0.70 | Impurity; held low for toughness and surface quality |
| Copper (Cu) | 0.15 | 0.40 | Adds strength; a small penalty in corrosion resistance |
| Manganese (Mn) | — | 0.15 | Grain structure control |
| Magnesium (Mg) | 0.80 | 1.20 | Main strengthening element with silicon |
| Chromium (Cr) | 0.04 | 0.35 | Limits recrystallisation, improves stress-corrosion resistance |
| Zinc (Zn) | — | 0.25 | Impurity |
| Titanium (Ti) | — | 0.15 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder | About 95.8 – 98.6 % |
Mechanical and physical properties of 6061 foil
Foil is normally supplied in O temper, so the guaranteed properties are maximums that confirm the material is soft enough to form. After heat treatment to T6, thin strip reaches the familiar 6061-T6 level. Elongation of very thin gauges is lower than for thicker sheet because the test piece is so thin.
| Condition | Tensile strength | Yield strength (0.2 %) | Note |
|---|---|---|---|
| O (as supplied) | ≤ 150 MPa / 22 ksi | ≤ 85 MPa / 12 ksi | Soft condition for forming, etching and heading |
| O, typical | About 125 MPa | About 55 MPa | Comparison only |
| T4 after heat treatment, typical | About 240 MPa | About 145 MPa | Formable; can be aged later |
| T6 after heat treatment, typical | About 310 MPa | About 276 MPa | Peak strength |
Data sheets that list 290 MPa tensile and 240 MPa yield for "6061-O foil" are quoting T6 values. O temper cannot reach those figures; check that the certificate reports properties for the temper you ordered.
Physical properties of 6061 (T6)
- Density
- 2.70 g/cm³ (0.0975 lb/in³)
- Modulus of elasticity
- 68.9 GPa (10,000 ksi)
- Thermal conductivity
- 167 W/m·K
- Electrical conductivity
- About 43 % IACS
- Coefficient of thermal expansion
- 23.6 µm/m·°C (20 – 100 °C)
- Melting range
- 582 – 652 °C
6061 foil and thin strip sizes
Supply range
- Thickness
- About 0.1 – 0.2 mm; 0.2 – 0.5 mm thin sheet also available
- Width
- 100 – 1700 mm; common slit widths 100, 200, 300 and 500 mm
- Length
- Coils, or sheets cut to length (generally up to about 6 m)
- Temper
- O as standard; T4 or T6 on request
- Surface
- Mill finish, degreased, matt or bright; lightly oiled or dry
- Packing
- Coils on cores in sealed, desiccated cases; sheets interleaved with paper
Thin strip is weighed at 2.70 kg per m² per millimetre, so a 0.15 mm sheet weighs about 0.41 kg per m². For shim work, state the thickness tolerance you need: precision shim stock is often specified to a few micrometres, much tighter than standard sheet tolerances.
Forming, etching, heat treatment and bonding
Heat treatment
Solution treatment around 530 °C with a rapid quench, then ageing around 160 – 175 °C. Thin parts distort easily, so use fixtures and controlled quench.
Chemical milling and etching
Etches evenly in standard alkaline etchants, which suits photo-etched shims and precision blanks.
Adhesive bonding
Anodise or acid-etch and prime before bonding for durable laminates.
Brazing
Can be furnace or dip brazed with low-melting Al-Si fillers under close temperature control, because the solidus is only about 580 °C.
Corrosion protection
Good corrosion resistance; anodise or conversion coat thin parts that will see moisture or salt.
6061 foil compared with other foil alloys
| Alloy | Heat-treatable | Typical use | Choose it when |
|---|---|---|---|
| 1145 / 1235 | No | Insulation, capacitors, packaging | Lowest cost and highest purity matter |
| 3003 | No | Containers, ducts, heat-exchanger fins | Good formability and modest strength are enough |
| 5052 / 5056 | No | Honeycomb core | Strength and corrosion resistance without heat treatment |
| 2024 | Yes | High-strength laminates and honeycomb | Highest strength is needed |
| 6061 | Yes | Shims, etched parts, formed covers | A weldable, heat-treatable 6061 match is required |
How to order 6061 foil
- SpecifyAlloy and temper, thickness and tolerance, width, coil or sheet format, quantity and the governing specification with its revision (for example ASTM B209 or a customer specification).
- ConfirmWe confirm the specification can be met, the tolerance class, any extra tests and the delivery terms (EXW, FOB, CIF or DAP).
- InspectMaterial is checked for dimensions, surface condition and identification; tests named on the order are carried out or arranged with a third party.
- DocumentEach lot ships with a mill test certificate to EN 10204 3.1 showing chemistry and mechanical results, traceable to the cast or lot number.
- Pack and shipExport packing in sealed, moisture-protected wooden cases or on pallets, shipped by sea or air to your port or door.
References and standards
- ASTM B209 – Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
- EN 573-3 – Aluminium and aluminium alloys: chemical composition and form of wrought products
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
- ASM Handbook, Vol. 2 – Properties and Selection: Nonferrous Alloys and Special-Purpose Materials
6061 aluminium (aluminum) foil: frequently asked questions
Why choose 6061 foil instead of ordinary aluminium foil?
Because 6061 can be heat-treated. Parts formed or etched in the soft O temper can be strengthened to T6 afterwards, which 1xxx, 3xxx and 8xxx foils cannot do.
What temper is 6061 foil supplied in?
Usually O (annealed), with a maximum tensile strength of about 150 MPa. T4 and T6 thin strip can be supplied on request but is harder to form.
How strong is 6061-O foil?
Typical tensile strength is about 125 MPa and yield about 55 MPa. Values of 290 MPa or more belong to the T6 temper, not to O.
Is 6061 foil used for aircraft insulation or meal trays?
Not normally. Insulation blankets use 1xxx foil and food trays use 3003 or 8011. 6061 is chosen for engineered thin parts such as shims and etched components.
Can you slit 6061 strip to narrow widths?
Yes. Thin strip can be slit to width and supplied in coils or cut sheets, packed in sealed cases, and shipped worldwide with a mill test certificate.
Need thin 6061 strip or foil?
Send thickness, width, temper, quantity and destination. Our team will reply with availability and a delivered price.
