What is the difference between 6061 and 7075?

7075 is substantially stronger — about 572 MPa tensile against 310 MPa for 6061 in the T6 temper — but it is less corrosion resistant, effectively unweldable and more expensive. 6061 is the general-purpose structural alloy; 7075 is used where strength is the limiting requirement.

Is aluminium 6061 heat treatable?

Yes. 6061 is a 6xxx series alloy and responds to solution treatment and artificial ageing, giving the T6 temper. The 1xxx, 3xxx and 5xxx series are not heat-treatable and gain strength only by strain hardening.

What does T6 mean in aluminium?

Solution heat treated and then artificially aged — the peak-strength condition for most heat-treatable alloys. Other common tempers are O (annealed), H (strain hardened) and T4 (solution treated and naturally aged).

Which aluminium is best for machining?

6061-T6 is the usual choice: it machines cleanly, holds tolerance well and is widely available. 2011 is a free-machining grade with better chip breaking but poorer corrosion resistance. All aluminium machines far faster than steel — ratings of 150–300% on the machinability scale are normal.

What is the strongest aluminium alloy?

The 7xxx series, and within it the high-zinc alloys such as 7075 and 7050, reaching about 570 MPa tensile in the T6 temper. This is comparable to some structural steels at roughly a third of the density.

Is 5052 or 6061 better for marine use?

5052, and the 5xxx series generally, has better corrosion resistance in salt water — it is the standard marine aluminium. 6061 is stronger and heat-treatable but less corrosion resistant, so it is usually specified with a protective coating in marine service.

Aluminium Grades Chart — AA Series, Properties and Uses

Sources and scope for this page: Aluminium Association International Alloy Designation System (the designation system is stable; compositions are registered as needed), covering alloy designations, series classification and temper nomenclature. No independent source check is recorded for this page: the content rests on the sources listed and on the working shown on the page. Full sources, values and limits on this page.

Page last changed 2026-10-19 · based on n/a — the designation system is stable; compositions are registered as needed

Quick Answer

The first digit of an aluminium designation is the series, and it tells you the main alloying element: 1xxx pure, 2xxx copper, 3xxx manganese, 5xxx magnesium, 6xxx magnesium-silicon, 7xxx zinc. Only the 2xxx, 6xxx and 7xxx series are heat-treatable.

Find a grade

Aluminium Alloy Grades

Designation^[1]	Series^[1]	Alloying^[1]	Typical use^[1]	Hardness^[1]	Heat treatment^[1]
1050 #	1xxx	Pure aluminium, 99.5%	Electrical, chemical equipment	27 HB	Non-heat-treatable
1100 #	1xxx	Pure aluminium, 99.0%	Deep drawing, spun parts	28 HB	Non-heat-treatable
2024 #	2xxx	Cu-Mg, high strength	Aircraft structures	120 HB	Heat-treatable
2011 #	2xxx	Cu, free-machining	Screw machine parts	95 HB	Heat-treatable
3003 #	3xxx	Mn, moderate strength	Cooking utensils, signage	40 HB	Non-heat-treatable
5052 #	5xxx	Mg, corrosion resistant	Marine, pressure vessels	60 HB	Non-heat-treatable
5083 #	5xxx	Mg-Mn, high strength	Welded marine structures	75 HB	Non-heat-treatable
6061 #	6xxx	Mg-Si, general structural	Frames, brackets, extrusions	95 HB	Heat-treatable
6063 #	6xxx	Mg-Si, extrusion alloy	Architectural extrusions	73 HB	Heat-treatable
6082 #	6xxx	Mg-Si-Mn, structural	Bridges, cranes, machined parts	95 HB	Heat-treatable
7050 #	7xxx	Zn-Cu-Mg, high strength	Thick aircraft sections	150 HB	Heat-treatable
7075 #	7xxx	Zn-Mg-Cu, very high strength	Aircraft, moulds	150 HB	Heat-treatable
2024-T4 #	2xxx	2024 solution treated	Aircraft skins	120 HB	Heat-treatable
6061-T6 #	6xxx	6061 peak aged	General structural	95 HB	Heat-treatable
7075-T6 #	7xxx	7075 peak aged	High-stress aircraft parts	150 HB	Heat-treatable

Hardness values are typical for the common temper of each grade. The temper designation — O, H, T4, T6 — follows the alloy number and matters as much as the alloy itself: 6061-O and 6061-T6 differ by a factor of three in strength.

The Four-Digit System

The AA designation encodes both the alloy family and the specific composition:

First digit — series, set by the principal alloying element. This is the part that matters most when choosing.
Second digit — a modification of the original alloy, or zero for the original.
Last two digits — a sequential identifier within the series. They do not encode composition the way steel designations do.

The temper follows a hyphen: 6061-T6 is alloy 6061 in the solution heat-treated and artificially aged condition. O is annealed, H is strain-hardened, T4 is solution treated and naturally aged, T6 is solution treated and artificially aged.

Choosing a Series

1xxx — pure. Excellent conductivity and corrosion resistance, very low strength. Electrical busbar, chemical equipment.
2xxx — copper. High strength and good fatigue performance, poor corrosion resistance without cladding, effectively unweldable. Aircraft skins.
3xxx — manganese. Moderate strength, good formability. Not heat-treatable. Cookware and signage.
5xxx — magnesium. Best corrosion resistance of the common series, good weldability, work-hardening. Marine work.
6xxx — magnesium and silicon. The general-purpose structural series: extrudable, weldable, heat-treatable, and the easiest aluminium to machine.
7xxx — zinc. The highest strength aluminium alloys, at the cost of corrosion resistance and weldability. Aircraft structure and moulds.

Frequently Asked Questions

What is the difference between 6061 and 7075?: 7075 is substantially stronger — about 572 MPa tensile against 310 MPa for 6061 in the T6 temper — but it is less corrosion resistant, effectively unweldable and more expensive. 6061 is the general-purpose structural alloy; 7075 is used where strength is the limiting requirement.
Is aluminium 6061 heat treatable?: Yes. 6061 is a 6xxx series alloy and responds to solution treatment and artificial ageing, giving the T6 temper. The 1xxx, 3xxx and 5xxx series are not heat-treatable and gain strength only by strain hardening.
What does T6 mean in aluminium?: Solution heat treated and then artificially aged — the peak-strength condition for most heat-treatable alloys. Other common tempers are O (annealed), H (strain hardened) and T4 (solution treated and naturally aged).
Which aluminium is best for machining?: 6061-T6 is the usual choice: it machines cleanly, holds tolerance well and is widely available. 2011 is a free-machining grade with better chip breaking but poorer corrosion resistance. All aluminium machines far faster than steel — ratings of 150–300% on the machinability scale are normal.
What is the strongest aluminium alloy?: The 7xxx series, and within it the high-zinc alloys such as 7075 and 7050, reaching about 570 MPa tensile in the T6 temper. This is comparable to some structural steels at roughly a third of the density.
Is 5052 or 6061 better for marine use?: 5052, and the 5xxx series generally, has better corrosion resistance in salt water — it is the standard marine aluminium. 6061 is stronger and heat-treatable but less corrosion resistant, so it is usually specified with a protective coating in marine service.

Value Sources

References and calculation methods used for this page are listed below. Numbered markers connect table columns where present. A reference listing does not itself establish that every value has been independently checked.

#	Source	Type	Revision / method
[1]	Aluminium Association designation system, with properties from published alloy data	reference	n/a — designation system with periodic composition revisions — source

Data Sources

Standard	Revision	What it covers on this page
Aluminium Association International Alloy Designation System	n/a — the designation system is stable; compositions are registered as needed	alloy designations, series classification and temper nomenclature

Verification scope

No page-specific independent source review is recorded here. The listed references and formulas explain the basis of the compilation; automated consistency checks do not verify the original sources or establish product conformity.

Typical values for the common temper of each grade. Temper matters as much as alloy — verify the specific temper's properties before design use.

Accuracy and use. Use the source notes and recorded verification scope above to assess each value. Calculated values follow the stated derivations; compilation values may lack a confirmed original document or product condition. No warranty, express or implied, is made as to the accuracy or completeness of this information, and no liability is accepted for any loss or damage arising from its use. Engineering reference data is provided for guidance in preliminary work — before a value is used for design, fabrication or acceptance testing, verify it against the current revision of the governing standard and against your own inspection. The user assumes all risk and responsibility in connection with the use of this information.

Cite This Page

Read the source notes, calculation methods and verification scope above before reusing a value. To cite this page:

Plain text

Engineering Reference. "Aluminium Grades Chart." https://refmanual.com/charts/aluminum-grades/ (accessed 2026-11-09). Data from Aluminium Association International Alloy Designation System, n/a — the designation system is stable; compositions are registered as needed.

BibTeX

@misc{aluminum-grades,
  title        = {Aluminium Grades Chart},
  author       = {{Engineering Reference}},
  howpublished = {\url{https://refmanual.com/charts/aluminum-grades/}},
  note         = {Accessed: 2026-11-09},
  source       = {Aluminium Association International Alloy Designation System, n/a — the designation system is stable; compositions are registered as needed}
}

RIS (EndNote, Zotero, Mendeley)

TY  - ELEC
TI  - Aluminium Grades Chart
AU  - Engineering Reference
PB  - Engineering Reference
UR  - https://refmanual.com/charts/aluminum-grades/
PY  - 2026
DA  - 2026-11-09
N1  - Source: Aluminium Association International Alloy Designation System, n/a — the designation system is stable; compositions are registered as needed
ER  -

Each row in the tables above also has a permanent link — hover a row and use the # link to cite a single value rather than the whole page.