2011A Aluminum

Representative aluminum raw/semi-finished material photo; exact grade not verified

2011A Aluminum (AA 2011A) is a registered wrought aluminum–copper alloy developed primarily for high-speed automatic machining. Its high copper content supports useful strength after solution heat treatment and aging, while controlled lead and bismuth additions promote short, easily broken chips and a clean machined finish. Relative to 2011, 2011A has a lower iron maximum and a 4.5–6.0% copper range. It is therefore a practical choice for turned, drilled, tapped, and screw-machined parts where productivity and dimensional consistency outweigh welding and corrosion-resistance requirements.

Chemical Composition (wt.%)
Chemical Composition wt.%
Element	Min	Max
Silicon	—	0.40
Iron	—	0.50
Copper	4.5	6.0
Zinc	—	0.30
Bismuth	0.20	0.60
Lead	0.20	0.60
Other elements, each	—	0.05
Other elements, total	—	0.15
Aluminum	Remainder

Composition notes

Silicon: Maximum
Iron: Maximum
Zinc: Maximum
Other elements, each: Maximum, unspecified other element
Other elements, total: Maximum, unspecified other elements total

Registered wrought composition limits for 2011A, in mass percent. Aluminum is the remainder. The 0.05% each and 0.15% total limits apply to unspecified other elements; the specified lead and bismuth ranges are listed separately.

The Aluminum Association Teal Sheets report the calculated nominal density for the registered 2011A wrought designation. Strength, conductivity, and thermal values vary substantially with product form and temper and are not stated numerically in the supplied grade-specific source excerpts.

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Table of 2011A Aluminum Properties

Table of 2011A Aluminum Properties
Physical Properties	Metric
Density	2.82 Mg/m³
Density	0.102 lb/in³2.82 g/cm³

Test conditions & data notes

Density: Calculated nominal density for active wrought 2011A
Density: Calculated nominal density for active wrought 2011A

Material Conditions & Tempers

2011A is supplied in condition-specific wrought product forms. Mechanical performance must be specified by the applicable product standard, size, and temper; the alloy designation alone does not define minimum tensile or yield strength.

Condition	Description	Notes
T3	Solution heat-treated, cold worked, and naturally aged to a substantially stable condition.	A 2011A-T3 condition is identified by an independent material comparison source; obtain certified product data for required design values.
T4	Solution heat-treated and naturally aged to a substantially stable condition.	Suitable where natural aging after solution treatment is specified.
T6	Solution heat-treated and artificially aged.	Artificial aging is used to develop the specified T6 condition.
T8	Solution heat-treated, cold worked, and artificially aged.	Used when a specification calls for post-solution cold work followed by artificial aging.

Advantages & Limitations

Advantages	Limitations
Exceptional machinability for automatic lathes, CNC turning, drilling, reaming, and tapping; lead and bismuth promote chip fragmentation. Copper provides a heat-treatable 2xxx-series matrix, allowing higher strength potential than non-heat-treatable free-machining aluminum grades. Produces fine chips and generally supports good surface finish at productive cutting speeds. Its registered chemistry controls iron to 0.50% maximum, lower than the 0.70% maximum listed for 2011. Low density remains beneficial for small precision components where weight reduction matters.	Lead and bismuth are deliberate alloying additions; material selection, machining-fluid handling, scrap segregation, and finished-part compliance should account for those elements. Corrosion resistance is generally less favorable than that of 5xxx or 6xxx alloys, particularly in persistently wet, saline, or chemically aggressive service. Fusion welding is generally avoided for critical 2011A parts because the free-machining additions and copper-rich chemistry can impair weld quality. It is intended for machined wrought stock rather than for forming-intensive sheet work or castings. Published mechanical requirements depend on temper, product form, and section size; use the applicable procurement specification rather than a generic alloy value.

Advantages

Limitations

Exceptional machinability for automatic lathes, CNC turning, drilling, reaming, and tapping; lead and bismuth promote chip fragmentation.
Copper provides a heat-treatable 2xxx-series matrix, allowing higher strength potential than non-heat-treatable free-machining aluminum grades.
Produces fine chips and generally supports good surface finish at productive cutting speeds.
Its registered chemistry controls iron to 0.50% maximum, lower than the 0.70% maximum listed for 2011.
Low density remains beneficial for small precision components where weight reduction matters.

Lead and bismuth are deliberate alloying additions; material selection, machining-fluid handling, scrap segregation, and finished-part compliance should account for those elements.
Corrosion resistance is generally less favorable than that of 5xxx or 6xxx alloys, particularly in persistently wet, saline, or chemically aggressive service.
Fusion welding is generally avoided for critical 2011A parts because the free-machining additions and copper-rich chemistry can impair weld quality.
It is intended for machined wrought stock rather than for forming-intensive sheet work or castings.
Published mechanical requirements depend on temper, product form, and section size; use the applicable procurement specification rather than a generic alloy value.

Processing & Fabrication

Process	Description
Machining	Use sharp tools, rigid workholding, and chip control appropriate to free-machining aluminum. The alloy’s lead and bismuth additions are intended to reduce long-stringer formation, making it well suited to high-volume turning and screw-machine operations.
Heat treatment	Where a heat-treated temper is required, use a controlled solution-treatment, quench, and aging route appropriate to the ordered product standard. T4 denotes natural aging after solution treatment; T6 denotes artificial aging.
Forming	Plan bending or other severe deformation around the selected temper. Heat-treated conditions provide greater strength but usually less forming latitude than softer starting conditions.
Joining	Prefer mechanical fastening or other qualified joining methods when practical. Do not assume ordinary fusion-welding practice will preserve the properties or machinability of the parent material.
Finishing and corrosion control	For exposed service, evaluate a suitable protective finish and the complete environment. Avoid specifying 2011A solely for corrosion resistance when a more corrosion-resistant aluminum alloy can meet the machining requirement.

Applications

2011A is best used for repetitive precision components made from bar, rod, or similar wrought stock, especially where cycle time, chip control, and finish are key purchasing criteria.

Automatic screw-machine parts: The lead–bismuth free-machining chemistry supports short chips and efficient production of high quantities of small turned components.
Threaded fittings, adapters, and inserts: The alloy machines cleanly in operations that combine turning, drilling, and internal or external threading.
Precision shafts, pins, and collars: Wrought stock and favorable machining behavior suit dimensionally controlled cylindrical components.
Instrument and optical hardware: Small intricate parts can be machined with good finish where moderate corrosion exposure and welding are not central requirements.
Electrical and mechanical connector components: It is useful for complex machined hardware when strength and machinability are more important than maximum electrical conductivity.

Standards & Designations

Designation	Value	Description
Aluminum Association International Alloy Designation System	2011A	Active registered wrought aluminum alloy designation; originally registered in 1982 by Switzerland.
Aluminum Association	AA 2011A	Common designation format for the same registered wrought alloy.
Temper designation system for wrought aluminum	T3, T4, T6, T8	Temper is a separate condition designation and must be specified in addition to alloy 2011A.

Frequently Asked Questions

What is the difference between 2011A and 2011 aluminum?

They are separate registered wrought alloys. In the Aluminum Association composition listing, 2011A has 4.5–6.0% copper and 0.50% maximum iron, while 2011 has 5.0–6.0% copper and 0.70% maximum iron. Both include lead and bismuth ranges for free-machining behavior, but they should not be substituted without checking the governing specification.

Why does 2011A machine so easily?

Its 0.20–0.60% lead and 0.20–0.60% bismuth additions are designed to promote chip breakage during cutting. This distinguishes 2011A from general-purpose structural aluminum alloys that can produce longer, more difficult-to-manage chips in high-speed automatic machining.

Is 2011A suitable for welded or outdoor corrosive service?

It is usually selected for machining rather than welding. The copper-rich, lead- and bismuth-containing composition makes it a less natural choice for fusion-welded assemblies, and its corrosion resistance is generally inferior to that of many 5xxx and 6xxx alloys. For exposed service, assess the environment and use a qualified protective finish or a different alloy where corrosion resistance is the primary need.

References & Data Notes

(n.d.). Aluminum Association — International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys, Revised December 2025. https://www.aluminum.org/sites/default/files/2026-01/Teal%20Sheets%20December%202025.pdf
(n.d.). 2011A-T6 Aluminum. https://www.makeitfrom.com/material-properties/2011A-T6-Aluminum
(n.d.). 2011A-T3 Aluminum compared with 2024-T3 Aluminum. https://www.makeitfrom.com/compare/2011A-T3-Aluminum/2024-T3-Aluminum

Composition limits and calculated nominal density are taken from the Aluminum Association’s registered wrought-alloy listing. Numerical mechanical, thermal, and electrical values are intentionally not shown because the supplied excerpts do not provide verified values for a specific 2011A product form and temper.