Aluminum 2091
AA 2091 · UNS A92091
2091 is a first-generation Al-Li sheet alloy (A92091) from the 2000 series Al-Cu family, developed in Europe for airframe weight reduction.
Reference datasheet — 2091 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the T8X condition
2091 tempers and conditions
2091 is supplied in 6 conditions, soft to hard. T8X is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition for forming and intermediate processing; must be re-solution treated and aged for service. | 145 | 260 | 22 | 65 HB | 23 % IACS |
Solution heat treated, cold worked and naturally aged | Damage-tolerant sheet condition, the direct low-density counterpart to 2024-T3 fuselage skin. | 240 | 395 | 22 | 100 HB | 17 % IACS |
T3, stress relieved by stretching | Plate condition with low residual stress for machined parts that will be aged later or used as-is for toughness. | 250 | 400 | 18 | 103 HB | 17 % IACS |
T8XDefault Solution heat treated, cold worked and artificially aged | Standard supplied condition for 2091 aerospace sheet: best combination of strength, toughness and fatigue-crack resistance at low density. | 370 | 450 | 10 | 125 HB | 19 % IACS |
Solution heat treated, cold worked and artificially aged to higher… | Higher-strength ageing variant of the T8 route when static strength outweighs toughness. | 390 | 465 | 8 | 132 HB | 20 % IACS |
T8, stress relieved by stretching | Peak-aged, low-residual-stress plate for machined structural parts; watch short-transverse ductility and SCC. | 405 | 470 | 6 | 135 HB | 20 % IACS |
What is 2091?
2091 is a first-generation Al-Li sheet alloy (A92091) from the 2000 series Al-Cu family, developed in Europe for airframe weight reduction. It is rolled to sheet in O, T3/T351 and T8X/T84/T851 tempers; the default condition gives 370 MPa yield, 450 MPa tensile, 10% elongation and 125 HB, with 19% IACS and a 120 °C service limit. It is more machinable than most Al-Li grades (68/100) but forms poorly (35/100), cannot be fusion welded, and bare surfaces pit and exfoliate in chlorides, so cladding or coating is mandatory. Clad 2024-T3 is the conventional alternative. 2091 has a density of 2.58 g/cm³ (0.0932 lb/in³), lighter than 98% of aluminum grades. It melts at 560°C (1,040 °F). 2091 has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 450 MPa (65.3 ksi) — stronger than 85% of aluminum grades. Elongation at break is 10% and the elastic modulus is 75 GPa (10.9 Msi).
What is 2091 used for?
- Aerospace sheet skins
- Secondary airframe structure
- Formed sheet brackets and clips
- Riveted panel assemblies
- Interior structural sheet parts
- Weight-reduction sheet substitutions
Advantages
- Tough — resists crack growth — 37 MPa·√m (33.7 ksi·√in), better than 94% of aluminum grades
- High strength — 370 MPa (53.7 ksi), better than 85% of aluminum grades
Limitations
- Low electrical conductivity — 19 % IACS, worse than 99% of aluminum grades
- Poor heat conductor — 95 W/m·K (54.9 BTU/hr·ft·°F), worse than 98% of aluminum grades
- High embodied carbon — 14.5 kg CO₂/kg, worse than 97% of aluminum grades
- Needs corrosion protection — 33/100, worse than 91% of aluminum grades
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
2091 properties
Typical room-temperature values for 2091-T8X; bars are the position among aluminum grades.
Physical3
2091 has a density of 2.58 g/cm³ (0.0932 lb/in³), lighter than 98% of aluminum grades. It melts at 560°C (1,040 °F).
Mechanical11
2091 has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 450 MPa (65.3 ksi) — stronger than 85% of aluminum grades. Elongation at break is 10% and the elastic modulus is 75 GPa (10.9 Msi).
Thermal6
2091 is rated for continuous service to 120°C (248 °F). It conducts heat at 95 W/m·K (54.9 BTU/hr·ft·°F), worse than 98% of aluminum grades. Thermal expansion is 23 µm/m·K (12.8 µin/in·°F).
Electrical3
2091 conducts electricity at 19 % IACS, worse than 99% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is poor (33/100), worse than 91% of aluminum grades.
Sustainability4
Producing a kilogram of 2091 takes about 225 MJ of energy and emits 14.5 kg of CO₂ — more than 96% of aluminum grades. Typical recycled content is 5%.
Manufacturability7
2091's machinability is good (68/100, better than 67% of aluminum grades); weldability poor (25/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the aluminum family
Yield strength against density for every aluminum grade FabDigit runs. 2091 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 2091
Is 2091 easy to machine?
Machines like 2024-T3 with sharp carbide tools, high speed and flood coolant; fine Li-bearing chips/dust are reactive — avoid dry grinding and collect swarf wet.
Can 2091 be welded?
Poor fusion weldability (Li oxide films, hydrogen porosity, hot cracking); join by riveting, bonding or friction stir welding rather than TIG/MIG.
Can 2091 be formed, bent or molded?
Form in O or T3 condition; T8X sheet has limited bendability and marked anisotropy, so orient bends relative to rolling direction and use generous radii or hot/creep forming.
2091 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Liprincipal density-reducing / δ' strengthening element | 1.7 – 2.3 | 2 |
| Cu | 1.8 – 2.5 | 2.1 |
| Mg | 1.1 – 1.9 | 1.5 |
| Zrgrain-structure control | 0.04 – 0.16 | 0.1 |
| Si | ≤ 0.2 | |
| Fe | ≤ 0.3 | |
| Mn | ≤ 0.1 | |
| Cr | ≤ 0.1 | |
| Zn | ≤ 0.25 | |
| Ti | ≤ 0.1 | |
| Others (each) | ≤ 0.05 | |
| Others (total) | ≤ 0.15 | |
| Al | balance |
What surface finishes work on 2091?
Chromic or sulfuric acid anodize plus chromate-free primer for aerospace protection; cladding or coating is essentially mandatory since bare surfaces pit and exfoliate in chloride service.
Surface treatments FabDigit runs on aluminum parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Equivalent designations
Standards and trade names that resolve to Aluminum 2091 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- A92091
How much does 2091 cost?
2091 is a high-cost aluminum ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
2091 — frequently asked
What is 2091 used for?
2091 is typically used for aerospace sheet skins, secondary airframe structure, formed sheet brackets and clips, riveted panel assemblies, interior structural sheet parts and weight-reduction sheet substitutions. In short: european first-generation Al-Li; best-machining Al-Li sheet; requires cladding or coating.
What is the yield strength of 2091?
2091 has a typical yield strength of 370 MPa (53.7 ksi) and a tensile strength of 450 MPa (65.3 ksi) — stronger than 85% of aluminum grades. Strength varies by condition: see the 6 listed tempers.
Is 2091 easy to machine?
Reasonably — machinability is rated good (68/100, better than 67% of aluminum grades). Machines like 2024-T3 with sharp carbide tools, high speed and flood coolant; fine Li-bearing chips/dust are reactive — avoid dry grinding and collect swarf wet.
Can 2091 be welded?
Not readily — weldability is rated poor (25/100). Poor fusion weldability (Li oxide films, hydrogen porosity, hot cracking); join by riveting, bonding or friction stir welding rather than TIG/MIG.
What surface finishes work on 2091?
Chromic or sulfuric acid anodize plus chromate-free primer for aerospace protection; cladding or coating is essentially mandatory since bare surfaces pit and exfoliate in chloride service.
Can 2091 be formed, bent or molded?
Form in O or T3 condition; T8X sheet has limited bendability and marked anisotropy, so orient bends relative to rolling direction and use generous radii or hot/creep forming.
What is the maximum service temperature of 2091?
2091 is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 2091-T8X and 2091-O?
T8X is the default condition — standard supplied condition for 2091 aerospace sheet: best combination of strength, toughness and fatigue-crack resistance at low density. O: softest condition for forming and intermediate processing; must be re-solution treated and aged for service. Yield strength is 370 MPa in T8X versus 145 MPa in O.
How much does 2091 cost?
2091 is a high-cost aluminum ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- ASM Handbook Vol. 2: Properties and Selection — Nonferrous Alloys and Special-Purpose Materials (Al-Li alloys) — ASM International (1990)
- Aluminum-Lithium Alloys: Processing, Properties and Applications — Butterworth-Heinemann/Elsevier (2014)
- Pechiney/Cegedur 2091 Al-Li aerospace sheet data — Pechiney (now Constellium) (1990)
- MMPDS / MIL-HDBK-5 background data on Al-Li alloys — Battelle/FAA (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.