Aluminum 8090-T81
Temper
AA 8090 · UNS A98090 · EN AW-8090, AlLi2.5Cu1.5Mg1
T81 = solution heat treated, ~1 % cold worked, artificially aged
Standard sheet temper for fuselage and secondary skins where damage tolerance and formability matter more than peak plate strength.
Values for the T81 condition
Other 8090 tempers and conditions
8090 is listed in 13 conditions; see the grade overview at 8090.
Compare all 13 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition, chosen for severe forming, stretch-forming or intermediate processing before solution treatment and aging. | 140 | 265 | 14 | 65 HB | 26 % IACS |
Solution heat treated and naturally aged | Naturally aged, most formable of the heat-treated conditions; used when parts are shaped then artificially aged. | 200 | 330 | 18 | 88 HB | 19 % IACS |
Solution heat treated, cold worked and naturally aged | Sheet condition with moderate strength and useful ductility for forming operations that are followed by artificial aging to T8. | 225 | 350 | 15 | 95 HB | 20 % IACS |
Solution heat treated and overaged (stabilized) | Overaged condition selected when stress-corrosion and exfoliation resistance outweigh maximum strength. | 350 | 430 | 7 | 120 HB | 25 % IACS |
Solution heat treated and artificially aged | Peak-aged without stretching; used for forgings and shapes where cold work before aging is impractical, but strength and toughness are below T8 tempers. | 370 | 465 | 5 | 128 HB | — |
T81This page Solution heat treated, ~1 % cold worked, artificially aged | Standard sheet temper for fuselage and secondary skins where damage tolerance and formability matter more than peak plate strength. | 370 | 455 | 7 | 128 HB | 24 % IACS |
Special underaged/toughness-optimised T8 | Proprietary aging practice trading a little yield strength for markedly better fracture toughness and short-transverse ductility in thick sections. | 390 | 470 | 8 | 130 HB | 24 % IACS |
T8 with compressive stress relief | Forging temper where cold work is applied by cold compression; chosen for helicopter frames and fittings needing low residual stress. | 400 | 470 | 6 | 132 HB | 23 % IACS |
Solution heat treated, cold worked and artificially aged | Generic peak-strength Al-Li condition: cold work before aging refines the strengthening precipitates, giving the best strength/stiffness combination. | 415 | 480 | 6 | 135 HB | 23 % IACS |
T6, stress relieved by stretching | Peak-aged 8090 Al-Li plate stretched 1.5–3 % after solution treatment for low residual stress; highest strength-to-density of the 8090 tempers but reduced short-transverse toughness and SCC resistance versus T8771. | 415 | 480 | 5 | 145 HB | 18 % IACS |
T851Default T8, stress relieved by stretching | The workhorse plate temper for machined aerospace structure: peak strength with low residual stress so thick plate machines flat without distortion. | 425 | 480 | 6 | 135 HB | 23 % IACS |
Solution treated, stretched, cold worked and artificially aged | Slightly higher-strength plate variant of T851 used where static strength governs and short-transverse ductility is less critical. | 435 | 490 | 5 | 138 HB | 23 % IACS |
T6, stress relieved by stretching, minor straightening | Peak-aged 8090 extrusion/bar temper: T651 practice plus permitted minor straightening after stretching, giving high longitudinal strength with strong directional (texture) anisotropy. | 440 | 495 | 5 | 150 HB | 18 % IACS |
What is 8090-T81?
8090-T81 is 8090 in the T81 temper — standard sheet temper for fuselage and secondary skins where damage tolerance and formability matter more than peak plate strength. 8090-T81 has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 455 MPa (66 ksi) — stronger than 85% of aluminum grades. Elongation at break is 7% and the elastic modulus is 79 GPa (11.5 Msi). 8090-T81 has a density of 2.54 g/cm³ (0.0918 lb/in³), lighter than 100% of aluminum grades. It melts at 600°C (1,112 °F). T851 is the default condition FabDigit quotes; T81 is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 35 MPa·√m (31.9 ksi·√in), better than 91% of aluminum grades
- High strength — 370 MPa (53.7 ksi), better than 85% of aluminum grades
Limitations
- Poor heat conductor — 95 W/m·K (54.9 BTU/hr·ft·°F), worse than 98% of aluminum grades
- Low electrical conductivity — 24 % IACS, worse than 95% of aluminum grades
- High embodied carbon — 14 kg CO₂/kg, worse than 95% of aluminum grades
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
- Difficult to weld — 25/100, worse than 76% of aluminum grades
8090-T81 properties
Typical room-temperature values for 8090-T81; 21 are specific to this condition. Other listed values are 8090 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
8090-T81 has a density of 2.54 g/cm³ (0.0918 lb/in³), lighter than 100% of aluminum grades. It melts at 600°C (1,112 °F).
Mechanical12
8090-T81 has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 455 MPa (66 ksi) — stronger than 85% of aluminum grades. Elongation at break is 7% and the elastic modulus is 79 GPa (11.5 Msi).
Thermal6
8090-T81 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 21.4 µm/m·K (11.9 µin/in·°F).
Electrical3
8090-T81 conducts electricity at 24 % IACS, worse than 95% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 69% of aluminum grades.
Sustainability4
Producing a kilogram of 8090-T81 takes about 220 MJ of energy and emits 14 kg of CO₂ — more than 95% of aluminum grades. Typical recycled content is 5%.
Manufacturability7
8090-T81's machinability is good (55/100, worse than 59% of aluminum grades); weldability poor (25/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 8090-T81
Is 8090 easy to machine?
Machines like a hard 2000-series alloy but Zr/Li constituents accelerate tool wear — use sharp carbide/PCD, high speed, generous coolant, and keep fine chips wet since Li-bearing dust is reactive.
Can 8090 be welded?
Fusion welding is problematic (Li oxide film, hydrogen porosity, hot cracking); joints are normally riveted, bonded or friction-stir/electron-beam welded rather than TIG/MIG.
Can 8090 be formed, bent or molded?
Form in O, T3 or T4; T8-type plate has low ductility and pronounced through-thickness anisotropy, so bend radii must be generous and short-transverse loading avoided.
What surface finishes work on 8090?
Chromic or sulfuric anodize plus primer is standard for aerospace corrosion protection; alkaline etch times must be controlled because Li-rich phases dissolve preferentially and can dull the finish.
8090 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′ forming element | 2.2 – 2.7 | 2.4 |
| Cu | 1 – 1.6 | 1.3 |
| Mg | 0.6 – 1.3 | 0.9 |
| Zrgrain-structure control | 0.04 – 0.16 | 0.1 |
| Fe | ≤ 0.3 | — |
| Si | ≤ 0.2 | — |
| Mn | ≤ 0.1 | — |
| Cr | ≤ 0.1 | — |
| Zn | ≤ 0.25 | — |
| Ti | ≤ 0.1 | — |
| Others (each)total 0.15 max | ≤ 0.05 | — |
| Al | balance | — |
8090-T81 — frequently asked
What is 8090-T81 used for?
8090-T81 is typically used for aerospace structural components, helicopter airframe parts, fuselage frames and bulkheads, wing ribs and stringers, machined structural fittings and seat tracks and floor structure. In short: low-density Al-Li; aerospace classic.
What is the yield strength of 8090-T81?
8090-T81 has a typical yield strength of 370 MPa (53.7 ksi) and a tensile strength of 455 MPa (66 ksi) — stronger than 85% of aluminum grades. Strength varies by condition: see the 13 listed tempers.
Is 8090-T81 easy to machine?
Reasonably — machinability is rated good (55/100, worse than 59% of aluminum grades). Machines like a hard 2000-series alloy but Zr/Li constituents accelerate tool wear — use sharp carbide/PCD, high speed, generous coolant, and keep fine chips wet since Li-bearing dust is reactive.
Can 8090-T81 be welded?
Not readily — weldability is rated poor (25/100). Fusion welding is problematic (Li oxide film, hydrogen porosity, hot cracking); joints are normally riveted, bonded or friction-stir/electron-beam welded rather than TIG/MIG.
What surface finishes work on 8090-T81?
Chromic or sulfuric anodize plus primer is standard for aerospace corrosion protection; alkaline etch times must be controlled because Li-rich phases dissolve preferentially and can dull the finish.
Can 8090-T81 be formed, bent or molded?
Form in O, T3 or T4; T8-type plate has low ductility and pronounced through-thickness anisotropy, so bend radii must be generous and short-transverse loading avoided.
What is the maximum service temperature of 8090-T81?
8090-T81 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 8090-T851 and 8090-O?
T851 is the default condition — the workhorse plate temper for machined aerospace structure: peak strength with low residual stress so thick plate machines flat without distortion. O: softest condition, chosen for severe forming, stretch-forming or intermediate processing before solution treatment and aging. Yield strength is 425 MPa in T851 versus 140 MPa in O.
Can FabDigit make parts in 8090-T81?
Yes — 8090-T81 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
- Aluminum-Lithium Alloys: Processing, Properties and Applications — Elsevier/Butterworth-Heinemann (2014)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Lital A / 8090 plate and sheet property data — British Alcan / Alcan Aerospace (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.