Aluminum 2097-O (Annealed)
Temper
AA 2097 · UNS A92097
Softest condition for maximum formability or intermediate machining; must be re-heat-treated for service strength.
Values for the O condition
Other 2097 tempers and conditions
2097 is listed in 7 conditions; see the grade overview at 2097.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OThis page Annealed | Softest condition for maximum formability or intermediate machining; must be re-heat-treated for service strength. | 140 | 250 | 16 | 70 HB | 32 % IACS |
As fabricated | Mill supply state before solution treatment; only for further processing, no guaranteed mechanicals. | 200 | 300 | 12 | 85 HB | 29 % IACS |
Solution heat treated, cold worked and naturally aged | Intermediate strength with better ductility than T8; used where parts are formed or machined before final artificial ageing. | 290 | 400 | 13 | 115 HB | 23 % IACS |
T3, stress relieved by stretching | Stretch-relieved plate/extrusion for low-distortion machining of large parts before final ageing to T851. | 295 | 405 | 12 | 118 HB | 23 % IACS |
T851Default T8, stress relieved by stretching | Standard aerospace thick-plate supply condition: high strength with low residual stress for heavy machined bulkheads and frames. | 435 | 490 | 9 | 140 HB | 26 % IACS |
Solution heat treated, cold worked and artificially aged | Peak-strength condition for extruded stringers and stiffeners where stiffness and strength dominate. | 450 | 500 | 8 | 145 HB | 26 % IACS |
T8 with 7 % cold work | Over-stretched/peak-aged variant for the highest yield strength where toughness requirements are less severe. | 470 | 515 | 7 | 150 HB | 27 % IACS |
What is 2097-O?
2097-O is 2097 in the O temper — softest condition for maximum formability or intermediate machining; must be re-heat-treated for service strength. 2097-O has a yield strength of 140 MPa (20.3 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 70% of aluminum grades. Elongation at break is 16% and the elastic modulus is 78 GPa (11.3 Msi). 2097-O has a density of 2.62 g/cm³ (0.0947 lb/in³), lighter than 96% of aluminum grades. It melts at 560°C (1,040 °F). T851 is the default condition FabDigit quotes; O is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 45 MPa·√m (41 ksi·√in), better than 100% of aluminum grades
- Ductile — tolerates forming and impact — 16%, better than 84% of aluminum grades
- Forms and bends easily — 70/100, better than 83% of aluminum grades
Limitations
- High embodied carbon — 14 kg CO₂/kg, worse than 95% of aluminum grades
- Poor heat conductor — 110 W/m·K (63.6 BTU/hr·ft·°F), worse than 88% of aluminum grades
2097-O properties
Typical room-temperature values for 2097-O; 22 are specific to this condition. Other listed values are 2097 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
2097-O has a density of 2.62 g/cm³ (0.0947 lb/in³), lighter than 96% of aluminum grades. It melts at 560°C (1,040 °F).
Mechanical12
2097-O has a yield strength of 140 MPa (20.3 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 70% of aluminum grades. Elongation at break is 16% and the elastic modulus is 78 GPa (11.3 Msi).
Thermal6
2097-O is rated for continuous service to 150°C (302 °F). It conducts heat at 110 W/m·K (63.6 BTU/hr·ft·°F), worse than 88% of aluminum grades. Thermal expansion is 21.4 µm/m·K (11.9 µin/in·°F).
Electrical3
2097-O conducts electricity at 32 % IACS, worse than 63% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 62% of aluminum grades.
Sustainability4
Producing a kilogram of 2097-O takes about 220 MJ of energy and emits 14 kg of CO₂ — more than 95% of aluminum grades. Typical recycled content is 5%.
Manufacturability7
2097-O's machinability is fair (50/100, worse than 65% of aluminum grades); weldability poor (32/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 2097-O
Is 2097 easy to machine?
Machines well in T8 tempers with sharp polished carbide tools, high speed and copious coolant; keep Li-bearing chips dry and segregated (fines are reactive) and avoid recirculating water-based swarf.
Can 2097 be welded?
Not recommended for fusion welding (Li oxide films, porosity, hot cracking); join by riveting/bolting or use friction stir welding with qualified parameters.
Can 2097 be formed, bent or molded?
Form in O or T3/T351 conditions; T8 plate has limited cold ductility and marked anisotropy, so hot forming or stretch-form-then-age routes are preferred.
What surface finishes work on 2097?
Chromic or sulphuric anodise plus chromate-free primer for corrosion protection; alkaline etch cycles must be short to avoid Li leaching, and dissimilar-metal joints need insulating sealant.
2097 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 |
|---|---|---|
| Cu | 2.5 – 3.5 | 2.8 |
| Liprimary density reducer / modulus booster | 1.2 – 1.8 | 1.5 |
| Mn | 0.1 – 0.6 | 0.35 |
| Zrgrain-structure control | 0.08 – 0.15 | 0.11 |
| Mg | 0 – 0.35 | — |
| Zn | 0 – 0.35 | — |
| Feimpurity limit | 0 – 0.15 | — |
| Siimpurity limit | 0 – 0.12 | — |
| Ti | 0 – 0.15 | — |
| Others (each)others total 0.15 max | 0 – 0.05 | — |
| Al | balance | — |
2097-O — frequently asked
What is 2097-O used for?
2097-O is typically used for aircraft stringers, extruded stiffeners and stringer sections, bulkhead and frame extrusions, machined structural fittings from plate, riveted fuselage substructure and weight-critical stiffened panel assemblies. In short: best-machining Al-Li grade; extrusion alloy for stringers; low density, high stiffness.
What is the yield strength of 2097-O?
2097-O has a typical yield strength of 140 MPa (20.3 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 70% of aluminum grades. Strength varies by condition: see the 7 listed tempers.
Is 2097-O easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 65% of aluminum grades). Machines well in T8 tempers with sharp polished carbide tools, high speed and copious coolant; keep Li-bearing chips dry and segregated (fines are reactive) and avoid recirculating water-based swarf.
Can 2097-O be welded?
Not readily — weldability is rated poor (32/100). Not recommended for fusion welding (Li oxide films, porosity, hot cracking); join by riveting/bolting or use friction stir welding with qualified parameters.
What surface finishes work on 2097-O?
Chromic or sulphuric anodise plus chromate-free primer for corrosion protection; alkaline etch cycles must be short to avoid Li leaching, and dissimilar-metal joints need insulating sealant.
Can 2097-O be formed, bent or molded?
Form in O or T3/T351 conditions; T8 plate has limited cold ductility and marked anisotropy, so hot forming or stretch-form-then-age routes are preferred.
What is the maximum service temperature of 2097-O?
2097-O is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 2097-T851 and 2097-O?
T851 is the default condition — standard aerospace thick-plate supply condition: high strength with low residual stress for heavy machined bulkheads and frames. O: softest condition for maximum formability or intermediate machining; must be re-heat-treated for service strength. Yield strength is 435 MPa in T851 versus 140 MPa in O.
Sources
- Registration Record of International Alloy Designations (Teal Sheets) — The Aluminum Association (2018)
- ASM Handbook Vol. 2: Properties and Selection — Nonferrous Alloys — ASM International (1990)
- Aluminum-Lithium Alloys: Processing, Properties, and Applications — Elsevier/Butterworth-Heinemann (2014)
- MMPDS-style typical property compilations for Al-Cu-Li plate — Battelle/FAA (2022)
- Al-Li aerospace plate and extrusion product data (2097/2197/2099 class) — Alcoa/Arconic (2016)
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.