Aluminum 2099-T3 vs 2099-T81
Aluminum · 2099 temper comparison
2099-T3 and 2099-T81 are two conditions of the same aluminum grade, 2099: T3 (solution heat treated, cold worked and naturally aged) versus T81 (solution heat treated, slightly cold worked, artificially aged). The chemistry is identical, so every difference below comes from the condition. 2099-T81 is the stronger of the two: yield strength 480 MPa (69.6 ksi) against 265 MPa (38.4 ksi) for 2099-T3, about 81% more; tensile strength follows at 530 MPa (76.9 ksi) vs 400 MPa (58 ksi). In exchange, 2099-T3 is the more ductile: elongation 15% versus 8% for 2099-T81, and 2099-T81 is harder (142 HB vs 110 HB). 2099-T81 runs hotter in service (150°C vs 120°C continuous) and 2099-T81 conducts heat better (115 W/m·K vs 93 W/m·K).
2099-T3Choose it when the part is bent, formed or impact-loaded.
2099-T81Choose it when strength drives the design, or when the part sees heat.
2099-T3 vs 2099-T81: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all aluminum grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all aluminum grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 78 GPa11.3 Msi · Shear Modulus 29.5 GPa4.3 Msi · Bulk Modulus 76 GPa11 Msi · Poisson's Ratio 0.33
Physical
Density and transition temperatures.
Same in both: Density 2.63 g/cm³0.1 lb/in³ · Melting Point (Solidus) 560°C1,040 °F · Liquidus Temperature 645°C1,193 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 900 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 21.9 µm/m·K12.2 µin/in·°F · Latent Heat of Fusion 385 J/g166 BTU/lb · Min Service Temperature -253°C-423 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.8 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Same in both: Brazeability / Solderability 15 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 215 MJ/kg92,433 BTU/lb · Embodied Carbon (primary production) 13.5 kg CO₂/kg · Embodied Water 1,200 L/kg144 gal/lb · Typical Recycled Content 5%
Strength versus weight
Yield strength against density for every aluminum grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
2099-T3 vs 2099-T81 — frequently asked
Is 2099-T81 stronger than 2099-T3?
Yes. 2099-T81 has a typical yield strength of 480 MPa (69.6 ksi) against 265 MPa (38.4 ksi) for 2099-T3 — about 81% more. Tensile strength is 530 MPa (76.9 ksi) vs 400 MPa (58 ksi).
Which condition does FabDigit quote by default, T3 or T81?
T83 is the default 2099 condition in the FabDigit quote flow (neither T3 nor T81). The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, 2099-T3 or 2099-T81?
2099-T81, by a small margin. Both rate good for machinability — 64/100 against 55/100 for 2099-T3.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 2099-T3 and 2099-T81 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.