Aluminum 2091-T351 vs 2091-T84
Aluminum · 2091 temper comparison
2091-T351 and 2091-T84 are two conditions of the same aluminum grade, 2091: T351 (T3, stress relieved by stretching) versus T84 (solution heat treated, cold worked and artificially aged to higher…). The chemistry is identical, so every difference below comes from the condition. 2091-T84 is the stronger of the two: yield strength 390 MPa (56.6 ksi) against 250 MPa (36.3 ksi) for 2091-T351, about 56% more; tensile strength follows at 465 MPa (67.4 ksi) vs 400 MPa (58 ksi). In exchange, 2091-T351 is the more ductile: elongation 18% versus 8% for 2091-T84, and 2091-T84 is harder (132 HB vs 103 HB). 2091-T84 runs hotter in service (120°C vs 100°C continuous) and 2091-T84 conducts heat better (100 W/m·K vs 85 W/m·K).
2091-T351Choose it when the part is bent, formed or impact-loaded.
2091-T84Choose it when strength drives the design, or when the part sees heat.
2091-T351 vs 2091-T84: 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.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Same in both: Shear Modulus 28.5 GPa4.1 Msi · Bulk Modulus 76 GPa11 Msi · Poisson's Ratio 0.34
Physical
Density and transition temperatures.
Same in both: Density 2.58 g/cm³0.09 lb/in³ · Melting Point (Solidus) 560°C1,040 °F · Liquidus Temperature 655°C1,211 °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 860 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 23 µm/m·K12.8 µin/in·°F · Latent Heat of Fusion 390 J/g168 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) -0.72 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Same in both: Brazeability / Solderability 10 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 225 MJ/kg96,733 BTU/lb · Embodied Carbon (primary production) 14.5 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.
2091-T351 vs 2091-T84 — frequently asked
Is 2091-T84 stronger than 2091-T351?
Yes. 2091-T84 has a typical yield strength of 390 MPa (56.6 ksi) against 250 MPa (36.3 ksi) for 2091-T351 — about 56% more. Tensile strength is 465 MPa (67.4 ksi) vs 400 MPa (58 ksi).
Which condition does FabDigit quote by default, T351 or T84?
T8X is the default 2091 condition in the FabDigit quote flow (neither T351 nor T84). 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, 2091-T351 or 2091-T84?
2091-T84. Its machinability rates very good (70/100) against good (63/100) for 2091-T351.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 2091-T351 and 2091-T84 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.