Aluminum 2124-O vs 2124-T851
Aluminum · 2124 temper comparison
2124-O and 2124-T851 are two conditions of the same aluminum grade, 2124: O (annealed) versus T851 (T8, stress relieved by stretching). The chemistry is identical, so every difference below comes from the condition. 2124-T851 is the stronger of the two: yield strength 440 MPa (63.8 ksi) against 75 MPa (10.9 ksi) for 2124-O, about 5.9 times as much; tensile strength follows at 490 MPa (71.1 ksi) vs 185 MPa (26.8 ksi). In exchange, 2124-O is the more ductile: elongation 20% versus 8% for 2124-T851, and 2124-T851 is harder (128 HB vs 47 HB). 2124-O conducts heat better (190 W/m·K vs 152 W/m·K). On the shop floor, 2124-T851 machines more easily (very good vs fair).
2124-OChoose it when the part is bent, formed or impact-loaded.
2124-T851Choose it when strength drives the design, or when the part is machined in volume.
2124-O vs 2124-T851: 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
Shear Strength
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 73.1 GPa10.6 Msi · Shear Modulus 28 GPa4.1 Msi · Bulk Modulus 76 GPa11 Msi · Poisson's Ratio 0.33 · Compressive Strength 450 MPa65.3 ksi · Fatigue Strength (Endurance Limit) 138 MPa20 ksi · Fracture Toughness (K_IC) 34 MPa·√m30.9 ksi·√in
Physical
Density and transition temperatures.
Same in both: Density 2.78 g/cm³0.1 lb/in³ · Melting Point (Solidus) 502°C936 °F · Liquidus Temperature 638°C1,180 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: Specific Heat Capacity 875 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 22.9 µm/m·K12.7 µin/in·°F · Latent Heat of Fusion 390 J/g168 BTU/lb · Max Service Temperature (continuous) 150°C302 °F · Min Service Temperature -196°C-321 °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) -0.64 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Formability (cold)
Same in both: Machinability Rating (AISI 1212 = 100 %) 70% · Weldability 20 / 100 · Brazeability / Solderability 10 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 210 MJ/kg90,284 BTU/lb · Embodied Carbon (primary production) 12.5 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.
2124-O vs 2124-T851 — frequently asked
Is 2124-T851 stronger than 2124-O?
Yes. 2124-T851 has a typical yield strength of 440 MPa (63.8 ksi) against 75 MPa (10.9 ksi) for 2124-O — about 5.9 times as much. Tensile strength is 490 MPa (71.1 ksi) vs 185 MPa (26.8 ksi).
Which condition does FabDigit quote by default, O or T851?
Specify the condition in the material field or the drawing note; FabDigit prices the quote for the state you call out.
Which is easier to machine, 2124-O or 2124-T851?
2124-T851. Its machinability rates very good (78/100) against fair (45/100) for 2124-O.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 2124-O and 2124-T851 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.