Aluminum 6061-T4 vs 6061-T5
Aluminum · 6061 temper comparison
6061-T4 and 6061-T5 are two conditions of the same aluminum grade, 6061: T4 (solution heat treated and naturally aged) versus T5 (cooled from hot working and artificially aged). The chemistry is identical, so every difference below comes from the condition. 6061-T5 is the stronger of the two: yield strength 240 MPa (34.8 ksi) against 145 MPa (21 ksi) for 6061-T4, about 66% more; tensile strength follows at 260 MPa (37.7 ksi) vs 241 MPa (35 ksi). In exchange, 6061-T4 is the more ductile: elongation 22% versus 11% for 6061-T5, and 6061-T5 is harder (85 HB vs 65 HB). 6061-T5 runs hotter in service (170°C vs 120°C continuous). On the shop floor, 6061-T5 machines more easily (68 vs 55 out of 100).
6061-T4Choose it when the part is bent, formed or impact-loaded.
6061-T5Choose it when strength drives the design, or when the part sees heat.
6061-T4 vs 6061-T5: 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
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 68.9 GPa10 Msi · Shear Modulus 26 GPa3.8 Msi · Bulk Modulus 69 GPa10 Msi · Poisson's Ratio 0.33
Physical
Density and transition temperatures.
Same in both: Density 2.7 g/cm³0.1 lb/in³ · Melting Point (Solidus) 582°C1,080 °F · Liquidus Temperature 652°C1,206 °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 896 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 23.6 µm/m·K13.1 µin/in·°F · Latent Heat of Fusion 397 J/g171 BTU/lb · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.83 V · Corrosion Resistance 55 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Formability (cold)
Same in both: Weldability 85 / 100 · Brazeability / Solderability 60 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb · Embodied Carbon (primary production) 12.5 kg CO₂/kg · Embodied Water 1,200 L/kg144 gal/lb · Typical Recycled Content 35%
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.
6061-T4 vs 6061-T5 — frequently asked
Is 6061-T5 stronger than 6061-T4?
Yes. 6061-T5 has a typical yield strength of 240 MPa (34.8 ksi) against 145 MPa (21 ksi) for 6061-T4 — about 66% more. Tensile strength is 260 MPa (37.7 ksi) vs 241 MPa (35 ksi).
Which condition does FabDigit quote by default, T4 or T5?
T6 is the default 6061 condition in the FabDigit quote flow (neither T4 nor T5). 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, 6061-T4 or 6061-T5?
6061-T5, by a small margin. Both rate good for machinability — 68/100 against 55/100 for 6061-T4.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 6061-T4 and 6061-T5 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.