Aluminum AC4D-T6 vs AC4D-T61
Aluminum · AC4D temper comparison
AC4D-T6 and AC4D-T61 are two conditions of the same aluminum grade, AC4D: T6 (solution heat treated and artificially aged) versus T61 (T6 variant, underaged). The chemistry is identical, so every difference below comes from the condition. AC4D-T61 is the stronger of the two: yield strength 245 MPa (35.5 ksi) against 180 MPa (26.1 ksi) for AC4D-T6, about 36% more; tensile strength follows at 280 MPa (40.6 ksi) vs 250 MPa (36.3 ksi). In exchange, AC4D-T6 is the more ductile: elongation 2.5% versus 1% for AC4D-T61, and AC4D-T61 is harder (96 HB vs 88 HB).
AC4D-T6Choose it when the part is bent, formed or impact-loaded.
AC4D-T61Choose it when strength drives the design.
AC4D-T6 vs AC4D-T61: 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
Fatigue Strength (Endurance Limit)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 71 GPa10.3 Msi · Shear Modulus 26.5 GPa3.8 Msi · Bulk Modulus 72 GPa10.4 Msi · Poisson's Ratio 0.33 · Fracture Toughness (K_IC) 20 MPa·√m18.2 ksi·√in · Charpy V-Notch Impact (RT) 4 J3 ft·lbf
Physical
Density and transition temperatures.
Same in both: Density 2.71 g/cm³0.1 lb/in³ · Melting Point (Solidus) 549°C1,020 °F · Liquidus Temperature 621°C1,150 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 151 W/m·K87.2 BTU/hr·ft·°F · Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 22.3 µm/m·K12.4 µin/in·°F · Latent Heat of Fusion 425 J/g183 BTU/lb · Max Service Temperature (continuous) 150°C302 °F · Min Service Temperature -50°C-58 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Same in both: Electrical Resistivity 4.42×10⁻⁸ Ω·m1.74 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.78 V · Corrosion Resistance 45 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Same in both: Machinability Rating (AISI 1212 = 100 %) 180% · Weldability 40 / 100 · Formability (cold) 10 / 100 · Castability 78 / 100 · Brazeability / Solderability 25 / 100 · Polishability 45 / 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 kg CO₂/kg · Embodied Water 1,200 L/kg144 gal/lb · Typical Recycled Content 70%
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.
AC4D-T6 vs AC4D-T61 — frequently asked
Is AC4D-T61 stronger than AC4D-T6?
Yes. AC4D-T61 has a typical yield strength of 245 MPa (35.5 ksi) against 180 MPa (26.1 ksi) for AC4D-T6 — about 36% more. Tensile strength is 280 MPa (40.6 ksi) vs 250 MPa (36.3 ksi).
Which condition does FabDigit quote by default, T6 or T61?
T6 is the default AC4D condition in the FabDigit quote flow. 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.
When should I choose AC4D-T6 over AC4D-T61?
Pick AC4D-T6 when the part is bent, formed or impact-loaded. Pick AC4D-T61 when strength drives the design.
Ready to make it?
Upload a CAD file and FabDigit prices the part in AC4D-T6 and AC4D-T61 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.