Aluminum AC4A-T4 vs AC4A-T5
Aluminum · AC4A temper comparison
AC4A-T4 and AC4A-T5 are two conditions of the same aluminum grade, AC4A: 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. AC4A-T5 is the stronger of the two: yield strength 145 MPa (21 ksi) against 115 MPa (16.7 ksi) for AC4A-T4, about 26% more. In exchange, AC4A-T4 is the more ductile: elongation 8% versus 2.5% for AC4A-T5, and AC4A-T5 is harder (70 HB vs 65 HB). AC4A-T5 runs hotter in service (150°C vs 100°C continuous) and AC4A-T5 conducts electricity better (41 % IACS vs 36 % IACS).
AC4A-T4Choose it when the part is bent, formed or impact-loaded.
AC4A-T5Choose it when strength drives the design, or when the part sees heat.
AC4A-T4 vs AC4A-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
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 71 GPa10.3 Msi · Shear Modulus 26.5 GPa3.8 Msi · Bulk Modulus 70 GPa10.2 Msi · Poisson's Ratio 0.33
Physical
Density and transition temperatures.
Same in both: Density 2.68 g/cm³0.1 lb/in³ · Melting Point (Solidus) 557°C1,035 °F · Liquidus Temperature 596°C1,105 °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 963 J/kg·K0.23 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 21.5 µm/m·K11.9 µin/in·°F · Latent Heat of Fusion 425 J/g183 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).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.83 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: Castability 88 / 100 · Brazeability / Solderability 25 / 100 · Polishability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 155 MJ/kg66,638 BTU/lb · Embodied Carbon (primary production) 9.5 kg CO₂/kg · Embodied Water 1,100 L/kg132 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.
AC4A-T4 vs AC4A-T5 — frequently asked
Is AC4A-T5 stronger than AC4A-T4?
Yes. AC4A-T5 has a typical yield strength of 145 MPa (21 ksi) against 115 MPa (16.7 ksi) for AC4A-T4 — about 26% more. Tensile strength is 205 MPa (29.7 ksi) vs 215 MPa (31.2 ksi).
Which condition does FabDigit quote by default, T4 or T5?
T6 is the default AC4A 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 welds better, AC4A-T4 or AC4A-T5?
AC4A-T4. Its weldability rates good (68/100) against good (62/100) for AC4A-T5.
Ready to make it?
Upload a CAD file and FabDigit prices the part in AC4A-T4 and AC4A-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.