Aluminum AlSi9Cu3-T5 vs AlSi9Cu3-T7
Aluminum · AlSi9Cu3 temper comparison
AlSi9Cu3-T5 and AlSi9Cu3-T7 are two conditions of the same aluminum grade, AlSi9Cu3: T5 (cooled from hot working and artificially aged) versus T7 (solution heat treated and overaged (stabilized)). The chemistry is identical, so every difference below comes from the condition. AlSi9Cu3-T5 is the stronger of the two: tensile strength 320 MPa (46.4 ksi) against 280 MPa (40.6 ksi) for AlSi9Cu3-T7, about 14% more. In exchange, AlSi9Cu3-T7 is the more ductile: elongation 2.5% versus 1.5% for AlSi9Cu3-T5. AlSi9Cu3-T7 runs hotter in service (200°C vs 175°C continuous) and AlSi9Cu3-T7 conducts electricity better (30 % IACS vs 26 % IACS).
AlSi9Cu3-T5Choose it when strength drives the design.
AlSi9Cu3-T7Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
AlSi9Cu3-T5 vs AlSi9Cu3-T7: 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)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Same in both: Elastic (Young's) Modulus 75 GPa10.9 Msi · Shear Modulus 28 GPa4.1 Msi · Bulk Modulus 73 GPa10.6 Msi · Poisson's Ratio 0.33 · Hardness, Brinell 95 HB · Hardness, Vickers 100 HV
Physical
Density and transition temperatures.
Same in both: Density 2.75 g/cm³0.1 lb/in³ · Melting Point (Solidus) 515°C959 °F · Liquidus Temperature 595°C1,103 °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 880 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 21 µm/m·K11.7 µin/in·°F · Latent Heat of Fusion 390 J/g168 BTU/lb · Min Service Temperature -100°C-148 °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) -0.78 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 95 / 100 · Brazeability / Solderability 20 / 100 · Polishability 40 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 190 MJ/kg81,685 BTU/lb · Embodied Carbon (primary production) 12.5 kg CO₂/kg · Embodied Water 1,200 L/kg144 gal/lb · Typical Recycled Content 85%
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.
AlSi9Cu3-T5 vs AlSi9Cu3-T7 — frequently asked
Is AlSi9Cu3-T5 stronger than AlSi9Cu3-T7?
Yes. AlSi9Cu3-T5 has a typical tensile strength of 320 MPa (46.4 ksi) against 280 MPa (40.6 ksi) for AlSi9Cu3-T7 — about 14% more.
Which condition does FabDigit quote by default, T5 or T7?
F is the default AlSi9Cu3 condition in the FabDigit quote flow (neither T5 nor T7). 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 AlSi9Cu3-T5 over AlSi9Cu3-T7?
Pick AlSi9Cu3-T5 when strength drives the design. Pick AlSi9Cu3-T7 when the part is bent, formed or impact-loaded, or when the part sees heat.
Ready to make it?
Upload a CAD file and FabDigit prices the part in AlSi9Cu3-T5 and AlSi9Cu3-T7 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.