Aluminum ZL109-T6 vs ZL109-T7
Aluminum · ZL109 temper comparison
ZL109-T6 and ZL109-T7 are two conditions of the same aluminum grade, ZL109: T6 (solution heat treated and artificially aged) versus T7 (solution heat treated and overaged (stabilized)). The chemistry is identical, so every difference below comes from the condition. ZL109-T6 is the stronger of the two: yield strength 225 MPa (32.6 ksi) against 195 MPa (28.3 ksi) for ZL109-T7, about 15% more; tensile strength follows at 265 MPa (38.4 ksi) vs 235 MPa (34.1 ksi). In exchange, ZL109-T7 is the more ductile: elongation 1% versus 0.8% for ZL109-T6, and ZL109-T6 is harder (115 HB vs 105 HB). ZL109-T7 runs hotter in service (300°C vs 250°C continuous) and ZL109-T7 conducts electricity better (30 % IACS vs 27 % IACS).
ZL109-T6Choose it when strength drives the design.
ZL109-T7Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
ZL109-T6 vs ZL109-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)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 80 GPa11.6 Msi · Shear Modulus 30 GPa4.4 Msi · Bulk Modulus 76 GPa11 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) 525°C977 °F · Liquidus Temperature 575°C1,067 °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) 19.5 µm/m·K10.8 µin/in·°F · Latent Heat of Fusion 490 J/g211 BTU/lb · Min Service Temperature -50°C-58 °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
Weldability
Formability (cold)
Same in both: Castability 90 / 100 · Brazeability / Solderability 20 / 100 · Polishability 50 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 150 MJ/kg64,488 BTU/lb · Embodied Carbon (primary production) 10.5 kg CO₂/kg · Embodied Water 1,100 L/kg132 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.
ZL109-T6 vs ZL109-T7 — frequently asked
Is ZL109-T6 stronger than ZL109-T7?
Yes. ZL109-T6 has a typical yield strength of 225 MPa (32.6 ksi) against 195 MPa (28.3 ksi) for ZL109-T7 — about 15% more. Tensile strength is 265 MPa (38.4 ksi) vs 235 MPa (34.1 ksi).
Which condition does FabDigit quote by default, T6 or T7?
T6 is the default ZL109 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 ZL109-T6 over ZL109-T7?
Pick ZL109-T6 when strength drives the design. Pick ZL109-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 ZL109-T6 and ZL109-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.