Aluminum 6065-T651 vs 6065-T9
Aluminum · 6065 temper comparison
6065-T651 and 6065-T9 are two conditions of the same aluminum grade, 6065: T651 (T6, stress relieved by stretching) versus T9 (solution heat treated, artificially aged and cold worked). The chemistry is identical, so every difference below comes from the condition. 6065-T9 is the stronger of the two: yield strength 400 MPa (58 ksi) against 370 MPa (53.7 ksi) for 6065-T651, about 8% more. 6065-T9 is harder — 125 HB against 118 HB for 6065-T651 — which matters for wear surfaces and threads.
6065-T9Choose it when strength drives the design, or when surface hardness matters.
6065-T651 vs 6065-T9: 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)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 69 GPa10 Msi · Shear Modulus 26 GPa3.8 Msi · Bulk Modulus 68 GPa9.9 Msi · Poisson's Ratio 0.33 · Elongation at Break 10% · Shear Strength 240 MPa34.8 ksi · Fatigue Strength (Endurance Limit) 90 MPa13.1 ksi · Fracture Toughness (K_IC) 29 MPa·√m26.4 ksi·√in
Physical
Density and transition temperatures.
Same in both: Density 2.71 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.
Same in both: Thermal Conductivity 172 W/m·K99.4 BTU/hr·ft·°F · Specific Heat Capacity 896 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 23.4 µm/m·K13 µin/in·°F · Latent Heat of Fusion 393 J/g169 BTU/lb · Max Service Temperature (continuous) 150°C302 °F · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 44 % IACS · Electrical Resistivity 3.9×10⁻⁸ Ω·m1.54 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.74 V · Corrosion Resistance 68 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Same in both: Weldability 35 / 100 · Castability 40 / 100 · Brazeability / Solderability 30 / 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 kg CO₂/kg · Embodied Water 1,200 L/kg144 gal/lb · Typical Recycled Content 25%
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.
6065-T651 vs 6065-T9 — frequently asked
Is 6065-T9 stronger than 6065-T651?
Yes. 6065-T9 has a typical yield strength of 400 MPa (58 ksi) against 370 MPa (53.7 ksi) for 6065-T651 — about 8% more. Tensile strength is 415 MPa (60.2 ksi) vs 400 MPa (58 ksi).
Which condition does FabDigit quote by default, T651 or T9?
T6 is the default 6065 condition in the FabDigit quote flow (neither T651 nor T9). 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 6065-T651 over 6065-T9?
Pick 6065-T9 when strength drives the design, or when surface hardness matters.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 6065-T651 and 6065-T9 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.