Aluminum 7039-T61 vs 7039-T651
Aluminum · 7039 temper comparison
7039-T61 and 7039-T651 are two conditions of the same aluminum grade, 7039: T61 (T6 variant, underaged) versus T651 (T6, stress relieved by stretching). The chemistry is identical, so every difference below comes from the condition. 7039-T651 is the stronger of the two: yield strength 379 MPa (55 ksi) against 345 MPa (50 ksi) for 7039-T61, about 10% more; tensile strength follows at 448 MPa (65 ksi) vs 415 MPa (60.2 ksi). 7039-T651 is harder — 133 HB against 122 HB for 7039-T61 — which matters for wear surfaces and threads.
7039-T651Choose it when strength drives the design, or when surface hardness matters.
7039-T61 vs 7039-T651: 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)
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 69.6 GPa10.1 Msi · Shear Modulus 26.2 GPa3.8 Msi · Bulk Modulus 69 GPa10 Msi · Poisson's Ratio 0.33 · Elongation at Break 13%
Physical
Density and transition temperatures.
Same in both: Density 2.74 g/cm³0.1 lb/in³ · Melting Point (Solidus) 585°C1,085 °F · Liquidus Temperature 640°C1,184 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: Specific Heat Capacity 960 J/kg·K0.23 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 23.4 µm/m·K13 µin/in·°F · Latent Heat of Fusion 390 J/g168 BTU/lb · Max Service Temperature (continuous) 120°C248 °F · 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) -0.84 V
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 75 / 100 · Castability 25 / 100 · Brazeability / Solderability 15 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 205 MJ/kg88,134 BTU/lb · Embodied Carbon (primary production) 12.5 kg CO₂/kg · Embodied Water 1,200 L/kg144 gal/lb · Typical Recycled Content 20%
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.
7039-T61 vs 7039-T651 — frequently asked
Is 7039-T651 stronger than 7039-T61?
Yes. 7039-T651 has a typical yield strength of 379 MPa (55 ksi) against 345 MPa (50 ksi) for 7039-T61 — about 10% more. Tensile strength is 448 MPa (65 ksi) vs 415 MPa (60.2 ksi).
Which condition does FabDigit quote by default, T61 or T651?
T6 is the default 7039 condition in the FabDigit quote flow (neither T61 nor T651). 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 7039-T61 over 7039-T651?
Pick 7039-T651 when strength drives the design, or when surface hardness matters.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 7039-T61 and 7039-T651 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.