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Aluminum 2020-T4 vs 2020-T6511

Aluminum · 2020 temper comparison

2020-T4 and 2020-T6511 are two conditions of the same aluminum grade, 2020: T4 (solution heat treated and naturally aged) versus T6511 (T6, stress relieved by stretching, minor straightening). The chemistry is identical, so every difference below comes from the condition. 2020-T6511 is the stronger of the two: yield strength 525 MPa (76.1 ksi) against 235 MPa (34.1 ksi) for 2020-T4, about 123% more; tensile strength follows at 575 MPa (83.4 ksi) vs 370 MPa (53.7 ksi). In exchange, 2020-T4 is the more ductile: elongation 10% versus 5% for 2020-T6511, and 2020-T6511 is harder (148 HB vs 100 HB). 2020-T6511 runs hotter in service (150°C vs 100°C continuous).

2020-T4Choose it when the part is bent, formed or impact-loaded.

2020-T6511Choose it when strength drives the design, or when the part sees heat.

2020-T4 vs 2020-T6511: properties

2020-T42020-T6511

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

370 MPa53.7 ksi
575 MPa83.4 ksi

Yield Strength (0.2% offset)

235 MPa34.1 ksi
525 MPa76.1 ksi

Elongation at Break

10%
5%

Shear Strength

225 MPa32.6 ksi
320 MPa46.4 ksi

Fatigue Strength (Endurance Limit)

110 MPa16 ksi
140 MPa20.3 ksi

Fracture Toughness (K_IC)

35 MPa·√m31.9 ksi·√in
24 MPa·√m21.8 ksi·√in

Hardness, Brinell

100 HB
148 HB

Same in both: Elastic (Young's) Modulus 76 GPa11 Msi · Shear Modulus 28.5 GPa4.1 Msi · Bulk Modulus 74 GPa10.7 Msi · Poisson's Ratio 0.33

Physical

Density and transition temperatures.

Same in both: Density 2.8 g/cm³0.1 lb/in³ · Melting Point (Solidus) 510°C950 °F · Liquidus Temperature 645°C1,193 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

128 W/m·K74 BTU/hr·ft·°F
140 W/m·K80.9 BTU/hr·ft·°F

Max Service Temperature (continuous)

100°C212 °F
150°C302 °F

Same in both: Specific Heat Capacity 865 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 22.5 µm/m·K12.5 µin/in·°F · Latent Heat of Fusion 390 J/g168 BTU/lb · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

30 % IACS
33 % IACS

Electrical Resistivity

5.75×10⁻⁸ Ω·m2.26 µΩ·in
5.2×10⁻⁸ Ω·m2.05 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

30 / 100
28 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.7 V

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

55 / 100
62 / 100

Machinability Rating (AISI 1212 = 100 %)

62%
70%

Formability (cold)

40 / 100
18 / 100

Same in both: Weldability 15 / 100 · Castability 20 / 100 · Brazeability / Solderability 10 / 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) 13 kg CO₂/kg · Embodied Water 1,200 L/kg144 gal/lb · Typical Recycled Content 0%

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.

20501002005002.22.42.62.83Density (g/cm³)Yield strength (MPa) — log scale2020

2020-T4 vs 2020-T6511 — frequently asked

Is 2020-T6511 stronger than 2020-T4?

Yes. 2020-T6511 has a typical yield strength of 525 MPa (76.1 ksi) against 235 MPa (34.1 ksi) for 2020-T4 — about 123% more. Tensile strength is 575 MPa (83.4 ksi) vs 370 MPa (53.7 ksi).

Which condition does FabDigit quote by default, T4 or T6511?

T651 is the default 2020 condition in the FabDigit quote flow (neither T4 nor T6511). 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 is easier to machine, 2020-T4 or 2020-T6511?

2020-T6511, by a small margin. Both rate good for machinability — 62/100 against 55/100 for 2020-T4.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 2020-T4 and 2020-T6511 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.