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Aluminum ZL205A-T4 vs ZL205A-T6

Aluminum · ZL205A temper comparison

ZL205A-T4 and ZL205A-T6 are two conditions of the same aluminum grade, ZL205A: T4 (solution heat treated and naturally aged) versus T6 (solution heat treated and artificially aged). The chemistry is identical, so every difference below comes from the condition. ZL205A-T6 is the stronger of the two: yield strength 380 MPa (55.1 ksi) against 250 MPa (36.3 ksi) for ZL205A-T4, about 52% more; tensile strength follows at 490 MPa (71.1 ksi) vs 400 MPa (58 ksi). In exchange, ZL205A-T4 is the more ductile: elongation 13% versus 5% for ZL205A-T6, and ZL205A-T6 is harder (125 HB vs 90 HB). ZL205A-T6 runs hotter in service (175°C vs 120°C continuous) and ZL205A-T6 conducts heat better (150 W/m·K vs 130 W/m·K). On the shop floor, ZL205A-T6 machines more easily (very good vs good).

ZL205A-T4Choose it when the part is bent, formed or impact-loaded.

ZL205A-T6Choose it when strength drives the design, or when the part sees heat.

ZL205A-T4 vs ZL205A-T6: properties

ZL205A-T4ZL205A-T6

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

400 MPa58 ksi
490 MPa71.1 ksi

Yield Strength (0.2% offset)

250 MPa36.3 ksi
380 MPa55.1 ksi

Elongation at Break

13%
5%

Compressive Strength

260 MPa37.7 ksi
330 MPa47.9 ksi

Shear Strength

240 MPa34.8 ksi
295 MPa42.8 ksi

Fatigue Strength (Endurance Limit)

95 MPa13.8 ksi
115 MPa16.7 ksi

Fracture Toughness (K_IC)

32 MPa·√m29.1 ksi·√in
24 MPa·√m21.8 ksi·√in

Charpy V-Notch Impact (RT)

18 J13.3 ft·lbf
8 J5.9 ft·lbf

Hardness, Brinell

90 HB
125 HB

Hardness, Vickers

96 HV
112 HV

Same in both: Elastic (Young's) Modulus 70 GPa10.2 Msi · Shear Modulus 26.5 GPa3.8 Msi · Bulk Modulus 70 GPa10.2 Msi · Poisson's Ratio 0.33

Physical

Density and transition temperatures.

Same in both: Density 2.82 g/cm³0.1 lb/in³ · Melting Point (Solidus) 545°C1,013 °F · Liquidus Temperature 650°C1,202 °F

Thermal

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

Thermal Conductivity

130 W/m·K75.1 BTU/hr·ft·°F
150 W/m·K86.7 BTU/hr·ft·°F

Max Service Temperature (continuous)

120°C248 °F
175°C347 °F

Same in both: Specific Heat Capacity 880 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

28 % IACS
36 % IACS

Electrical Resistivity

6.2×10⁻⁸ Ω·m2.44 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) -0.73 V

Manufacturability

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

Machinability

68 / 100
78 / 100

Machinability Rating (AISI 1212 = 100 %)

135%
150%

Formability (cold)

14 / 100
10 / 100

Same in both: Weldability 45 / 100 · Castability 40 / 100 · Brazeability / Solderability 25 / 100 · Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb · Embodied Carbon (primary production) 12.5 kg CO₂/kg · Embodied Water 1,150 L/kg138 gal/lb · Typical Recycled Content 10%

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 scaleZL205A

ZL205A-T4 vs ZL205A-T6 — frequently asked

Is ZL205A-T6 stronger than ZL205A-T4?

Yes. ZL205A-T6 has a typical yield strength of 380 MPa (55.1 ksi) against 250 MPa (36.3 ksi) for ZL205A-T4 — about 52% more. Tensile strength is 490 MPa (71.1 ksi) vs 400 MPa (58 ksi).

Which condition does FabDigit quote by default, T4 or T6?

T5 is the default ZL205A condition in the FabDigit quote flow (neither T4 nor T6). 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, ZL205A-T4 or ZL205A-T6?

ZL205A-T6. Its machinability rates very good (78/100) against good (68/100) for ZL205A-T4.

Ready to make it?

Upload a CAD file and FabDigit prices the part in ZL205A-T4 and ZL205A-T6 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.