Aluminum 7075-O vs 7075-T73
Aluminum · 7075 temper comparison
7075-O and 7075-T73 are two conditions of the same aluminum grade, 7075: O (annealed) versus T73 (solution heat treated and overaged for stress-corrosion resistance). The chemistry is identical, so every difference below comes from the condition. 7075-T73 is the stronger of the two: yield strength 435 MPa (63.1 ksi) against 103 MPa (14.9 ksi) for 7075-O, about 4.2 times as much; tensile strength follows at 505 MPa (73.2 ksi) vs 228 MPa (33.1 ksi). In exchange, 7075-O is the more ductile: elongation 17% versus 13% for 7075-T73, and 7075-T73 is harder (135 HB vs 60 HB). 7075-O conducts heat better (173 W/m·K vs 155 W/m·K). On the shop floor, 7075-T73 machines more easily (very good vs fair).
7075-OChoose it when the part is bent, formed or impact-loaded.
7075-T73Choose it when strength drives the design, or when the part is machined in volume.
7075-O vs 7075-T73: 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, Rockwell B
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 71.7 GPa10.4 Msi · Shear Modulus 26.9 GPa3.9 Msi · Bulk Modulus 70 GPa10.2 Msi · Poisson's Ratio 0.33 · Reduction in Area 25% · Compressive Strength 505 MPa73.2 ksi · Charpy V-Notch Impact (RT) 8 J5.9 ft·lbf
Physical
Density and transition temperatures.
Same in both: Density 2.81 g/cm³0.1 lb/in³ · Melting Point (Solidus) 477°C891 °F · Liquidus Temperature 635°C1,175 °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) 23.6 µm/m·K13.1 µin/in·°F · Latent Heat of Fusion 395 J/g170 BTU/lb · Max Service Temperature (continuous) 150°C302 °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) -0.83 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Formability (cold)
Same in both: Machinability Rating (AISI 1212 = 100 %) 160% · Weldability 18 / 100 · Brazeability / Solderability 10 / 100 · Polishability 60 / 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 15%
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.
7075-O vs 7075-T73 — frequently asked
Is 7075-T73 stronger than 7075-O?
Yes. 7075-T73 has a typical yield strength of 435 MPa (63.1 ksi) against 103 MPa (14.9 ksi) for 7075-O — about 4.2 times as much. Tensile strength is 505 MPa (73.2 ksi) vs 228 MPa (33.1 ksi).
Which condition does FabDigit quote by default, O or T73?
T6 is the default 7075 condition in the FabDigit quote flow (neither O nor T73). 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, 7075-O or 7075-T73?
7075-T73. Its machinability rates very good (75/100) against fair (45/100) for 7075-O.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 7075-O and 7075-T73 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.