Aluminum 7A77 Stress Relieved vs 7A77-T73
Aluminum · 7A77 temper comparison
7A77 Stress Relieved and 7A77-T73 are two conditions of the same aluminum grade, 7A77: Stress Relieved versus T73 (solution heat treated and overaged for stress-corrosion resistance). The chemistry is identical, so every difference below comes from the condition. 7A77-T73 is the stronger of the two: yield strength 400 MPa (58 ksi) against 270 MPa (39.2 ksi) for 7A77 Stress Relieved, about 48% more; tensile strength follows at 470 MPa (68.2 ksi) vs 360 MPa (52.2 ksi). 7A77-T73 is the more ductile: elongation 8% versus 7% for 7A77 Stress Relieved, and 7A77-T73 is harder (135 HB vs 100 HB). 7A77-T73 conducts heat better (150 W/m·K vs 120 W/m·K).
7A77-T73Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
7A77 Stress Relieved vs 7A77-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
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 70 GPa10.2 Msi · Shear Modulus 26.5 GPa3.8 Msi · Bulk Modulus 69 GPa10 Msi · Poisson's Ratio 0.33
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) 23.4 µm/m·K13 µin/in·°F · Latent Heat of Fusion 390 J/g168 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
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Same in both: Castability 35 / 100 · Brazeability / Solderability 15 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 215 MJ/kg92,433 BTU/lb · Embodied Carbon (primary production) 13 kg CO₂/kg · Embodied Water 1,250 L/kg150 gal/lb · Typical Recycled Content 5%
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.
7A77 Stress Relieved vs 7A77-T73 — frequently asked
Is 7A77-T73 stronger than 7A77 Stress Relieved?
Yes. 7A77-T73 has a typical yield strength of 400 MPa (58 ksi) against 270 MPa (39.2 ksi) for 7A77 Stress Relieved — about 48% more. Tensile strength is 470 MPa (68.2 ksi) vs 360 MPa (52.2 ksi).
Which condition does FabDigit quote by default, Stress Relieved or T73?
As Printed is the default 7A77 condition in the FabDigit quote flow (neither Stress Relieved 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.
When should I choose 7A77 Stress Relieved over 7A77-T73?
Pick 7A77-T73 when strength drives the design, or when the part is bent, formed or impact-loaded.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 7A77 Stress Relieved and 7A77-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.