Aluminum 7A77 vs AlSi12
Aluminum · grade comparison
Aluminum 7A77 and AlSi12 are both aluminum grades. 7A77 is the stronger of the two: yield strength 310 MPa (45 ksi) against 250 MPa (36.3 ksi) for AlSi12, about 24% more. AlSi12 is lighter (2.67 g/cm³ vs 2.81 g/cm³ for 7A77) and AlSi12 runs hotter in service (120°C vs 100°C continuous). On the shop floor, 7A77 machines more easily (good vs fair), AlSi12 welds better (very good vs poor), and AlSi12 sits in a lower cost tier (premium, $$$) than 7A77 (specialty, $$$$$).
7A77Choose it when strength drives the design, or when the part is machined in volume.
AlSi12Choose it when weight is the constraint, or when the part sees heat.
7A77 vs AlSi12: 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.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Yield Strength (0.2% offset)
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Same in both: Poisson's Ratio 0.33 · Tensile Strength (Ultimate) 400 MPa58 ksi · Elongation at Break 5% · Hardness, Vickers 115 HV
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Same in both: 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)
Castability
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Water
Typical Recycled Content
Same in both: Embodied Energy (primary production) 215 MJ/kg92,433 BTU/lb · Embodied Carbon (primary production) 13 kg CO₂/kg
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | 7A77 | AlSi12 |
|---|---|---|
| Default condition | As Printed | As Printed |
| Relative cost | $$$$$ Specialty | $$$ Premium |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both are offered for 3D printing. Both take the same 6 finishes: Anodized (Aluminum AM), Electroless Nickel (EN), Epoxy Coating, Gold Plating, Plated (Metal AM), Silver Plating.
7A77 vs AlSi12 — frequently asked
Is 7A77 stronger than AlSi12?
Yes. 7A77 has a typical yield strength of 310 MPa (45 ksi) against 250 MPa (36.3 ksi) for AlSi12 — about 24% more. Tensile strength is 400 MPa (58 ksi) vs 400 MPa (58 ksi).
Which is cheaper, 7A77 or AlSi12?
AlSi12 is the lower-cost material: it sits in the premium tier ($$$) while 7A77 is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, 7A77 or AlSi12?
7A77. Its machinability rates good (65/100) against fair (50/100) for AlSi12; for welding the order is AlSi12 first (very good, 80/100) then 7A77 (poor, 25/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 7A77 and AlSi12 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.