Aluminum 7A77 vs AlSi7Mg
Aluminum · grade comparison
Aluminum 7A77 and AlSi7Mg are both aluminum grades. 7A77 is the stronger of the two: yield strength 310 MPa (45 ksi) against 240 MPa (34.8 ksi) for AlSi7Mg, about 29% more; tensile strength follows at 400 MPa (58 ksi) vs 350 MPa (50.8 ksi). In exchange, AlSi7Mg is the more ductile: elongation 8% versus 5% for 7A77. AlSi7Mg is lighter (2.67 g/cm³ vs 2.81 g/cm³ for 7A77) and AlSi7Mg runs hotter in service (120°C vs 100°C continuous). On the shop floor, AlSi7Mg welds better (very good vs poor) and AlSi7Mg sits in a lower cost tier (premium, $$$) than 7A77 (specialty, $$$$$).
7A77Choose it when strength drives the design.
AlSi7MgChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
7A77 vs AlSi7Mg: 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
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Hardness, Brinell
Same in both: Shear Modulus 26.5 GPa3.8 Msi · Bulk Modulus 69 GPa10 Msi · Poisson's Ratio 0.33 · Fracture Toughness (K_IC) 20 MPa·√m18.2 ksi·√in · Charpy V-Notch Impact (RT) 6 J4.4 ft·lbf · 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
Weldability
Castability
Brazeability / Solderability
Same in both: Machinability Rating (AISI 1212 = 100 %) 70% · Formability (cold) 20 / 100 · Polishability 60 / 100
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 | AlSi7Mg |
|---|---|---|
| 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 AlSi7Mg — frequently asked
Is 7A77 stronger than AlSi7Mg?
Yes. 7A77 has a typical yield strength of 310 MPa (45 ksi) against 240 MPa (34.8 ksi) for AlSi7Mg — about 29% more. Tensile strength is 400 MPa (58 ksi) vs 350 MPa (50.8 ksi).
Which is cheaper, 7A77 or AlSi7Mg?
AlSi7Mg 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 AlSi7Mg?
7A77, by a small margin. Both rate good for machinability — 65/100 against 58/100 for AlSi7Mg; for welding the order is AlSi7Mg first (very good, 70/100) then 7A77 (poor, 25/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 7A77 and AlSi7Mg 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.