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Aluminum 7A77 vs AlSi10Mg

Aluminum · grade comparison

Aluminum 7A77 and AlSi10Mg are both aluminum grades. 7A77 is the stronger of the two: yield strength 310 MPa (45 ksi) against 265 MPa (38.4 ksi) for AlSi10Mg, about 17% more. In exchange, AlSi10Mg is the more ductile: elongation 7% versus 5% for 7A77, and AlSi10Mg is harder (119 HB vs 110 HB). AlSi10Mg is lighter (2.67 g/cm³ vs 2.81 g/cm³ for 7A77) and AlSi10Mg runs hotter in service (150°C vs 100°C continuous). On the shop floor, 7A77 machines more easily (good vs fair), AlSi10Mg welds better (good vs poor), and AlSi10Mg 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.

AlSi10MgChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.

7A77 vs AlSi10Mg: properties

7A77AlSi10Mg

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

400 MPa58 ksi
460 MPa66.7 ksi

Yield Strength (0.2% offset)

310 MPa45 ksi
265 MPa38.4 ksi

Elongation at Break

5%
7%

Compressive Strength

320 MPa46.4 ksi
480 MPa69.6 ksi

Shear Strength

245 MPa35.5 ksi
280 MPa40.6 ksi

Fatigue Strength (Endurance Limit)

110 MPa16 ksi
90 MPa13.1 ksi

Fracture Toughness (K_IC)

20 MPa·√m18.2 ksi·√in
22 MPa·√m20 ksi·√in

Charpy V-Notch Impact (RT)

6 J4.4 ft·lbf
4 J2.6 ft·lbf

Hardness, Brinell

110 HB
119 HB

Hardness, Vickers

115 HV
125 HV

Hardness, Rockwell B

—
66 HRB

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.

Density

2.81 g/cm³0.1 lb/in³
2.67 g/cm³0.1 lb/in³

Melting Point (Solidus)

477°C891 °F
557°C1,035 °F

Liquidus Temperature

635°C1,175 °F
596°C1,105 °F

Thermal

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

Thermal Conductivity

105 W/m·K60.7 BTU/hr·ft·°F
120 W/m·K69.3 BTU/hr·ft·°F

Specific Heat Capacity

960 J/kg·K0.23 BTU/lb·°F
900 J/kg·K0.21 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

23.4 µm/m·K13 µin/in·°F
21 µm/m·K11.7 µin/in·°F

Latent Heat of Fusion

390 J/g168 BTU/lb
425 J/g183 BTU/lb

Max Service Temperature (continuous)

100°C212 °F
150°C302 °F

Same in both: Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

26 % IACS
24 % IACS

Electrical Resistivity

6.6×10⁻⁸ Ω·m2.6 µΩ·in
7.2×10⁻⁸ Ω·m2.83 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

40 / 100
55 / 100

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

65 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

70%
50%

Weldability

25 / 100
60 / 100

Formability (cold)

20 / 100
10 / 100

Castability

35 / 100
92 / 100

Brazeability / Solderability

15 / 100
30 / 100

Polishability

60 / 100
55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

215 MJ/kg92,433 BTU/lb
240 MJ/kg103,182 BTU/lb

Embodied Carbon (primary production)

13 kg CO₂/kg
15 kg CO₂/kg

Embodied Water

1,250 L/kg150 gal/lb
1,200 L/kg144 gal/lb

Same in both: Typical Recycled Content 5%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

142 kN·m/kg
172 kN·m/kg

Specific Stiffness (E / density)

24.9 MN·m/kg
26.2 MN·m/kg

Modulus of Resilience

686 kJ/m³
502 kJ/m³

Thermal Diffusivity

38.9 mm²/s
49.9 mm²/s

Thermal Shock Resistance Index

26
38

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 scaleAlSi10Mg7A77

Manufacturing and finishing

Capability7A77AlSi10Mg
Default conditionAs PrintedAs 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 AlSi10Mg — frequently asked

Is 7A77 stronger than AlSi10Mg?

Yes. 7A77 has a typical yield strength of 310 MPa (45 ksi) against 265 MPa (38.4 ksi) for AlSi10Mg — about 17% more. Tensile strength is 400 MPa (58 ksi) vs 460 MPa (66.7 ksi).

Which is cheaper, 7A77 or AlSi10Mg?

AlSi10Mg 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 AlSi10Mg?

7A77. Its machinability rates good (65/100) against fair (50/100) for AlSi10Mg; for welding the order is AlSi10Mg first (good, 60/100) then 7A77 (poor, 25/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 7A77 and AlSi10Mg 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.