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Aluminum AC2A vs AC8B

Aluminum · grade comparison

Aluminum AC2A and AC8B are both aluminum grades. AC8B is the stronger of the two: yield strength 235 MPa (34.1 ksi) against 170 MPa (24.7 ksi) for AC2A, about 38% more; tensile strength follows at 280 MPa (40.6 ksi) vs 250 MPa (36.3 ksi). In exchange, AC2A is the more ductile: elongation 2% versus 1% for AC8B, and AC8B is harder (110 HB vs 85 HB). AC8B is stiffer (82 GPa vs 74 GPa) and AC8B runs hotter in service (230°C vs 175°C continuous). On the shop floor, AC2A machines more easily (very good vs fair) and AC2A welds better (fair vs poor).

AC2AChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

AC8BChoose it when strength drives the design, or when the part sees heat.

AC2A vs AC8B: properties

AC2AAC8B

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

74 GPa10.7 Msi
82 GPa11.9 Msi

Shear Modulus

27.5 GPa4 Msi
31 GPa4.5 Msi

Bulk Modulus

72 GPa10.4 Msi
73 GPa10.6 Msi

Tensile Strength (Ultimate)

250 MPa36.3 ksi
280 MPa40.6 ksi

Yield Strength (0.2% offset)

170 MPa24.7 ksi
235 MPa34.1 ksi

Elongation at Break

2%
1%

Shear Strength

165 MPa23.9 ksi
200 MPa29 ksi

Fatigue Strength (Endurance Limit)

75 MPa10.9 ksi
82 MPa11.9 ksi

Fracture Toughness (K_IC)

18 MPa·√m16.4 ksi·√in
15 MPa·√m13.7 ksi·√in

Hardness, Brinell

85 HB
110 HB

Compressive Strength

—
260 MPa37.7 ksi

Same in both: Poisson's Ratio 0.33 · Charpy V-Notch Impact (RT) 3 J2.2 ft·lbf

Physical

Density and transition temperatures.

Density

2.79 g/cm³0.1 lb/in³
2.76 g/cm³0.1 lb/in³

Melting Point (Solidus)

516°C961 °F
521°C970 °F

Liquidus Temperature

604°C1,119 °F
582°C1,080 °F

Thermal

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

Thermal Conductivity

110 W/m·K63.6 BTU/hr·ft·°F
96 W/m·K55.5 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

21.5 µm/m·K11.9 µin/in·°F
20.7 µm/m·K11.5 µin/in·°F

Max Service Temperature (continuous)

175°C347 °F
230°C446 °F

Min Service Temperature

-196°C-321 °F
-60°C-76 °F

Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Latent Heat of Fusion 389 J/g167 BTU/lb

Electrical

Conductivity and insulation.

Electrical Conductivity

27 % IACS
25 % IACS

Electrical Resistivity

6.4×10⁻⁸ Ω·m2.52 µΩ·in
6.6×10⁻⁸ Ω·m2.6 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.75 V
-0.78 V

Corrosion Resistance

42 / 100
38 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

72 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

70%
200%

Weldability

35 / 100
22 / 100

Formability (cold)

10 / 100
—

Castability

75 / 100
85 / 100

Brazeability / Solderability

25 / 100
20 / 100

Same in both: Polishability 40 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Water

1,150 L/kg138 gal/lb
1,100 L/kg132 gal/lb

Typical Recycled Content

80%
75%

Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb · Embodied Carbon (primary production) 12 kg CO₂/kg

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

90 kN·m/kg
101 kN·m/kg

Specific Stiffness (E / density)

26.5 MN·m/kg
29.7 MN·m/kg

Modulus of Resilience

195 kJ/m³
337 kJ/m³

Thermal Diffusivity

40.9 mm²/s
36.1 mm²/s

Thermal Shock Resistance Index

17
16

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 scaleAC2AAC8B

Manufacturing and finishing

CapabilityAC2AAC8B
Default condition——
Relative cost$$ Standard$$ Standard
Min. machined wall——
Best machined surface——

Both take the same 4 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Silver Plating.

AC2A vs AC8B — frequently asked

Is AC8B stronger than AC2A?

Yes. AC8B has a typical yield strength of 235 MPa (34.1 ksi) against 170 MPa (24.7 ksi) for AC2A — about 38% more. Tensile strength is 280 MPa (40.6 ksi) vs 250 MPa (36.3 ksi).

Which is cheaper, AC2A or AC8B?

Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, AC2A or AC8B?

AC2A. Its machinability rates very good (72/100) against fair (50/100) for AC8B; for welding the order is AC2A first (fair, 35/100) then AC8B (poor, 22/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in AC2A and AC8B 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.