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Aluminum AC2A vs AC4C

Aluminum · grade comparison

Aluminum AC2A and AC4C are both aluminum grades. AC4C is the stronger of the two: yield strength 180 MPa (26.1 ksi) against 170 MPa (24.7 ksi) for AC2A, about 6% more. AC4C is the more ductile: elongation 5% versus 2% for AC2A, and AC2A is harder (85 HB vs 80 HB). AC4C is lighter (2.68 g/cm³ vs 2.79 g/cm³ for AC2A) and AC2A runs hotter in service (175°C vs 150°C continuous). On the shop floor, AC2A machines more easily (very good vs good) and AC4C welds better (very good vs fair).

AC2AChoose it when the part sees heat, or when the part is machined in volume.

AC4CChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

AC2A vs AC4C: properties

AC2AAC4C

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

74 GPa10.7 Msi
72.4 GPa10.5 Msi

Shear Modulus

27.5 GPa4 Msi
27 GPa3.9 Msi

Bulk Modulus

72 GPa10.4 Msi
71 GPa10.3 Msi

Yield Strength (0.2% offset)

170 MPa24.7 ksi
180 MPa26.1 ksi

Elongation at Break

2%
5%

Shear Strength

165 MPa23.9 ksi
180 MPa26.1 ksi

Fatigue Strength (Endurance Limit)

75 MPa10.9 ksi
90 MPa13.1 ksi

Fracture Toughness (K_IC)

18 MPa·√m16.4 ksi·√in
20 MPa·√m18.2 ksi·√in

Charpy V-Notch Impact (RT)

3 J2.2 ft·lbf
5 J3.7 ft·lbf

Hardness, Brinell

85 HB
80 HB

Compressive Strength

—
185 MPa26.8 ksi

Hardness, Vickers

—
85 HV

Same in both: Poisson's Ratio 0.33 · Tensile Strength (Ultimate) 250 MPa36.3 ksi

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

516°C961 °F
557°C1,035 °F

Liquidus Temperature

604°C1,119 °F
613°C1,135 °F

Thermal

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

Thermal Conductivity

110 W/m·K63.6 BTU/hr·ft·°F
151 W/m·K87.2 BTU/hr·ft·°F

Max Service Temperature (continuous)

175°C347 °F
150°C302 °F

Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 21.5 µm/m·K11.9 µin/in·°F · Latent Heat of Fusion 389 J/g167 BTU/lb · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

27 % IACS
39 % IACS

Electrical Resistivity

6.4×10⁻⁸ Ω·m2.52 µΩ·in
4.4×10⁻⁸ Ω·m1.73 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.75 V
-0.83 V

Corrosion Resistance

42 / 100
58 / 100

Manufacturability

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

Machinability

72 / 100
62 / 100

Machinability Rating (AISI 1212 = 100 %)

70%
—

Weldability

35 / 100
75 / 100

Formability (cold)

10 / 100
12 / 100

Castability

75 / 100
93 / 100

Brazeability / Solderability

25 / 100
30 / 100

Polishability

40 / 100
50 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

200 MJ/kg85,985 BTU/lb
175 MJ/kg75,237 BTU/lb

Embodied Carbon (primary production)

12 kg CO₂/kg
11.5 kg CO₂/kg

Embodied Water

1,150 L/kg138 gal/lb
1,200 L/kg144 gal/lb

Typical Recycled Content

80%
55%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

90 kN·m/kg
93 kN·m/kg

Specific Stiffness (E / density)

26.5 MN·m/kg
27 MN·m/kg

Modulus of Resilience

195 kJ/m³
224 kJ/m³

Thermal Diffusivity

40.9 mm²/s
58.5 mm²/s

Thermal Shock Resistance Index

17
24

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 scaleAC2AAC4C

Manufacturing and finishing

CapabilityAC2AAC4C
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 AC4C — frequently asked

Is AC4C stronger than AC2A?

Yes. AC4C has a typical yield strength of 180 MPa (26.1 ksi) against 170 MPa (24.7 ksi) for AC2A — about 6% more. Tensile strength is 250 MPa (36.3 ksi) vs 250 MPa (36.3 ksi).

Which is cheaper, AC2A or AC4C?

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 AC4C?

AC2A. Its machinability rates very good (72/100) against good (62/100) for AC4C; for welding the order is AC4C first (very good, 75/100) then AC2A (fair, 35/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in AC2A and AC4C 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.