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Aluminum AC4A vs AC4C

Aluminum · grade comparison

Aluminum AC4A and AC4C are both aluminum grades. AC4A is the stronger of the two: yield strength 200 MPa (29 ksi) against 180 MPa (26.1 ksi) for AC4C, about 11% more. In exchange, AC4C is the more ductile: elongation 5% versus 3% for AC4A, and AC4A is harder (90 HB vs 80 HB). On the shop floor, AC4C machines more easily (good vs fair) and AC4C welds better (very good vs good).

AC4AChoose it when strength drives the design.

AC4CChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

AC4A vs AC4C: properties

AC4AAC4C

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

71 GPa10.3 Msi
72.4 GPa10.5 Msi

Shear Modulus

26.5 GPa3.8 Msi
27 GPa3.9 Msi

Bulk Modulus

70 GPa10.2 Msi
71 GPa10.3 Msi

Tensile Strength (Ultimate)

260 MPa37.7 ksi
250 MPa36.3 ksi

Yield Strength (0.2% offset)

200 MPa29 ksi
180 MPa26.1 ksi

Elongation at Break

3%
5%

Compressive Strength

205 MPa29.7 ksi
185 MPa26.8 ksi

Fracture Toughness (K_IC)

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

Charpy V-Notch Impact (RT)

4 J3 ft·lbf
5 J3.7 ft·lbf

Hardness, Brinell

90 HB
80 HB

Hardness, Vickers

—
85 HV

Same in both: Poisson's Ratio 0.33 · Shear Strength 180 MPa26.1 ksi · Fatigue Strength (Endurance Limit) 90 MPa13.1 ksi

Physical

Density and transition temperatures.

Liquidus Temperature

596°C1,105 °F
613°C1,135 °F

Same in both: Density 2.68 g/cm³0.1 lb/in³ · Melting Point (Solidus) 557°C1,035 °F

Thermal

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

Thermal Conductivity

150 W/m·K86.7 BTU/hr·ft·°F
151 W/m·K87.2 BTU/hr·ft·°F

Latent Heat of Fusion

425 J/g183 BTU/lb
389 J/g167 BTU/lb

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 · Max Service Temperature (continuous) 150°C302 °F · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 39 % IACS · Electrical Resistivity 4.4×10⁻⁸ Ω·m1.73 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.83 V · Corrosion Resistance 58 / 100

Manufacturability

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

Machinability

50 / 100
62 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
—

Weldability

65 / 100
75 / 100

Formability (cold)

10 / 100
12 / 100

Castability

88 / 100
93 / 100

Brazeability / Solderability

25 / 100
30 / 100

Polishability

45 / 100
50 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

155 MJ/kg66,638 BTU/lb
175 MJ/kg75,237 BTU/lb

Embodied Carbon (primary production)

9.5 kg CO₂/kg
11.5 kg CO₂/kg

Embodied Water

1,100 L/kg132 gal/lb
1,200 L/kg144 gal/lb

Typical Recycled Content

70%
55%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

97 kN·m/kg
93 kN·m/kg

Specific Stiffness (E / density)

26.5 MN·m/kg
27 MN·m/kg

Modulus of Resilience

282 kJ/m³
224 kJ/m³

Thermal Diffusivity

58.1 mm²/s
58.5 mm²/s

Thermal Shock Resistance Index

26
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 scaleAC4AAC4C

Manufacturing and finishing

CapabilityAC4AAC4C
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.

AC4A vs AC4C — frequently asked

Is AC4A stronger than AC4C?

Yes. AC4A has a typical yield strength of 200 MPa (29 ksi) against 180 MPa (26.1 ksi) for AC4C — about 11% more. Tensile strength is 260 MPa (37.7 ksi) vs 250 MPa (36.3 ksi).

Which is cheaper, AC4A 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, AC4A or AC4C?

AC4C. Its machinability rates good (62/100) against fair (50/100) for AC4A; for welding the order is AC4C first (very good, 75/100) then AC4A (good, 65/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in AC4A 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.