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Aluminum AC2A vs AC9B

Aluminum · grade comparison

Aluminum AC2A and AC9B are both aluminum grades. AC9B is the stronger of the two: yield strength 200 MPa (29 ksi) against 170 MPa (24.7 ksi) for AC2A, about 18% more. In exchange, AC2A is the more ductile: elongation 2% versus 0.5% for AC9B, and AC9B is harder (140 HB vs 85 HB). AC9B is lighter (2.68 g/cm³ vs 2.79 g/cm³ for AC2A) and AC9B is stiffer (82 GPa vs 74 GPa). On the shop floor, AC2A machines more easily (very good vs poor) 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.

AC9BChoose it when strength drives the design, or when weight is the constraint.

AC2A vs AC9B: properties

AC2AAC9B

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
76 GPa11 Msi

Tensile Strength (Ultimate)

250 MPa36.3 ksi
220 MPa31.9 ksi

Yield Strength (0.2% offset)

170 MPa24.7 ksi
200 MPa29 ksi

Elongation at Break

2%
0.5%

Shear Strength

165 MPa23.9 ksi
155 MPa22.5 ksi

Fatigue Strength (Endurance Limit)

75 MPa10.9 ksi
90 MPa13.1 ksi

Fracture Toughness (K_IC)

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

Charpy V-Notch Impact (RT)

3 J2.2 ft·lbf
2 J1.1 ft·lbf

Hardness, Brinell

85 HB
140 HB

Compressive Strength

—
450 MPa65.3 ksi

Same in both: Poisson's Ratio 0.33

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
507°C945 °F

Liquidus Temperature

604°C1,119 °F
670°C1,238 °F

Thermal

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

Thermal Conductivity

110 W/m·K63.6 BTU/hr·ft·°F
130 W/m·K75.1 BTU/hr·ft·°F

Specific Heat Capacity

963 J/kg·K0.23 BTU/lb·°F
880 J/kg·K0.21 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

21.5 µm/m·K11.9 µin/in·°F
17.8 µm/m·K9.9 µin/in·°F

Latent Heat of Fusion

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

Max Service Temperature (continuous)

175°C347 °F
250°C482 °F

Min Service Temperature

-196°C-321 °F
-80°C-112 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

27 % IACS
25 % IACS

Electrical Resistivity

6.4×10⁻⁸ Ω·m2.52 µΩ·in
6.9×10⁻⁸ Ω·m2.72 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.75 V
-0.8 V

Corrosion Resistance

42 / 100
48 / 100

Manufacturability

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

Machinability

72 / 100
28 / 100

Machinability Rating (AISI 1212 = 100 %)

70%
40%

Weldability

35 / 100
22 / 100

Formability (cold)

10 / 100
3 / 100

Castability

75 / 100
70 / 100

Brazeability / Solderability

25 / 100
20 / 100

Polishability

40 / 100
45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

200 MJ/kg85,985 BTU/lb
155 MJ/kg66,638 BTU/lb

Embodied Carbon (primary production)

12 kg CO₂/kg
10.5 kg CO₂/kg

Embodied Water

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

Typical Recycled Content

80%
55%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

90 kN·m/kg
82 kN·m/kg

Specific Stiffness (E / density)

26.5 MN·m/kg
30.6 MN·m/kg

Modulus of Resilience

195 kJ/m³
244 kJ/m³

Thermal Diffusivity

40.9 mm²/s
55.1 mm²/s

Thermal Shock Resistance Index

17
20

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 scaleAC2AAC9B

Manufacturing and finishing

CapabilityAC2AAC9B
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 AC9B — frequently asked

Is AC9B stronger than AC2A?

Yes. AC9B has a typical yield strength of 200 MPa (29 ksi) against 170 MPa (24.7 ksi) for AC2A — about 18% more. Tensile strength is 220 MPa (31.9 ksi) vs 250 MPa (36.3 ksi).

Which is cheaper, AC2A or AC9B?

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 AC9B?

AC2A. Its machinability rates very good (72/100) against poor (28/100) for AC9B; for welding the order is AC2A first (fair, 35/100) then AC9B (poor, 22/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in AC2A and AC9B 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.