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Magnesium Alloy AZ91D vs MC2

Magnesium Alloy · grade comparison

Magnesium Alloy AZ91D and MC2 are both magnesium alloy grades. AZ91D is the stronger of the two: yield strength 160 MPa (23.2 ksi) against 145 MPa (21 ksi) for MC2, about 10% more. MC2 is harder — 84 HB against 63 HB for AZ91D — which matters for wear surfaces and threads. On the shop floor, MC2 welds better (good vs fair).

AZ91DChoose it when strength drives the design.

MC2Choose it when surface hardness matters, or when it will be welded.

AZ91D vs MC2: properties

AZ91DMC2

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

230 MPa33.4 ksi
275 MPa39.9 ksi

Yield Strength (0.2% offset)

160 MPa23.2 ksi
145 MPa21 ksi

Compressive Strength

165 MPa23.9 ksi
350 MPa50.8 ksi

Shear Strength

140 MPa20.3 ksi
150 MPa21.8 ksi

Fatigue Strength (Endurance Limit)

97 MPa14.1 ksi
75 MPa10.9 ksi

Charpy V-Notch Impact (RT)

2 J1.6 ft·lbf
1 J1 ft·lbf

Hardness, Brinell

63 HB
84 HB

Hardness, Vickers

75 HV
88 HV

Same in both: Elastic (Young's) Modulus 45 GPa6.5 Msi · Shear Modulus 17 GPa2.5 Msi · Bulk Modulus 45 GPa6.5 Msi · Poisson's Ratio 0.35 · Elongation at Break 3% · Fracture Toughness (K_IC) 13 MPa·√m11.8 ksi·√in

Physical

Density and transition temperatures.

Density

1.81 g/cm³0.07 lb/in³
1.83 g/cm³0.07 lb/in³

Melting Point (Solidus)

470°C878 °F
443°C829 °F

Liquidus Temperature

595°C1,103 °F
596°C1,105 °F

Thermal

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

Specific Heat Capacity

1,020 J/kg·K0.24 BTU/lb·°F
1,050 J/kg·K0.25 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

26 µm/m·K14.4 µin/in·°F
25.2 µm/m·K14 µin/in·°F

Max Service Temperature (continuous)

120°C248 °F
130°C266 °F

Same in both: Thermal Conductivity 72 W/m·K41.6 BTU/hr·ft·°F · Latent Heat of Fusion 373 J/g160 BTU/lb · Min Service Temperature -60°C-76 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

12.2 % IACS
12 % IACS

Electrical Resistivity

1.41×10⁻⁷ Ω·m5.55 µΩ·in
1.45×10⁻⁷ Ω·m5.71 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-1.55 V
-1.6 V

Corrosion Resistance

30 / 100
20 / 100

Manufacturability

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

Machinability

98 / 100
95 / 100

Machinability Rating (AISI 1212 = 100 %)

400%
480%

Weldability

40 / 100
60 / 100

Formability (cold)

15 / 100
10 / 100

Castability

92 / 100
80 / 100

Brazeability / Solderability

20 / 100
25 / 100

Same in both: Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

320 MJ/kg137,575 BTU/lb
350 MJ/kg150,473 BTU/lb

Embodied Carbon (primary production)

32 kg CO₂/kg
30 kg CO₂/kg

Typical Recycled Content

35%
30%

Same in both: Embodied Water 500 L/kg59.9 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

127 kN·m/kg
150 kN·m/kg

Specific Stiffness (E / density)

24.9 MN·m/kg
24.6 MN·m/kg

Modulus of Resilience

284 kJ/m³
234 kJ/m³

Thermal Diffusivity

39 mm²/s
37.5 mm²/s

Thermal Shock Resistance Index

14
17

Strength versus weight

Yield strength against density for every magnesium alloy grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

701001502001.41.51.61.71.8Density (g/cm³)Yield strength (MPa) — log scaleAZ91DMC2

Manufacturing and finishing

CapabilityAZ91DMC2
CNC machiningYes—
Casting & forgingYes—
Default conditionAs Cast—
Relative cost$$ Standard$$ Standard
Min. machined wall0.8 mm—
Best machined surfaceRa 0.8 µm—
Anodizing Type IIYes—
Chem Film (Alodine)Yes—
E-CoatingYes—
Hard Anodize Type III w/ PTFEYes—
Hard Anodizing Type IIIYes—
PaintingYes—
Powder CoatingYes—

AZ91D vs MC2 — frequently asked

Is AZ91D stronger than MC2?

Yes. AZ91D has a typical yield strength of 160 MPa (23.2 ksi) against 145 MPa (21 ksi) for MC2 — about 10% more. Tensile strength is 230 MPa (33.4 ksi) vs 275 MPa (39.9 ksi).

Which is cheaper, AZ91D or MC2?

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 welds better, AZ91D or MC2?

MC2. Its weldability rates good (60/100) against fair (40/100) for AZ91D.

Ready to make it?

Upload a CAD file and FabDigit prices the part in AZ91D and MC2 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.