Magnesium Alloy AZ91D vs MC3
Magnesium Alloy · grade comparison
Magnesium Alloy AZ91D and MC3 are both magnesium alloy grades. MC3 is the stronger of the two: tensile strength 275 MPa (39.9 ksi) against 230 MPa (33.4 ksi) for AZ91D, about 20% more. MC3 is the more ductile: elongation 3.5% versus 3% for AZ91D. MC3 runs hotter in service (150°C vs 120°C continuous) and MC3 conducts heat better (109 W/m·K vs 72 W/m·K). On the shop floor, AZ91D welds better (fair vs poor) and AZ91D sits in a lower cost tier (standard, $$) than MC3 (high, $$$$).
AZ91DChoose it when it will be welded, or when cost is the deciding factor.
MC3Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
AZ91D vs MC3: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all magnesium alloy grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all magnesium alloy grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
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 · Compressive Strength 165 MPa23.9 ksi
Physical
Density and transition temperatures.
Melting Point (Solidus)
Liquidus Temperature
Same in both: Density 1.81 g/cm³0.07 lb/in³
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -1.55 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Castability
Same in both: Machinability Rating (AISI 1212 = 100 %) 400% · Brazeability / Solderability 20 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Typical Recycled Content
Same in both: Embodied Carbon (primary production) 32 kg CO₂/kg · Embodied Water 500 L/kg59.9 gal/lb
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
Same in both: Specific Stiffness (E / density) 24.9 MN·m/kg
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.
Manufacturing and finishing
| Capability | AZ91D | MC3 |
|---|---|---|
| CNC machining | Yes | — |
| Casting & forging | Yes | — |
| Default condition | As Cast | — |
| Relative cost | $$ Standard | $$$$ High |
| Min. machined wall | 0.8 mm | — |
| Best machined surface | Ra 0.8 µm | — |
| Anodizing Type II | Yes | — |
| Chem Film (Alodine) | Yes | — |
| E-Coating | Yes | — |
| Hard Anodize Type III w/ PTFE | Yes | — |
| Hard Anodizing Type III | Yes | — |
| Painting | Yes | — |
| Powder Coating | Yes | — |
AZ91D vs MC3 — frequently asked
Is MC3 stronger than AZ91D?
Yes. MC3 has a typical tensile strength of 275 MPa (39.9 ksi) against 230 MPa (33.4 ksi) for AZ91D — about 20% more.
Which is cheaper, AZ91D or MC3?
AZ91D is the lower-cost material: it sits in the standard tier ($$) while MC3 is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which welds better, AZ91D or MC3?
AZ91D. Its weldability rates fair (40/100) against poor (30/100) for MC3.
Ready to make it?
Upload a CAD file and FabDigit prices the part in AZ91D and MC3 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.