Magnesium Alloy AZ31B vs MB2
Magnesium Alloy · grade comparison
Magnesium Alloy AZ31B and MB2 are both magnesium alloy grades. MB2 is the stronger of the two: yield strength 220 MPa (31.9 ksi) against 150 MPa (21.8 ksi) for AZ31B, about 47% more; tensile strength follows at 290 MPa (42.1 ksi) vs 255 MPa (37 ksi). In exchange, AZ31B is the more ductile: elongation 21% versus 15% for MB2, and MB2 is harder (73 HB vs 49 HB). On the shop floor, AZ31B sits in a lower cost tier (standard, $$) than MB2 (premium, $$$).
AZ31BChoose it when the part is bent, formed or impact-loaded, or when cost is the deciding factor.
MB2Choose it when strength drives the design.
AZ31B vs MB2: 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.
Bulk Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 45 GPa6.5 Msi · Shear Modulus 17 GPa2.5 Msi · Poisson's Ratio 0.35 · Charpy V-Notch Impact (RT) 5 J3.7 ft·lbf
Physical
Density and transition temperatures.
Density
Same in both: Melting Point (Solidus) 566°C1,051 °F · Liquidus Temperature 632°C1,170 °F
Thermal
How each material carries heat and how hot it can run.
Latent Heat of Fusion
Min Service Temperature
Same in both: Thermal Conductivity 96 W/m·K55.5 BTU/hr·ft·°F · Specific Heat Capacity 1,000 J/kg·K0.24 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 26 µm/m·K14.4 µin/in·°F · Max Service Temperature (continuous) 120°C248 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Same in both: Electrical Resistivity 9.2×10⁻⁸ Ω·m3.62 µΩ·in
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.
Formability (cold)
Castability
Brazeability / Solderability
Same in both: Machinability 95 / 100 · Machinability Rating (AISI 1212 = 100 %) 400% · Weldability 70 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Same in both: Embodied Water 500 L/kg59.9 gal/lb · Typical Recycled Content 25%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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 | AZ31B | MB2 |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| Default condition | O | — |
| Relative cost | $$ Standard | $$$ Premium |
| 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 | — |
AZ31B vs MB2 — frequently asked
Is MB2 stronger than AZ31B?
Yes. MB2 has a typical yield strength of 220 MPa (31.9 ksi) against 150 MPa (21.8 ksi) for AZ31B — about 47% more. Tensile strength is 290 MPa (42.1 ksi) vs 255 MPa (37 ksi).
Which is cheaper, AZ31B or MB2?
AZ31B is the lower-cost material: it sits in the standard tier ($$) while MB2 is premium ($$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
When should I choose AZ31B over MB2?
Pick AZ31B when the part is bent, formed or impact-loaded, or when cost is the deciding factor. Pick MB2 when strength drives the design.
Ready to make it?
Upload a CAD file and FabDigit prices the part in AZ31B and MB2 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.