Magnesium Alloy AZ31B vs AZ31C
Magnesium Alloy · grade comparison
Magnesium Alloy AZ31B and AZ31C are both magnesium alloy grades. AZ31C is the stronger of the two: yield strength 200 MPa (29 ksi) against 150 MPa (21.8 ksi) for AZ31B, about 33% more. In exchange, AZ31B is the more ductile: elongation 21% versus 15% for AZ31C. On the shop floor, AZ31B sits in a lower cost tier (standard, $$) than AZ31C (premium, $$$).
AZ31BChoose it when the part is bent, formed or impact-loaded, or when cost is the deciding factor.
AZ31CChoose it when strength drives the design.
AZ31B vs AZ31C: 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
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Rockwell B
Same in both: Elastic (Young's) Modulus 45 GPa6.5 Msi · Shear Modulus 17 GPa2.5 Msi · Poisson's Ratio 0.35 · Compressive Strength 97 MPa14.1 ksi · Charpy V-Notch Impact (RT) 5 J3.7 ft·lbf · Hardness, Brinell 49 HB · Hardness, Vickers 55 HV
Physical
Density and transition temperatures.
Same in both: Density 1.77 g/cm³0.06 lb/in³ · 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.
Same in both: Electrical Conductivity 18.5 % IACS · 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.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Brazeability / Solderability
Same in both: Castability 40 / 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
Same in both: Specific Stiffness (E / density) 25.4 MN·m/kg · Thermal Diffusivity 54.2 mm²/s · Thermal Shock Resistance Index 21
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 | AZ31C |
|---|---|---|
| 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 AZ31C — frequently asked
Is AZ31C stronger than AZ31B?
Yes. AZ31C has a typical yield strength of 200 MPa (29 ksi) against 150 MPa (21.8 ksi) for AZ31B — about 33% more. Tensile strength is 260 MPa (37.7 ksi) vs 255 MPa (37 ksi).
Which is cheaper, AZ31B or AZ31C?
AZ31B is the lower-cost material: it sits in the standard tier ($$) while AZ31C is premium ($$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, AZ31B or AZ31C?
AZ31C, by a small margin. Both rate excellent for machinability — 100/100 against 95/100 for AZ31B; for welding the order is AZ31C first (very good, 75/100) then AZ31B (very good, 70/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in AZ31B and AZ31C 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.