Magnesium Alloy AZ91C vs AZ91D
Magnesium Alloy · grade comparison
Magnesium Alloy AZ91C and AZ91D are both magnesium alloy grades. AZ91D is the stronger of the two: yield strength 160 MPa (23.2 ksi) against 97 MPa (14.1 ksi) for AZ91C, about 65% more; tensile strength follows at 230 MPa (33.4 ksi) vs 165 MPa (23.9 ksi). AZ91D is the more ductile: elongation 3% versus 2.5% for AZ91C. On the shop floor, AZ91C welds better (very good vs fair).
AZ91CChoose it when it will be welded.
AZ91DChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
AZ91C vs AZ91D: 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
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
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 · Fracture Toughness (K_IC) 13 MPa·√m11.8 ksi·√in
Physical
Density and transition temperatures.
Same in both: Density 1.81 g/cm³0.07 lb/in³ · Melting Point (Solidus) 470°C878 °F · Liquidus Temperature 595°C1,103 °F
Thermal
How each material carries heat and how hot it can run.
Specific Heat Capacity
Min Service Temperature
Same in both: Thermal Conductivity 72 W/m·K41.6 BTU/hr·ft·°F · Thermal Expansion (CTE, 20–100 °C) 26 µm/m·K14.4 µin/in·°F · Latent Heat of Fusion 373 J/g160 BTU/lb · Max Service Temperature (continuous) 120°C248 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Same in both: Electrical Resistivity 1.41×10⁻⁷ Ω·m5.55 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)
Castability
Same in both: Brazeability / Solderability 20 / 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 35%
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 | AZ91C | AZ91D |
|---|---|---|
| CNC machining | — | Yes |
| Casting & forging | — | Yes |
| Default condition | — | As Cast |
| Relative cost | $$ Standard | $$ Standard |
| 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 |
AZ91C vs AZ91D — frequently asked
Is AZ91D stronger than AZ91C?
Yes. AZ91D has a typical yield strength of 160 MPa (23.2 ksi) against 97 MPa (14.1 ksi) for AZ91C — about 65% more. Tensile strength is 230 MPa (33.4 ksi) vs 165 MPa (23.9 ksi).
Which is cheaper, AZ91C or AZ91D?
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, AZ91C or AZ91D?
AZ91C. Its weldability rates very good (70/100) against fair (40/100) for AZ91D.
Ready to make it?
Upload a CAD file and FabDigit prices the part in AZ91C and AZ91D 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.