Magnesium Alloy ZK40A vs ZK51A
Magnesium Alloy · grade comparison
Magnesium Alloy ZK40A and ZK51A are both magnesium alloy grades. ZK51A is the stronger of the two: yield strength 165 MPa (23.9 ksi) against 145 MPa (21 ksi) for ZK40A, about 14% more. In exchange, ZK40A is the more ductile: elongation 5% versus 3.5% for ZK51A. On the shop floor, ZK40A welds better (30 vs 15 out of 100).
ZK40AChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
ZK51AChoose it when strength drives the design.
ZK40A vs ZK51A: 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)
Same in both: Elastic (Young's) Modulus 45 GPa6.5 Msi · Shear Modulus 16.5 GPa2.4 Msi · Bulk Modulus 45 GPa6.5 Msi · Poisson's Ratio 0.35 · Fracture Toughness (K_IC) 14 MPa·√m12.7 ksi·√in · Hardness, Brinell 65 HB
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Latent Heat of Fusion
Same in both: Specific Heat Capacity 1,000 J/kg·K0.24 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 27 µm/m·K15 µin/in·°F · Max Service Temperature (continuous) 120°C248 °F · Min Service Temperature -100°C-148 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Castability
Polishability
Same in both: Brazeability / Solderability 15 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Typical Recycled Content
Same in both: Embodied Water 500 L/kg59.9 gal/lb
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 | ZK40A | ZK51A |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$ Premium | $$$ Premium |
| Min. machined wall | — | — |
| Best machined surface | — | — |
ZK40A vs ZK51A — frequently asked
Is ZK51A stronger than ZK40A?
Yes. ZK51A has a typical yield strength of 165 MPa (23.9 ksi) against 145 MPa (21 ksi) for ZK40A — about 14% more. Tensile strength is 205 MPa (29.7 ksi) vs 250 MPa (36.3 ksi).
Which is cheaper, ZK40A or ZK51A?
Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, ZK40A or ZK51A?
ZK40A. Its weldability rates poor (30/100) against poor (15/100) for ZK51A.
Ready to make it?
Upload a CAD file and FabDigit prices the part in ZK40A and ZK51A 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.