FabDigitFabDigit

Magnesium Alloy ZC63A vs ZK51A

Magnesium Alloy · grade comparison

Magnesium Alloy ZC63A 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 ZC63A, about 14% more. In exchange, ZC63A is the more ductile: elongation 5% versus 3.5% for ZK51A, and ZK51A is harder (65 HB vs 60 HB). ZK51A is lighter (1.81 g/cm³ vs 1.87 g/cm³ for ZC63A) and ZC63A runs hotter in service (150°C vs 120°C continuous). On the shop floor, ZC63A welds better (fair vs poor).

ZC63AChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.

ZK51AChoose it when strength drives the design, or when weight is the constraint.

ZC63A vs ZK51A: properties

ZC63AZK51A

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

17 GPa2.5 Msi
16.5 GPa2.4 Msi

Tensile Strength (Ultimate)

210 MPa30.5 ksi
205 MPa29.7 ksi

Yield Strength (0.2% offset)

145 MPa21 ksi
165 MPa23.9 ksi

Elongation at Break

5%
3.5%

Reduction in Area

6%
—

Compressive Strength

130 MPa18.9 ksi
170 MPa24.7 ksi

Shear Strength

140 MPa20.3 ksi
160 MPa23.2 ksi

Fatigue Strength (Endurance Limit)

80 MPa11.6 ksi
70 MPa10.2 ksi

Fracture Toughness (K_IC)

13 MPa·√m11.8 ksi·√in
14 MPa·√m12.7 ksi·√in

Charpy V-Notch Impact (RT)

3 J2.2 ft·lbf
3 J1.8 ft·lbf

Hardness, Brinell

60 HB
65 HB

Hardness, Vickers

63 HV
—

Same in both: Elastic (Young's) Modulus 45 GPa6.5 Msi · Bulk Modulus 45 GPa6.5 Msi · Poisson's Ratio 0.35

Physical

Density and transition temperatures.

Density

1.87 g/cm³0.07 lb/in³
1.81 g/cm³0.07 lb/in³

Melting Point (Solidus)

465°C869 °F
549°C1,020 °F

Liquidus Temperature

635°C1,175 °F
640°C1,184 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

122 W/m·K70.5 BTU/hr·ft·°F
109 W/m·K63 BTU/hr·ft·°F

Max Service Temperature (continuous)

150°C302 °F
120°C248 °F

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 · Latent Heat of Fusion 340 J/g146 BTU/lb · Min Service Temperature -100°C-148 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

24 % IACS
27 % IACS

Electrical Resistivity

7.2×10⁻⁸ Ω·m2.83 µΩ·in
6.4×10⁻⁸ Ω·m2.52 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-1.55 V
-1.58 V

Corrosion Resistance

18 / 100
22 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

95 / 100
98 / 100

Weldability

40 / 100
15 / 100

Castability

80 / 100
60 / 100

Brazeability / Solderability

20 / 100
15 / 100

Polishability

50 / 100
55 / 100

Same in both: Machinability Rating (AISI 1212 = 100 %) 500% · Formability (cold) 10 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

330 MJ/kg141,875 BTU/lb
320 MJ/kg137,575 BTU/lb

Embodied Carbon (primary production)

33 kg CO₂/kg
32 kg CO₂/kg

Typical Recycled Content

25%
20%

Same in both: Embodied Water 500 L/kg59.9 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

112 kN·m/kg
113 kN·m/kg

Specific Stiffness (E / density)

24.1 MN·m/kg
24.9 MN·m/kg

Modulus of Resilience

234 kJ/m³
303 kJ/m³

Thermal Diffusivity

65.2 mm²/s
60.2 mm²/s

Thermal Shock Resistance Index

21
18

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.

701001502001.41.51.61.71.8Density (g/cm³)Yield strength (MPa) — log scaleZC63AZK51A

Manufacturing and finishing

CapabilityZC63AZK51A
Default condition——
Relative cost$$$ Premium$$$ Premium
Min. machined wall——
Best machined surface——

ZC63A vs ZK51A — frequently asked

Is ZK51A stronger than ZC63A?

Yes. ZK51A has a typical yield strength of 165 MPa (23.9 ksi) against 145 MPa (21 ksi) for ZC63A — about 14% more. Tensile strength is 205 MPa (29.7 ksi) vs 210 MPa (30.5 ksi).

Which is cheaper, ZC63A 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, ZC63A or ZK51A?

ZC63A. Its weldability rates fair (40/100) against poor (15/100) for ZK51A.

Ready to make it?

Upload a CAD file and FabDigit prices the part in ZC63A 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.