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ZK51A (ZK51A-T5, M16510) Magnesium

ZK51A magnesium is a magnesium alloy. It is typically furnished in the T5 temper. To achieve this temper, the metal is artificially aged until it meets standard mechanical property requirements. ZK51A is the ASTM designation for this material. M16510 is the UNS number.

It has a moderately high thermal conductivity and a moderately high base cost relative to other magnesium alloys.

The graph bars on the material properties cards below compare ZK51A magnesium to other magnesium alloys (top) and the entire database (bottom).

Mechanical Properties

Elastic (Young's, Tensile) Modulus

45 GPa 6.6 x 106 psi

Elongation at Break

4.7 %

Fatigue Strength

62 MPa 9.0 x 103 psi

Poisson's Ratio


Shear Modulus

18 GPa 2.6 x 106 psi

Shear Strength

160 MPa 23 x 103 psi

Tensile Strength: Ultimate (UTS)

240 MPa 35 x 103 psi

Tensile Strength: Yield (Proof)

150 MPa 22 x 103 psi

Thermal Properties

Melting Completion (Liquidus)

640 °C 1190 °F

Melting Onset (Solidus)

550 °C 1020 °F

Solidification (Pattern Maker's) Shrinkage

1.3 %

Specific Heat Capacity

970 J/kg-K 0.23 BTU/lb-°F

Thermal Conductivity

110 W/m-K 64 BTU/h-ft-°F

Thermal Expansion

26 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

28 % IACS

Electrical Conductivity: Equal Weight (Specific)

140 % IACS

Otherwise Unclassified Properties

Base Metal Price

13 % relative


1.8 g/cm3 120 lb/ft3

Embodied Carbon

24 kg CO2/kg material

Embodied Energy

160 MJ/kg 71 x 103 BTU/lb

Embodied Water

940 L/kg 110 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

10 MJ/m3

Resilience: Unit (Modulus of Resilience)

260 kJ/m3

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

64 points

Strength to Weight: Axial

36 points

Strength to Weight: Bending

47 points

Thermal Diffusivity

61 m2/s

Thermal Shock Resistance

15 points

Alloy Composition

Magnesium (Mg) 93.1 to 95.9
Zinc (Zn) 3.6 to 5.5
Zirconium (Zr) 0.5 to 1.0
Copper (Cu) 0 to 0.1
Nickel (Ni) 0 to 0.010
Residuals 0 to 0.3

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

Welding and Joining of Magnesium Alloys, Liming Liu (editor), 2010

ASTM B80: Standard Specification for Magnesium-Alloy Sand Castings

Essential Readings in Magnesium Technology, Suveen N. Mathaudhu et al. (editors), 2014

Environmental Degradation of Advanced and Traditional Engineering Materials, Lloyd H. Hihara et al., 2014.

Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM Handbook vol. 2, ASM International, 1993