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ZK40A (ZK40A-T5, M16400) Magnesium

ZK40A 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. ZK40A is the ASTM designation for this material. M16400 is the UNS number.

It has a moderately high thermal conductivity among magnesium alloys. In addition, it has a moderately high base cost and a fairly high tensile strength.

The graph bars on the material properties cards below compare ZK40A magnesium to other magnesium alloys (top) and the entire database (bottom).

Mechanical Properties

Elastic (Young's, Tensile) Modulus

45 GPa 6.5 x 106 psi

Elongation at Break

4.2 %

Fatigue Strength

190 MPa 28 x 103 psi

Poisson's Ratio

0.29

Shear Modulus

17 GPa 2.5 x 106 psi

Shear Strength

160 MPa 24 x 103 psi

Tensile Strength: Ultimate (UTS)

280 MPa 41 x 103 psi

Tensile Strength: Yield (Proof)

260 MPa 38 x 103 psi

Thermal Properties

Melting Completion (Liquidus)

600 °C 1110 °F

Melting Onset (Solidus)

540 °C 1010 °F

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

Otherwise Unclassified Properties

Base Metal Price

13 % relative

Density

1.8 g/cm3 110 lb/ft3

Embodied Carbon

24 kg CO2/kg material

Embodied Energy

160 MJ/kg 71 x 103 BTU/lb

Embodied Water

950 L/kg 110 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

12 MJ/m3

Resilience: Unit (Modulus of Resilience)

740 kJ/m3

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

65 points

Strength to Weight: Axial

43 points

Strength to Weight: Bending

53 points

Thermal Diffusivity

62 m2/s

Thermal Shock Resistance

17 points

Alloy Composition

Magnesium (Mg) 94.2 to 96.1
Zinc (Zn) 3.5 to 4.5
Zirconium (Zr) 0.45 to 1.0
Residuals 0 to 0.3

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

Followup Questions

Similar Alloys

Further Reading

ASTM B107: Standard Specification for Magnesium-Alloy Extruded Bars, Rods, Profiles, Tubes, and Wire

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