# 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 10 ^{6} psi*

Elongation at Break

4.2 *%*

Fatigue Strength

190 *MPa* 28 *x 10 ^{3} psi*

Poisson's Ratio

0.29

Shear Modulus

17 *GPa* 2.5 *x 10 ^{6} psi*

Shear Strength

160 *MPa* 24 *x 10 ^{3} psi*

Tensile Strength: Ultimate (UTS)

280 *MPa* 41 *x 10 ^{3} psi*

Tensile Strength: Yield (Proof)

260 *MPa* 38 *x 10 ^{3} 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/cm ^{3}* 110

*lb/ft*

^{3}Embodied Carbon

24 *kg CO _{2}/kg material*

Embodied Energy

160 *MJ/kg* 71 *x 10 ^{3} BTU/lb*

Embodied Water

950 *L/kg* 110 *gal/lb*

## Common Calculations

Resilience: Ultimate (Unit Rupture Work)

12 *MJ/m ^{3}*

Resilience: Unit (Modulus of Resilience)

740 *kJ/m ^{3}*

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 *m ^{2}/s*

Thermal Shock Resistance

17 *points*

## Alloy Composition

Mg | 94.2 to 96.1 | |

Zn | 3.5 to 4.5 | |

Zr | 0.45 to 1.0 | |

res. | 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.