# ZK40A (ZK40A-T5, M16400) Magnesium

ZK40A magnesium is a magnesium alloy. Cited properties are appropriate for 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 base cost among magnesium alloys. In addition, it has a fairly high electrical conductivity and a moderately high thermal conductivity.

The graph bars on the material properties cards below compare ZK40A magnesium to other magnesium alloys (top) and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

## 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

Latent Heat of Fusion

340 *J/g*

Maximum Temperature: Mechanical

120 *°C* 250 *°F*

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*

## Electrical Properties

Electrical Conductivity: Equal Volume

27 *% IACS*

Electrical Conductivity: Equal Weight (Specific)

130 *% IACS*

## 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 *mm ^{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

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.

CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015