# AZ91C-T4 Magnesium

AZ91C-T4 magnesium is AZ91C magnesium in the T4 temper. To achieve this temper, the metal is solution heat-treated and naturally aged. It has the highest ductility compared to the other variants of AZ91C magnesium. The graph bars on the material properties cards below compare AZ91C-T4 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

46 *GPa* 6.7 *x 10 ^{6} psi*

Elongation at Break

7.9 *%*

Fatigue Strength

85 *MPa* 12 *x 10 ^{3} psi*

Poisson's Ratio

0.29

Shear Modulus

18 *GPa* 2.6 *x 10 ^{6} psi*

Shear Strength

160 *MPa* 23 *x 10 ^{3} psi*

Tensile Strength: Ultimate (UTS)

270 *MPa* 38 *x 10 ^{3} psi*

Tensile Strength: Yield (Proof)

83 *MPa* 12 *x 10 ^{3} psi*

## Thermal Properties

Latent Heat of Fusion

350 *J/g*

Maximum Temperature: Mechanical

130 *°C* 270 *°F*

Melting Completion (Liquidus)

600 *°C* 1100 *°F*

Melting Onset (Solidus)

470 *°C* 870 *°F*

Solidification (Pattern Maker's) Shrinkage

1.3 *%*

Specific Heat Capacity

990 *J/kg-K* 0.24 *BTU/lb-°F*

Thermal Conductivity

73 *W/m-K* 42 *BTU/h-ft-°F*

Thermal Expansion

26 *µm/m-K*

## Electrical Properties

Electrical Conductivity: Equal Volume

9.9 *% IACS*

Electrical Conductivity: Equal Weight (Specific)

52 *% IACS*

## Otherwise Unclassified Properties

Base Metal Price

12 *% relative*

Density

1.7 *g/cm ^{3}* 110

*lb/ft*

^{3}Embodied Carbon

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

Embodied Energy

160 *MJ/kg* 67 *x 10 ^{3} BTU/lb*

Embodied Water

990 *L/kg* 120 *gal/lb*

## Common Calculations

Resilience: Ultimate (Unit Rupture Work)

16 *MJ/m ^{3}*

Resilience: Unit (Modulus of Resilience)

75 *kJ/m ^{3}*

Stiffness to Weight: Axial

15 *points*

Stiffness to Weight: Bending

69 *points*

Strength to Weight: Axial

43 *points*

Strength to Weight: Bending

53 *points*

Thermal Diffusivity

43 *mm ^{2}/s*

Thermal Shock Resistance

16 *points*

## Alloy Composition

Mg | 88.6 to 91.4 | |

Al | 8.1 to 9.3 | |

Zn | 0.4 to 1.0 | |

Mn | 0.13 to 0.35 | |

Si | 0 to 0.3 | |

Cu | 0 to 0.1 | |

Ni | 0 to 0.010 | |

res. | 0 to 0.3 |

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

## Followup Questions

## Further Reading

ASTM B199: Standard Specification for Magnesium-Alloy Permanent Mold Castings

ASTM B403: Standard Specification for Magnesium-Alloy Investment Castings

ASTM B80: Standard Specification for Magnesium-Alloy Sand Castings

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

Advanced Materials in Automotive Engineering, Jason Rowe (editor), 2012

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