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AZ81A-T4 Magnesium

AZ81A-T4 magnesium is AZ81A magnesium in the T4 temper. To achieve this temper, the metal is solution heat-treated and naturally aged. The graph bars on the material properties cards below compare AZ81A-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

Brinell Hardness

55

Compressive (Crushing) Strength

370 MPa 54 x 103 psi

Elastic (Young's, Tensile) Modulus

46 GPa 6.6 x 106 psi

Elongation at Break

8.8 %

Fatigue Strength

78 MPa 11 x 103 psi

Poisson's Ratio

0.29

Shear Modulus

18 GPa 2.6 x 106 psi

Shear Strength

130 MPa 19 x 103 psi

Tensile Strength: Ultimate (UTS)

240 MPa 35 x 103 psi

Tensile Strength: Yield (Proof)

84 MPa 12 x 103 psi

Thermal Properties

Latent Heat of Fusion

350 J/g

Maximum Temperature: Mechanical

130 °C 260 °F

Melting Completion (Liquidus)

600 °C 1120 °F

Melting Onset (Solidus)

500 °C 940 °F

Solidification (Pattern Maker's) Shrinkage

1.3 %

Specific Heat Capacity

990 J/kg-K 0.24 BTU/lb-°F

Thermal Conductivity

84 W/m-K 49 BTU/h-ft-°F

Thermal Expansion

27 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

12 % IACS

Electrical Conductivity: Equal Weight (Specific)

65 % IACS

Otherwise Unclassified Properties

Base Metal Price

12 % relative

Density

1.7 g/cm3 110 lb/ft3

Embodied Carbon

23 kg CO2/kg material

Embodied Energy

160 MJ/kg 67 x 103 BTU/lb

Embodied Water

990 L/kg 120 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

17 MJ/m3

Resilience: Unit (Modulus of Resilience)

78 kJ/m3

Stiffness to Weight: Axial

15 points

Stiffness to Weight: Bending

70 points

Strength to Weight: Axial

39 points

Strength to Weight: Bending

50 points

Thermal Diffusivity

50 mm2/s

Thermal Shock Resistance

14 points

Alloy Composition

Magnesium (Mg)Mg 89.8 to 92.5
Aluminum (Al)Al 7.0 to 8.1
Zinc (Zn)Zn 0.4 to 1.0
Manganese (Mn)Mn 0.13 to 0.35
Silicon (Si)Si 0 to 0.3
Copper (Cu)Cu 0 to 0.1
Nickel (Ni)Ni 0 to 0.010
Residualsres. 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

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.

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

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