AZ81A (M11810) Magnesium
AZ81A magnesium is a magnesium alloy. AZ81A is the ASTM designation for this material. M11810 is the UNS number.
The properties of AZ81A magnesium include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare AZ81A 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
310 to 370 MPa 45 to 54 x 103 psi
Elastic (Young's, Tensile) Modulus
46 GPa 6.6 x 106 psi
Elongation at Break
3.0 to 8.8 %
Fatigue Strength
78 to 80 MPa 11 to 12 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
18 GPa 2.6 x 106 psi
Shear Strength
91 to 130 MPa 13 to 19 x 103 psi
Tensile Strength: Ultimate (UTS)
160 to 240 MPa 23 to 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)
4.0 to 17 MJ/m3
Resilience: Unit (Modulus of Resilience)
77 to 78 kJ/m3
Stiffness to Weight: Axial
15 points
Stiffness to Weight: Bending
70 points
Strength to Weight: Axial
26 to 39 points
Strength to Weight: Bending
38 to 50 points
Thermal Diffusivity
50 mm2/s
Thermal Shock Resistance
9.1 to 14 points
Alloy Composition
| Mg | 89.8 to 92.5 | |
| Al | 7.0 to 8.1 | |
| 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
Similar Alloys
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