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
| 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
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