AZ91D (M11916) Magnesium
AZ91D magnesium is a magnesium alloy. AZ91D is the ASTM designation for this material. M11916 is the UNS number. It can have a moderately low tensile strength among magnesium alloys. In addition, it has a moderately low electrical conductivity and a moderately low melting temperature.
The properties of AZ91D magnesium include three common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare AZ91D 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
60 to 80
Compressive (Crushing) Strength
310 to 430 MPa 45 to 62 x 103 psi
Elastic (Young's, Tensile) Modulus
46 GPa 6.7 x 106 psi
Elongation at Break
2.3 to 4.5 %
Fatigue Strength
74 to 85 MPa 11 to 12 x 103 psi
Impact Strength: V-Notched Charpy
2.7 J 2.0 ft-lb
Poisson's Ratio
0.29
Rockwell F Hardness
75
Shear Modulus
18 GPa 2.6 x 106 psi
Shear Strength
120 to 140 MPa 17 to 20 x 103 psi
Tensile Strength: Ultimate (UTS)
160 to 220 MPa 23 to 31 x 103 psi
Tensile Strength: Yield (Proof)
80 to 130 MPa 12 to 18 x 103 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)
490 °C 920 °F
Specific Heat Capacity
990 J/kg-K 0.24 BTU/lb-°F
Thermal Conductivity
78 W/m-K 45 BTU/h-ft-°F
Thermal Expansion
27 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
11 % IACS
Electrical Conductivity: Equal Weight (Specific)
58 % IACS
Otherwise Unclassified Properties
Base Metal Price
12 % relative
Density
1.7 g/cm3 110 lb/ft3
Embodied Carbon
22 kg CO2/kg material
Embodied Energy
160 MJ/kg 68 x 103 BTU/lb
Embodied Water
990 L/kg 120 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
4.2 to 7.7 MJ/m3
Resilience: Unit (Modulus of Resilience)
69 to 170 kJ/m3
Stiffness to Weight: Axial
15 points
Stiffness to Weight: Bending
69 points
Strength to Weight: Axial
26 to 34 points
Strength to Weight: Bending
38 to 46 points
Thermal Diffusivity
45 mm2/s
Thermal Shock Resistance
9.5 to 13 points
Alloy Composition
| Mg | 88.7 to 91.2 | |
| Al | 8.3 to 9.7 | |
| Zn | 0.35 to 1.0 | |
| Mn | 0.15 to 0.5 | |
| Si | 0 to 0.1 | |
| Cu | 0 to 0.030 | |
| Fe | 0 to 0.0050 | |
| Ni | 0 to 0.0020 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B94: Standard Specification for Magnesium-Alloy Die 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