AZ91C (M11914) Magnesium
AZ91C magnesium is a magnesium alloy. AZ91C is the ASTM designation for this material. M11914 is the UNS number. It has a moderately low melting temperature among the magnesium alloys in the database.
The properties of AZ91C magnesium include four 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 AZ91C 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 106 psi
Elongation at Break
2.3 to 7.9 %
Fatigue Strength
56 to 85 MPa 8.1 to 12 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
18 GPa 2.6 x 106 psi
Shear Strength
96 to 160 MPa 14 to 23 x 103 psi
Tensile Strength: Ultimate (UTS)
170 to 270 MPa 24 to 39 x 103 psi
Tensile Strength: Yield (Proof)
83 to 130 MPa 12 to 19 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)
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 to 12 % IACS
Electrical Conductivity: Equal Weight (Specific)
52 to 60 % 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 67 x 103 BTU/lb
Embodied Water
990 L/kg 120 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
3.2 to 16 MJ/m3
Resilience: Unit (Modulus of Resilience)
75 to 180 kJ/m3
Stiffness to Weight: Axial
15 points
Stiffness to Weight: Bending
69 points
Strength to Weight: Axial
27 to 43 points
Strength to Weight: Bending
39 to 53 points
Thermal Diffusivity
43 mm2/s
Thermal Shock Resistance
9.9 to 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
Similar Alloys
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
Environmental Degradation of Advanced and Traditional Engineering Materials, Lloyd H. Hihara et al., 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