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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 relative to other magnesium alloys in the database.

The properties of AZ91C magnesium include four common variations. The property values on this page show 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).

Mechanical Properties

Elastic (Young's, Tensile) Modulus

46 GPa 6.7 x 106 psi

Elongation at Break

2.3 to 7.9 %

Fatigue Strength

65 to 85 MPa 9.4 to 12 x 103 psi

Poisson's Ratio


Shear Modulus

18 GPa 2.6 x 106 psi

Shear Strength

98 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

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


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)

3.1 to 18 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 m2/s

Thermal Shock Resistance

9.9 to 16 points

Alloy Composition

Magnesium (Mg) 88.6 to 91.4
Aluminum (Al) 8.1 to 9.3
Zinc (Zn) 0.4 to 1.0
Manganese (Mn) 0.13 to 0.35
Silicon (Si) 0 to 0.3
Copper (Cu) 0 to 0.1
Nickel (Ni) 0 to 0.010
Residuals 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.

CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015