AZ31B-O Magnesium
AZ31B-O magnesium is AZ31B magnesium in the annealed condition. It has the lowest strength and highest ductility compared to the other variants of AZ31B magnesium. The graph bars on the material properties cards below compare AZ31B-O 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
56
Elastic (Young's, Tensile) Modulus
45 GPa 6.5 x 106 psi
Elongation at Break
12 %
Fatigue Strength
120 MPa 18 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
17 GPa 2.5 x 106 psi
Shear Strength
140 MPa 21 x 103 psi
Tensile Strength: Ultimate (UTS)
240 MPa 34 x 103 psi
Tensile Strength: Yield (Proof)
120 MPa 18 x 103 psi
Thermal Properties
Latent Heat of Fusion
350 J/g
Maximum Temperature: Mechanical
150 °C 300 °F
Melting Completion (Liquidus)
600 °C 1110 °F
Melting Onset (Solidus)
600 °C 1120 °F
Specific Heat Capacity
990 J/kg-K 0.24 BTU/lb-°F
Thermal Conductivity
100 W/m-K 60 BTU/h-ft-°F
Thermal Expansion
26 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
18 % IACS
Electrical Conductivity: Equal Weight (Specific)
95 % 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
970 L/kg 120 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
25 MJ/m3
Resilience: Unit (Modulus of Resilience)
170 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
62 mm2/s
Thermal Shock Resistance
14 points
Alloy Composition
| Mg | 93.6 to 97.1 | |
| Al | 2.4 to 3.6 | |
| Zn | 0.5 to 1.5 | |
| Mn | 0.050 to 1.0 | |
| Si | 0 to 0.1 | |
| Fe | 0 to 0.050 | |
| Cu | 0 to 0.050 | |
| Ca | 0 to 0.040 | |
| Ni | 0 to 0.0050 | |
| res. | 0 to 0.3 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Further Reading
ASTM B90: Standard Specification for Magnesium-Alloy Sheet and Plate
Advances in Wrought Magnesium Alloys: Fundamentals of Processing, Properties and Applications, Colleen Bettles and Matthew Barnett (editors), 2012
ASTM B91: Standard Specification for Magnesium-Alloy Forgings
ISO 3116: Magnesium and magnesium alloys - Wrought magnesium alloys
Welding and Joining of Magnesium Alloys, Liming Liu (editor), 2010
Essential Readings in Magnesium Technology, Suveen N. Mathaudhu et al. (editors), 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