ASTM B631 Class B vs. AZ81A Magnesium
ASTM B631 class B belongs to the otherwise unclassified metals classification, while AZ81A magnesium belongs to the magnesium alloys. There are 16 material properties with values for both materials. Properties with values for just one material (18, in this case) are not shown. Please note that the two materials have significantly dissimilar densities. This means that additional care is required when interpreting the data, because some material properties are based on units of mass, while others are based on units of area or volume.
For each property being compared, the top bar is ASTM B631 class B and the bottom bar is AZ81A magnesium.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 210 | |
| 46 |
| Poisson's Ratio | 0.31 | |
| 0.29 |
| Shear Modulus, GPa | 78 to 79 | |
| 18 |
Thermal Properties
| Latent Heat of Fusion, J/g | 150 | |
| 350 |
| Melting Completion (Liquidus), °C | 2460 to 2480 | |
| 600 |
| Specific Heat Capacity, J/kg-K | 170 | |
| 990 |
| Thermal Conductivity, W/m-K | 450 | |
| 84 |
| Thermal Expansion, µm/m-K | 12 | |
| 27 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 50 to 53 | |
| 12 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 32 to 34 | |
| 65 |
Otherwise Unclassified Properties
| Density, g/cm3 | 14 | |
| 1.7 |
| Embodied Carbon, kg CO2/kg material | 49 | |
| 23 |
| Embodied Energy, MJ/kg | 760 | |
| 160 |
Common Calculations
| Stiffness to Weight: Axial, points | 8.1 | |
| 15 |
| Stiffness to Weight: Bending, points | 14 | |
| 70 |
| Thermal Diffusivity, mm2/s | 190 | |
| 50 |