AZ91D Magnesium vs. 7178 Aluminum
AZ91D magnesium belongs to the magnesium alloys classification, while 7178 aluminum belongs to the aluminum alloys. There are 30 material properties with values for both materials. Properties with values for just one material (4, in this case) are not shown.
For each property being compared, the top bar is AZ91D magnesium and the bottom bar is 7178 aluminum.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 46 | |
| 71 |
| Elongation at Break, % | 2.3 to 4.5 | |
| 4.5 to 12 |
| Fatigue Strength, MPa | 74 to 85 | |
| 120 to 210 |
| Poisson's Ratio | 0.29 | |
| 0.32 |
| Shear Modulus, GPa | 18 | |
| 27 |
| Shear Strength, MPa | 120 to 140 | |
| 140 to 380 |
| Tensile Strength: Ultimate (UTS), MPa | 160 to 220 | |
| 240 to 640 |
| Tensile Strength: Yield (Proof), MPa | 80 to 130 | |
| 120 to 560 |
Thermal Properties
| Latent Heat of Fusion, J/g | 350 | |
| 370 |
| Maximum Temperature: Mechanical, °C | 130 | |
| 180 |
| Melting Completion (Liquidus), °C | 600 | |
| 630 |
| Melting Onset (Solidus), °C | 490 | |
| 480 |
| Specific Heat Capacity, J/kg-K | 990 | |
| 860 |
| Thermal Conductivity, W/m-K | 78 | |
| 130 |
| Thermal Expansion, µm/m-K | 27 | |
| 23 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 11 | |
| 31 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 58 | |
| 91 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 12 | |
| 10 |
| Density, g/cm3 | 1.7 | |
| 3.1 |
| Embodied Carbon, kg CO2/kg material | 22 | |
| 8.2 |
| Embodied Energy, MJ/kg | 160 | |
| 150 |
| Embodied Water, L/kg | 990 | |
| 1110 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 4.2 to 7.7 | |
| 24 to 52 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 69 to 170 | |
| 110 to 2220 |
| Stiffness to Weight: Axial, points | 15 | |
| 13 |
| Stiffness to Weight: Bending, points | 69 | |
| 45 |
| Strength to Weight: Axial, points | 26 to 34 | |
| 21 to 58 |
| Strength to Weight: Bending, points | 38 to 46 | |
| 28 to 54 |
| Thermal Diffusivity, mm2/s | 45 | |
| 47 |
| Thermal Shock Resistance, points | 9.5 to 13 | |
| 10 to 28 |
Alloy Composition
| Aluminum (Al), % | 8.3 to 9.7 | |
| 85.4 to 89.5 |
| Chromium (Cr), % | 0 | |
| 0.18 to 0.28 |
| Copper (Cu), % | 0 to 0.030 | |
| 1.6 to 2.4 |
| Iron (Fe), % | 0 to 0.0050 | |
| 0 to 0.5 |
| Magnesium (Mg), % | 88.7 to 91.2 | |
| 2.4 to 3.1 |
| Manganese (Mn), % | 0.15 to 0.5 | |
| 0 to 0.3 |
| Nickel (Ni), % | 0 to 0.0020 | |
| 0 |
| Silicon (Si), % | 0 to 0.1 | |
| 0 to 0.4 |
| Titanium (Ti), % | 0 | |
| 0 to 0.2 |
| Zinc (Zn), % | 0.35 to 1.0 | |
| 6.3 to 7.3 |
| Residuals, % | 0 | |
| 0 to 0.15 |