Ductile Cast Iron vs. 7021 Aluminum
Ductile cast iron belongs to the iron alloys classification, while 7021 aluminum belongs to the aluminum alloys. There are 29 material properties with values for both materials. Properties with values for just one material (3, 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 ductile cast iron and the bottom bar is 7021 aluminum.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 170 to 180 | |
| 69 |
| Elongation at Break, % | 2.1 to 20 | |
| 9.4 |
| Poisson's Ratio | 0.28 to 0.31 | |
| 0.32 |
| Shear Modulus, GPa | 64 to 70 | |
| 26 |
| Shear Strength, MPa | 420 to 800 | |
| 270 |
| Tensile Strength: Ultimate (UTS), MPa | 460 to 920 | |
| 460 |
| Tensile Strength: Yield (Proof), MPa | 310 to 670 | |
| 390 |
Thermal Properties
| Latent Heat of Fusion, J/g | 270 | |
| 380 |
| Maximum Temperature: Mechanical, °C | 290 | |
| 200 |
| Melting Completion (Liquidus), °C | 1160 | |
| 630 |
| Melting Onset (Solidus), °C | 1120 | |
| 510 |
| Specific Heat Capacity, J/kg-K | 490 | |
| 870 |
| Thermal Conductivity, W/m-K | 31 to 36 | |
| 150 |
| Thermal Expansion, µm/m-K | 11 | |
| 24 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.4 | |
| 38 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.8 to 9.4 | |
| 120 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 1.9 | |
| 9.5 |
| Density, g/cm3 | 7.1 to 7.5 | |
| 2.9 |
| Embodied Carbon, kg CO2/kg material | 1.5 | |
| 8.3 |
| Embodied Energy, MJ/kg | 21 | |
| 150 |
| Embodied Water, L/kg | 43 | |
| 1140 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 17 to 80 | |
| 41 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 280 to 1330 | |
| 1110 |
| Stiffness to Weight: Axial, points | 12 to 14 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 to 26 | |
| 47 |
| Strength to Weight: Axial, points | 17 to 35 | |
| 44 |
| Strength to Weight: Bending, points | 18 to 29 | |
| 45 |
| Thermal Diffusivity, mm2/s | 8.9 to 10 | |
| 59 |
| Thermal Shock Resistance, points | 17 to 35 | |
| 20 |
Alloy Composition
| Aluminum (Al), % | 0 | |
| 90.7 to 93.7 |
| Carbon (C), % | 3.0 to 3.5 | |
| 0 |
| Chromium (Cr), % | 0 | |
| 0 to 0.050 |
| Copper (Cu), % | 0 | |
| 0 to 0.25 |
| Iron (Fe), % | 93.7 to 95.5 | |
| 0 to 0.4 |
| Magnesium (Mg), % | 0 | |
| 1.2 to 1.8 |
| Manganese (Mn), % | 0 | |
| 0 to 0.1 |
| Phosphorus (P), % | 0 to 0.080 | |
| 0 |
| Silicon (Si), % | 1.5 to 2.8 | |
| 0 to 0.25 |
| Titanium (Ti), % | 0 | |
| 0 to 0.1 |
| Zinc (Zn), % | 0 | |
| 5.0 to 6.0 |
| Zirconium (Zr), % | 0 | |
| 0.080 to 0.18 |
| Residuals, % | 0 | |
| 0 to 0.15 |