7021 Aluminum vs. R30155 Cobalt
7021 aluminum belongs to the aluminum alloys classification, while R30155 cobalt belongs to the iron alloys. There are 28 material properties with values for both materials. Properties with values for just one material (6, 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 7021 aluminum and the bottom bar is R30155 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 69 | |
| 210 |
| Elongation at Break, % | 9.4 | |
| 34 |
| Fatigue Strength, MPa | 150 | |
| 310 |
| Poisson's Ratio | 0.32 | |
| 0.29 |
| Shear Modulus, GPa | 26 | |
| 81 |
| Shear Strength, MPa | 270 | |
| 570 |
| Tensile Strength: Ultimate (UTS), MPa | 460 | |
| 850 |
| Tensile Strength: Yield (Proof), MPa | 390 | |
| 390 |
Thermal Properties
| Latent Heat of Fusion, J/g | 380 | |
| 300 |
| Maximum Temperature: Mechanical, °C | 200 | |
| 1100 |
| Melting Completion (Liquidus), °C | 630 | |
| 1470 |
| Melting Onset (Solidus), °C | 510 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 870 | |
| 450 |
| Thermal Conductivity, W/m-K | 150 | |
| 12 |
| Thermal Expansion, µm/m-K | 24 | |
| 14 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 9.5 | |
| 80 |
| Density, g/cm3 | 2.9 | |
| 8.5 |
| Embodied Carbon, kg CO2/kg material | 8.3 | |
| 9.7 |
| Embodied Energy, MJ/kg | 150 | |
| 150 |
| Embodied Water, L/kg | 1140 | |
| 300 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 41 | |
| 230 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 1110 | |
| 370 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 47 | |
| 23 |
| Strength to Weight: Axial, points | 44 | |
| 28 |
| Strength to Weight: Bending, points | 45 | |
| 24 |
| Thermal Diffusivity, mm2/s | 59 | |
| 3.2 |
| Thermal Shock Resistance, points | 20 | |
| 21 |
Alloy Composition
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| Aluminum (Al), % | 90.7 to 93.7 | |
| 0 |
| Carbon (C), % | 0 | |
| 0.080 to 0.16 |
| Chromium (Cr), % | 0 to 0.050 | |
| 20 to 22.5 |
| Cobalt (Co), % | 0 | |
| 18.5 to 21 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 |
| Iron (Fe), % | 0 to 0.4 | |
| 24.3 to 36.2 |
| Magnesium (Mg), % | 1.2 to 1.8 | |
| 0 |
| Manganese (Mn), % | 0 to 0.1 | |
| 1.0 to 2.0 |
| Molybdenum (Mo), % | 0 | |
| 2.5 to 3.5 |
| Nickel (Ni), % | 0 | |
| 19 to 21 |
| Niobium (Nb), % | 0 | |
| 0.75 to 1.3 |
| Nitrogen (N), % | 0 | |
| 0 to 0.2 |
| Phosphorus (P), % | 0 | |
| 0 to 0.040 |
| Silicon (Si), % | 0 to 0.25 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 | |
| 0 to 0.030 |
| Tantalum (Ta), % | 0 | |
| 0.75 to 1.3 |
| Titanium (Ti), % | 0 to 0.1 | |
| 0 |
| Tungsten (W), % | 0 | |
| 2.0 to 3.0 |
| Zinc (Zn), % | 5.0 to 6.0 | |
| 0 |
| Zirconium (Zr), % | 0.080 to 0.18 | |
| 0 |
| Residuals, % | 0 to 0.15 | |
| 0 |