7021 Aluminum vs. S20910 Stainless Steel
7021 aluminum belongs to the aluminum alloys classification, while S20910 stainless steel 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 S20910 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 69 | |
| 200 |
| Elongation at Break, % | 9.4 | |
| 14 to 39 |
| Fatigue Strength, MPa | 150 | |
| 310 to 460 |
| Poisson's Ratio | 0.32 | |
| 0.28 |
| Shear Modulus, GPa | 26 | |
| 79 |
| Shear Strength, MPa | 270 | |
| 500 to 570 |
| Tensile Strength: Ultimate (UTS), MPa | 460 | |
| 780 to 940 |
| Tensile Strength: Yield (Proof), MPa | 390 | |
| 430 to 810 |
Thermal Properties
| Latent Heat of Fusion, J/g | 380 | |
| 300 |
| Maximum Temperature: Mechanical, °C | 200 | |
| 1080 |
| Melting Completion (Liquidus), °C | 630 | |
| 1420 |
| Melting Onset (Solidus), °C | 510 | |
| 1380 |
| Specific Heat Capacity, J/kg-K | 870 | |
| 480 |
| Thermal Conductivity, W/m-K | 150 | |
| 13 |
| Thermal Expansion, µm/m-K | 24 | |
| 16 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 9.5 | |
| 22 |
| Density, g/cm3 | 2.9 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 8.3 | |
| 4.8 |
| Embodied Energy, MJ/kg | 150 | |
| 68 |
| Embodied Water, L/kg | 1140 | |
| 180 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 41 | |
| 120 to 260 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 1110 | |
| 460 to 1640 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 47 | |
| 25 |
| Strength to Weight: Axial, points | 44 | |
| 28 to 33 |
| Strength to Weight: Bending, points | 45 | |
| 24 to 27 |
| Thermal Diffusivity, mm2/s | 59 | |
| 3.6 |
| Thermal Shock Resistance, points | 20 | |
| 17 to 21 |
Alloy Composition
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| Aluminum (Al), % | 90.7 to 93.7 | |
| 0 |
| Carbon (C), % | 0 | |
| 0 to 0.060 |
| Chromium (Cr), % | 0 to 0.050 | |
| 20.5 to 23.5 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 |
| Iron (Fe), % | 0 to 0.4 | |
| 52.1 to 62.1 |
| Magnesium (Mg), % | 1.2 to 1.8 | |
| 0 |
| Manganese (Mn), % | 0 to 0.1 | |
| 4.0 to 6.0 |
| Molybdenum (Mo), % | 0 | |
| 1.5 to 3.0 |
| Nickel (Ni), % | 0 | |
| 11.5 to 13.5 |
| Niobium (Nb), % | 0 | |
| 0.1 to 0.3 |
| Nitrogen (N), % | 0 | |
| 0.2 to 0.4 |
| Phosphorus (P), % | 0 | |
| 0 to 0.040 |
| Silicon (Si), % | 0 to 0.25 | |
| 0 to 0.75 |
| Sulfur (S), % | 0 | |
| 0 to 0.030 |
| Titanium (Ti), % | 0 to 0.1 | |
| 0 |
| Vanadium (V), % | 0 | |
| 0.1 to 0.3 |
| Zinc (Zn), % | 5.0 to 6.0 | |
| 0 |
| Zirconium (Zr), % | 0.080 to 0.18 | |
| 0 |
| Residuals, % | 0 to 0.15 | |
| 0 |