7021 Aluminum vs. S35500 Stainless Steel
7021 aluminum belongs to the aluminum alloys classification, while S35500 stainless steel belongs to the iron alloys. There are 30 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 7021 aluminum and the bottom bar is S35500 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 69 | |
| 200 |
| Elongation at Break, % | 9.4 | |
| 14 |
| Fatigue Strength, MPa | 150 | |
| 690 to 730 |
| Poisson's Ratio | 0.32 | |
| 0.28 |
| Shear Modulus, GPa | 26 | |
| 78 |
| Shear Strength, MPa | 270 | |
| 810 to 910 |
| Tensile Strength: Ultimate (UTS), MPa | 460 | |
| 1330 to 1490 |
| Tensile Strength: Yield (Proof), MPa | 390 | |
| 1200 to 1280 |
Thermal Properties
| Latent Heat of Fusion, J/g | 380 | |
| 280 |
| Maximum Temperature: Mechanical, °C | 200 | |
| 870 |
| Melting Completion (Liquidus), °C | 630 | |
| 1460 |
| Melting Onset (Solidus), °C | 510 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 870 | |
| 470 |
| Thermal Conductivity, W/m-K | 150 | |
| 16 |
| Thermal Expansion, µm/m-K | 24 | |
| 11 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 38 | |
| 2.2 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 120 | |
| 2.5 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 9.5 | |
| 16 |
| Density, g/cm3 | 2.9 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 8.3 | |
| 3.5 |
| Embodied Energy, MJ/kg | 150 | |
| 47 |
| Embodied Water, L/kg | 1140 | |
| 130 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 41 | |
| 180 to 190 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 1110 | |
| 3610 to 4100 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 47 | |
| 25 |
| Strength to Weight: Axial, points | 44 | |
| 47 to 53 |
| Strength to Weight: Bending, points | 45 | |
| 34 to 37 |
| Thermal Diffusivity, mm2/s | 59 | |
| 4.4 |
| Thermal Shock Resistance, points | 20 | |
| 44 to 49 |
Alloy Composition
| Aluminum (Al), % | 90.7 to 93.7 | |
| 0 |
| Carbon (C), % | 0 | |
| 0.1 to 0.15 |
| Chromium (Cr), % | 0 to 0.050 | |
| 15 to 16 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 |
| Iron (Fe), % | 0 to 0.4 | |
| 73.2 to 77.7 |
| Magnesium (Mg), % | 1.2 to 1.8 | |
| 0 |
| Manganese (Mn), % | 0 to 0.1 | |
| 0.5 to 1.3 |
| Molybdenum (Mo), % | 0 | |
| 2.5 to 3.2 |
| Nickel (Ni), % | 0 | |
| 4.0 to 5.0 |
| Niobium (Nb), % | 0 | |
| 0.1 to 0.5 |
| Nitrogen (N), % | 0 | |
| 0.070 to 0.13 |
| Phosphorus (P), % | 0 | |
| 0 to 0.040 |
| Silicon (Si), % | 0 to 0.25 | |
| 0 to 0.5 |
| Sulfur (S), % | 0 | |
| 0 to 0.030 |
| Titanium (Ti), % | 0 to 0.1 | |
| 0 |
| Zinc (Zn), % | 5.0 to 6.0 | |
| 0 |
| Zirconium (Zr), % | 0.080 to 0.18 | |
| 0 |
| Residuals, % | 0 to 0.15 | |
| 0 |