AISI 321 Stainless Steel vs. 5251 Aluminum
AISI 321 stainless steel belongs to the iron alloys classification, while 5251 aluminum belongs to the aluminum alloys. There are 31 material properties with values for both materials. Properties with values for just one material (2, 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 AISI 321 stainless steel and the bottom bar is 5251 aluminum.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 170 to 210 | |
| 44 to 79 |
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 68 |
| Elongation at Break, % | 34 to 50 | |
| 2.0 to 19 |
| Fatigue Strength, MPa | 220 to 270 | |
| 59 to 110 |
| Poisson's Ratio | 0.28 | |
| 0.33 |
| Shear Modulus, GPa | 77 | |
| 26 |
| Shear Strength, MPa | 420 to 460 | |
| 110 to 160 |
| Tensile Strength: Ultimate (UTS), MPa | 590 to 690 | |
| 180 to 280 |
| Tensile Strength: Yield (Proof), MPa | 220 to 350 | |
| 67 to 250 |
Thermal Properties
| Latent Heat of Fusion, J/g | 290 | |
| 400 |
| Maximum Temperature: Mechanical, °C | 870 | |
| 180 |
| Melting Completion (Liquidus), °C | 1430 | |
| 650 |
| Melting Onset (Solidus), °C | 1400 | |
| 610 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 900 |
| Thermal Conductivity, W/m-K | 16 | |
| 150 |
| Thermal Expansion, µm/m-K | 17 | |
| 24 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.4 | |
| 37 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.7 | |
| 120 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 16 | |
| 9.5 |
| Density, g/cm3 | 7.8 | |
| 2.7 |
| Embodied Carbon, kg CO2/kg material | 3.2 | |
| 8.5 |
| Embodied Energy, MJ/kg | 45 | |
| 150 |
| Embodied Water, L/kg | 140 | |
| 1180 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 190 to 230 | |
| 5.4 to 27 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 130 to 310 | |
| 33 to 450 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 50 |
| Strength to Weight: Axial, points | 21 to 25 | |
| 18 to 29 |
| Strength to Weight: Bending, points | 20 to 22 | |
| 26 to 35 |
| Thermal Diffusivity, mm2/s | 4.1 | |
| 61 |
| Thermal Shock Resistance, points | 13 to 15 | |
| 7.9 to 13 |
Alloy Composition
| Aluminum (Al), % | 0 | |
| 95.5 to 98.2 |
| Carbon (C), % | 0 to 0.080 | |
| 0 |
| Chromium (Cr), % | 17 to 19 | |
| 0 to 0.15 |
| Copper (Cu), % | 0 | |
| 0 to 0.15 |
| Iron (Fe), % | 65.3 to 74 | |
| 0 to 0.5 |
| Magnesium (Mg), % | 0 | |
| 1.7 to 2.4 |
| Manganese (Mn), % | 0 to 2.0 | |
| 0.1 to 0.5 |
| Nickel (Ni), % | 9.0 to 12 | |
| 0 |
| Nitrogen (N), % | 0 to 0.1 | |
| 0 |
| Phosphorus (P), % | 0 to 0.045 | |
| 0 |
| Silicon (Si), % | 0 to 0.75 | |
| 0 to 0.4 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 |
| Titanium (Ti), % | 0 to 0.7 | |
| 0 to 0.15 |
| Zinc (Zn), % | 0 | |
| 0 to 0.15 |
| Residuals, % | 0 | |
| 0 to 0.15 |