Solder Alloy 721 vs. S21904 Stainless Steel
Solder alloy 721 belongs to the otherwise unclassified metals classification, while S21904 stainless steel belongs to the iron alloys. There are 22 material properties with values for both materials. Properties with values for just one material (11, in this case) are not shown.
For each property being compared, the top bar is solder alloy 721 and the bottom bar is S21904 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 51 | |
| 200 |
| Elongation at Break, % | 17 | |
| 17 to 51 |
| Poisson's Ratio | 0.36 | |
| 0.28 |
| Shear Modulus, GPa | 19 | |
| 78 |
| Tensile Strength: Ultimate (UTS), MPa | 50 | |
| 700 to 1000 |
Thermal Properties
| Latent Heat of Fusion, J/g | 61 | |
| 290 |
| Melting Completion (Liquidus), °C | 220 | |
| 1400 |
| Melting Onset (Solidus), °C | 210 | |
| 1350 |
| Specific Heat Capacity, J/kg-K | 220 | |
| 480 |
| Thermal Conductivity, W/m-K | 56 | |
| 14 |
| Thermal Expansion, µm/m-K | 22 | |
| 17 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 14 | |
| 2.5 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 17 | |
| 2.9 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.4 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 17 | |
| 3.0 |
| Embodied Energy, MJ/kg | 280 | |
| 43 |
Common Calculations
| Stiffness to Weight: Axial, points | 3.8 | |
| 14 |
| Stiffness to Weight: Bending, points | 17 | |
| 25 |
| Strength to Weight: Axial, points | 1.9 | |
| 25 to 36 |
| Strength to Weight: Bending, points | 4.1 | |
| 23 to 29 |
| Thermal Diffusivity, mm2/s | 34 | |
| 3.8 |
| Thermal Shock Resistance, points | 3.2 | |
| 15 to 21 |
Alloy Composition
| Aluminum (Al), % | 0 to 0.0010 | |
| 0 |
| Antimony (Sb), % | 0 to 0.1 | |
| 0 |
| Arsenic (As), % | 0 to 0.030 | |
| 0 |
| Bismuth (Bi), % | 0.8 to 1.2 | |
| 0 |
| Cadmium (Cd), % | 0 to 0.0020 | |
| 0 |
| Carbon (C), % | 0 | |
| 0 to 0.040 |
| Chromium (Cr), % | 0 | |
| 19 to 21.5 |
| Copper (Cu), % | 0.3 to 0.7 | |
| 0 |
| Gold (Au), % | 0 to 0.050 | |
| 0 |
| Indium (In), % | 0 to 0.1 | |
| 0 |
| Iron (Fe), % | 0 to 0.020 | |
| 59.5 to 67.4 |
| Lead (Pb), % | 0 to 0.070 | |
| 0 |
| Manganese (Mn), % | 0 | |
| 8.0 to 10 |
| Nickel (Ni), % | 0 to 0.010 | |
| 5.5 to 7.5 |
| Nitrogen (N), % | 0 | |
| 0.15 to 0.4 |
| Phosphorus (P), % | 0 | |
| 0 to 0.045 |
| Silicon (Si), % | 0 | |
| 0 to 1.0 |
| Silver (Ag), % | 2.3 to 2.7 | |
| 0 |
| Sulfur (S), % | 0 | |
| 0 to 0.030 |
| Tin (Sn), % | 95 to 96.6 | |
| 0 |
| Zinc (Zn), % | 0 to 0.0010 | |
| 0 |