R30021 Cobalt vs. Nickel 685
R30021 cobalt belongs to the cobalt alloys classification, while nickel 685 belongs to the nickel alloys. They have 41% of their average alloy composition in common. There are 25 material properties with values for both materials. Properties with values for just one material (9, in this case) are not shown.
For each property being compared, the top bar is R30021 cobalt and the bottom bar is nickel 685.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 220 | |
| 200 |
| Elongation at Break, % | 9.0 | |
| 17 |
| Fatigue Strength, MPa | 250 | |
| 470 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 86 | |
| 77 |
| Tensile Strength: Ultimate (UTS), MPa | 700 | |
| 1250 |
| Tensile Strength: Yield (Proof), MPa | 500 | |
| 850 |
Thermal Properties
| Latent Heat of Fusion, J/g | 330 | |
| 320 |
| Melting Completion (Liquidus), °C | 1350 | |
| 1380 |
| Melting Onset (Solidus), °C | 1190 | |
| 1330 |
| Specific Heat Capacity, J/kg-K | 450 | |
| 460 |
| Thermal Conductivity, W/m-K | 15 | |
| 13 |
| Thermal Expansion, µm/m-K | 11 | |
| 12 |
Otherwise Unclassified Properties
| Density, g/cm3 | 8.4 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 8.0 | |
| 10 |
| Embodied Energy, MJ/kg | 110 | |
| 140 |
| Embodied Water, L/kg | 520 | |
| 340 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 57 | |
| 190 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 570 | |
| 1820 |
| Stiffness to Weight: Axial, points | 15 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 23 |
| Strength to Weight: Axial, points | 23 | |
| 42 |
| Strength to Weight: Bending, points | 21 | |
| 31 |
| Thermal Diffusivity, mm2/s | 3.8 | |
| 3.3 |
| Thermal Shock Resistance, points | 21 | |
| 37 |
Alloy Composition
| Aluminum (Al), % | 0 | |
| 1.2 to 1.6 |
| Boron (B), % | 0 | |
| 0.0030 to 0.010 |
| Carbon (C), % | 0.2 to 0.35 | |
| 0.030 to 0.1 |
| Chromium (Cr), % | 26 to 29 | |
| 18 to 21 |
| Cobalt (Co), % | 61.7 to 67.3 | |
| 12 to 15 |
| Copper (Cu), % | 0 | |
| 0 to 0.5 |
| Iron (Fe), % | 0 to 3.0 | |
| 0 to 2.0 |
| Manganese (Mn), % | 0 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 4.5 to 6.0 | |
| 3.5 to 5.0 |
| Nickel (Ni), % | 2.0 to 3.0 | |
| 49.6 to 62.5 |
| Phosphorus (P), % | 0 | |
| 0 to 0.030 |
| Silicon (Si), % | 0 to 1.5 | |
| 0 to 0.75 |
| Sulfur (S), % | 0 | |
| 0 to 0.030 |
| Titanium (Ti), % | 0 | |
| 2.8 to 3.3 |
| Zinc (Zn), % | 0 | |
| 0.020 to 0.12 |