Grade 21 Titanium vs. R31538 Cobalt
Grade 21 titanium belongs to the titanium alloys classification, while R31538 cobalt belongs to the cobalt alloys. There are 26 material properties with values for both materials. Properties with values for just one material (6, in this case) are not shown.
For each property being compared, the top bar is grade 21 titanium and the bottom bar is R31538 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 140 | |
| 220 |
| Elongation at Break, % | 9.0 to 17 | |
| 13 to 23 |
| Fatigue Strength, MPa | 550 to 660 | |
| 310 to 480 |
| Poisson's Ratio | 0.32 | |
| 0.29 |
| Reduction in Area, % | 22 | |
| 13 to 22 |
| Shear Modulus, GPa | 51 | |
| 86 |
| Tensile Strength: Ultimate (UTS), MPa | 890 to 1340 | |
| 1020 to 1360 |
| Tensile Strength: Yield (Proof), MPa | 870 to 1170 | |
| 580 to 930 |
Thermal Properties
| Latent Heat of Fusion, J/g | 410 | |
| 320 |
| Melting Completion (Liquidus), °C | 1740 | |
| 1360 |
| Melting Onset (Solidus), °C | 1690 | |
| 1290 |
| Specific Heat Capacity, J/kg-K | 500 | |
| 450 |
| Thermal Conductivity, W/m-K | 7.5 | |
| 13 |
| Thermal Expansion, µm/m-K | 7.1 | |
| 13 |
Otherwise Unclassified Properties
| Density, g/cm3 | 5.4 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 32 | |
| 8.1 |
| Embodied Energy, MJ/kg | 490 | |
| 110 |
| Embodied Water, L/kg | 180 | |
| 530 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 110 to 180 | |
| 140 to 200 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 2760 to 5010 | |
| 750 to 1920 |
| Stiffness to Weight: Axial, points | 14 | |
| 15 |
| Stiffness to Weight: Bending, points | 32 | |
| 24 |
| Strength to Weight: Axial, points | 46 to 69 | |
| 34 to 45 |
| Strength to Weight: Bending, points | 38 to 50 | |
| 27 to 32 |
| Thermal Diffusivity, mm2/s | 2.8 | |
| 3.5 |
| Thermal Shock Resistance, points | 66 to 100 | |
| 25 to 33 |
Alloy Composition
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| Aluminum (Al), % | 2.5 to 3.5 | |
| 0 |
| Carbon (C), % | 0 to 0.050 | |
| 0.15 to 0.35 |
| Chromium (Cr), % | 0 | |
| 26 to 30 |
| Cobalt (Co), % | 0 | |
| 58.7 to 68.9 |
| Hydrogen (H), % | 0 to 0.015 | |
| 0 |
| Iron (Fe), % | 0 to 0.4 | |
| 0 to 0.75 |
| Manganese (Mn), % | 0 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 14 to 16 | |
| 5.0 to 7.0 |
| Nickel (Ni), % | 0 | |
| 0 to 1.0 |
| Niobium (Nb), % | 2.2 to 3.2 | |
| 0 |
| Nitrogen (N), % | 0 to 0.030 | |
| 0 to 0.25 |
| Oxygen (O), % | 0 to 0.17 | |
| 0 |
| Silicon (Si), % | 0.15 to 0.25 | |
| 0 to 1.0 |
| Titanium (Ti), % | 76 to 81.2 | |
| 0 |
| Residuals, % | 0 to 0.4 | |
| 0 |