Grade 21 Titanium vs. SAE-AISI 1078 Steel
Grade 21 titanium belongs to the titanium alloys classification, while SAE-AISI 1078 steel belongs to the iron alloys. There are 29 material properties with values for both materials. Properties with values for just one material (3, in this case) are not shown.
For each property being compared, the top bar is grade 21 titanium and the bottom bar is SAE-AISI 1078 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 140 | |
| 190 |
| Elongation at Break, % | 9.0 to 17 | |
| 11 to 14 |
| Fatigue Strength, MPa | 550 to 660 | |
| 270 to 350 |
| Poisson's Ratio | 0.32 | |
| 0.29 |
| Reduction in Area, % | 22 | |
| 34 to 45 |
| Shear Modulus, GPa | 51 | |
| 72 |
| Shear Strength, MPa | 550 to 790 | |
| 440 to 470 |
| Tensile Strength: Ultimate (UTS), MPa | 890 to 1340 | |
| 730 to 780 |
| Tensile Strength: Yield (Proof), MPa | 870 to 1170 | |
| 430 to 570 |
Thermal Properties
| Latent Heat of Fusion, J/g | 410 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 310 | |
| 400 |
| Melting Completion (Liquidus), °C | 1740 | |
| 1460 |
| Melting Onset (Solidus), °C | 1690 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 500 | |
| 470 |
| Thermal Conductivity, W/m-K | 7.5 | |
| 49 |
| Thermal Expansion, µm/m-K | 7.1 | |
| 11 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 60 | |
| 1.8 |
| Density, g/cm3 | 5.4 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 32 | |
| 1.4 |
| Embodied Energy, MJ/kg | 490 | |
| 18 |
| Embodied Water, L/kg | 180 | |
| 45 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 110 to 180 | |
| 77 to 90 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 2760 to 5010 | |
| 490 to 860 |
| Stiffness to Weight: Axial, points | 14 | |
| 13 |
| Stiffness to Weight: Bending, points | 32 | |
| 24 |
| Strength to Weight: Axial, points | 46 to 69 | |
| 26 to 28 |
| Strength to Weight: Bending, points | 38 to 50 | |
| 23 to 24 |
| Thermal Diffusivity, mm2/s | 2.8 | |
| 13 |
| Thermal Shock Resistance, points | 66 to 100 | |
| 25 to 26 |
Alloy Composition
| Aluminum (Al), % | 2.5 to 3.5 | |
| 0 |
| Carbon (C), % | 0 to 0.050 | |
| 0.72 to 0.85 |
| Hydrogen (H), % | 0 to 0.015 | |
| 0 |
| Iron (Fe), % | 0 to 0.4 | |
| 98.5 to 99 |
| Manganese (Mn), % | 0 | |
| 0.3 to 0.6 |
| Molybdenum (Mo), % | 14 to 16 | |
| 0 |
| Niobium (Nb), % | 2.2 to 3.2 | |
| 0 |
| Nitrogen (N), % | 0 to 0.030 | |
| 0 |
| Oxygen (O), % | 0 to 0.17 | |
| 0 |
| Phosphorus (P), % | 0 | |
| 0 to 0.040 |
| Silicon (Si), % | 0.15 to 0.25 | |
| 0 |
| Sulfur (S), % | 0 | |
| 0 to 0.050 |
| Titanium (Ti), % | 76 to 81.2 | |
| 0 |
| Residuals, % | 0 to 0.4 | |
| 0 |