Grade 21 Titanium vs. Titanium 4-4-2
Both grade 21 titanium and titanium 4-4-2 are titanium alloys. They have 86% of their average alloy composition in common.
For each property being compared, the top bar is grade 21 titanium and the bottom bar is titanium 4-4-2.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 140 | |
| 110 |
| Elongation at Break, % | 9.0 to 17 | |
| 10 |
| Fatigue Strength, MPa | 550 to 660 | |
| 590 to 620 |
| Poisson's Ratio | 0.32 | |
| 0.32 |
| Reduction in Area, % | 22 | |
| 20 |
| Shear Modulus, GPa | 51 | |
| 42 |
| Shear Strength, MPa | 550 to 790 | |
| 690 to 750 |
| Tensile Strength: Ultimate (UTS), MPa | 890 to 1340 | |
| 1150 to 1250 |
| Tensile Strength: Yield (Proof), MPa | 870 to 1170 | |
| 1030 to 1080 |
Thermal Properties
| Latent Heat of Fusion, J/g | 410 | |
| 410 |
| Maximum Temperature: Mechanical, °C | 310 | |
| 310 |
| Melting Completion (Liquidus), °C | 1740 | |
| 1610 |
| Melting Onset (Solidus), °C | 1690 | |
| 1560 |
| Specific Heat Capacity, J/kg-K | 500 | |
| 540 |
| Thermal Conductivity, W/m-K | 7.5 | |
| 6.7 |
| Thermal Expansion, µm/m-K | 7.1 | |
| 8.6 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 60 | |
| 39 |
| Density, g/cm3 | 5.4 | |
| 4.7 |
| Embodied Carbon, kg CO2/kg material | 32 | |
| 30 |
| Embodied Energy, MJ/kg | 490 | |
| 480 |
| Embodied Water, L/kg | 180 | |
| 180 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 110 to 180 | |
| 110 to 120 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 2760 to 5010 | |
| 4700 to 5160 |
| Stiffness to Weight: Axial, points | 14 | |
| 13 |
| Stiffness to Weight: Bending, points | 32 | |
| 34 |
| Strength to Weight: Axial, points | 46 to 69 | |
| 68 to 74 |
| Strength to Weight: Bending, points | 38 to 50 | |
| 52 to 55 |
| Thermal Diffusivity, mm2/s | 2.8 | |
| 2.6 |
| Thermal Shock Resistance, points | 66 to 100 | |
| 86 to 93 |
Alloy Composition
| Aluminum (Al), % | 2.5 to 3.5 | |
| 3.0 to 5.0 |
| Carbon (C), % | 0 to 0.050 | |
| 0 to 0.080 |
| Hydrogen (H), % | 0 to 0.015 | |
| 0 to 0.015 |
| Iron (Fe), % | 0 to 0.4 | |
| 0 to 0.2 |
| Molybdenum (Mo), % | 14 to 16 | |
| 3.0 to 5.0 |
| Niobium (Nb), % | 2.2 to 3.2 | |
| 0 |
| Nitrogen (N), % | 0 to 0.030 | |
| 0 to 0.050 |
| Oxygen (O), % | 0 to 0.17 | |
| 0 to 0.25 |
| Silicon (Si), % | 0.15 to 0.25 | |
| 0.3 to 0.7 |
| Tin (Sn), % | 0 | |
| 1.5 to 2.5 |
| Titanium (Ti), % | 76 to 81.2 | |
| 85.8 to 92.2 |
| Residuals, % | 0 | |
| 0 to 0.4 |