Grade 21 Titanium vs. 4047 Aluminum
Grade 21 titanium belongs to the titanium alloys classification, while 4047 aluminum belongs to the aluminum alloys. There are 28 material properties with values for both materials. Properties with values for just one material (4, in this case) are not shown. Please note that the two materials have significantly dissimilar densities. This means that additional care is required when interpreting the data, because some material properties are based on units of mass, while others are based on units of area or volume.
For each property being compared, the top bar is grade 21 titanium and the bottom bar is 4047 aluminum.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 140 | |
| 72 |
| Elongation at Break, % | 9.0 to 17 | |
| 3.4 |
| Fatigue Strength, MPa | 550 to 660 | |
| 45 |
| Poisson's Ratio | 0.32 | |
| 0.33 |
| Shear Modulus, GPa | 51 | |
| 27 |
| Shear Strength, MPa | 550 to 790 | |
| 69 |
| Tensile Strength: Ultimate (UTS), MPa | 890 to 1340 | |
| 120 |
| Tensile Strength: Yield (Proof), MPa | 870 to 1170 | |
| 64 |
Thermal Properties
| Latent Heat of Fusion, J/g | 410 | |
| 570 |
| Maximum Temperature: Mechanical, °C | 310 | |
| 160 |
| Melting Completion (Liquidus), °C | 1740 | |
| 580 |
| Melting Onset (Solidus), °C | 1690 | |
| 580 |
| Specific Heat Capacity, J/kg-K | 500 | |
| 900 |
| Thermal Conductivity, W/m-K | 7.5 | |
| 130 |
| Thermal Expansion, µm/m-K | 7.1 | |
| 21 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 60 | |
| 9.5 |
| Density, g/cm3 | 5.4 | |
| 2.5 |
| Embodied Carbon, kg CO2/kg material | 32 | |
| 7.7 |
| Embodied Energy, MJ/kg | 490 | |
| 140 |
| Embodied Water, L/kg | 180 | |
| 1050 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 110 to 180 | |
| 3.5 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 2760 to 5010 | |
| 28 |
| Stiffness to Weight: Axial, points | 14 | |
| 16 |
| Stiffness to Weight: Bending, points | 32 | |
| 55 |
| Strength to Weight: Axial, points | 46 to 69 | |
| 13 |
| Strength to Weight: Bending, points | 38 to 50 | |
| 21 |
| Thermal Diffusivity, mm2/s | 2.8 | |
| 59 |
| Thermal Shock Resistance, points | 66 to 100 | |
| 5.6 |
Alloy Composition
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| Aluminum (Al), % | 2.5 to 3.5 | |
| 85.3 to 89 |
| Carbon (C), % | 0 to 0.050 | |
| 0 |
| Copper (Cu), % | 0 | |
| 0 to 0.3 |
| Hydrogen (H), % | 0 to 0.015 | |
| 0 |
| Iron (Fe), % | 0 to 0.4 | |
| 0 to 0.8 |
| Magnesium (Mg), % | 0 | |
| 0 to 0.1 |
| Manganese (Mn), % | 0 | |
| 0 to 0.15 |
| 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 |
| Silicon (Si), % | 0.15 to 0.25 | |
| 11 to 13 |
| Titanium (Ti), % | 76 to 81.2 | |
| 0 |
| Zinc (Zn), % | 0 | |
| 0 to 0.2 |
| Residuals, % | 0 to 0.4 | |
| 0 to 0.15 |