Titanium Properties
| Property | Value |
| Atomic number | 22 |
| Atomic weight | 47.9 |
| Atomic volume | 10.6 W/D |
| Covalent radius | 1.32 Å |
| Ionization potential | 6.8282 V |
| Thermal neutron absorption cross section | 5.6 barns/atom |
| Crystal structure | |
| Alpha (=882.5 °C, or 1620 °F) | Close-packed hexagonal |
| Beta ( =882.5 °C, or 1620 °F) | Body-centered cubic |
| Color | Dark gray |
| Density | 4.51 g/cm3 (0.163 lb/in.3) |
| Melting point | 1668 ± 10 °C (3035 °F) |
| Solidus/liquidus | 1725 °C (3135 °F) |
| Boiling point | 3260 °C (5900 °F) |
| Specific heat (at 25 °C) | 0.5223 kJ/kg K |
| Thermal conductivity | 11.4 W/m K |
| Heat of fusion | 440 kJ/kg (estimated) |
| Heat of vaporization | 9.83 MJ/kg |
| Specific gravity | 4.5 |
| Hardness | 70 to 74 HRB |
| Tensile strength | 240 MPa (35 ksi) min |
| Young’s modulus | 120 GPa (17 × 106 psi) |
| Poisson’s ratio | 0.361 |
| Coefficient of friction | |
| At 40 m/min (125 ft/min) | 0.8 |
| At 300 m/min (1000 ft/min) | 0.68 |
| Coefficient of linear thermal expansion | 8.41 µm/m K |
| Electrical conductivity | 3% IACS (where copper = 100% IACS) Electrical resistivity (at 20 °C) |
| Electronegativity | 1.5 Pauling’s |
| Temperature coefficient of electrical resistance | 0.0026/°C |
| Magnetic susceptibility (volume, at room temperature) | 180 ( ±1.7) × 10–6 mks |
Colour and Physical Properties
Pure Titanium’s colour is metallic white with a gentle lustre. It is situated in the forth group of the periodic table and has the highest strength to weight ratio of any element. Its specific strength is 288 kNm/kg. Its density, 4.5g/cm3 is considerably less than steel’s which is 7.8 g/cm3. It is these properties which explain why titanium’s has been responsible for vast improvements in the thrust to weight ratio of jet engines.
Mechanical Properties
Titanium has excellent ductility and tensile strength. It’s minimum yield strength is between 240 and 241 MPa in commercially pure grade 1. Ti-10V-2Fe-3Al has the highest yield strength of all titanium’s alloys at 1260 MPa.
Commercially pure grade 1 titanium has a Rockwell B Hardness of 70 – 74 and a fracture toughness of 66 MPa-m½. It’s Young’s modulus of elasticity for pure titanium is 120 GPA with a shear modulus of 45 GPA.
Electrical Properties
Titanium has low electrical conductivity 3.1% IACS (International Annealed Copper Standard). That makes it ill suited to applications where electrical conductivity is desirable. However, it’s physical and mechanical properties more than compensate.
Thermal Properties
Titanium has low thermal conductivity of 11.4 W/m K which is an important consideration during machining, titanium tends to heat up the tool instead of distributing heat through the metal which shortens tool life and can risk damaging the performance of the metal.
- Melting point 1668 ± 10 °C (3035 °F)
- Solidus/liquidus 1725 °C (3135 °F)
- Boiling point 3260 °C (5900 °F)
- Specific heat (at 25 °C) 0.5223 kJ/kg K
- Thermal conductivity 11.4 W/m K
- Heat of fusion 440 kJ/kg (estimated)
- Heat of vaporization 9.83 MJ/kg
Chemical Properties
Like aluminium pure titanium is highly reactive. Atmospheric passivation forms an oxide layer on the metals surface rendering it inert. This process not only happens in air but also under water. A 1-2 Nanometer thick layer forms instantaneously and thickens to 25 nanometres after 4 years.
With this oxide layer titanium is immune to attack from hydrochloric and sulphuric acid. Further improvements to its chemical resistant come from the addition of palladium in grades 11 and 17 for applications in salt water and chemical plant environments.
Above 800 degrees Titanium will burn in nitrogen to form Titanium Nitride. Titanium without its oxide coating presents a high risk of combustion in oxygen. For the properties of Titanium’s most commonly used alloy Ti 6Al 4V view our grade 5 data sheet.