Titanium is a chemical element with the symbol Ti and atomic number 22. It is a lustrous transition metal with a silver color, low density, and high strength. Titanium is resistant to corrosion in sea water, aqua regia, and chlorine. It belonging to Group 4 of the periodic table. It is a lightweight, high-strength, low-corrosion structural metal and is used in alloy form for parts in high-speed aircraft. A compound of Ti was discovered in Cornwall, Great Britain, by William Gregor in 1791 and was named by Martin Heinrich Klaproth after the Titans of Greek mythology.
It is widely distributed and constitutes 0.44% of the Earth’s crust. The metal is found combined in practically all rocks, sand, clay, and other soils. It is also present in plants and animals, natural waters and deep-sea dredgings, and meteorites and stars.
Physical Properties of Titanium
- As a metal, titanium is recognized for its high strength-to-weight ratio. It is a strong metal with low density that is quite ductile (especially in an oxygen-free environment), lustrous, and metallic-white in color.
- Relatively high melting point more than 1,650 °C or 3,000 °F, makes it useful as a refractory metal. It is paramagnetic and has fairly low electrical and thermal conductivity compared to other metals.
- Titanium is superconducting when cooled below its critical temperature of 0.49 K.
- Commercially pure (99.2% pure) grades of titanium have ultimate tensile strength of about 434 MPa (63,000 psi), equal to that of common, low-grade steel alloys, but are less dense.
- It is 60% denser than aluminium, but more than twice as strong as the most commonly used 6061-T6 aluminium alloy. Certain titanium alloys (e.g., Beta C) achieve tensile strengths of over 1,400 MPa (200,000 psi). However, titanium loses strength when heated above 430 °C (806 °F).
- It is non-magnetic and a poor conductor of heat and electricity. Machining requires precautions, because the material can gall unless sharp tools and proper cooling methods are used. Like steel structures, those made from titanium have a fatigue limit that guarantees longevity in some applications.