9. Titanium

Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color.

The element occurs within a number of mineral deposits, principally rutile and ilmenite, it is found in almost all living things, rocks, water bodies, and soils.The metal is extracted from its principal mineral ores via the Kroll processor the Hunter process. Its most common compound, titanium dioxide, is a popular photocatalyst and is used in the manufacture of white pigments.

Titanium can be alloyed with iron, aluminium, vanadium, molybdenum, among other elements, to produce strong lightweight alloys for aerospace, military, industrial process, automotive, agri-food, medical prostheses, orthopedic implants, dental and endodontic instruments and files, dental implants, sporting goods, jewelry, mobile phones, and other applications.

The two most useful properties of the metal form are corrosion resistance and the highest strength-to-weight ratio of any metal. In its unalloyed condition, titanium is as strong as some steels, but 45% lighter. There are two allotropic forms and five naturally occurring isotopes of this element, ⁴⁶Ti through ⁵⁰Ti, with ⁴⁸Ti being the most abundant (73.8%).Titanium’s properties are chemically and physically similar to zirconium, because both of them have the same number of valence electrons and are in the same group in the periodic table.

As an engineering material titanium has been widely applied only in the last years. Titanium is a silvery-white metal which melts at approximately 1668°C and has a specific gravity of 4.505. Commercially pure titanium possesses high strength properties. The tensile strength of most titanium alloys ranges from 100 to 140 kg/mm², in conjunction with high elongation.

The hardness, tensile strength and yield point of titanium are increased with the degree of cold deformation. The elongation value drops rapidly when the degree of cold deformation (reduction) exceeds 50 per cent and becomes equal to 10 per cent. Impurities found in com­mercial titanium can be divided into two groups: elements which form interstitial solid solutions with titanium (O₂, N, C and H₂) and elements which form substitution solid solutions (Fe and other metallic elements). The first have a much greater effect on the mechanical properties than those in the second group.

Task 1. Match the terms with their definitions

1 density	the property of being rigid and resistant to pressure; not easily scratched
2 compound	a measure of how much of some entity is within a fixed amount of space. mass per volume
3 gravity	produced by the union of several ingredients, parts, or things.
4 strength	the force of attraction between all masses in the universe
5 hardness	the property of materials by which they endure the application of force without yielding or breaking

Task 2. Mark the sentences “True” or “False”

1) The metal is extracted from its principal mineral ores via the Bessemer process.

2)As an engineering material titanium has been widely applied only in the last years.

3) Titanium’s properties are chemically and physically similar to zinc.

4) Titanium was discovered in 1791 and named for the Titans of Greek mythology.

5) The hardness, tensile strength and yield point of titanium decrease with the degree of cold deformation.

Task 3. Match the beginnings of sentences to their endings

1 Titanium can be alloyed with other elements	which melts at approximately 1668°C and has a specific gravity of 4.505.
2 Titanium is contained in meteorites	and is connected with the presence of dissolved hydrogen in the beta-phase.
3 Titanium is a silvery-white metal	enable titanium to be used in building supersonic air craft.
4 The brittleness of titanium is a result of strain ageing	and has been detected in the sun and in M-typestars.
5 High mechanical properties and excellent corrosion resistance	to produce strong lightweight alloys for aerospace.

Task 4. Complete the sentences with the appropriate words

a) strong b) elongation c) density d) lightweight e) periodic table

Titanium is a strong, lustrous, corrosion-resistant transition metal with a low _(1)_. It can be alloyed with iron, aluminium, vanadium, and molybdenum to produce strong _(2)_ alloys. In its unalloyed condition, titanium is as _(3)_as some steels, but 45% lighter. As an engineering material titanium has been widely applied only in the last years. Commercially pure titanium possesses high strength properties. The tensile strength of most titanium alloys ranges from 100 to 140 kg/mm², in conjunction with high _(4)_. Titanium’s properties are chemically and physically similar to zirconium, because both of them have the same number of valence electrons and are in the same group in the _(5)_.