Question

Write the constituents and the uses of the following alloys.
(a) Brass
(b) Invar steel.

Answer 1

Hint: Alloys are mixtures of two or more metals formed together with other elements or materials to create new metals with improved mechanical and other properties of the base metal.
Metals are classified into ferrous and non-ferrous metals. Brass is included in non-ferrous metals while invar steel is an example of ferrous metal.

Complete step by step answer:
(a) Brass is an alloy of copper and zinc. The proportions of copper and zinc may vary to create a range of brasses with varying properties. It is used for decoration for its bright gold-like appearance. It is used for applications where low friction is required such as lock, gears, bearings, etc. They are often used in situations where it is important that sparks not be struck, as in fittings and tools around explosive gases.
(b) Invar steel is an alloy of iron and nickel. In this alloy, iron is the base element. It may also contain cobalt, chromium, carbon, manganese, phosphorus, silicon, sulfur, aluminium, magnesium, zirconium and titanium. They are used in precision instruments because it maintains a low coefficient if thermal expansion. They are also used in clocks, scientific instruments, bimetal strips in thermostats and other materials that require consistent monitoring systems.

Additional information:
Brass may also include small proportions of arsenic, lead, phosphorus, aluminium, manganese and silicon. It is used where there is a large corrosion risk.

Note:
Some alloy steels and its element composition is given in the table.

Alloy steel	Composition
Stainless steel	${\text{Cr}}\left( {10 - 20\% } \right)$
Nickel steel	${\text{Ni}}\left( {3.5\% } \right)$
Invar steel	\[{\text{Ni}}\left( {30 - 40\% } \right)\]
Vanadium steel	${\text{V}}\left( {0.1 - 2\% } \right)$
Tungsten steel	${\text{W}}\left( {14 - 20\% } \right)$
Manganese steel	${\text{Mn}}\left( {12 - 15\% } \right)$