Question

Write the composition and its percentage (approx.) and their uses of the following alloys :
i.) Gunmetal
ii.) Bronze
iii.) Duralumin

Answer 1

Hint: Gunmetal is an alloy of copper, tin, zinc and lead while the bronze is an alloy of copper, tin and some other metal in low proportion. And duralumin is called a copper-aluminium alloy.

Complete step by step answer:
i.) Gunmetal :- It is commonly called as red brass. It is a type of bronze. It is an alloy of copper, tin, zinc and lead sometimes with different proportions. It has good strength and is corrosion resistant.
Composition- Copper(Cu), Tin(Sn), Zinc(Zn)
Percentage-

Element	Percentage
Copper	88%
Tin	8-10%
Zinc	2-4%

Uses of gunmetal include-
These were used to make mirror cases, church doors, fonts and statues. These are majorly used in valves, pipe fittings and pumps where tight pressure is required. They have even been used frequently for bearings where loads and speed are normal. It is mainly used in making guns.
ii.) Bronze :- It is also an alloy composed of copper, tin and some other metal. This alloy is harder than copper only and thus has many useful applications.
Composition- Copper(Cu), Tin(Sn) and some other metal like Al, Mg, Ni or Zn
Percentage-

Element	Percentage
Copper	88%
Tin	12%

Uses of Bronze include-
These are used for the formation of coins. Earlier, they had use in boat and ship fittings. Now, it is used in ship propellers and submerged bearings. These find wide applications as electrical connectors and springs. It is used to make hammers, mallets, wrenches and many other tools.
iii.) Duralumin :- It is an alloy of copper, aluminium in prime amounts with some other elements.
Composition- Copper(Cu), Aluminium(Al) and some other element like Mg.
Percentage-
Element
Percentage

Element	Percentage
Aluminium	95%
Copper	4%
Magnesium	1%

Uses of Duralumin include-
It is used in the aircraft industry. It has wide applications in space booster tankage, rivets, hardware, truck wheels, screw machine products etc.

Note:
Gunmetal withstands atmospheric, steam and seawater corrosion. This made it earlier more popular but now it is largely replaced by steel.
Bronze is highly stiff, ductile and less brittle than iron
Duralumin is a lightweight alloy. It is soft in nature and is ductile.