Question

Duralumin is an alloy of:
(A) $\text{Al + Mg}$
(B) $\text{Al + Cu + Mg + Mn}$
(C) $\text{Al + Zn + Mg + Ni}$
(D) $\text{Al + Cu}$

Answer 1

Hint: Any metal made by the combination of two or more metallic elements is known as an alloy. Duralumin mainly consists of aluminium.

Step by step answer:
Duralumin is an alloy of aluminium. The composition of duralumin is as follows:
Aluminium - $90\mathrm{\%}$
Copper - $4\mathrm{\%}$
Magnesium - $1\mathrm{\%}$
Manganese - $0.5\mathrm{\%}\text{ to }1\mathrm{\%}$
Thus, duralumin is an alloy of $\text{Al + Cu + Mg + Mn}$.
Thus, the correct option is (B) $\text{Al + Cu + Mg + Mn}$.

Additional Information: Duralumin is very strong and hard. It is light in weight. Thus, duralumin is used when high strength but lightweight material is required.
Uses of duralumin are as follows:
- Aircraft fittings
- Space booster tankage
- Heavy duty forgings
- Wheels
- Plates
- Making wire, bar, rods for screw machines

Other alloys of aluminium are as follows:
AA-80000: It is used in manufacturing of wires.
Alclad: It is an aluminium sheet.
Al-Li: It contains aluminium and lithium. Sometimes mercury is also added.
Alnico: It contains aluminium, nickel and copper.
Birmabright: It contains aluminium and magnesium.
Hindalium: It contains aluminium, magnesium, manganese and silicon.
Magnalium: It contains aluminium along with $5\mathrm{\%}$ magnesium.
Magnox: It contains aluminium and magnesium oxide.
Nambe: It contains aluminium along with seven other unspecified metals.
Silumin: It contains aluminium and silicon.

Note: Duralumin corrodes more easily than pure aluminium. The electric and thermal conductance of duralumin is less than pure aluminium.