Question

The reason for using aluminum in the alloy duralumin is:

• A. Aluminum is brittle.
• B. Aluminum gives strength.
• C. Aluminum brings lightness.
• D. Aluminum lowers melting point.

Answer 1

Answer: (B), (C)

Aluminum brings lightness.

Explanation for the correct option:

(B) Aluminium gives strength

• Pure aluminium does not have strength. When it is mixed with an alloy, it provides strength to the alloy.

(C) Aluminum brings lightness

• Duralumin is an alloy of aluminum having composition $\mathrm{Al}-95\%,\mathrm{Cu}-4\%,\mathrm{Mg}+\mathrm{Mn}-1\%$ used for making aircraft bodies.
• Aluminum brings lightness to aircraft bodies so it is used in duralumin.

Explanation for the incorrect option:

(A) Aluminium is brittle

• Aluminium is a metal and metals are hard but not brittle.

(D) Aluminum lowers melting point

• Aluminium does not lower the melting point of the alloy.

Therefore, The reason for using aluminum in the alloy duralumin is that aluminum gives strength and aluminum brings lightness.