Which metal is the principal component of the alloy duralumin?

Aluminium is the principal component of the alloy duralumin.

Duralumin is an aluminium alloy strengthened mainly with copper, along with smaller amounts of magnesium and manganese. It was developed in the early twentieth century and became important because it offered much greater strength than pure aluminium while remaining relatively lightweight.

The alloy’s strength comes partly from heat treatment and age hardening. After suitable processing, tiny particles form within the aluminium structure and hinder the movement of dislocations, making the material stronger. Duralumin was especially significant in early aircraft construction.

The name is sometimes used loosely for several aluminium alloys, so historical compositions are not always identical. Modern aircraft use many advanced aluminium alloys and composite materials, but the basic attraction remains the same: combining low density with useful structural strength.