Properties and applications: Electrical conductivity

The electrical conductivity of aluminium with a 99.99% degree of purity is 63.8% of the International Annealed Copper Standard. On a weight-to-weight basis, however, the electrical conductivity of aluminium is about twice that of copper. For this reason, aluminium has been used exclusively in overhead power lines for a good many years.

Electrical conductivity depends on chemical composition and microstructure as well as on heat treatment (the so-called ‘alloy temper’). Electrical conductivity measurements are actually used to check certain age-hardenable alloys after heat treatment.
The following figure shows the interrelationship between electrical conductivity, cold work and intermediate annealing temperature for unalloyed aluminium Al99,5.