Something that’s commonly seen in wiring since the 1970s is copper-clad aluminium (CCA) wire. This is basically what the name says: an aluminium core that is clad in copper, making it a bimetal.
[Ken] boils down his process of building enclosures out of copper clad (PDF) circuit board material ... Next, he uses some 20 gauge wire as a shim between a ninety-degree joint and a right angle ...
Clad steel conductors consist of a steel core fused to an outer shell of aluminum or copper. Round conductor size is measured in American Wire Gauge (AWG) in the United States. The higher the gauge ...