The large plates in the background are made of aluminium bronze.
5 franc coins made of aluminium bronze from 1940.
Aluminium bronze with 20% Aluminium at 500x magnification
Aluminium bronze is a type of bronze in which aluminium is the main alloyingmetal added to copper, in contrast to standard bronze (copper and tin) or brass (copper and zinc). A variety of aluminium bronzes of differing compositions have found industrial use, with most ranging from 5% to 11% aluminium by weight, the remaining mass being copper; other alloying agents such as iron, nickel, manganese, and silicon are also sometimes added to aluminium bronzes.
The following table lists the most common standard aluminium bronze wrought alloy compositions, by ISO 428 designations. The percentages show the proportional composition of the alloy by weight. Copper is the remainder by weight and is not listed: