ABSTRACT
The good resistance to oxidation of aluminium bronzes means that a very much lighter scale is formed during heat treatment than on other copper alloys. The same heat treatment will also be applied if the final product is required in a ductile condition. One of the most common forms of heat treatment consists in tempering after hot or cold working. The most common and readily controlled method of heat treatment involves quenching from a high temperature, followed by tempering at a lower temperature. The purpose of annealing is essentially to soften the metal and improve its ductility at the expense of proof strength and tensile strength. Reducing magnetic permeability applies to the high manganese Cu/Mn/Al/Fe/Ni alloys which experience a considerable increase in magnetic permeability below 500°C. In practice, binary and tertiary alloys with duplex structures are chosen for their mechanical properties rather than for corrosion resistance which can nevertheless be improved in certain circumstances.
