ABSTRACT
Alloys containing 9–12% aluminium with additions of up to 6% each of iron and nickel represent a most important group of commercial aluminium bronzes. The high temperature ß-phase is an intermediate solid solution with a random body-centred cubic (bec) structure and has a higher percentage of aluminium than the alloy as a whole. Nickel–aluminium bronze has a high resistance to sea water corrosion thanks to its protective oxide film which is only slightly permeable to liquids. The incidence of crevice corrosion in nickel–aluminium bronze is rare. If the alloy is cathodically protected by vicinity of a steel structure or by a sacrificial anode, crevice corrosion is unlikely to occur. The combination of grain size and distribution of the κ precipitates largely determine the strength and fatigue properties of the alloy. A fast cooling rate, as in die-casting, produces a fine structure with an even distribution of fine precipitates resulting in significantly better tensile and proof strength but lower elongation.
