Aluminium bronze is one of a family of copper-based alloys that offer a combination of mechanical and chemical properties unmatched by any other series of alloys. In this article we tell you everything you need to know about this material.
What is aluminium bronze
Aluminium bronze is a type of alloy in which aluminum is the main alloying metal. They contain between 5% and 12% aluminium. The properties of these alloys are governed by the properties of copper and aluminium when they are melted and fused together in well-controlled, rigorous processes. Aluminium is soluble in copper up to about 8% by weight.
Aluminum, in this case, enhances copper by imparting oxidation resistance in the form of a thin, tightly adherent aluminium oxide film. Additionally, other metals such as manganese, nickel, silicon and iron can be added to further improve strength or anti-corrosion properties.
Types of aluminium bronze
According to the Unified Numbering System, there are numerous types of aluminium bronze. These alloys are distinguished mainly on the basis of the amount of primary element (in this case aluminium) and the number of secondary elements alloyed with copper.
Basically, these types of aluminum bronze can be classified into four main types:
Single-phase low-alloy alloys
They contain less than 8% aluminium. They have excellent cold ductility properties, ideal for cold working in tubes, sheets and wires.
Moderately alloyed two-phase alloys
Contain 8-11% aluminium, with small amounts of other elements for strength. These are ideal for hot work applications.
Copper-aluminium-silicon alloys or silicon-aluminium bronzes
They contain up to 6% aluminium and 2% silicon. Like other bronzes, they have low magnetic permeability, as well as exceptional resistance to shock loads and vibration.
Copper-manganese-aluminium alloys or manganese-aluminium bronzes
Unlike other aluminium bronzes, manganese is the main alloying element by weight, about 13%, while aluminium makes up 8-9%. They have excellent resistance to impact, cavitation and wear.
Aluminium bronze applications
Thanks to its mechanical properties, superior corrosion resistance and high castability and machinability, aluminium bronze is used in a wide range of fields.
The oxide film produced by aluminium bronze gives it outstanding corrosion resistance in seawater environments. Wear and erosion resistance make it suitable for impellers, propellers and other marine equipment.
The corrosion resistance of aluminium bronze can be highly beneficial for components used in the water treatment and water supply industry.
Oil and petrochemical industry
Aluminium bronze is also known for its anti-sparking characteristics. This characteristic is especially useful for parts used in the oil and gas industry, where the surrounding atmosphere may contain explosive or flammable gas, vapour or dust.