Types and Classifications of Aluminium Alloys
– Aluminium alloys consist of aluminium as the predominant metal.
– Common alloying elements include copper, magnesium, manganese, silicon, tin, nickel, and zinc.
– Two principal classifications: casting alloys and wrought alloys.
– Casting alloys can be further categorized as heat-treatable or non-heat-treatable.
– Wrought products account for approximately 85% of aluminium usage.
Applications in Aerospace Manufacturing
– Aluminium-magnesium alloys are lighter and less flammable than other aluminium alloys.
– These alloys have been crucial in aerospace manufacturing since the introduction of metal-skinned aircraft.
– They offer a balance between weight reduction and structural integrity.
– Aluminium alloys are used in various aerospace components, including aircraft frames and panels.
– The properties of aluminium alloys make them suitable for aerospace applications.
Corrosion and Protection
– Unprotected aluminium alloy surfaces develop a protective layer of aluminium oxide.
– Anodizing and correct painting procedures can prevent the formation of this layer.
– Galvanic corrosion occurs when an aluminium alloy comes into contact with metals with higher corrosion potentials.
– Exfoliation and intergranular corrosion are common forms of dissimilar-metal corrosion.
– Improper heat treatment can lead to internal element separation and corrosion from within.
Standards and Compositions
– Aluminium alloy compositions are registered with The Aluminum Association.
– The Society of Automotive Engineers and ASTM International publish specific standards for aluminium alloy manufacture.
– These standards ensure quality and consistency in the production of aluminium alloys.
– Standardization organizations help in defining alloy systems and their properties.
– Compliance with standards is important for various industries that use aluminium alloys.
Engineering Use and Properties
– Aluminium alloys exhibit a wide range of properties suitable for engineering structures.
– The choice of alloy system depends on the desired characteristics.
– Alloy systems are classified using a number system (ANSI) or specific names.
– Aluminium alloys find applications in various engineering structures and components.
– Their properties, such as light weight and corrosion resistance, make them valuable in engineering. Source: https://en.wikipedia.org/wiki/Aluminium_alloy
An aluminium alloy (UK/IUPAC) or aluminum alloy (NA; see spelling differences) is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat-treatable and non-heat-treatable. About 85% of aluminium is used for wrought products, for example rolled plate, foils and extrusions. Cast aluminium alloys yield cost-effective products due to the low melting point, although they generally have lower tensile strengths than wrought alloys. The most important cast aluminium alloy system is Al–Si, where the high levels of silicon (4–13%) contribute to give good casting characteristics. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required.
Alloys composed mostly of aluminium have been very important in aerospace manufacturing since the introduction of metal-skinned aircraft. Aluminium–magnesium alloys are both lighter than other aluminium alloys and much less flammable than other alloys that contain a very high percentage of magnesium.
Aluminium alloy surfaces will develop a white, protective layer of aluminium oxide if left unprotected by anodizing and/or correct painting procedures. In a wet environment, galvanic corrosion can occur when an aluminium alloy is placed in electrical contact with other metals with more positive corrosion potentials than aluminium, and an electrolyte is present that allows ion exchange. Also referred to as dissimilar-metal corrosion, this process can occur as exfoliation or as intergranular corrosion. Aluminium alloys can be improperly heat treated, causing internal element separation which corrodes the metal from the inside out.[citation needed]
Aluminium alloy compositions are registered with The Aluminum Association. Many organizations publish more specific standards for the manufacture of aluminium alloy, including the Society of Automotive Engineers standards organization, specifically its aerospace standards subgroups, and ASTM International.
