Supplement: Aerospace

Aluminium alloys

in the aerospace

industry

24 dpaonthenet.net

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In this article, Marta Danylenko, Marketing

Manager at online materials database Mat-

match, explains the common alloys used in

aerospace engineering and their applications,

as well as some less well-known ones, and

what the future holds for aerospace materials.

A brief historyThe Wright brothers chose aluminium for

the cylinder block and other engine parts

for their first manned flight in 1903. It was

also the first time an aluminium alloy had

been heat-strengthened. This discovery

prompted the preference for aluminium in

aerospace engineering.

Over the years, the aerospace industry has

become more demanding in what it needs

from materials. The advent of jumbo jets

and long-haul international flights meant

that the shell and engine parts had to be

extremely durable and resistant to fatigue.

This has led to the development and use of

many different types of aluminium alloys.

Commonly used aluminium alloys in the aerospace industrySecond only to AA 2024 in terms of its pop-

ularity in aerospace engineering, AA2014 is a

strong and tough metal and is suitable for arc

and resistance welding. However, it has poor

corrosion resistance, and for that reason, it is

often found in the internal structure or frame-

work of aircraft rather than the shell.

Aluminium alloy 2024 is probably the most

widely used alloy for aircraft. It was devel-

oped after experiments allowing small

amounts of cold deformation and a peri-

od of natural ageing led to an increased

yield strength. 2024 is a high-grade alloy

with excellent fatigue resistance. It’s used

primarily in sheet forms such as for the

fuselage and wings due to its high tensile

strength of roughly 470 MPa.

Of the non-heat treatable grades of alloy,

AA 5052 provides the highest strength

and is highly ductile, so it can be formed

into a variety of shapes including engine

components and fittings. It is also highly

corrosion resistant.

AA 6061 alloy is very common in light

aircraft, especially homemade ones. It’s

easily welded and manipulated, is very

light and fairly strong, making it ideal for

fuselage and wings.

AA 7050 has high corrosion resistance and

maintains strength in wide sections. This

makes it more resistant to fractures than

other alloys. It’s commonly used in wing

skins and fuselage, especially in military

aircraft.

AA 7068 is the strongest alloy available to-

day. Combined with its low mass, it is per-

fect for military aircraft that need to stand

up to tough conditions and attacks.

With similar strength properties to steel due

to its high levels of Zinc, AA 7075 has excel-

lent fatigue resistance. It can be machined

easily which meant it was a popular choice

for fighter planes in World War II, including

the Mitsubishi A6M Zero fighter used by

the Japanese Imperial Navy on their carri-

ers between 1940 and 1945. It is still used

frequently in military aircraft to this day.

Less common aluminium alloys in the aerospace industryIf you need an aluminium alloy that provides

maximum strength at elevated tempera-

tures, AA 2219 is the best bet. It was used

for the external fuel tank of the first suc-

cessfully launched space shuttle, Columbia.

Aluminium has a long and successful history in the aerospace industry. As far back as the 19th century, Count Ferdinand Zeppelin made the frames of his iconic airships from it.

Aluminium was chosen as it is lightweight, strong, and has a high resistance to corrosion.

Supplement: Aerospace

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It has good weldability, but the welds need

heat-treating to preserve resistance against

corrosion.

AA 6063 is mainly used for aesthetic and

architectural finishes and can be found in

the finer details of an aircraft. It is used pri-

marily for intricate extrusions. AA 7475 is

highly resistant to fracture and fatigue. Due

to its toughness, it is sometimes found in

fuselage bulkheads of larger aircraft.

The future of aluminium alloys in aerospaceIndustry experts are positive about the fu-

ture of aluminium alloys in aerospace. It is

projected that demand for aluminium will

double over the next decade.

By 2025, there will be a global demand

of 80 million tonnes. For this reason, the

aerospace industry is increasingly looking

to recycled alloys to satisfy their high de-

mand. There is also a push for innovation

in the materials used, as well as the design

structure of aircraft.

For instance, aluminum-lithium alloys have

been developed for the aerospace industry

to reduce the weight of aircraft and there-

fore improve performance of the aircraft.

Al-Lithium alloys are advanced materials

because of their low density, high specific

modulus, and excellent fatigue and cryo-

genic toughness properties.

As developing countries become more in-

volved in the aerospace industry, and with

increased investment, there will be further

innovation in aluminium alloys over the

years to come.

If you’re looking for a tool to compare en-

gineering material properties, Matmatch’s

online database helps you to find materials,

compare them side-by-side and choose ma-

terials that perfectly fit the intended applica-

tion, the budget for the project and your goals.

www.matmatch.com