Aluminium is a versatile metal used in building and construction, transportation, packaging, etc. One such industry is also the aerospace sector. In the last few decades, aluminium alloys have played a vital role in aerospace engineering. So when did it all start? What does the future hold for aluminium in this industry? Here's what you need to know.
An age-old tale:
Aerospace and aluminium are not a new pair. They go back in time to when the Wright Brothers introduced the winged vehicle to the world for the first time in 1903. Aluminium was used in the cylinder block and other parts of history's first aircraft.
It is believed that the inventors used aluminium to reduce the weight yet make a strong frame. Despite having limited resources and knowledge of aerodynamics and low wind-speed availability, the goal was to lift the aircraft with an intended weight. Well, you know the rest is history. Modern aerospace engineers carry on the bright legacy of the Wright Brothers as they continue to use aluminium alloys in contemporary aircraft.
Types of aluminium alloys used in aerospace applications:
Aluminium and its alloys mixed with other metals have been widely used in different aerospace industry applications. The 2xxx and 7xxx series of alloys are predominantly used in the aerospace sector. Aluminium alloys can be used with copper or zinc to increase their strength while offering flexibility and workability. The essential aluminium alloys (AA) associated with the industry are as follows:
- AA 2024: The AA 2024 alloy comprises a large amount of copper. It is often used to manage high strength-to-weight ratios. This alloy is vastly used to construct wings and fuselages since the components demand high tension requirements.
- AA 2014: This alloy is the second most popular in the aerospace industry, but with a major drawback. It has a low resistance to corrosive elements. Hence, AA 2014 is used in making the internal components of an aircraft rather than the external parts.
- AA 5052: It is a popular alloy in the aerospace industry and the strongest in the non-heat treatable category. It is highly flexible and can be used for a variety of configurations. In addition, it also has a high resistance to corrosion from seawater, therefore an ideal choice for marine applications.
- AA 6061: The fourth one on the list is the most common alloy. However, it is usually used by amateur aircraft builders. This alloy is primarily used in the manufacture of wings and fuselages.
- AA 7075: Comprising zinc, this alloy provides steel-like strength, and to date, it is used in several aircraft components. It was also used in World War II.
- AA 7050: This alloy surpasses the characteristics of the AA 7050 alloy. It is more durable and highly resistant to corrosion. Therefore, it is a much sought-after alloy in the aerospace industry.
- AA 7068: It is the strongest of all alloys and can withstand harsh conditions. The AA1068 alloy also has a low mass. Therefore, it is widely used in making military applications.
- Others: Apart from the alloys mentioned above, alloys like AA 3003, AA 1100 and AA 1145 are highly effective for transferring heat and are used in making fin stock.
Aluminium alloys v/s Composite material: What's better?
Composite materials are a new entrant in the aerospace sector, and the most common one is fibreglass. They are known for their tensile strength and resistance to compression. All these factors make it a suitable material for aircraft construction.
Now the question is will aluminium lose its place in the aerospace sector? Not soon! Both materials have their qualities. However, aluminium is better positioned. In addition, it is cheaper and has an established production and pricing process. A major drawback of composite materials is that they are prone to degradation from UV rays, unlike aluminium. So right now, aluminium is ahead in the race.
The future of aluminium in aerospace:
The aerospace industry has benefitted from its long-term association with aluminium, and the future will be no different. As innovation progresses, the industry will likely use aluminium-lithium or Al-Li alloys. These alloys reduce the aircraft's weight by 10% compared to composite materials. In the future, aluminium will contribute to making lighter and safer aircraft. The versatile metal will continue to thrive in the industry, reaping mutual benefits.
