The aerospace industry is unique in terms of what it looks for in materials, with the oil and gas industry being the closest. Since aircrafts need to be able to resist the force of gravity while maximizing air support, aerospace materials need to be lightweight but strong. At the same time, they need to be resistant to heat, fatigue and corrosion because these materials will be exposed to extreme temperatures and harsh environments.
The Leading Materials Used in Modern Aerospace
Aluminum and composites are the two most utilized materials when it comes to constructing aerospace structures.
The reign of aluminum as the most popular aerospace material was thought to be over after the discovery of better materials such as composites and titanium. However, aluminum is gradually making a comeback to the aerospace industry as a lot of manufacturers still prefer it over the more expensive composites.
To increase the strength of aluminum, it is often alloyed with silicon, manganese, titanium, zinc and many other elements. In fact, aluminum has hundreds of alloys which are available in various forms.
The Characteristics of Aluminum
Aluminum is lightweight with a low density of 2.7g/cm3. But, despite being light, it has high strength properties and is highly resistant to corrosion. Plus, its ability to conduct thermal heat and electricity is very good.
The downside to aluminum is that it weakens in high temperatures. This is why aluminum isn’t used as a material for the surface of aircrafts.
Examples of the Uses of Aluminum
- NASA is currently developing the Orion MPCV (Multi-Purpose Crew Vehicle) which will be able to fit a crew of four astronauts and send them beyond the low Earth orbit. Its primary structures will be made of the aluminum-lithium alloy.
- The aluminum alloy 7068 is currently the strongest alloy available. This makes it a favorite when it comes to military aircraft construction.
Composites combine at least two materials – the basin and the resin – to achieve better properties. In general, composites are much better than aluminum, but its high-cost production limit its usage in aerospace engineering.
The Characteristics of Composites
Composite materials are light which means that aircrafts made using this material have better fuel efficiency. They also possess high tensile strength and are highly resistant to compression and corrosion.
Moreover, composites can easily be made into complex shapes. This is a great feature since metallics require machining and the creation of joints to be shaped into complicated forms.
As for it disadvantages, composite materials are costly to produce and require immediate repair when damaged. It also weakens when exposed to fire.
Examples of the Uses of Composite Materials
- Fifty percent of the weight of the commercial aircraft Boeing 787 Dreamliner is made of composite materials.
- The Airbus A350 XWB is another commercial aircraft which will be utilizing composite materials for its construction.
Other Materials Used in Aerospace Construction
Aside from aluminum and composites, there are many other materials that are used in the construction of aerospace structures. This includes steel and titanium which are both used for specific purposes in the aerospace industry thanks to their respective properties.
An alloy of iron and carbon, steel is stronger, heavier and harder than aluminum. These properties make it the perfect material for the aircraft’s landing gear. On the other hand, its resistance to high temperatures makes it suitable for use on the skin surface.
Like the materials above, titanium and its many alloys are known for having high strength properties. It also has better resistance to high temperatures and corrosion than aluminum and steel. On the downside, it is expensive to produce. It is commonly used in the hydraulic systems as well as the panel and swivel wing assemblies.