Why are aluminium and titanium used on airplanes?

Finding the right aerospace material is tough. A wrong choice compromises safety and budget. Understanding aluminum and titanium's roles gives you the confidence to select the best option.

Airplanes are built using both aluminum and titanium for specific reasons. Aluminum makes up the bulk of the airframe because it's lightweight and easy to shape. Titanium is used in high-stress, high-temperature areas like engines and landing gear for its superior strength and heat resistance.

I remember talking to Sophie, a technical sales rep from Canada. She often explains these material choices to her aerospace clients. She told me the question she gets most is about titanium's specific role. It’s a great question because titanium isn’t used everywhere. But where it is used, it’s absolutely essential. Let's explore why that is. So, let’s get into the details of each metal, starting with the high-performer: titanium.

Why is titanium used in aircraft?

Aircraft engines and frames face extreme stress and heat. A material failure isn't an option. Titanium offers unmatched strength-to-weight and heat resistance, ensuring aircraft integrity and passenger safety.

Titanium is used in airplanes because of its incredible strength-to-weight ratio and ability to withstand extreme temperatures. It's essential for engine components, landing gear, and other high-stress parts where steel would be too heavy and aluminum would be too weak. It ensures reliability under harsh conditions.

At my company, we frequently supply Ti-6Al-4V, a specific titanium alloy, to our aerospace clients. This grade is the workhorse of the industry for a reason. I explain to purchasing managers that its true value isn't just raw strength; it's strength that doesn't quit when things get hot. When an airplane engine is running, temperatures can soar. Aluminum would soften, but titanium holds its form.

Key Performance Areas

Think about the parts that take the most abuse: fan blades in the engine, landing gear, and fasteners holding the wing structure together. These parts need to be strong but also as light as possible. Titanium is about 40% lighter than steel but just as strong in many cases. This weight saving directly translates to better fuel efficiency.

Common Titanium Aerospace Applications

So, when a client asks for titanium, they're really asking for performance assurance in the most demanding parts of the aircraft.

Why is aluminium used in airplanes?

An aircraft needs to be strong but also light enough to fly. Using heavy metals everywhere would make it too expensive and inefficient. Aluminum offers the perfect solution for this problem.

Aluminum is the primary material for airplanes because it is lightweight, relatively strong, and easy to manufacture into the large, curved panels needed for the fuselage and wings. Its low density allows the aircraft to carry more payload or fuel, making flights more economical and efficient.

When I talk to clients like Sophie, we often discuss the bigger picture of the airframe. The skin, the ribs, the stringers—these parts make up most of the plane's body. They don't face the same extreme heat as engine parts, so using expensive titanium here would be wasteful. This is where aluminum shines. Its low density is its biggest advantage. Less weight means the plane needs less thrust to take off and stay in the air.

Formability and Cost

Another huge factor is formability. It's relatively easy to machine, bend, and rivet aluminum sheets to create the smooth, aerodynamic shape of a plane. This makes manufacturing faster and cheaper. At trade shows, I meet buyers who manage huge budgets. For them, aluminum's lower cost makes it possible to build aircraft at scale. Some of our most innovative clients are now using hybrid structures¹. They combine aluminum frames with titanium in specific joints to get the best of both worlds, achieving significant weight savings of up to 15%.

Are planes made of aluminium or titanium?

People often ask if planes are made of aluminum or titanium. This question suggests it's one or the other. But thinking this way misses the smart engineering behind modern aircraft.

Modern airplanes are primarily made of aluminum alloys. This includes the main body (fuselage) and wings. Titanium is used strategically in much smaller amounts for specific parts like engine components, landing gear, and areas requiring high strength, which makes up a small percentage of the total weight.

The best way to answer this is to say planes are made of both. Think of it like building a house. You use concrete for the foundation because it's strong, but you use wood for the walls because it's lighter and easier to work with. It's the same principle. I often point to examples from major manufacturers like Boeing and Airbus. Their newer planes, like the 787 or A350, actually use a lot of carbon fiber composites², but the philosophy is the same.

A Partnership of Metals

They use a material mix to optimize the entire structure. Aluminum alloys still form large parts of the internal framework. Titanium alloys are used where metal parts connect to these new composite structures, as titanium doesn't cause galvanic corrosion like aluminum would. They also use it for critical load-bearing parts, like the pylon that holds the engine to the wing. So, it's not a competition between the two metals; it's a partnership. Each one is a tool used for a specific job to ensure strength and corrosion resistance.

What are the disadvantages of titanium in aircraft?

Given titanium's amazing properties, you might wonder why the whole plane isn't made of it. This thinking overlooks a huge real-world limitation. The reality is that titanium has significant disadvantages.

The biggest disadvantage of titanium is its very high cost, both for the raw material and for manufacturing. It is difficult to extract and process. It is also much harder to machine than aluminum, which requires special tools and more time, driving up the final price significantly.

Cost is the number one reason. When I prepare quotes for clients, the price difference is stark. Raw titanium can be over five times more expensive than aerospace-grade aluminum. But the cost doesn't stop there. The entire manufacturing process is more difficult and expensive.

Manufacturing Challenges

Titanium has a very high melting point and is reactive, so it has to be melted in a vacuum furnace. When it comes to machining—cutting, drilling, and shaping the metal—it’s tough. It wears down cutting tools quickly and requires slower machine speeds. This all adds up to more time and money. I always advise my customers, like Sophie, to be strategic. We carefully review the blueprints and pinpoint exactly where titanium's performance is non-negotiable. For all other areas, aluminum or another material is often the smarter financial choice. It's a balancing act between ultimate performance and budget reality.

Заключение

In short, airplanes use a smart mix of materials. Aluminum offers a lightweight frame, and titanium provides essential strength where needed, creating safe, efficient, and cost-effective aircraft designs.