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Why does the Aerospace Industry Rely on Titanium?

May 02,2024

In 1971, the use of titanium shook the aerospace industry, which was predominantly dominated by steel and aluminum. Since then, titanium alloys have become the primary material for aerospace applications, whether through traditional manufacturing or additive manufacturing.

This article will introduce why the aerospace industry is heavily reliant on titanium metal and how titanium plays its role in the aerospace sector.

Aerospace Industry

What Makes Titanium So Great For Aerospace?

The combination of strength, lightweight, corrosion resistance and high-temperature resistance makes titanium a very ideal material for aerospace applications, contributing to its widespread use in the industry. The specific performance is as follows:

Strength-to-Weight Ratio

Titanium has become a popular choice in aerospace manufacturing due to its exceptionally high strength-to-weight ratio. This crucial mechanical property allows for the construction of durable yet lightweight aeroplane frames and spacecraft that can withstand demanding environmental conditions and carry substantial amounts of fuel.

Notably, this advantage extends beyond commercial aircraft to military aircraft as well. By utilizing titanium alloy, the aviation industry has been able to mitigate high operating costs by manufacturing more fuel-efficient aeroplanes.

In the case of larger aircraft like the 787s, the incorporation of numerous titanium parts helps maintain a lighter weight and reduces fuel consumption. Similarly, military aircraft rely on titanium components to achieve enhanced durability, enabling them to sustain extended flight durations without refuelling.

Strength-to-Weight Ratio

High Resistance

As is well known, aerospace components operate in various extreme environmental conditions, and certain metals tend to expand and deform when exposed to high temperatures, which can lead to shortened lifespan or even failure.

In contrast, titanium has a low thermal expansion rate, making it an ideal material for aerospace applications that experience significant temperature variations at different altitudes and climates.

Test results have shown that titanium alloys have a strength 1.3 times that of aluminum alloys.  Its excellent thermal strength is suitable for aerospace manufacturing, allowing it to work for extended periods at temperatures ranging from 450℃ to 500℃.

Furthermore, titanium alloys can withstand high and low temperatures, maintaining a certain level of plasticity even at -253℃.  Its ability to withstand high temperatures also makes it a superior alternative to aluminum.

Corrosion Resistance for Durability

Aerospace systems are exposed to extreme conditions, including high altitudes, temperature variations, and moisture. Corrosion is a significant concern, which is where the corrosion-resistant properties of titanium shine.

Titanium can withstand the corrosive effects of high altitudes, humidity, and exposure to various chemicals used in aircraft maintenance. This exceptional durability ensures that aircraft can operate efficiently and safely over extended periods without succumbing to the detrimental effects of corrosion.

Applications in Aerospace

Here are some applications of titanium in the aerospace industry:

Airframe

As mentioned earlier, titanium is widely regarded as an excellent choice for lightweight materials.    It is extensively utilized in aircraft manufacturing, making it the preferred lightweight structural material alongside steel and aluminum alloys.

Titanium plays a crucial role in aircraft construction, particularly in the fuselage and engines.    Its lightweight titanium alloy contributes significantly to weight reduction when used as a body material.

Aircraft Engine

Titanium is widely utilized in engines for its exceptional strength and durability, particularly in compressor blades, rotors, and other critical components.

These parts are subjected to extreme temperatures, rotational forces, and vibrations. The remarkable capability of titanium to retain its strength even at high temperatures ensures that engine components remain intact and operational.

Landing gear systems

Landing gear systems often benefit from the exceptional properties of titanium. These gears play a crucial role in supporting the entire weight of the aircraft during the high-stress moments of landing, both mechanically and thermally.

The corrosion resistance and fatigue strength of titanium are of utmost importance in such applications, as they endure regular exposure to harsh operational environments, which include the presence of deicing chemicals and fluctuating climatic conditions.

Other applications

Titanium is commonly used in the internal mechanisms of flight control surfaces such as ailerons, elevators and rudders. These control surfaces play a vital role in accurately responding to pilot input and withstanding aerodynamic forces.

The use of titanium in these mechanisms ensures precise control and reliable operation, which is critical to the safety and operability of the aircraft.

In the world of fasteners such as bolts, nuts and screws, titanium is chosen for its superior strength, corrosion resistance and ability to withstand temperature changes without compromising structural integrity.

Titanium fasteners are particularly advantageous in securing critical components of airframes and engines, where failure is simply impossible.

Landing gear systems

Additive Manufacturing With Titanium

Additive manufacturing of titanium offers a viable solution for smaller aerospace companies that want to leverage titanium without making large investments in traditional manufacturing. This is particularly beneficial for creating prototypes or proofs of concept models.

Key factors that determine the effectiveness of titanium alloys in aerospace 3D printing include sphericity and flowability. During the printing process, the spherical metal powders easily clump together, ensuring structural stability for even the smallest parts.

High-flow powder allows for a smoother printing process and faster manufacturing times. Aerospace manufacturers can consider titanium 3D printing as a favourable option for a variety of small parts applications.

Additive Manufacturing With Titanium

Titanium Alloys in Aerospace

Through the development of various alloys, the inherent properties of titanium materials have been greatly enhanced. Among them, Ti-6Al-4V stands out as the most widely recognized and used alloy.

Ti-6Al-4V, also known as grade 5 titanium, is an alloy favored in the aerospace industry because of its excellent strength-to-weight ratio (beyond pure titanium). Notably, it maintains strength even at high temperatures and exhibits excellent corrosion resistance under different environmental conditions.

The versatility of Ti-6Al-4V is particularly advantageous for the production of airframe and engine components, where optimal performance is critical.

Its unique combination of ductility, strength and lightweight properties make it the material of choice for critical applications such as landing gear, compressor blades and hydraulic systems.

Another important alloy is Ti-6Al-2Sn-4Zr-2Mo, commonly known as Ti-6242. It is often used on jet engine components such as disks and compressor blades that are exposed to high temperatures for extended periods of time.

For applications requiring excellent corrosion resistance, especially in environments such as seawater or acidic conditions, Ti-6Al-4V ELI (Extra Low Clearance) or Grade 23 is preferred.

The ELI version features reduced interstitial elements such as oxygen and iron, which further enhances the alloy’s ductility and welding suitability. It is commonly used on airframe components, especially those that require welding during the manufacturing process.

Ti-3Al-2.5V, or grade 9 titanium, is another alloy with low aluminum and vanadium content. In the aerospace industry, it is also used in piping systems and parts that need to be easily formed.

Another famous alloy is Ti-5Al-2Sn-2Zr-4Mo-4Cr, known as Ti-17. This alloy is known for its exceptional strength and good resistance to deformation at temperatures up to 600 degrees Celsius. It is mainly used to manufacture high-temperature components such as engine casings and compressor disks..

The Challenges of Titanium

Casting titanium presents significantly greater challenges than aluminum or steel, largely attributable to its superior strength. Despite recent advancements in manufacturing technology that have contributed to reductions in the cost of titanium components, titanium persists as a relatively more expensive material when compared to alternatives.

Conclusion

Titanium’s enduring legacy in aerospace applications positions it as an indispensable resource for meeting the evolving demands of the industry.

With advancements in titanium alloy development, engineers can push the boundaries of design and performance, enhancing the efficiency of air travel, exploring outer space, and contributing to sustainable practices within the industry. For more information on titanium in the aerospace industry, please contact us.

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