Aluminium is crucial for constructing diverse vehicles—ranging from cars and trucks to planes, ships, and space shuttles—enabling remarkable feats like high-speed travel, ocean crossings, and space exploration. Currently, the transportation sector represents the largest share of aluminium consumption, accounting for 27 per cent of its usage, a figure anticipated to rise in the coming years. The extensive application of aluminium in vehicles is crucial in advancing low-carbon mobility. By reducing vehicle weight, aluminium significantly lowers the energy needed for movement, leading to decreased CO2 emissions, improved air quality, and cost savings.
Essential Aluminium Properties for Vehicle Applications
Aluminium’s unique characteristics make it an outstanding choice for a wide range of vehicles, enhancing performance and efficiency. Here are some unique properties that contribute to its effectiveness in automotive design.
Lightweight: In engineering, achieving the ideal balance often involves navigating a series of possibilities and trade-offs. Aluminium offers a remarkable solution to this challenge by significantly reducing vehicle weight, thereby enhancing fuel efficiency and lowering CO2 emissions. This lightweight material accomplishes these goals while still meeting advanced technological needs without compromising on safety, durability, or performance.
Aluminium’s advantage lies in its weight; it is up to 50% lighter than steel, opening up numerous opportunities for lightweighting across various vehicle components. Alloys like 1050, known for their lightweight properties, are particularly useful for battery and electric motor housings. This weight reduction translates into better fuel economy and lower emissions, making aluminium an increasingly attractive choice for visionary OEMs and cutting-edge vehicle models. By leveraging the benefits of aluminium, manufacturers can create vehicles that are not only more efficient but also maintain the high standards of performance and safety that consumers demand.
Safety and Strength: Is it possible for a material to be lighter while still ensuring passenger safety? Can it maintain its strength while offering more formability? Absolutely. Automotive aluminium boasts exceptional properties, providing a tensile strength of around 700 MPa. Alloys such as 7075-T6 are ideal for high-stress applications like suspension components and wheels due to their exceptional strength and durability. While its strength and durability are on par with steel, aluminium excels by folding more predictably during a collision. This capability enhances crumple zones and improves crash absorption, ensuring that the reduction in vehicle weight does not compromise passenger safety.
Performance: Aluminium’s lightweight and adaptable properties significantly boost vehicle performance. Alloys such as 6061-T6 and 6063 offer superb mechanical properties, making them ideal for chassis components, structural parts, and body panels. It enhances driver control, provides better handling, and enables quicker acceleration and deceleration. Its malleability and flexibility also promote innovative design opportunities, opening up new possibilities. These qualities make aluminium a preferred material in high-performance cars and an increasing number of mass-produced vehicles. Moreover, aluminium is well-suited for electric vehicles, contributing to their superior performance and efficiency.
Aluminium Applications across Different Vehicle Sectors
Aviation and Aerospace: Aluminium is widely recognized as the essential material that made flight possible. Its lightweight, strong, and flexible properties make it ideal for constructing heavier-than-air aircraft, earning it the nickname “winged metal.”
In modern aircraft, aluminium comprises about 75-80% of the structure, and its use in aviation predates aeroplanes. Count Ferdinand Zeppelin originally used it for his airship frames. A landmark event in aviation history occurred in 1903 when the Wright brothers successfully piloted the Flyer-1, the first aircraft capable of being steered. Since then, aluminium has been crucial in aircraft manufacturing. Alloys like 2024-T3 and 7075-T6 are extensively used in aircraft construction due to their high strength and durability. Although alloys have evolved, the primary goal remains the same: to create the lightest aircraft with maximum capacity and fuel efficiency. Today, aluminium is found throughout modern aircraft, from fuselages to engine components.
Aluminium’s role also extends to the aerospace industry, where its low weight and high strength are vital. The first satellite launched by the USSR in 1957 was made from aluminium alloy. Modern spacecraft contain 50% to 90% aluminium alloys in their parts, and they are used in Space Shuttle vehicles, rocket tanks, and other essential components.
Automobiles: Cars are the most prevalent mode of transportation globally, primarily constructed from affordable steel. However, as the automotive industry increasingly focuses on fuel efficiency and reducing CO2 emissions, aluminium is becoming a crucial material in modern vehicles.
Every kilogram of aluminium used in a car translates to a reduction of one kilogram in overall vehicle weight. This has led to a growing number of components, including engine radiators, suspension parts, wheels, bumpers, and body panels, manufactured from aluminium. Alloys such as 5052-H32, known for their excellent formability and weldability, and 5083, which offers high corrosion resistance, are often used for chassis components and structural members.
In addition to enhancing fuel efficiency and lowering emissions, aluminium excels in shock absorption, outperforming steel by a factor of two. This property makes it an ideal choice for bumpers. For instance, the Tesla electric car features 8-mm thick aluminium alloy sheets at the bottom to ensure safety at high speeds. Furthermore, alloys like 3003, used for heat exchangers and radiators, are chosen for their excellent thermal conductivity and resistance to corrosion. Aluminium’s ability to localize deformation during impacts enhances passenger safety by maintaining the integrity of the passenger compartment.
Rail Transport: Aluminium started being used in rail transport soon after it was mass-produced, mainly for cargo transport due to its lightweight, which increases cargo capacity. Today, aluminium freight cars carry minerals, coal, acids, and grains. Special cars transport finished goods like new vehicles.
Aluminium freight cars are a third lighter than steel ones and, despite higher initial costs, are more cost-effective over time due to greater capacity and resistance to corrosion. They lose only about 10 per cent of their value over forty years. For passenger cars, aluminium’s lighter weight saves energy in rapid transit and suburban systems, reducing costs for frequent stops. Aluminium cars are also easier to produce with fewer parts. Aluminium became the key material in high-speed trains, especially from the 1980s. Using aluminium in such trains reduces the weight, which lessens rail bending and decreases friction resistance.
Ship Building: Modern ships are increasingly constructed from marine aluminium, a term encompassing various aluminium-magnesium alloys (with 3-6% magnesium content) used in mechanical engineering. These alloys are highly resistant to corrosion in both fresh and saltwater. Marine aluminium is characterized by its high strength and excellent weldability. High-speed hydrofoil passenger boats, which travel over 80 kmph, also use magnalium or duralumin. These materials ensure the boats remain lightweight, enhancing manoeuvrability and speed.
Marine aluminium resists corrosion far better than steel, with a corrosion rate of only 1 mm per year compared to steel’s 120 mm per year. Additionally, marine aluminium is very strong and flexible, able to withstand powerful impacts without damage. Aluminium frames enhance seaworthiness and safety and reduce maintenance costs. For these reasons, aluminium is used in motor boats, yachts, underwater craft, and cutters.
Conclusion:
Engineered aluminium stands as a cornerstone in the advancement of modern vehicles, offering unparalleled benefits in terms of durability, lightweight properties, and corrosion resistance. Its pivotal role in improving fuel efficiency and promoting sustainability has led to widespread adoption across various industries, including automotive, aerospace, rail, and maritime. Ongoing innovations in alloy development and manufacturing technologies will elevate aluminium’s contributions further. As the quest for lightweight materials persists, engineered aluminium is poised to remain a critical component in the evolution and design of future vehicles.
(Disclaimer: Mr. A S Ganeshan, Associate Vice President, Domestic Sales and Marketing, Jindal Aluminium. Views are personal)
