Revealed: Why Is Aluminum Widely Used in Transportation?

  The widespread use of aluminum in the transportation industry is closely related to its excellent physical and chemical properties, and the diversified development of aluminum alloys has further expanded its application scenarios.

1. Core Reasons for Aluminum Application in the Transportation Industry
(1). Significant Lightweight Advantages
  Aluminum has a density of approximately 2.7g/cm³, which is only about 1/3 of steel. In transportation vehicles, lightweighting can directly reduce energy consumption (e.g., for every 100kg weight reduction in a car, fuel consumption per 100 kilometers can be reduced by 0.3-0.6L), improve endurance (e.g., weight reduction in electric vehicles extends driving range), and reduce the load on the power system.
(2). High Specific Strength (Strength/Weight Ratio)
  Pure aluminum has low strength, but high-strength aluminum alloys can be formed through alloying (e.g., adding copper, magnesium, zinc). The strength of some aluminum alloys (e.g., 7075) is even close to that of high-strength steel, meeting the load-bearing requirements of structural parts.
(3). Excellent Corrosion Resistance
  A dense aluminum oxide (Al₂O₃) film forms easily on the surface of aluminum, effectively resisting corrosion from rain, moisture, and salt spray. It is particularly suitable for ships, coastal transportation vehicles, and outdoor scenarios (e.g., truck bodies).
(4). Good Formability
  Aluminum has high ductility and can be processed into complex-shaped components (e.g., automotive body panels, aircraft skins) through extrusion, stamping, and casting. It also exhibits good weldability (e.g., 5XXX series alloys are suitable for welded structures).
(5). Strong Recyclability and High Environmental Benefits
  The energy consumption for aluminum recycling is only 5% of primary aluminum production, and its performance remains largely unchanged after recycling. After transportation vehicles are scrapped, aluminum parts can be efficiently recycled, aligning with the needs of a circular economy (e.g., the recycling rate of automotive aluminum wheels exceeds 90%).
(6). Thermal Conductivity and Vibration Damping
  Aluminum has high thermal conductivity, making it suitable for heat dissipation components (e.g., engine cylinders, battery cooling systems). Its good vibration damping performance also reduces vibration and noise during vehicle operation (e.g., high-speed rail carriage structures).

2. Specific Application Scenarios of Aluminum in the Transportation Industry
(1). Automobiles and New Energy Vehicles
  Body Components: Aluminum alloy body frames, doors, hoods, and trunk lids (e.g., Tesla Model S uses over 70% aluminum alloy in its body), reducing weight while improving collision safety.
  Powertrain: Engine blocks, cylinder heads, and transmission housings (replacing cast iron to reduce engine weight), aluminum alloy battery enclosures (protecting batteries and dissipating heat).
  Chassis and Running Gear: Aluminum alloy wheels (reducing unsprung mass to enhance handling), suspension system components (e.g., control arms).
  Others: Air conditioning condensers (excellent thermal conductivity), body anti-collision beams (better energy absorption than steel).
(2). Aerospace
  Aircraft Structures: Fuselage skins (e.g., Boeing 787 uses ~20% aluminum alloy in its fuselage), wing frames, and tail components (2XXX and 7XXX series high-strength alloys).
  Landing Gear and Engines: Landing gear hubs, engine fan blades (7075 aluminum alloy), and engine nacelle components resistant to high temperatures.
  Spacecraft: Satellite shells, rocket fuel tanks (aluminum-lithium alloys for further weight reduction and high strength).
(3). Rail Transit (Trains, Subways, High-Speed Rail)
  Carriage Bodies: Car shells welded from aluminum alloy profiles (e.g., China’s CRH high-speed rail series uses 6005A aluminum alloy profiles), reducing weight while meeting fire safety standards.
  Internal Structures: Overhead luggage racks, seat frames, and floor supports (corrosion-resistant and easy to clean).
  Bogies and Braking Systems: Aluminum alloy brake discs, bogie frames (reducing train weight and increasing operating speed).
(4). Ships and Marine Transportation
  Hulls and Decks: Hulls of coastal vessels and yachts (5XXX series aluminum alloy, resistant to seawater corrosion), such as aluminum alloy speedboats that are over 50% lighter than steel hulls.
  Internal Equipment: Cabin partitions, piping systems (resistant to salt spray corrosion, reducing maintenance costs).
(5). Other Transportation Means
  Motorcycles and Bicycles: Aluminum alloy frames and wheels (e.g., high-end bicycle frames often use 7005 aluminum alloy), reducing weight to improve riding efficiency.
  Containers and Logistics Equipment: Aluminum alloy containers (40% lighter than steel and rust-resistant), logistics vehicle compartment panels.

3. Common Aluminum Alloy Types and Applications in the Transportation Industry
  Aluminum alloys are classified into major series based on alloying elements and properties. The characteristics and transportation applications of each series are as follows:

  Aluminum and its alloys have become the preferred material for the transportation industry to achieve "energy-saving, efficient, and environmentally friendly" goals, balancing lightweighting, high strength, and corrosion resistance. From automobiles to aviation, and from land to sea, diversified aluminum alloy series have driven technological upgrades in transportation vehicles.