In 2014, Ford raised eyebrows—and some traditionalist hackles—by announcing that its best selling F-150 would be receiving an all aluminum body for the 2015 year. In 2017, the company announced that its larger super duty trucks would be receiving the same treatment. In many ways, this announcement about the most popular vehicles in the United States switching to all-aluminum construction represented the fulfillment of a dream.
The history of aluminum in the automotive industry dates back to 1901, but that history is a distinctly checkered one.
The Advantages of Aluminum in the Automotive Industry
While aluminum is not usually as strong as steel, it has the potential to reach a comparable level of strength. Aluminum’s strength allows it to replace steel in various applications through clever engineering. Despite being significantly lighter (about one-third the weight of steel), it maintains comparable strength. This weight advantage leads to energy savings during vehicle acceleration and maintaining speed.
The benefits of using aluminum in the automotive industry are clear: Race cars achieve top speeds and quicker acceleration, leading to improved fuel efficiency. Similarly, passenger haulers and cargo carriers can transport heavier loads over a longer range, or utilize the weight and energy savings to accommodate more cargo within the same range. In addition to the advantage of weight reduction, aluminum also offers the following advantages:
- Safety Benefits: One unappreciated side effect of aluminum’s light weight is the inertial savings in a collision—which reduces some of the force from a crash. It is also more ductile than steel. Therefore, aluminum used in body panels and structural elements can soak up more energy as it crumples than a steel equivalent, enhancing automotive safety during collisions.
- Thermal Conductivity: Aluminum is one of the best thermal conductors there is. When used to make mechanical components like engine blocks or engine headers the ability to transfer heat quickly reduces the chances of thermal damage to components.
- Corrosion Resistance: As vehicles made of steel age, rust becomes a persistent problem. However, with aluminum, although it can undergo oxidation, the process is fundamentally different from that of steel or iron. Aluminum oxides form a protective barrier on the aluminum’s surface that prevents further corrosion. Anodizing aluminum is actually a deliberate effort to thicken this natural barrier to provide further protection.
In many ways, replacing steel with aluminum in the automotive industry represents a win. The result is lighter, safer, and more efficient vehicles. However, it still took over a hundred years from Mercedes-Benz introducing the first aluminum engine block in 1901 to Ford mass-producing an all-aluminum vehicle. This is partly due to the fact that aluminum can be a challenging material to work with. Another factor is the expense of aluminum, as it is more costly pound for pound than steel. The biggest factor that has interfered with the widespread adoption of aluminum in the automotive industry is most likely perception, and it has simply taken this long to overcome public misconceptions of aluminum.
Overcoming the Challenges of Aluminum in Automobiles
The aluminum that most people are familiar with is aluminum beverage cans, and these easily crushed cans cause many consumers to underestimate the strength of aluminum. Indeed, one of the challenges that Ford faced when unveiling its new aluminum vehicles was a competitor’s refrain about their product, “not being made out of beer cans.” This deliberate underestimation of the strength available from aluminum alloy types is probably the single biggest reason it has taken so long for aluminum in the automotive industry to experience widespread use. It can be hard to spend extra money on a more expensive material, and it is even harder to justify spending the extra money if the target market may see that material as a disadvantage.
Contrary to the common misconception about the strength of aluminum among the general public, automotive enthusiasts have widely recognized and appreciated the metal’s strength. Aluminum cylinders heads, headers, and other components of exhaust systems have long been one of the first things enthusiasts would purchase for their vehicles—even if these parts weren’t available from traditional aftermarket suppliers and needed to be custom machined at great expense.
Even in an age where more and more automobiles are coming straight from the factory with aluminum engine blocks and bodies, enthusiasts continue to look for ways to shed weight by increasing the use of aluminum in their automobiles beyond what comes from the factory. This is expected to increase as fuel efficiency standards become ever more stringent, vehicles become more electrified, and we enter into a more energy efficient future.
By increasing the utilization of aluminum in the automotive industry, we can make the sight of a rusting rambler in the driveway a thing of the past.