Aluminum was considered a “precious” metal during the first half of the 19th century due to its relative rarity. At the Paris Exhibition of 1855, a bar of aluminum was exhibited as a marvel. Nowadays, of course, aluminum is common. Yet in some regards, it seems somewhat dear when it comes to applications in North American vehicles, at least if we absent engine blocks and wheels. In fact, when you look at the body applications in the U.S., as compared with the doors, hoods, fenders, and deck lids produced for European manufacturers, the difference is nothing short of astonishing. According to Thomas P. Gannon, vice president, Sales & Marketing, Industrial and Automotive Products, Alcan Aluminum Corp. (Farmington Hills, MI), there are no aluminum doors produced in North America. Meanwhile, over in Europe, aluminum doors are produced for vehicles ranging from the $350,000 MaybachA to the $12K VW Lupo. The vehicle manufacturers that are taking advantage of the lightweight material include not only the prestigious brands like JaguarB, Aston Martin, Lotus, and Audi, but also the much more accessible ones like smart and Peugeot. In effect, perhaps, the Europeans have gotten over the aluminum bar in the glass case, while U.S. manufacturers, with few exceptions, are still looking at aluminum through the glass.

The Maybach 57 has a wheelbase of 133.5 in.;the Maybach 62 has a wheelbase of 150.7 in. The latter is claimed to be the longest production car in the world (total length: 242.5 in.). The doors are a study in aluminum. Not only are the door outers made with aluminum, but so too are other components. The window surrounds are produced with multi-chamber extrusions that are laser welded together. Superplastic forming, which involves both heat (up to 500 degrees C) and pressure, was used to produce the internal components and the hinge reinforcements. Other aluminum panels on the Maybach body shell are the roof, hood, and front fenders.The overall weight of the body shell of the Maybach 57 is 1,289 lb.; it's 1,368lb. for the Maybach 62.

Which is not to say that aluminum isn’t being used in significant quantities in North America. It is. According to Gannon, the overall transportation market is the biggest user of aluminum in North America and that the passenger vehicle market is the biggest within transportation, accounting for some 5.3 billion pounds of the stuff. And when cars are looked at from a weight standpoint, aluminum is the third most-used material, following steel and iron. Says Gannon: “It overtook plastic in 2001 by two pounds. We’re widening the gap and are just a few pounds away from iron. We’ll probably overtake iron by 2007.” The steel producers probably shouldn’t be inordinately worried, as they tip the scales at around 1,800 lb. in a car, and second place is just a bit more than 300 lb. According to a report by Ducker Worldwide, “Global Automotive Aluminum Content Forecast Through 2010,” it is projected that there will be 318 lb. of aluminum used in North American light vehicles by 2010. Gannon says that they’re a bit more optimistic at Alcan, thinking that the average is more likely to be on the order of 350 lb.

The XJ8 is an aluminum-intensive vehicle that is apparently the forerunner for things that Jaguar will be doing as time goes on, such as in producing the XK replacement (the X150). Shown here is the R-D6 concept. It has an aluminum chassis. The body combines both aluminum and composite materials. The 21-in. wheels are, of course, aluminum, as well. It doesn't, however, have an aluminum engine block. Rather, the V6 diesel (which will be used in the S-Type mid-2004) has a compacted graphite iron block.

The argument for greater use is based on weight savings and the fact that consumers are apparently looking for vehicles that are (1) full of amenities and (2) large. So, in order to have powered doors, seats, windows, etc., nav systems, third rows of seatsC, and so on, all of which add weight, vehicle manufacturers must find the ways and means to reduce mass elsewhere, which could lead them to select aluminum rather than steel because a rule of thumb is that one pound of aluminum can be used in place of two pounds of steel. Second, there is the size issue. One of the issues with sport utility vehicles is their high center of gravity. Gannon suggests that one way to maintain the size of the vehicle yet to lower the center of gravity is to use aluminum body panels: “You can reduce the weight of your vehicle without sacrificing size or strength.” Although aluminum may be lighter, he argues that aluminum handles crash energy quite well, in a predictable manner, so “light” doesn’t equate to “flimsy” or “unsafe.”

Apparently, in order to offset the weight of the third row of seats in the Yukon, GM engineers moved to aluminum for the lift gates for its GMT 830 vehicles. According to Gannon, the stamped aluminum parts are run at the same rate that the steel components had been.

One of the considerations that can be made about what is arguably still a premium material (and one that is likely to remain so, at least compared with steel) is retaining its value. Gannon cites a closed-loop recycling process that Alcan has developed with Ford at the Ford Chicago Stamping Plant. There, hoods are stamped, some 1.3 million annually. There is offal. And there is (probably) some scrap. The AA6111 scrap is kept segregated from other materials. It is bundled and shipped to Alcan’s Oswego, NY, plant, where it is melted, then rolled back into aluminum sheet. The sheet is then shipped back to Chicago Stamping, where it can be transformed into more hoods. The material doesn’t degrade, so it is hood-to-hood, not, say, hood-to-engine block (which would be the case, Gannon admits, if other aluminum alloys were mixed in with the AA6111). So the issue here is that there can be value realized by reusing the material. (In Europe, where there is a requirement for the OEMs to handle the recycling of used products, this can help justify aluminum use.)