There are several factors which make the use of aluminum alloys in automobile applications necessary. These mileage regulations conflict with other government regulated mandates for safety features such as airbags, side-impact collision beams, and antilock braking systems and consumer demands for features such as power windows and door locks. All of these features add weight to the vehicle which reduces the fuel efficiency. To accommodate these conflicting demands, automobile manufacturers have been looking for low density materials to use in place of steel.
Aluminum alloys appear to be the most promising of the lighter materials available.
Table 1 shows the principal alloying element along with the corresponding designation. For about 10 years, the automotive industry has been using aluminum in parts such as wheels and radiators. To further reduce vehicle weight, however, the possibility of using aluminum alloys in other applications is being explored. The use of these alloys is limited because they require a high temperature baking cycle to acquire the needed strength for body panel applications. This strength is normally achieved by age hardening during the paint baking process.