LIGHTWEIGHT MATERIALS FOR AUTOMOTIVE APPLICATIONS

As a result of more stringent requirements for improved fuel economy and emissions, there is a growing trend to substitute Al and Mg for conventional steel and cast irons in vehicles. This article describes some of the technical issues that must be considered if the automotive industry is to utilize these lightweight materials in larger volumes. Lightweight metals may be used in the vehicle in both wrought and cast forms. Aluminum, in the form of stamped sheet, has the potential to be used extensively in vehicle structures and closures. However compared to steel, aluminum is more difficult to stamp and spot weld. Current research is exploring ways of improving the formability of Al alloys and developing alternate joining methods including adhesive bonding and fasteners. Mg, Al, and metal-matrix composite castings have the potential to be used as replacements for many ferrous castings in power-train and chassis components. However, because of their different tribology, strength, and ductility, light-metal castings require improved foundry procedures and more sophisticated design rules before product engineers will use them in larger quantities. A major challenge for lightweight materials is the ability to produce a functional component at an acceptable price. The presentation will conclude with a cost-benefit perspective for typical light-metal applications in the automotive industry.