Expanding world economic prosperity and probable peaking of conventional petroleum production in the coming decades requires efforts to increase the efficiency of, and the development of alternatives to, petroleum-based fuels used in automotive transportation. North America has been aggressively pursuing both approaches for over ten years. Mainly as a result of lower prices due to global sourcing, magnesium has recently emerged as a serious candidate for lightweighting, and thus increasing the fuel efficiency of, automotive transportation. Automotive vehicles produced in North America currently use more Mg than vehicles produced elsewhere in the world, but the amounts per vehicle are very small in comparison to other materials such as steel, aluminum and plastics. The reasons, besides price, are primarily a less-developed state of technology for Mg in automotive transportation applications and lack of familiarity by the vehicle manufacturers with the material. This paper reviews some publicly-known, recent, present and future North American research and development activities in Mg for automotive applications.

Magnesium is increasingly becoming an attractive alternative to steel, aluminum, and polymer composites for vehicle weight reduction due to its ability to meet vehicle performance requirements. To meet the Corporate Average Fuel Economy (CAFÉ) standard and to maximize the weight reduction of vehicles in the coming years, the magnesium applications are expected to increase significantly in both structural and powertrain components where material creep resistance is required. This first half of the paper will give an overview of recent automotive magnesium R&D programs including Light Metal Cast, Magnesium Powertrain Cast Components, and Structural Cast Magnesium Development supported by the United States Council for Automotive Research (USCAR) and the US Department of Energy. The USCAR is the umbrella organization of DaimlerChrysler Corporation, Ford Motor Company and General Motors, which was formed in 1992 to further strengthen the technology base of the US automotive industry through cooperative, pre-competitive research. During the last decade, the magnesium foundry industry has grown, yet the material and manufacturing process costs of magnesium die-casting has impeded large-scale implementation into the automotive industry. As a result, Ford Motor Company initiated a Cost Reduced Magnesium Die Castings Using Heated Runners (CORMAG) program in partnership of the Advanced Technology Program of the US National Institute of Standards and Technology. The second half of this paper will briefly present the program goal, progress and its impact. In addition, this paper will present some magnesium applications, including a 2004 Ford F-150 light truck Front End Support Assembly and a 2005 Ford GT instrument panel structure.

High pressure die cast magnesium alloy AM50 is currently used extensively in complex shaped automotive components with various cross-section thicknesses. Understanding of the effect of section thicknesses on mechanical behavior of AM50 is critical for proper design of different applications. In the present study, magnesium alloy AM50 was high pressure die cast into rectangular coupons with section thicknesses of 2, 6 and 10 mm. The prepared coupons were tensile tested at room temperature. Microstructure analysis and porosity measurement were performed on the representative specimens. The results of tensile testing show that the tensile properties including yield strength (YS), ultimate tensile strength (UTS) and elongation(Ef) decreases with an increase in section thicknesses of die cast AM50. Microstructure and porosity analyses indicate that the observed tensile behavior of die cast AM50 is primarily attributed to the level of porosity which resulted from entrapped gases during the high pressure die casting process.