A review of magnesium die-castings for closure applications

Vehicle mass reduction in the automotive industry has become an industry-wide objective. Increasing fuel efficiency and greenhouse gas emission targets for engine-powered vehicles, and ambitions for extended range electric vehicles have motivated these reductions in vehicle mass. Mass reduction opportunities in structural automotive applications are increasingly realized through lightweight alloy castings, such as magnesium, primarily due to the ease of component substitution. The traditional benefits of magnesium die-castings including lightweighting and associated compounded mass savings, excellent strength-to-weight ratio, part consolidation, near net-shape forming, dimensional repeatability, and integration of additional components can be realized in closure applications. One recent example is the application of a magnesium die-casting for the structural inner of the liftgate in the 2017 Chrysler Pacifica, replacing nine parts in the previous generation and resulting in a liftgate assembly weight reduction of nearly 50%. The work presented here reviews past and current developments of magnesium die-castings in closure applications and discusses the benefits and challenges of magnesium alloys for these applications, including casting design, corrosion and fastening strategies, and the manufacturing design and assembly methodologies.