The North American auto industry is about to go on a diet and that's good news for automakers, consumers and the environment. Automotive Partnership Canada (APC) and four Canadian companies are contributing $6 million towards an industry-led effort to make vehicles up to 40 percent lighter by replacing components comprised of traditional, low carbon steel with advanced, high strength steel, aluminum and magnesium—the lightest of all structural metals.

Driven by more stringent regulations for fuel efficiency and greenhouse gas emissions, "lightweighting" of vehicles has become a top priority for automakers and their suppliers, many of them located in southern Ontario. It's considered the most cost-effective way to cut carbon dioxide emissions and lower energy consumption in the transportation sector.

Automakers and suppliers on both sides of the border are making major investments to reduce vehicle weight by substituting magnesium alloys as part of a multi-material strategy to replace traditional, low carbon steel within body structure, closure, suspension and chassis components. Magnesium weighs 35 percent less than aluminum and 78 percent less than steel, putting it on par with many plastics. The goal is to reduce vehicle weight by as much as 50 percent by the year 2020.

The Government of Canada's Lightweight Materials Innovation Strategy estimates that every 10 percent reduction in weight can improve fuel efficiency by six percent for conventional vehicles, and extend the driving range of an electric vehicle by four percent on a single charge. It's a strong incentive for companies to innovate.

Industry partner Huys Industries in Weston, Ontario, expects to use the results from the demonstration project to expand its product and processes portfolio through the development of new spot welding technologies to join magnesium with other lightweight metals.

"Resistance welding currently accounts for about 90 percent of the joints in a vehicle, but some of these lightweight alloys are not amenable to resistance welding," says Nigel Scotchmer, President of Huys Industries.

As part of the project, Huys will assess a new solid-state joining process—called refill friction stir-spot welding—as a potential replacement for resistance welding and rivets in some assemblies.

"This project will provide both the basic science, and the validation we need to make it affordable and practical to business," adds Scotchmer.

Another key outcome of the research will be the development of design guidelines for using magnesium alloys in multi-material structures.

"No single company could undertake this project on its own," says Tim Skszek, Director of Sales, Cosma International, which is located in Brampton, Ontario. "But with this project we have all the supply chain links in the development chain. The project brings together all the players needed to move new technologies from the lab to full commercial implementation."

Those players include scientists and engineers from the University of Waterloo, McMaster University, the University of Western Ontario and CANMET Materials, along with industry partners Cosma, Huys, 3M Canada (Saint-Laurent, Quebec) and Meridian Lightweight Technologies (Strathroy, Ontario). Together, they will work on new joining technologies for lightweight materials; casting and forming processes to improve the quality of magnesium parts; computer modelling; durability; and corrosion- and crash-testing of new, multi-material structures.

Testing will be carried out on state-of-the-art infrastructure that will be available to industry over the long term. For example, APC funding will be used to establish a crash sled at the University of Waterloo to demonstrate the strength of new materials and joining processes by propelling them at high speeds into a rigid barrier. The resulting data will be used to develop computer simulations to predict the behaviour of future automotive structures. New corrosion facilities at McMaster University will enable corrosion testing of multi-material structures, and new die-casting infrastructure at CANMET Materials will enhance magnesium part quality.

Building a tech cluster
The research challenges are significant. Magnesium easily corrodes, which may compromise safety in the event of a crash. The lead researcher on the project, Michael Worswick at the University of Waterloo, says the project will focus on developing a multi-material, lightweight vehicle architecture that combines magnesium alloys, high strength steels and aluminum. How these metals are joined—whether rivets, adhesives or welding—will be critical to increasing strength and avoiding corrosion.

"There's a lot known about magnesium and its alloys but less is understood on how to join that material to other metals like steel and aluminum," says Dr. Worswick. "3M's work on adhesives could be the answer to some of the inherent corrosion problems that occur when you join dissimilar metals."

The APC project builds on Canada's efforts to create a technology cluster where automotive companies can access world-class analytical and experimental testing resources related to lightweight, multi-material structures. That expertise and infrastructure will strengthen Canada's position in attracting commercialization-driven research stemming from other large research programs, including the Canada-United States (U.S.) multi-material lightweight vehicle demonstration project; and the Magnesium Front End Research and Development project, involving Canada, the U.S. and China; and the Natural Sciences and Engineering Research Council of Canada Magnesium Network (MagNET).

"APC has had an enormous impact on the Canadian auto sector," says Dr. Worswick. "It has been a real magnet for attracting industry to the table."