When Dr. Mukesh Jain describes the state of automotive materials science, it can sometimes sound like he’s calling a horse race.

“Steel is fighting back. Aluminum is making inroads. Magnesium is coming around.”

And in some ways, a horse race is just what it is. As auto manufacturers experiment with different materials to make their products lighter and therefore more fuel efficient, the traditional favourite—metal—is fighting off a challenge by upstart plastics and composites.

Polymer-based materials have been replacing metal in cars for years, beginning with interior components like dashboards and door liners, and moving more recently to bumpers and exterior body panels. The main reason is polymer’s two-fold advantage over metal: it’s lighter and it’s easier to shape.

This race, however, is just entering the stretch, and it’s far too early to call. To stay competitive, steel makers are experimenting with new, lighter alloys. Aluminum companies—anxious to build on their weight advantage over steel—are looking at new ways to formulate and cast their product. And then there’s newcomer magnesium—the strongest contender yet for the lightweight metal crown. Metal also has two other big advantages over polymers: it’s stronger and it’s easier to recycle.

The new alloys, however, don’t always play nice with existing means of shaping sheet metal for car bodies; techniques developed for traditional formulations can make the new alloys crack. And that’s the reason that scientists like Dr. Jain at the McMaster Manufacturing Research Institute are looking for ways to make the new lightweight metals more formable, and to develop better ways to shape them.

He and his colleagues start by using advanced computational resources—provided in part by the Ontario Innovation Trust—to develop fundamental “material models” of the new metals. Based on the alloys’ molecular structures, the models can be used to predict general behaviour under the kinds of forces generated by an industrial press. The models also enable researchers to experiment virtually with alternate formulations that make the alloys more “ductile” or formable.

The researchers then build the material models into “finite element models” that can predict how an alloy will respond when stamped into a given shape—that of a fender, for example—by a particular process. The models let researchers experiment with new approaches to die design and press processes—all without the traditional trial-and-error techniques. “Before you make a single die,” explains Dr. Jain, “you can assess in a virtual environment whether a particular material can be made into a particular part. That means you save a lot of costs in terms of prototype tooling.”

The results of the simulations are of obvious value to metal manufacturers and carmakers alike. But
mathematical models can sometimes be flawed. And for that reason, the McMaster institute relies on its own 1,500-tonne industrial press—also funded in part by the Trust—to verify the modeling results. The press is heavily instrumented and widely adjustable, making it a valuable tool for assessing real world shaping techniques, and developing new ones.

Will there ultimately be a winner in the materials race? Dr. Jain is hedging his bets. “The car companies are taking a piece-meal approach,” he says, “They’re looking at things part-by-part.” But it’s obviously clear to him and his McMaster colleagues that metal will still have a place in the winner’s circle for a long time to come.

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