Foam in the Crash Box
Auto safety: Aluminum with bubbles for cars that go boom.
by Illustration by: Garry Marshall
Crash-absorbing aluminum foam might soon be integrated into many automobile components (seen here in orange) to better guard against collisions.
It looks like a silver Rice Krispies treat, but biting into it is not advised. It’s actually a superstrong lightweight material called stabilized aluminum foam, and one day it might save your life.
The foam’s high strength-to-weight ratio and its ability to withstand powerful impacts make it an ideal material for an automobile’s crash box–the part of a car’s front end that absorbs the blow during a collision. Tests by MIT’s Impact and Crashworthiness Lab have shown that the foam boosts the impact-absorbing ability of automotive parts as much as 600 percent.
Toronto-based Cymat makes the foam by mixing ceramic particles with molten aluminum and blowing gas into the mix. The bubbles that form remain until the metal cools, leaving behind a foam-like structure. “It’s like blowing bubbles into chocolate milk,” explains Michael Liik, CEO of Cymat. “If you blow bubbles into regular milk, they disappear when you stop blowing. But when you do the same with the chocolate variety, they stick around.” That’s because the chocolate particles shore up bubble walls and keep the milk contained.
After several fatal crashes this past year, NASCAR is working to integrate the foam into its racecars by this summer to guard against frontal collisions. Three-time Winston Cup winner Jeff Gordon is on the bandwagon: “That stuff,” he recently told a reporter, “is incredible.”