Some things haven't changed for generations. Baseball is one of them. So is mom's apple pie. And, of course, many car parts, like the brake rotor, those devices that help make you stop when you hit the brakes. They're typically made out of cast iron--or, actually, they were traditionally made out of cast iron, that is.
Students at
Michigan Technological University are looking to design a new rotor, one that is made of aluminum, which would save about 50 pounds on the typical car.
"That's a big number on a car," says Paul Sanders, an assistant professor of materials science and engineering at Michigan Tech. "Every 10 percent saved in weight on a vehicle equals roughly 4 percent in fuel economy. You could save 0.8 percent in fuel. It doesn't sound like much, but it can be huge for the fleet."
Manufacturers haven't made the switch because aluminum starts losing strength at relatively low temperatures, 250 degrees Celsius (about 480 degrees Fahrenheit).
"If you had aluminum brakes, driving down Pike's Peak would do you in," Sanders says. "We wanted to design aluminum alloys which maintain their strength up to 400 degrees."
To do that, Sanders and his team of graduate students and undergraduates are using different elements in making the aluminum alloy. Traditionally, silicon, copper and magnesium are added to aluminum to improve its properties. Sanders is replacing them with minute quantities of an exotic blend of zirconium and rare earths, including scandium.
So far, his strategy is working: the hardness of the new alloy peaks at the magic 400 degrees. Now, the team is preparing to run tensile tests on the metal in cooperation with students from Northwestern University. A high-strength, high-temp aluminum might also replace other parts on vehicles, such as turbochargers and pistons.
Writer: Sam EgglestonSource: Paul Sanders, Michigan Technological University
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