Developing Affordable Creep-resistant Aluminum Alloys for Car Brake Rotors

Currently, cast-iron is nearly exclusively used for car brake rotors. Replacing cast-iron by a high- temperature, creep-resistant aluminum alloy could translate into about 80 lbs (36 kg) in weight reduction for a typical car, thus improving its gasoline mileage and reducing its greenhouse gas emissions. Current commercial, castable, age-hardening aluminum alloys cannot withstand temperatures above 430 F (220 C). Thus, replacing cast-iron in car brake rotors by these aluminum alloys is impossible, due to the high heat generation during harsh braking events of the front brakes. Aluminum-scandium based alloys are good candidates to replace cast-iron as they are creep- and coarsening-resistant to 570-750 F (300-400 C). Scandium, however, is very rare and expensive, prohibiting its usage for large-scale, cost-sensitive automotive applications. NanoAl LLC, a high-technology start-up company with leading expertise in designing novel precipitation-strengthened aluminum alloys, proposes under this SBIR program to develop a new, affordable, aluminum-zirconium alloy, which is completely free of scandium, while having improved room-temperature mechanical strength and high-temperature creep-resistance as compared to scandium-containing alloys. NanoAl LLC will design and assess castable, heat- treatable aluminum-zirconium alloy ingots with nanometric Zr-based precipitates nucleated by trace levels of novel elements and will demonstrate their applicability in terms of strength, creep- and coarsening-resistance to brake rotor applications. Using the designed aluminum alloy, NanoAl LLC will manufacture (by casting and heat-treating) and testing a prototype functional brake rotor. Commercial applications and other benefits include providing automakers a novel solution to safely and economically reduce an automobiles mass and emissions, while reducing gasoline consumption to meet the new Corporate Average Fuel Economy (CAFE) regulations and standards. Replacing cast-iron in automobile brake-rotors by high-temperature creep-resistant aluminum- alloys translates into 80 lbs weight reduction, and much improvement in gasoline mileage and reduced emissions. NanoAl LLC, a leading expert in designing novel aluminum alloys, proposes to develop a cost-effective aluminum-zirconium alloy strong enough to replace cast-iron in car brake-rotor applications.