A trial to apply Fe-Al intermetallic alloys to brake rotors

Fe-Al intermetallic alloys, FeAl- and Fe3Al-based, were tried to be applied to brake rotors for automobile use. FeAl revealed better tribological properties but lower ductility than cast iron which had been conventionally used for brake rotors. Then a new FeAl-based alloy containing small amounts of Mo, Zr, C and B was proposed to improve ductility and comparatively good results were obtained. Ti addition to Fe3Al improved the tribological properties, especially at elevated temperatures. Since their temperature dependence was quite different from that of cast iron, new applications are expected. In order to obtain guidelines for producing better tribo-materials, trials to correlate mechanical properties with tribological ones were also made. A very clear correlation was found between the strain hardening rate and the wear rate, while other mechanical properties such as yield strength and hardness showed no clear correlation. This suggests the importance of dynamic mechanical properties in taking correlation with tribological properties