Comparative Evaluation of the Tribological Performance of Al-MMC and GCI Brake Rotors Through an AK-Master Dynamometer Testing

The increasing demand for lightweight and high-performance brake rotors has led to the exploration of aluminum metal matrix composites (Al-MMCs) as alternatives to conventional cast iron rotors. This study evaluated the tribological performance of squeeze-cast aluminum metal matrix composite (Al-MMC) brake rotors using an AK-Master dynamometer test and compared them with conventional gray cast iron (GCI) rotors. The Al-MMC rotors exhibited stable coefficients of friction (CoFs) with reduced wear rates compared with the GCI rotors. Surface examination revealed the dominant wear mechanisms, including abrasive and oxidative wear. The Al-MMC rotors exhibited pressure and speed sensitivity, with a decreasing CoF at higher pressures and speeds, whereas the GCI rotors maintained a stable CoF. At elevated temperatures, the GCI rotors exhibited superior thermal stability and fade resistance compared to the Al-MMC variants. Wear analysis indicated material transfer from brake pads to Al-MMC rotors, resulting in protective tribofilm formation, whereas GCI rotors exhibited conventional abrasive wear. These findings highlight the potential of squeeze-cast Al-MMCs for automotive braking applications, offering advantages in weight reduction and wear resistance, but also suggest the need for further material optimization to enhance high-temperature performance and friction stability.