Characterization and Tribological Properties of Novel AlCu4.5SiMg Alloy–(B4C/TiO2/nGr) Quaternary Hybrid Composites Sintered via Microwave

In the future, hybrid aluminum matrix composites, which are the second generation composites, will be replaced by solid reinforced third-generation quaternary hybrid composites in which nano- and micro-scale reinforcement particles are used together. In this study, microwave sinterability of B 4 C, TiO 2 (nm + µm), and nGr reinforced quaternary hybrid composites that had AlCu4.5SiMg alloyed Matrix, and their microstructural and tribological properties after sintering were examined. The proportion of nGr in the composite sample was taken as 0.5 wt%, while B 4 C and TiO 2 were used in three different proportions (3, 9, 12 wt%). After being compressed under 600 MPa pressure, the composite samples were sintered for 60 min at 550 °C by a microwave oven with a power of 2.9 kW and a frequency of 2.45 GHz. It was determined that due to its high microwave absorbency, B 4 C reinforcement improved the microwave sinterability more compared to TiO 2 . In XRD analyses, whereas Al 4 C 3 and Al 3 BC reaction products were not seen as harmful, the intermetallic phase of Al 2 Cu was detected. It was determined that both friction coefficient and wear resistance increased as the proportion of B 4 C increased in composite samples. In AlCu4.5SiMg–(12 wt% B 4 C/3 wt% TiO 2 /0.5 wt% nGr) quaternary hybrid composites with the highest hardness (97.6 HV), the lowest specific wear rate (0.118 mm 3 Nm × 10 −3 ) was detected. Graphic Abstract