Aluminium-Nano Ceria-Fly Ash Hybrid Composite Prepared by High Energy Milling

The research work introduces a novel dual-reinforcement aluminium matrix hybrid composite prepared by powder metallurgy route. The aluminium matrix hybrid composites were prepared using nanosize cerium oxide (0.5, 1, and 1.5 wt.%) and fly ash (5 and 10 wt.%) derived from industrial waste as reinforcements. Firstly, the nanocrystalline aluminium composite matrix was prepared by high-energy ball milling using nanosize cerium oxide and aluminium powders. Further, the second reinforcement, i.e., fly ash, was ultrasonically blended into the nanocrystalline aluminium composite matrix to produce aluminium-nanosize cerium oxide-fly ash hybrid composite powder. The synthesised hybrid composite powder was then compacted and sintered in a vacuum tube furnace to produce a bulk hybrid composite by powder metallurgy route. This approach allows precise control of microstructure and also minimizes the formation of intermetallic phases. The highest microhardness obtained was 59Hv in bulk aluminium matrix hybrid composite reinforced with 1wt.% nanosize cerium oxide and 5 wt.% of fly ash vacuum sintered at 550⁰C. The bulk hybrid composite synthesized by the powder metallurgy route exhibited significantly high microhardness values as compared to pure aluminium. It also has high density values, indicating strong interfacial bonding between reinforcement phases and matrix phase. The synergetic integration of nanosize cerium oxide and fly ash as reinforcements in aluminium matrix delivers superior mechanical properties, which can offer lightweight and durable solutions for automotive and aerospace applications.