Production and characterization of micro and nano Al ₂O ₃ particle-reinforced LM25 aluminium alloy composites

LM25 aluminum alloy metal matrix composites (MMCs) reinforced with weight fractions of micro and nano Al ₂O ₃ particles up to 10 wt. % were produced by stir casting. The composites thus produced were characterized for their mechanical properties such as hardness and tensile strength as well as for the dispersion of the micro and nano Al ₂O ₃ particles. The results reveal that stir casting could be an economical route for the production of nano composites. Nano particle reinforced MMCs exhibit better hardness and strength when compared to micro particles reinforced composites. Scanning electron microscopic observations of the microstructures revealed that the dispersion of the micron size particles where more uniform while nano particles led to agglomeration of the particles.