Role of nano-size reinforcement and milling on the synthesis of nano-crystalline aluminium alloy composites by mechanical alloying

High-energy wet ball milling was successfully employed to synthesize nano-crystalline Al 6063 alloy powders reinforced with 1.3 vol.%Al2O3, 1.3 vol.%Y2O3 and 0.65 vol.%Al2O3/0.65 vol.%Y2O3 at nano-size level. In the present study, the crystallite size of the matrix powder particle was affected by the addition of different types of nanoceramic particles separately and in combination keeping total volume percentages of such addition as constant. The nano-composite powders were characterized by SEM, FESEM, HRTEM, XRD, particle size analyzer, EDAX and DTA. Using Williamson–Hall equation, crystallite size and lattice strain of various aluminium composite powders were estimated with broadening of XRD peaks. XRD results showed that the crystallite size of aluminium reached 53 and 37 nm, respectively, after 40 h milling in case of pure Al 6063 and Al 6063/0.65 vol.%Al2O3/0.65 vol.%Y2O3 nano-composite powder with uniform particle size distribution. HRTEM observation confirmed the nano-crystalline nature of Al 6063/0.65 vol.%Al2O3/0.65 vol.%Y2O3 milled powder.