Workability and mechanical properties of ultrasonically cast Al-Al2O3 nanocomposites

Workability and mechanical properties of the ultrasonically cast Al-X wt% Al2O3 (X=2, 3.57 and 4.69) metal matrix nanocomposites were reported in the present investigation. The Al-Al2O3 (average size ∼10 nm) composites showed maximum reduction ratios of 2, 1.75 and 1.41 at room temperature, and 8, 7 and 6 at 300 °C. The elastic modulus, nanoindentation hardness, microhardness and Vickers hardness were measured on the as-cast, cold and hot rolled specimens. The tensile properties were also evaluated for the as-cast composites for different wt% of reinforcement. The microstructural examination was done by optical, scanning and transmission electron microscopy. The strength and workability of the nanocomposites were discussed in the light of dislocation/particle interaction, particle size and its concentration, inter-particle spacing and working temperature. 2 wt% of Al2O3 reinforcement showed better combination of workability and mechanical properties possibly due to better distribution of particulates in the matrix.