Properties and deformation behaviourOf Mg-Y2O3 nanocomposites

Composites of Mg reinforced with 0.5, 1 and 2 vol.% of nanosized Y2O3 particles were fabricated using the disintegrated melt deposition technique. The nanocomposites were found to be thermally more stable than monolithic pure Mg and the tensile yield strength increased by 29% with the addition of 2 vol.% of Y2O3 nanoparticles. The yield strength improvement was attributed to (i) load-bearing effects due to the presence of nanosized reinforcements, (ii) generation of geometrically necessary dislocations to accommodate CTE mismatch between the matrix and the particles, (iii) Orowan strengthening, and (iv) the Hall-Petch effect due to grain size refinement. Basal slip and twinning were found to be the main deformation modes during extrusion, while non-basal slip was activated during tensile deformation at room temperature due to the alignment of basal planes along the tensile axis after extrusion. (C) 2007 Acta Materialia, Inc. Published by Elsevier Ltd. All rights reserved.