Mechanical behavior of AZ31/Al2O3 magnesium alloy nanocomposites prepared using ultrasound assisted stir casting

摘要

Effect of ultrasound-assisted solidification processing on the mechanical behavior of AZ31/Al2O3 magnesium metal matrix nanocomposites (MMNCs) is studied. The melt was subjected to ultrasonic treatment (UST) under two different conditions i.e. UST performed outside the furnace during air-cooling and nearly isothermal UST within the furnace. Different concentrations of alumina nanoparticles (0.5, 1.0, and 2.0 wt%) were used. The significantly improved mechanical behavior of AZ31/Al2O3 Mg MMNCs is explained based on the incorporation of externally added alumina nanoparticles and the in situ reaction of particles with the matrix to form the MgAl2O4 spinel. Results of optical microscopy, SEM and XRD are used to explain the observed enhancement in yield strength and tensile strength. Contribution of different strengthening mechanisms is assessed. Finally, the processing conditions are correlated with ductility of the nanocomposites supported by detailed fractographic analysis. (C) 2017 Elsevier Ltd. All rights reserved.