Numerical modeling of the dispersion of ceramic nanoparticles during ultrasonic processing of aluminum-based nanocomposites

The metal-matrix-nano-composites (MMNCs) in this study consist of a 6061 alloy matrix reinforced with 1.0 wt.% SiC nanoparticles that are dispersed within the matrix using an ultrasonic cavitation dispersion technique available in the Solidification Laboratory at the University of Alabama. The required ultrasonic parameters to achieve (i) the required stirring and cavitation for suitable degassing and refining of the aluminum alloy and (ii) the adequate fluid flow characteristics for uniform dispersion of the nanoparticles into the 6061 matrix are being investigated in this study by using an in-house developed CFD ultrasonic cavitation model. The multiphase CFD model accounts for turbulent fluid flow, heat transfer, and the complex interaction between the molten alloy and nanoparticles by using the ANSYS's Fluent DDPM. The modeling parametric study includes the effects of the fluid flow, the ultrasonic probe location, nanoparticle size distribution, and initial location where the nanoparticles are released into the molten alloy. It was determined that the nanoparticles can be distributed quickly and uniformly into the molten 6061 alloy. (C) 2014 Brazilian Metallurgical, Materials and Mining Association. Published by Elsevier Editora Ltda.