The influence of ultrasound on the microstructure formation during solidification of a356 ingots processed via a 2-zone induction melting furnace

Abstract

To study the microstructure formation including columnar equiaxed transformation in the presence of ultrasound, a set of new equipment consisting of a 2-zone furnace and an ultrasound system was set up in the Ultrasonic and Solidification Processing Laboratory at the University of Alabama. The 2-zone furnace is an induction furnace with two separate coils (a top coil and a bottom coil). By controlling both the top and bottom coil output power independently, the furnace can create various temperature gradients including a mushy zone and cooling rates in different regions of the graphite crucible. A water-cooled chill block was applied at the bottom of the crucible. The ultrasound probe was inserted at the top of the crucible. A numerical model was developed to predict the temperature gradients and mushy zone evolution in the crucible. The influence area of the ultrasound on the A356 microstructure was studied.