Improvement of AA5052 sheet properties by electromagnetic twin-roll casting

Electromagnetic fields were used in twin-roll casting (TRC) of aluminum alloy 5052 (AA5052) for improvement of the microstructure and mechanical properties. A static magnetic field induces an inhibiting effect on the melt in the cast-rolling area and reduces diffusion of the solutes. It also results in more nucleating opportunities and less segregation, thus enhancing the mechanical properties. However, the static magnetic field does not change the orientation of crystal growth and columnar crystals still exist in microstructure. On the other hand, an oscillating magnetic field can refine the suspended particles and induce strong convection. This leads to more uniform distribution of temperature and solute elements, simultaneously increasing nucleating opportunities and decreasing segregation, thereby enhancing the mechanical properties. An oscillating magnetic field also inhibits the orientation of crystal growth and makes finer and equiaxed grains.