Improvement of AA5052 sheet properties by electromagnetic twin-roll casting

Abstract

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.

Effect of harmonic magnetic field and pulse magnetic field on microstructure of high purity Cu during electromagnetic direct chill casting

“…Similarly, PMF is generated by transient pulse current, and the magnetic field changes periodically. Different types of electromagnetic fields change the solidification behavior during casting in different ways, and finally result in various as-cast microstructures [7] . For example, HMF with low frequency was reported to be effective in grain refinement, as well as microstructure and surface quality improvement for DC cast ferrous and nonferrous metals [8] .…”