Effect of electric current pulse on flow behaviour of Al melt in parallel electrode process

Electric current pulse (ECP) was commonly applied to solidification process of Al melt to achieve fine solidification microstructure. In this paper, numerical simulation method was employed to analyse flow behaviour of the melt and the mechanism of ECP on the grain refinement during the solidification. The calculation results showed that the ECP led to fluctuation of the Al liquid surface, and the liquid flowed inward and down in a circular motion. The fluctuation and circular flow behaviour were caused by the forces including Lorentz force, surface tension and buoyancy. The results also revealed that the higher the frequency and peak value of the ECP, the larger the flow velocity was. On the other hand, the depth of the electrodes in the liquid had little influence on the convection flow of the liquid. In summary, our simulation results explained the refinement mechanism of the ECP on solidification microstructure and provided a novel and feasible approach to evaluate and optimise the structure refinement of the ECP.