The laser melt injection method is always used to prepare a metal-matrix composite (MMC) layer on the surface of a substrate. In the LMI process, the laser beam melts the surface layer of substrate locally while simultaneously injecting particles of additional material. In order to control the distribution of reinforced particles in laser melt injection layer, an electric-magnetic composite field can be applied to assist the laser melt injection process. The effect of electric-magnetic synergistic on the reinforced particles distribution in laser melt injection was investigated using experimental and numerical method. The spherical WC particles were used as the reinforced particles, because the regular shape was most close to the simulation conditions and good tracer performance in the melt flow. The distribution state of WC particles in longitudinal section was observed by SEM and calculated by computer graphics processing. Meanwhile, The trajectory of WC particles in the melt pool were simulated by a 2D model coupled the equations of heat transfer, fluid dynamics, drag force, Lorenz force and phase transition.
The simulation results are compared with experimental data and show good agreement. The results indicated that, the effect of electric-magnetic synergistic on the reinforced particles distribution in laser melt injection was verified. The distribution of WC particles in LMI layer was influenced by the direction of Lorenz force induced by electric-magnetic composite field. When the Lorenz force and gravity force are in the same direction, the vast majority of particles are trapped in the upper region of laser melt injection layer, and when the Lorenz force and gravity force are in the opposite direction, most particles are concentrated in the lower region.