Investigation on the transient phenomena during the evolution of melt pool

The melt pool is the general process of the laser additive manufacture. A deep understanding of the evolution of melt pool will facilitate obtaining an optimum mechanical performance. In this paper a novel 2D transient model smoothly incorporating a multiphase capture method is presented and validated. The investigations on the transient phenomena and the effects of two different energy input patterns on evolution of the melt pool are carried out. The results show that with continuously high energy input, the melt pool gradually grows. The deformation of free surface, the velocity and temperature all increases. After quenching, the melt pool continuously shrinks. As the laser energy per unit length (LEPUL) increases or even when the LEPUL keeps the same but scan speed and laser power increase, the shapes of the free surface change significantly and the heat transfer in workpiece also becomes faster.