Effect of non-contact electrostatic field on controlling the microstructure of 316L during laser additive manufacturing process

Laser additive manufacturing (LAM) is a novel technology that uses high-energy laser beam to obtain high performance entities and coatings. However, in this process, it is difficult to control the microstructure of materials effectively by changing the laser parameters. Based on this situation, we proposed a method that using direct electrostatic field (DESF) to assist LAM process. In this paper, we investigated the changes in 316L microstructure after assisted by DESF, and discuss the effect of electrostatic field. Microstructures of the 316L stainless steel sample fabricated by this method were tested. The result showed the solidification direction and grain morphology was influenced by the direction and value of DESF obviously. While the ESF direction is opposite to the laser scanning direction, the grains in the longitudinal-section perform orderly growth and the directions are biased to the laser scanning direction. While the DESF direction is the same as the scanning direction, the original solidification direction is obviously changed and the direction tended to be opposite to the scanning direction.