EBSD Observation of Grains Microstructures Produced by Selective Laser Melting

摘要

In the selective laser melting process, metallic powder beds are successively and locally melted tobuild dense parts. The parameters used to melt the powder have a strong influence on the melt poolbehaviour and on the subsequent grain microstructure. The observation of the grains has beenpossible through the use of electron backscatter diffraction. The present paper aims to show theevolution of the size and the shape of grains with the increase of the energy per surface unit providedby the laser beam for a specific scanning strategy. It is shown that for low energy, the grains arecolumnar and quite long in regard to the layer thickness. The grain orientation is kept for severallayers so that grains grow epitaxialy. With the increase of the energy, the grains tend to be quitesmaller so that the epitaxial growth does no longer occur.