Caracterización de la microestructura binaria ("chessboard pattern") en muestras de Ti-6Al-4V fabricadas por SLM (Selective Laser Melting)

Abstract

Selective laser melting (SLM) is an additive manufacturing process that offers efficient manufacturing of complex parts with good mechanical properties. For SLM, process parameters and post-processing are of importance as they affect the microstructure. A feature in the microstructure,due to the fast cooling rate in SLM, is a binary microstructure pattern (BMP). The BMP is found in the horizontal plane and is formed with various laser scan angles between adjacent layers. The easiest distinguishable strategy is 90°,which renders a shape similar to a chess board. In this work, the BMP phenomenon was investigated in detail and a microstructural characterization was performed on the fine microstructure zone (FMZ) that separates the coarse microstructure zones (CMZ), by using light optical and scanning electron microscopes (SEM) that were equipped with electron backscattered (EBSD) and energy dispersive x-ray spectroscopy (EDS) detectors. Moreover,theeffectoftheprocessparameterhatchdistanceontheBMPwasinvestigatedandtheoverlappingbetween neighboringscantracks in SLM was found to influence the size of the BMP, while the thickness of the FMZ remained constant. EBSD and β grain reconstruc